ASR_BASE
Change-Id: Icf3719cc0afe3eeb3edc7fa80a2eb5199ca9dda1
diff --git a/marvell/linux/fs/btrfs/extent-tree.c b/marvell/linux/fs/btrfs/extent-tree.c
new file mode 100644
index 0000000..7e5ac18
--- /dev/null
+++ b/marvell/linux/fs/btrfs/extent-tree.c
@@ -0,0 +1,5865 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2007 Oracle. All rights reserved.
+ */
+
+#include <linux/sched.h>
+#include <linux/sched/signal.h>
+#include <linux/pagemap.h>
+#include <linux/writeback.h>
+#include <linux/blkdev.h>
+#include <linux/sort.h>
+#include <linux/rcupdate.h>
+#include <linux/kthread.h>
+#include <linux/slab.h>
+#include <linux/ratelimit.h>
+#include <linux/percpu_counter.h>
+#include <linux/lockdep.h>
+#include <linux/crc32c.h>
+#include "misc.h"
+#include "tree-log.h"
+#include "disk-io.h"
+#include "print-tree.h"
+#include "volumes.h"
+#include "raid56.h"
+#include "locking.h"
+#include "free-space-cache.h"
+#include "free-space-tree.h"
+#include "sysfs.h"
+#include "qgroup.h"
+#include "ref-verify.h"
+#include "space-info.h"
+#include "block-rsv.h"
+#include "delalloc-space.h"
+#include "block-group.h"
+#include "rcu-string.h"
+
+#undef SCRAMBLE_DELAYED_REFS
+
+
+static int __btrfs_free_extent(struct btrfs_trans_handle *trans,
+ struct btrfs_delayed_ref_node *node, u64 parent,
+ u64 root_objectid, u64 owner_objectid,
+ u64 owner_offset, int refs_to_drop,
+ struct btrfs_delayed_extent_op *extra_op);
+static void __run_delayed_extent_op(struct btrfs_delayed_extent_op *extent_op,
+ struct extent_buffer *leaf,
+ struct btrfs_extent_item *ei);
+static int alloc_reserved_file_extent(struct btrfs_trans_handle *trans,
+ u64 parent, u64 root_objectid,
+ u64 flags, u64 owner, u64 offset,
+ struct btrfs_key *ins, int ref_mod);
+static int alloc_reserved_tree_block(struct btrfs_trans_handle *trans,
+ struct btrfs_delayed_ref_node *node,
+ struct btrfs_delayed_extent_op *extent_op);
+static int find_next_key(struct btrfs_path *path, int level,
+ struct btrfs_key *key);
+
+static int block_group_bits(struct btrfs_block_group_cache *cache, u64 bits)
+{
+ return (cache->flags & bits) == bits;
+}
+
+int btrfs_add_excluded_extent(struct btrfs_fs_info *fs_info,
+ u64 start, u64 num_bytes)
+{
+ u64 end = start + num_bytes - 1;
+ set_extent_bits(&fs_info->freed_extents[0],
+ start, end, EXTENT_UPTODATE);
+ set_extent_bits(&fs_info->freed_extents[1],
+ start, end, EXTENT_UPTODATE);
+ return 0;
+}
+
+void btrfs_free_excluded_extents(struct btrfs_block_group_cache *cache)
+{
+ struct btrfs_fs_info *fs_info = cache->fs_info;
+ u64 start, end;
+
+ start = cache->key.objectid;
+ end = start + cache->key.offset - 1;
+
+ clear_extent_bits(&fs_info->freed_extents[0],
+ start, end, EXTENT_UPTODATE);
+ clear_extent_bits(&fs_info->freed_extents[1],
+ start, end, EXTENT_UPTODATE);
+}
+
+static u64 generic_ref_to_space_flags(struct btrfs_ref *ref)
+{
+ if (ref->type == BTRFS_REF_METADATA) {
+ if (ref->tree_ref.root == BTRFS_CHUNK_TREE_OBJECTID)
+ return BTRFS_BLOCK_GROUP_SYSTEM;
+ else
+ return BTRFS_BLOCK_GROUP_METADATA;
+ }
+ return BTRFS_BLOCK_GROUP_DATA;
+}
+
+static void add_pinned_bytes(struct btrfs_fs_info *fs_info,
+ struct btrfs_ref *ref)
+{
+ struct btrfs_space_info *space_info;
+ u64 flags = generic_ref_to_space_flags(ref);
+
+ space_info = btrfs_find_space_info(fs_info, flags);
+ ASSERT(space_info);
+ percpu_counter_add_batch(&space_info->total_bytes_pinned, ref->len,
+ BTRFS_TOTAL_BYTES_PINNED_BATCH);
+}
+
+static void sub_pinned_bytes(struct btrfs_fs_info *fs_info,
+ struct btrfs_ref *ref)
+{
+ struct btrfs_space_info *space_info;
+ u64 flags = generic_ref_to_space_flags(ref);
+
+ space_info = btrfs_find_space_info(fs_info, flags);
+ ASSERT(space_info);
+ percpu_counter_add_batch(&space_info->total_bytes_pinned, -ref->len,
+ BTRFS_TOTAL_BYTES_PINNED_BATCH);
+}
+
+/* simple helper to search for an existing data extent at a given offset */
+int btrfs_lookup_data_extent(struct btrfs_fs_info *fs_info, u64 start, u64 len)
+{
+ int ret;
+ struct btrfs_key key;
+ struct btrfs_path *path;
+
+ path = btrfs_alloc_path();
+ if (!path)
+ return -ENOMEM;
+
+ key.objectid = start;
+ key.offset = len;
+ key.type = BTRFS_EXTENT_ITEM_KEY;
+ ret = btrfs_search_slot(NULL, fs_info->extent_root, &key, path, 0, 0);
+ btrfs_free_path(path);
+ return ret;
+}
+
+/*
+ * helper function to lookup reference count and flags of a tree block.
+ *
+ * the head node for delayed ref is used to store the sum of all the
+ * reference count modifications queued up in the rbtree. the head
+ * node may also store the extent flags to set. This way you can check
+ * to see what the reference count and extent flags would be if all of
+ * the delayed refs are not processed.
+ */
+int btrfs_lookup_extent_info(struct btrfs_trans_handle *trans,
+ struct btrfs_fs_info *fs_info, u64 bytenr,
+ u64 offset, int metadata, u64 *refs, u64 *flags)
+{
+ struct btrfs_delayed_ref_head *head;
+ struct btrfs_delayed_ref_root *delayed_refs;
+ struct btrfs_path *path;
+ struct btrfs_extent_item *ei;
+ struct extent_buffer *leaf;
+ struct btrfs_key key;
+ u32 item_size;
+ u64 num_refs;
+ u64 extent_flags;
+ int ret;
+
+ /*
+ * If we don't have skinny metadata, don't bother doing anything
+ * different
+ */
+ if (metadata && !btrfs_fs_incompat(fs_info, SKINNY_METADATA)) {
+ offset = fs_info->nodesize;
+ metadata = 0;
+ }
+
+ path = btrfs_alloc_path();
+ if (!path)
+ return -ENOMEM;
+
+ if (!trans) {
+ path->skip_locking = 1;
+ path->search_commit_root = 1;
+ }
+
+search_again:
+ key.objectid = bytenr;
+ key.offset = offset;
+ if (metadata)
+ key.type = BTRFS_METADATA_ITEM_KEY;
+ else
+ key.type = BTRFS_EXTENT_ITEM_KEY;
+
+ ret = btrfs_search_slot(trans, fs_info->extent_root, &key, path, 0, 0);
+ if (ret < 0)
+ goto out_free;
+
+ if (ret > 0 && metadata && key.type == BTRFS_METADATA_ITEM_KEY) {
+ if (path->slots[0]) {
+ path->slots[0]--;
+ btrfs_item_key_to_cpu(path->nodes[0], &key,
+ path->slots[0]);
+ if (key.objectid == bytenr &&
+ key.type == BTRFS_EXTENT_ITEM_KEY &&
+ key.offset == fs_info->nodesize)
+ ret = 0;
+ }
+ }
+
+ if (ret == 0) {
+ leaf = path->nodes[0];
+ item_size = btrfs_item_size_nr(leaf, path->slots[0]);
+ if (item_size >= sizeof(*ei)) {
+ ei = btrfs_item_ptr(leaf, path->slots[0],
+ struct btrfs_extent_item);
+ num_refs = btrfs_extent_refs(leaf, ei);
+ extent_flags = btrfs_extent_flags(leaf, ei);
+ } else {
+ ret = -EINVAL;
+ btrfs_print_v0_err(fs_info);
+ if (trans)
+ btrfs_abort_transaction(trans, ret);
+ else
+ btrfs_handle_fs_error(fs_info, ret, NULL);
+
+ goto out_free;
+ }
+
+ BUG_ON(num_refs == 0);
+ } else {
+ num_refs = 0;
+ extent_flags = 0;
+ ret = 0;
+ }
+
+ if (!trans)
+ goto out;
+
+ delayed_refs = &trans->transaction->delayed_refs;
+ spin_lock(&delayed_refs->lock);
+ head = btrfs_find_delayed_ref_head(delayed_refs, bytenr);
+ if (head) {
+ if (!mutex_trylock(&head->mutex)) {
+ refcount_inc(&head->refs);
+ spin_unlock(&delayed_refs->lock);
+
+ btrfs_release_path(path);
+
+ /*
+ * Mutex was contended, block until it's released and try
+ * again
+ */
+ mutex_lock(&head->mutex);
+ mutex_unlock(&head->mutex);
+ btrfs_put_delayed_ref_head(head);
+ goto search_again;
+ }
+ spin_lock(&head->lock);
+ if (head->extent_op && head->extent_op->update_flags)
+ extent_flags |= head->extent_op->flags_to_set;
+ else
+ BUG_ON(num_refs == 0);
+
+ num_refs += head->ref_mod;
+ spin_unlock(&head->lock);
+ mutex_unlock(&head->mutex);
+ }
+ spin_unlock(&delayed_refs->lock);
+out:
+ WARN_ON(num_refs == 0);
+ if (refs)
+ *refs = num_refs;
+ if (flags)
+ *flags = extent_flags;
+out_free:
+ btrfs_free_path(path);
+ return ret;
+}
+
+/*
+ * Back reference rules. Back refs have three main goals:
+ *
+ * 1) differentiate between all holders of references to an extent so that
+ * when a reference is dropped we can make sure it was a valid reference
+ * before freeing the extent.
+ *
+ * 2) Provide enough information to quickly find the holders of an extent
+ * if we notice a given block is corrupted or bad.
+ *
+ * 3) Make it easy to migrate blocks for FS shrinking or storage pool
+ * maintenance. This is actually the same as #2, but with a slightly
+ * different use case.
+ *
+ * There are two kinds of back refs. The implicit back refs is optimized
+ * for pointers in non-shared tree blocks. For a given pointer in a block,
+ * back refs of this kind provide information about the block's owner tree
+ * and the pointer's key. These information allow us to find the block by
+ * b-tree searching. The full back refs is for pointers in tree blocks not
+ * referenced by their owner trees. The location of tree block is recorded
+ * in the back refs. Actually the full back refs is generic, and can be
+ * used in all cases the implicit back refs is used. The major shortcoming
+ * of the full back refs is its overhead. Every time a tree block gets
+ * COWed, we have to update back refs entry for all pointers in it.
+ *
+ * For a newly allocated tree block, we use implicit back refs for
+ * pointers in it. This means most tree related operations only involve
+ * implicit back refs. For a tree block created in old transaction, the
+ * only way to drop a reference to it is COW it. So we can detect the
+ * event that tree block loses its owner tree's reference and do the
+ * back refs conversion.
+ *
+ * When a tree block is COWed through a tree, there are four cases:
+ *
+ * The reference count of the block is one and the tree is the block's
+ * owner tree. Nothing to do in this case.
+ *
+ * The reference count of the block is one and the tree is not the
+ * block's owner tree. In this case, full back refs is used for pointers
+ * in the block. Remove these full back refs, add implicit back refs for
+ * every pointers in the new block.
+ *
+ * The reference count of the block is greater than one and the tree is
+ * the block's owner tree. In this case, implicit back refs is used for
+ * pointers in the block. Add full back refs for every pointers in the
+ * block, increase lower level extents' reference counts. The original
+ * implicit back refs are entailed to the new block.
+ *
+ * The reference count of the block is greater than one and the tree is
+ * not the block's owner tree. Add implicit back refs for every pointer in
+ * the new block, increase lower level extents' reference count.
+ *
+ * Back Reference Key composing:
+ *
+ * The key objectid corresponds to the first byte in the extent,
+ * The key type is used to differentiate between types of back refs.
+ * There are different meanings of the key offset for different types
+ * of back refs.
+ *
+ * File extents can be referenced by:
+ *
+ * - multiple snapshots, subvolumes, or different generations in one subvol
+ * - different files inside a single subvolume
+ * - different offsets inside a file (bookend extents in file.c)
+ *
+ * The extent ref structure for the implicit back refs has fields for:
+ *
+ * - Objectid of the subvolume root
+ * - objectid of the file holding the reference
+ * - original offset in the file
+ * - how many bookend extents
+ *
+ * The key offset for the implicit back refs is hash of the first
+ * three fields.
+ *
+ * The extent ref structure for the full back refs has field for:
+ *
+ * - number of pointers in the tree leaf
+ *
+ * The key offset for the implicit back refs is the first byte of
+ * the tree leaf
+ *
+ * When a file extent is allocated, The implicit back refs is used.
+ * the fields are filled in:
+ *
+ * (root_key.objectid, inode objectid, offset in file, 1)
+ *
+ * When a file extent is removed file truncation, we find the
+ * corresponding implicit back refs and check the following fields:
+ *
+ * (btrfs_header_owner(leaf), inode objectid, offset in file)
+ *
+ * Btree extents can be referenced by:
+ *
+ * - Different subvolumes
+ *
+ * Both the implicit back refs and the full back refs for tree blocks
+ * only consist of key. The key offset for the implicit back refs is
+ * objectid of block's owner tree. The key offset for the full back refs
+ * is the first byte of parent block.
+ *
+ * When implicit back refs is used, information about the lowest key and
+ * level of the tree block are required. These information are stored in
+ * tree block info structure.
+ */
+
+/*
+ * is_data == BTRFS_REF_TYPE_BLOCK, tree block type is required,
+ * is_data == BTRFS_REF_TYPE_DATA, data type is requiried,
+ * is_data == BTRFS_REF_TYPE_ANY, either type is OK.
+ */
+int btrfs_get_extent_inline_ref_type(const struct extent_buffer *eb,
+ struct btrfs_extent_inline_ref *iref,
+ enum btrfs_inline_ref_type is_data)
+{
+ int type = btrfs_extent_inline_ref_type(eb, iref);
+ u64 offset = btrfs_extent_inline_ref_offset(eb, iref);
+
+ if (type == BTRFS_TREE_BLOCK_REF_KEY ||
+ type == BTRFS_SHARED_BLOCK_REF_KEY ||
+ type == BTRFS_SHARED_DATA_REF_KEY ||
+ type == BTRFS_EXTENT_DATA_REF_KEY) {
+ if (is_data == BTRFS_REF_TYPE_BLOCK) {
+ if (type == BTRFS_TREE_BLOCK_REF_KEY)
+ return type;
+ if (type == BTRFS_SHARED_BLOCK_REF_KEY) {
+ ASSERT(eb->fs_info);
+ /*
+ * Every shared one has parent tree block,
+ * which must be aligned to sector size.
+ */
+ if (offset &&
+ IS_ALIGNED(offset, eb->fs_info->sectorsize))
+ return type;
+ }
+ } else if (is_data == BTRFS_REF_TYPE_DATA) {
+ if (type == BTRFS_EXTENT_DATA_REF_KEY)
+ return type;
+ if (type == BTRFS_SHARED_DATA_REF_KEY) {
+ ASSERT(eb->fs_info);
+ /*
+ * Every shared one has parent tree block,
+ * which must be aligned to sector size.
+ */
+ if (offset &&
+ IS_ALIGNED(offset, eb->fs_info->sectorsize))
+ return type;
+ }
+ } else {
+ ASSERT(is_data == BTRFS_REF_TYPE_ANY);
+ return type;
+ }
+ }
+
+ btrfs_print_leaf((struct extent_buffer *)eb);
+ btrfs_err(eb->fs_info,
+ "eb %llu iref 0x%lx invalid extent inline ref type %d",
+ eb->start, (unsigned long)iref, type);
+ WARN_ON(1);
+
+ return BTRFS_REF_TYPE_INVALID;
+}
+
+u64 hash_extent_data_ref(u64 root_objectid, u64 owner, u64 offset)
+{
+ u32 high_crc = ~(u32)0;
+ u32 low_crc = ~(u32)0;
+ __le64 lenum;
+
+ lenum = cpu_to_le64(root_objectid);
+ high_crc = btrfs_crc32c(high_crc, &lenum, sizeof(lenum));
+ lenum = cpu_to_le64(owner);
+ low_crc = btrfs_crc32c(low_crc, &lenum, sizeof(lenum));
+ lenum = cpu_to_le64(offset);
+ low_crc = btrfs_crc32c(low_crc, &lenum, sizeof(lenum));
+
+ return ((u64)high_crc << 31) ^ (u64)low_crc;
+}
+
+static u64 hash_extent_data_ref_item(struct extent_buffer *leaf,
+ struct btrfs_extent_data_ref *ref)
+{
+ return hash_extent_data_ref(btrfs_extent_data_ref_root(leaf, ref),
+ btrfs_extent_data_ref_objectid(leaf, ref),
+ btrfs_extent_data_ref_offset(leaf, ref));
+}
+
+static int match_extent_data_ref(struct extent_buffer *leaf,
+ struct btrfs_extent_data_ref *ref,
+ u64 root_objectid, u64 owner, u64 offset)
+{
+ if (btrfs_extent_data_ref_root(leaf, ref) != root_objectid ||
+ btrfs_extent_data_ref_objectid(leaf, ref) != owner ||
+ btrfs_extent_data_ref_offset(leaf, ref) != offset)
+ return 0;
+ return 1;
+}
+
+static noinline int lookup_extent_data_ref(struct btrfs_trans_handle *trans,
+ struct btrfs_path *path,
+ u64 bytenr, u64 parent,
+ u64 root_objectid,
+ u64 owner, u64 offset)
+{
+ struct btrfs_root *root = trans->fs_info->extent_root;
+ struct btrfs_key key;
+ struct btrfs_extent_data_ref *ref;
+ struct extent_buffer *leaf;
+ u32 nritems;
+ int ret;
+ int recow;
+ int err = -ENOENT;
+
+ key.objectid = bytenr;
+ if (parent) {
+ key.type = BTRFS_SHARED_DATA_REF_KEY;
+ key.offset = parent;
+ } else {
+ key.type = BTRFS_EXTENT_DATA_REF_KEY;
+ key.offset = hash_extent_data_ref(root_objectid,
+ owner, offset);
+ }
+again:
+ recow = 0;
+ ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
+ if (ret < 0) {
+ err = ret;
+ goto fail;
+ }
+
+ if (parent) {
+ if (!ret)
+ return 0;
+ goto fail;
+ }
+
+ leaf = path->nodes[0];
+ nritems = btrfs_header_nritems(leaf);
+ while (1) {
+ if (path->slots[0] >= nritems) {
+ ret = btrfs_next_leaf(root, path);
+ if (ret < 0)
+ err = ret;
+ if (ret)
+ goto fail;
+
+ leaf = path->nodes[0];
+ nritems = btrfs_header_nritems(leaf);
+ recow = 1;
+ }
+
+ btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
+ if (key.objectid != bytenr ||
+ key.type != BTRFS_EXTENT_DATA_REF_KEY)
+ goto fail;
+
+ ref = btrfs_item_ptr(leaf, path->slots[0],
+ struct btrfs_extent_data_ref);
+
+ if (match_extent_data_ref(leaf, ref, root_objectid,
+ owner, offset)) {
+ if (recow) {
+ btrfs_release_path(path);
+ goto again;
+ }
+ err = 0;
+ break;
+ }
+ path->slots[0]++;
+ }
+fail:
+ return err;
+}
+
+static noinline int insert_extent_data_ref(struct btrfs_trans_handle *trans,
+ struct btrfs_path *path,
+ u64 bytenr, u64 parent,
+ u64 root_objectid, u64 owner,
+ u64 offset, int refs_to_add)
+{
+ struct btrfs_root *root = trans->fs_info->extent_root;
+ struct btrfs_key key;
+ struct extent_buffer *leaf;
+ u32 size;
+ u32 num_refs;
+ int ret;
+
+ key.objectid = bytenr;
+ if (parent) {
+ key.type = BTRFS_SHARED_DATA_REF_KEY;
+ key.offset = parent;
+ size = sizeof(struct btrfs_shared_data_ref);
+ } else {
+ key.type = BTRFS_EXTENT_DATA_REF_KEY;
+ key.offset = hash_extent_data_ref(root_objectid,
+ owner, offset);
+ size = sizeof(struct btrfs_extent_data_ref);
+ }
+
+ ret = btrfs_insert_empty_item(trans, root, path, &key, size);
+ if (ret && ret != -EEXIST)
+ goto fail;
+
+ leaf = path->nodes[0];
+ if (parent) {
+ struct btrfs_shared_data_ref *ref;
+ ref = btrfs_item_ptr(leaf, path->slots[0],
+ struct btrfs_shared_data_ref);
+ if (ret == 0) {
+ btrfs_set_shared_data_ref_count(leaf, ref, refs_to_add);
+ } else {
+ num_refs = btrfs_shared_data_ref_count(leaf, ref);
+ num_refs += refs_to_add;
+ btrfs_set_shared_data_ref_count(leaf, ref, num_refs);
+ }
+ } else {
+ struct btrfs_extent_data_ref *ref;
+ while (ret == -EEXIST) {
+ ref = btrfs_item_ptr(leaf, path->slots[0],
+ struct btrfs_extent_data_ref);
+ if (match_extent_data_ref(leaf, ref, root_objectid,
+ owner, offset))
+ break;
+ btrfs_release_path(path);
+ key.offset++;
+ ret = btrfs_insert_empty_item(trans, root, path, &key,
+ size);
+ if (ret && ret != -EEXIST)
+ goto fail;
+
+ leaf = path->nodes[0];
+ }
+ ref = btrfs_item_ptr(leaf, path->slots[0],
+ struct btrfs_extent_data_ref);
+ if (ret == 0) {
+ btrfs_set_extent_data_ref_root(leaf, ref,
+ root_objectid);
+ btrfs_set_extent_data_ref_objectid(leaf, ref, owner);
+ btrfs_set_extent_data_ref_offset(leaf, ref, offset);
+ btrfs_set_extent_data_ref_count(leaf, ref, refs_to_add);
+ } else {
+ num_refs = btrfs_extent_data_ref_count(leaf, ref);
+ num_refs += refs_to_add;
+ btrfs_set_extent_data_ref_count(leaf, ref, num_refs);
+ }
+ }
+ btrfs_mark_buffer_dirty(leaf);
+ ret = 0;
+fail:
+ btrfs_release_path(path);
+ return ret;
+}
+
+static noinline int remove_extent_data_ref(struct btrfs_trans_handle *trans,
+ struct btrfs_path *path,
+ int refs_to_drop, int *last_ref)
+{
+ struct btrfs_key key;
+ struct btrfs_extent_data_ref *ref1 = NULL;
+ struct btrfs_shared_data_ref *ref2 = NULL;
+ struct extent_buffer *leaf;
+ u32 num_refs = 0;
+ int ret = 0;
+
+ leaf = path->nodes[0];
+ btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
+
+ if (key.type == BTRFS_EXTENT_DATA_REF_KEY) {
+ ref1 = btrfs_item_ptr(leaf, path->slots[0],
+ struct btrfs_extent_data_ref);
+ num_refs = btrfs_extent_data_ref_count(leaf, ref1);
+ } else if (key.type == BTRFS_SHARED_DATA_REF_KEY) {
+ ref2 = btrfs_item_ptr(leaf, path->slots[0],
+ struct btrfs_shared_data_ref);
+ num_refs = btrfs_shared_data_ref_count(leaf, ref2);
+ } else if (unlikely(key.type == BTRFS_EXTENT_REF_V0_KEY)) {
+ btrfs_print_v0_err(trans->fs_info);
+ btrfs_abort_transaction(trans, -EINVAL);
+ return -EINVAL;
+ } else {
+ BUG();
+ }
+
+ BUG_ON(num_refs < refs_to_drop);
+ num_refs -= refs_to_drop;
+
+ if (num_refs == 0) {
+ ret = btrfs_del_item(trans, trans->fs_info->extent_root, path);
+ *last_ref = 1;
+ } else {
+ if (key.type == BTRFS_EXTENT_DATA_REF_KEY)
+ btrfs_set_extent_data_ref_count(leaf, ref1, num_refs);
+ else if (key.type == BTRFS_SHARED_DATA_REF_KEY)
+ btrfs_set_shared_data_ref_count(leaf, ref2, num_refs);
+ btrfs_mark_buffer_dirty(leaf);
+ }
+ return ret;
+}
+
+static noinline u32 extent_data_ref_count(struct btrfs_path *path,
+ struct btrfs_extent_inline_ref *iref)
+{
+ struct btrfs_key key;
+ struct extent_buffer *leaf;
+ struct btrfs_extent_data_ref *ref1;
+ struct btrfs_shared_data_ref *ref2;
+ u32 num_refs = 0;
+ int type;
+
+ leaf = path->nodes[0];
+ btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
+
+ BUG_ON(key.type == BTRFS_EXTENT_REF_V0_KEY);
+ if (iref) {
+ /*
+ * If type is invalid, we should have bailed out earlier than
+ * this call.
+ */
+ type = btrfs_get_extent_inline_ref_type(leaf, iref, BTRFS_REF_TYPE_DATA);
+ ASSERT(type != BTRFS_REF_TYPE_INVALID);
+ if (type == BTRFS_EXTENT_DATA_REF_KEY) {
+ ref1 = (struct btrfs_extent_data_ref *)(&iref->offset);
+ num_refs = btrfs_extent_data_ref_count(leaf, ref1);
+ } else {
+ ref2 = (struct btrfs_shared_data_ref *)(iref + 1);
+ num_refs = btrfs_shared_data_ref_count(leaf, ref2);
+ }
+ } else if (key.type == BTRFS_EXTENT_DATA_REF_KEY) {
+ ref1 = btrfs_item_ptr(leaf, path->slots[0],
+ struct btrfs_extent_data_ref);
+ num_refs = btrfs_extent_data_ref_count(leaf, ref1);
+ } else if (key.type == BTRFS_SHARED_DATA_REF_KEY) {
+ ref2 = btrfs_item_ptr(leaf, path->slots[0],
+ struct btrfs_shared_data_ref);
+ num_refs = btrfs_shared_data_ref_count(leaf, ref2);
+ } else {
+ WARN_ON(1);
+ }
+ return num_refs;
+}
+
+static noinline int lookup_tree_block_ref(struct btrfs_trans_handle *trans,
+ struct btrfs_path *path,
+ u64 bytenr, u64 parent,
+ u64 root_objectid)
+{
+ struct btrfs_root *root = trans->fs_info->extent_root;
+ struct btrfs_key key;
+ int ret;
+
+ key.objectid = bytenr;
+ if (parent) {
+ key.type = BTRFS_SHARED_BLOCK_REF_KEY;
+ key.offset = parent;
+ } else {
+ key.type = BTRFS_TREE_BLOCK_REF_KEY;
+ key.offset = root_objectid;
+ }
+
+ ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
+ if (ret > 0)
+ ret = -ENOENT;
+ return ret;
+}
+
+static noinline int insert_tree_block_ref(struct btrfs_trans_handle *trans,
+ struct btrfs_path *path,
+ u64 bytenr, u64 parent,
+ u64 root_objectid)
+{
+ struct btrfs_key key;
+ int ret;
+
+ key.objectid = bytenr;
+ if (parent) {
+ key.type = BTRFS_SHARED_BLOCK_REF_KEY;
+ key.offset = parent;
+ } else {
+ key.type = BTRFS_TREE_BLOCK_REF_KEY;
+ key.offset = root_objectid;
+ }
+
+ ret = btrfs_insert_empty_item(trans, trans->fs_info->extent_root,
+ path, &key, 0);
+ btrfs_release_path(path);
+ return ret;
+}
+
+static inline int extent_ref_type(u64 parent, u64 owner)
+{
+ int type;
+ if (owner < BTRFS_FIRST_FREE_OBJECTID) {
+ if (parent > 0)
+ type = BTRFS_SHARED_BLOCK_REF_KEY;
+ else
+ type = BTRFS_TREE_BLOCK_REF_KEY;
+ } else {
+ if (parent > 0)
+ type = BTRFS_SHARED_DATA_REF_KEY;
+ else
+ type = BTRFS_EXTENT_DATA_REF_KEY;
+ }
+ return type;
+}
+
+static int find_next_key(struct btrfs_path *path, int level,
+ struct btrfs_key *key)
+
+{
+ for (; level < BTRFS_MAX_LEVEL; level++) {
+ if (!path->nodes[level])
+ break;
+ if (path->slots[level] + 1 >=
+ btrfs_header_nritems(path->nodes[level]))
+ continue;
+ if (level == 0)
+ btrfs_item_key_to_cpu(path->nodes[level], key,
+ path->slots[level] + 1);
+ else
+ btrfs_node_key_to_cpu(path->nodes[level], key,
+ path->slots[level] + 1);
+ return 0;
+ }
+ return 1;
+}
+
+/*
+ * look for inline back ref. if back ref is found, *ref_ret is set
+ * to the address of inline back ref, and 0 is returned.
+ *
+ * if back ref isn't found, *ref_ret is set to the address where it
+ * should be inserted, and -ENOENT is returned.
+ *
+ * if insert is true and there are too many inline back refs, the path
+ * points to the extent item, and -EAGAIN is returned.
+ *
+ * NOTE: inline back refs are ordered in the same way that back ref
+ * items in the tree are ordered.
+ */
+static noinline_for_stack
+int lookup_inline_extent_backref(struct btrfs_trans_handle *trans,
+ struct btrfs_path *path,
+ struct btrfs_extent_inline_ref **ref_ret,
+ u64 bytenr, u64 num_bytes,
+ u64 parent, u64 root_objectid,
+ u64 owner, u64 offset, int insert)
+{
+ struct btrfs_fs_info *fs_info = trans->fs_info;
+ struct btrfs_root *root = fs_info->extent_root;
+ struct btrfs_key key;
+ struct extent_buffer *leaf;
+ struct btrfs_extent_item *ei;
+ struct btrfs_extent_inline_ref *iref;
+ u64 flags;
+ u64 item_size;
+ unsigned long ptr;
+ unsigned long end;
+ int extra_size;
+ int type;
+ int want;
+ int ret;
+ int err = 0;
+ bool skinny_metadata = btrfs_fs_incompat(fs_info, SKINNY_METADATA);
+ int needed;
+
+ key.objectid = bytenr;
+ key.type = BTRFS_EXTENT_ITEM_KEY;
+ key.offset = num_bytes;
+
+ want = extent_ref_type(parent, owner);
+ if (insert) {
+ extra_size = btrfs_extent_inline_ref_size(want);
+ path->keep_locks = 1;
+ } else
+ extra_size = -1;
+
+ /*
+ * Owner is our level, so we can just add one to get the level for the
+ * block we are interested in.
+ */
+ if (skinny_metadata && owner < BTRFS_FIRST_FREE_OBJECTID) {
+ key.type = BTRFS_METADATA_ITEM_KEY;
+ key.offset = owner;
+ }
+
+again:
+ ret = btrfs_search_slot(trans, root, &key, path, extra_size, 1);
+ if (ret < 0) {
+ err = ret;
+ goto out;
+ }
+
+ /*
+ * We may be a newly converted file system which still has the old fat
+ * extent entries for metadata, so try and see if we have one of those.
+ */
+ if (ret > 0 && skinny_metadata) {
+ skinny_metadata = false;
+ if (path->slots[0]) {
+ path->slots[0]--;
+ btrfs_item_key_to_cpu(path->nodes[0], &key,
+ path->slots[0]);
+ if (key.objectid == bytenr &&
+ key.type == BTRFS_EXTENT_ITEM_KEY &&
+ key.offset == num_bytes)
+ ret = 0;
+ }
+ if (ret) {
+ key.objectid = bytenr;
+ key.type = BTRFS_EXTENT_ITEM_KEY;
+ key.offset = num_bytes;
+ btrfs_release_path(path);
+ goto again;
+ }
+ }
+
+ if (ret && !insert) {
+ err = -ENOENT;
+ goto out;
+ } else if (WARN_ON(ret)) {
+ btrfs_print_leaf(path->nodes[0]);
+ btrfs_err(fs_info,
+"extent item not found for insert, bytenr %llu num_bytes %llu parent %llu root_objectid %llu owner %llu offset %llu",
+ bytenr, num_bytes, parent, root_objectid, owner,
+ offset);
+ err = -EIO;
+ goto out;
+ }
+
+ leaf = path->nodes[0];
+ item_size = btrfs_item_size_nr(leaf, path->slots[0]);
+ if (unlikely(item_size < sizeof(*ei))) {
+ err = -EINVAL;
+ btrfs_print_v0_err(fs_info);
+ btrfs_abort_transaction(trans, err);
+ goto out;
+ }
+
+ ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
+ flags = btrfs_extent_flags(leaf, ei);
+
+ ptr = (unsigned long)(ei + 1);
+ end = (unsigned long)ei + item_size;
+
+ if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK && !skinny_metadata) {
+ ptr += sizeof(struct btrfs_tree_block_info);
+ BUG_ON(ptr > end);
+ }
+
+ if (owner >= BTRFS_FIRST_FREE_OBJECTID)
+ needed = BTRFS_REF_TYPE_DATA;
+ else
+ needed = BTRFS_REF_TYPE_BLOCK;
+
+ err = -ENOENT;
+ while (1) {
+ if (ptr >= end) {
+ WARN_ON(ptr > end);
+ break;
+ }
+ iref = (struct btrfs_extent_inline_ref *)ptr;
+ type = btrfs_get_extent_inline_ref_type(leaf, iref, needed);
+ if (type == BTRFS_REF_TYPE_INVALID) {
+ err = -EUCLEAN;
+ goto out;
+ }
+
+ if (want < type)
+ break;
+ if (want > type) {
+ ptr += btrfs_extent_inline_ref_size(type);
+ continue;
+ }
+
+ if (type == BTRFS_EXTENT_DATA_REF_KEY) {
+ struct btrfs_extent_data_ref *dref;
+ dref = (struct btrfs_extent_data_ref *)(&iref->offset);
+ if (match_extent_data_ref(leaf, dref, root_objectid,
+ owner, offset)) {
+ err = 0;
+ break;
+ }
+ if (hash_extent_data_ref_item(leaf, dref) <
+ hash_extent_data_ref(root_objectid, owner, offset))
+ break;
+ } else {
+ u64 ref_offset;
+ ref_offset = btrfs_extent_inline_ref_offset(leaf, iref);
+ if (parent > 0) {
+ if (parent == ref_offset) {
+ err = 0;
+ break;
+ }
+ if (ref_offset < parent)
+ break;
+ } else {
+ if (root_objectid == ref_offset) {
+ err = 0;
+ break;
+ }
+ if (ref_offset < root_objectid)
+ break;
+ }
+ }
+ ptr += btrfs_extent_inline_ref_size(type);
+ }
+ if (err == -ENOENT && insert) {
+ if (item_size + extra_size >=
+ BTRFS_MAX_EXTENT_ITEM_SIZE(root)) {
+ err = -EAGAIN;
+ goto out;
+ }
+ /*
+ * To add new inline back ref, we have to make sure
+ * there is no corresponding back ref item.
+ * For simplicity, we just do not add new inline back
+ * ref if there is any kind of item for this block
+ */
+ if (find_next_key(path, 0, &key) == 0 &&
+ key.objectid == bytenr &&
+ key.type < BTRFS_BLOCK_GROUP_ITEM_KEY) {
+ err = -EAGAIN;
+ goto out;
+ }
+ }
+ *ref_ret = (struct btrfs_extent_inline_ref *)ptr;
+out:
+ if (insert) {
+ path->keep_locks = 0;
+ btrfs_unlock_up_safe(path, 1);
+ }
+ return err;
+}
+
+/*
+ * helper to add new inline back ref
+ */
+static noinline_for_stack
+void setup_inline_extent_backref(struct btrfs_fs_info *fs_info,
+ struct btrfs_path *path,
+ struct btrfs_extent_inline_ref *iref,
+ u64 parent, u64 root_objectid,
+ u64 owner, u64 offset, int refs_to_add,
+ struct btrfs_delayed_extent_op *extent_op)
+{
+ struct extent_buffer *leaf;
+ struct btrfs_extent_item *ei;
+ unsigned long ptr;
+ unsigned long end;
+ unsigned long item_offset;
+ u64 refs;
+ int size;
+ int type;
+
+ leaf = path->nodes[0];
+ ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
+ item_offset = (unsigned long)iref - (unsigned long)ei;
+
+ type = extent_ref_type(parent, owner);
+ size = btrfs_extent_inline_ref_size(type);
+
+ btrfs_extend_item(path, size);
+
+ ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
+ refs = btrfs_extent_refs(leaf, ei);
+ refs += refs_to_add;
+ btrfs_set_extent_refs(leaf, ei, refs);
+ if (extent_op)
+ __run_delayed_extent_op(extent_op, leaf, ei);
+
+ ptr = (unsigned long)ei + item_offset;
+ end = (unsigned long)ei + btrfs_item_size_nr(leaf, path->slots[0]);
+ if (ptr < end - size)
+ memmove_extent_buffer(leaf, ptr + size, ptr,
+ end - size - ptr);
+
+ iref = (struct btrfs_extent_inline_ref *)ptr;
+ btrfs_set_extent_inline_ref_type(leaf, iref, type);
+ if (type == BTRFS_EXTENT_DATA_REF_KEY) {
+ struct btrfs_extent_data_ref *dref;
+ dref = (struct btrfs_extent_data_ref *)(&iref->offset);
+ btrfs_set_extent_data_ref_root(leaf, dref, root_objectid);
+ btrfs_set_extent_data_ref_objectid(leaf, dref, owner);
+ btrfs_set_extent_data_ref_offset(leaf, dref, offset);
+ btrfs_set_extent_data_ref_count(leaf, dref, refs_to_add);
+ } else if (type == BTRFS_SHARED_DATA_REF_KEY) {
+ struct btrfs_shared_data_ref *sref;
+ sref = (struct btrfs_shared_data_ref *)(iref + 1);
+ btrfs_set_shared_data_ref_count(leaf, sref, refs_to_add);
+ btrfs_set_extent_inline_ref_offset(leaf, iref, parent);
+ } else if (type == BTRFS_SHARED_BLOCK_REF_KEY) {
+ btrfs_set_extent_inline_ref_offset(leaf, iref, parent);
+ } else {
+ btrfs_set_extent_inline_ref_offset(leaf, iref, root_objectid);
+ }
+ btrfs_mark_buffer_dirty(leaf);
+}
+
+static int lookup_extent_backref(struct btrfs_trans_handle *trans,
+ struct btrfs_path *path,
+ struct btrfs_extent_inline_ref **ref_ret,
+ u64 bytenr, u64 num_bytes, u64 parent,
+ u64 root_objectid, u64 owner, u64 offset)
+{
+ int ret;
+
+ ret = lookup_inline_extent_backref(trans, path, ref_ret, bytenr,
+ num_bytes, parent, root_objectid,
+ owner, offset, 0);
+ if (ret != -ENOENT)
+ return ret;
+
+ btrfs_release_path(path);
+ *ref_ret = NULL;
+
+ if (owner < BTRFS_FIRST_FREE_OBJECTID) {
+ ret = lookup_tree_block_ref(trans, path, bytenr, parent,
+ root_objectid);
+ } else {
+ ret = lookup_extent_data_ref(trans, path, bytenr, parent,
+ root_objectid, owner, offset);
+ }
+ return ret;
+}
+
+/*
+ * helper to update/remove inline back ref
+ */
+static noinline_for_stack
+void update_inline_extent_backref(struct btrfs_path *path,
+ struct btrfs_extent_inline_ref *iref,
+ int refs_to_mod,
+ struct btrfs_delayed_extent_op *extent_op,
+ int *last_ref)
+{
+ struct extent_buffer *leaf = path->nodes[0];
+ struct btrfs_extent_item *ei;
+ struct btrfs_extent_data_ref *dref = NULL;
+ struct btrfs_shared_data_ref *sref = NULL;
+ unsigned long ptr;
+ unsigned long end;
+ u32 item_size;
+ int size;
+ int type;
+ u64 refs;
+
+ ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
+ refs = btrfs_extent_refs(leaf, ei);
+ WARN_ON(refs_to_mod < 0 && refs + refs_to_mod <= 0);
+ refs += refs_to_mod;
+ btrfs_set_extent_refs(leaf, ei, refs);
+ if (extent_op)
+ __run_delayed_extent_op(extent_op, leaf, ei);
+
+ /*
+ * If type is invalid, we should have bailed out after
+ * lookup_inline_extent_backref().
+ */
+ type = btrfs_get_extent_inline_ref_type(leaf, iref, BTRFS_REF_TYPE_ANY);
+ ASSERT(type != BTRFS_REF_TYPE_INVALID);
+
+ if (type == BTRFS_EXTENT_DATA_REF_KEY) {
+ dref = (struct btrfs_extent_data_ref *)(&iref->offset);
+ refs = btrfs_extent_data_ref_count(leaf, dref);
+ } else if (type == BTRFS_SHARED_DATA_REF_KEY) {
+ sref = (struct btrfs_shared_data_ref *)(iref + 1);
+ refs = btrfs_shared_data_ref_count(leaf, sref);
+ } else {
+ refs = 1;
+ BUG_ON(refs_to_mod != -1);
+ }
+
+ BUG_ON(refs_to_mod < 0 && refs < -refs_to_mod);
+ refs += refs_to_mod;
+
+ if (refs > 0) {
+ if (type == BTRFS_EXTENT_DATA_REF_KEY)
+ btrfs_set_extent_data_ref_count(leaf, dref, refs);
+ else
+ btrfs_set_shared_data_ref_count(leaf, sref, refs);
+ } else {
+ *last_ref = 1;
+ size = btrfs_extent_inline_ref_size(type);
+ item_size = btrfs_item_size_nr(leaf, path->slots[0]);
+ ptr = (unsigned long)iref;
+ end = (unsigned long)ei + item_size;
+ if (ptr + size < end)
+ memmove_extent_buffer(leaf, ptr, ptr + size,
+ end - ptr - size);
+ item_size -= size;
+ btrfs_truncate_item(path, item_size, 1);
+ }
+ btrfs_mark_buffer_dirty(leaf);
+}
+
+static noinline_for_stack
+int insert_inline_extent_backref(struct btrfs_trans_handle *trans,
+ struct btrfs_path *path,
+ u64 bytenr, u64 num_bytes, u64 parent,
+ u64 root_objectid, u64 owner,
+ u64 offset, int refs_to_add,
+ struct btrfs_delayed_extent_op *extent_op)
+{
+ struct btrfs_extent_inline_ref *iref;
+ int ret;
+
+ ret = lookup_inline_extent_backref(trans, path, &iref, bytenr,
+ num_bytes, parent, root_objectid,
+ owner, offset, 1);
+ if (ret == 0) {
+ BUG_ON(owner < BTRFS_FIRST_FREE_OBJECTID);
+ update_inline_extent_backref(path, iref, refs_to_add,
+ extent_op, NULL);
+ } else if (ret == -ENOENT) {
+ setup_inline_extent_backref(trans->fs_info, path, iref, parent,
+ root_objectid, owner, offset,
+ refs_to_add, extent_op);
+ ret = 0;
+ }
+ return ret;
+}
+
+static int insert_extent_backref(struct btrfs_trans_handle *trans,
+ struct btrfs_path *path,
+ u64 bytenr, u64 parent, u64 root_objectid,
+ u64 owner, u64 offset, int refs_to_add)
+{
+ int ret;
+ if (owner < BTRFS_FIRST_FREE_OBJECTID) {
+ BUG_ON(refs_to_add != 1);
+ ret = insert_tree_block_ref(trans, path, bytenr, parent,
+ root_objectid);
+ } else {
+ ret = insert_extent_data_ref(trans, path, bytenr, parent,
+ root_objectid, owner, offset,
+ refs_to_add);
+ }
+ return ret;
+}
+
+static int remove_extent_backref(struct btrfs_trans_handle *trans,
+ struct btrfs_path *path,
+ struct btrfs_extent_inline_ref *iref,
+ int refs_to_drop, int is_data, int *last_ref)
+{
+ int ret = 0;
+
+ BUG_ON(!is_data && refs_to_drop != 1);
+ if (iref) {
+ update_inline_extent_backref(path, iref, -refs_to_drop, NULL,
+ last_ref);
+ } else if (is_data) {
+ ret = remove_extent_data_ref(trans, path, refs_to_drop,
+ last_ref);
+ } else {
+ *last_ref = 1;
+ ret = btrfs_del_item(trans, trans->fs_info->extent_root, path);
+ }
+ return ret;
+}
+
+static int btrfs_issue_discard(struct block_device *bdev, u64 start, u64 len,
+ u64 *discarded_bytes)
+{
+ int j, ret = 0;
+ u64 bytes_left, end;
+ u64 aligned_start = ALIGN(start, 1 << 9);
+
+ /* Adjust the range to be aligned to 512B sectors if necessary. */
+ if (start != aligned_start) {
+ len -= aligned_start - start;
+ len = round_down(len, 1 << 9);
+ start = aligned_start;
+ }
+
+ *discarded_bytes = 0;
+
+ if (!len)
+ return 0;
+
+ end = start + len;
+ bytes_left = len;
+
+ /* Skip any superblocks on this device. */
+ for (j = 0; j < BTRFS_SUPER_MIRROR_MAX; j++) {
+ u64 sb_start = btrfs_sb_offset(j);
+ u64 sb_end = sb_start + BTRFS_SUPER_INFO_SIZE;
+ u64 size = sb_start - start;
+
+ if (!in_range(sb_start, start, bytes_left) &&
+ !in_range(sb_end, start, bytes_left) &&
+ !in_range(start, sb_start, BTRFS_SUPER_INFO_SIZE))
+ continue;
+
+ /*
+ * Superblock spans beginning of range. Adjust start and
+ * try again.
+ */
+ if (sb_start <= start) {
+ start += sb_end - start;
+ if (start > end) {
+ bytes_left = 0;
+ break;
+ }
+ bytes_left = end - start;
+ continue;
+ }
+
+ if (size) {
+ ret = blkdev_issue_discard(bdev, start >> 9, size >> 9,
+ GFP_NOFS, 0);
+ if (!ret)
+ *discarded_bytes += size;
+ else if (ret != -EOPNOTSUPP)
+ return ret;
+ }
+
+ start = sb_end;
+ if (start > end) {
+ bytes_left = 0;
+ break;
+ }
+ bytes_left = end - start;
+ }
+
+ if (bytes_left) {
+ ret = blkdev_issue_discard(bdev, start >> 9, bytes_left >> 9,
+ GFP_NOFS, 0);
+ if (!ret)
+ *discarded_bytes += bytes_left;
+ }
+ return ret;
+}
+
+int btrfs_discard_extent(struct btrfs_fs_info *fs_info, u64 bytenr,
+ u64 num_bytes, u64 *actual_bytes)
+{
+ int ret = 0;
+ u64 discarded_bytes = 0;
+ u64 end = bytenr + num_bytes;
+ u64 cur = bytenr;
+ struct btrfs_bio *bbio = NULL;
+
+
+ /*
+ * Avoid races with device replace and make sure our bbio has devices
+ * associated to its stripes that don't go away while we are discarding.
+ */
+ btrfs_bio_counter_inc_blocked(fs_info);
+ while (cur < end) {
+ struct btrfs_bio_stripe *stripe;
+ int i;
+
+ num_bytes = end - cur;
+ /* Tell the block device(s) that the sectors can be discarded */
+ ret = btrfs_map_block(fs_info, BTRFS_MAP_DISCARD, cur,
+ &num_bytes, &bbio, 0);
+ /*
+ * Error can be -ENOMEM, -ENOENT (no such chunk mapping) or
+ * -EOPNOTSUPP. For any such error, @num_bytes is not updated,
+ * thus we can't continue anyway.
+ */
+ if (ret < 0)
+ goto out;
+
+ stripe = bbio->stripes;
+ for (i = 0; i < bbio->num_stripes; i++, stripe++) {
+ u64 bytes;
+ struct request_queue *req_q;
+ struct btrfs_device *device = stripe->dev;
+
+ if (!device->bdev) {
+ ASSERT(btrfs_test_opt(fs_info, DEGRADED));
+ continue;
+ }
+ req_q = bdev_get_queue(device->bdev);
+ if (!blk_queue_discard(req_q))
+ continue;
+
+ if (!test_bit(BTRFS_DEV_STATE_WRITEABLE, &device->dev_state))
+ continue;
+
+ ret = btrfs_issue_discard(device->bdev,
+ stripe->physical,
+ stripe->length,
+ &bytes);
+ if (!ret) {
+ discarded_bytes += bytes;
+ } else if (ret != -EOPNOTSUPP) {
+ /*
+ * Logic errors or -ENOMEM, or -EIO, but
+ * unlikely to happen.
+ *
+ * And since there are two loops, explicitly
+ * go to out to avoid confusion.
+ */
+ btrfs_put_bbio(bbio);
+ goto out;
+ }
+
+ /*
+ * Just in case we get back EOPNOTSUPP for some reason,
+ * just ignore the return value so we don't screw up
+ * people calling discard_extent.
+ */
+ ret = 0;
+ }
+ btrfs_put_bbio(bbio);
+ cur += num_bytes;
+ }
+out:
+ btrfs_bio_counter_dec(fs_info);
+
+ if (actual_bytes)
+ *actual_bytes = discarded_bytes;
+
+
+ if (ret == -EOPNOTSUPP)
+ ret = 0;
+ return ret;
+}
+
+/* Can return -ENOMEM */
+int btrfs_inc_extent_ref(struct btrfs_trans_handle *trans,
+ struct btrfs_ref *generic_ref)
+{
+ struct btrfs_fs_info *fs_info = trans->fs_info;
+ int old_ref_mod, new_ref_mod;
+ int ret;
+
+ ASSERT(generic_ref->type != BTRFS_REF_NOT_SET &&
+ generic_ref->action);
+ BUG_ON(generic_ref->type == BTRFS_REF_METADATA &&
+ generic_ref->tree_ref.root == BTRFS_TREE_LOG_OBJECTID);
+
+ if (generic_ref->type == BTRFS_REF_METADATA)
+ ret = btrfs_add_delayed_tree_ref(trans, generic_ref,
+ NULL, &old_ref_mod, &new_ref_mod);
+ else
+ ret = btrfs_add_delayed_data_ref(trans, generic_ref, 0,
+ &old_ref_mod, &new_ref_mod);
+
+ btrfs_ref_tree_mod(fs_info, generic_ref);
+
+ if (ret == 0 && old_ref_mod < 0 && new_ref_mod >= 0)
+ sub_pinned_bytes(fs_info, generic_ref);
+
+ return ret;
+}
+
+/*
+ * __btrfs_inc_extent_ref - insert backreference for a given extent
+ *
+ * @trans: Handle of transaction
+ *
+ * @node: The delayed ref node used to get the bytenr/length for
+ * extent whose references are incremented.
+ *
+ * @parent: If this is a shared extent (BTRFS_SHARED_DATA_REF_KEY/
+ * BTRFS_SHARED_BLOCK_REF_KEY) then it holds the logical
+ * bytenr of the parent block. Since new extents are always
+ * created with indirect references, this will only be the case
+ * when relocating a shared extent. In that case, root_objectid
+ * will be BTRFS_TREE_RELOC_OBJECTID. Otheriwse, parent must
+ * be 0
+ *
+ * @root_objectid: The id of the root where this modification has originated,
+ * this can be either one of the well-known metadata trees or
+ * the subvolume id which references this extent.
+ *
+ * @owner: For data extents it is the inode number of the owning file.
+ * For metadata extents this parameter holds the level in the
+ * tree of the extent.
+ *
+ * @offset: For metadata extents the offset is ignored and is currently
+ * always passed as 0. For data extents it is the fileoffset
+ * this extent belongs to.
+ *
+ * @refs_to_add Number of references to add
+ *
+ * @extent_op Pointer to a structure, holding information necessary when
+ * updating a tree block's flags
+ *
+ */
+static int __btrfs_inc_extent_ref(struct btrfs_trans_handle *trans,
+ struct btrfs_delayed_ref_node *node,
+ u64 parent, u64 root_objectid,
+ u64 owner, u64 offset, int refs_to_add,
+ struct btrfs_delayed_extent_op *extent_op)
+{
+ struct btrfs_path *path;
+ struct extent_buffer *leaf;
+ struct btrfs_extent_item *item;
+ struct btrfs_key key;
+ u64 bytenr = node->bytenr;
+ u64 num_bytes = node->num_bytes;
+ u64 refs;
+ int ret;
+
+ path = btrfs_alloc_path();
+ if (!path)
+ return -ENOMEM;
+
+ path->reada = READA_FORWARD;
+ path->leave_spinning = 1;
+ /* this will setup the path even if it fails to insert the back ref */
+ ret = insert_inline_extent_backref(trans, path, bytenr, num_bytes,
+ parent, root_objectid, owner,
+ offset, refs_to_add, extent_op);
+ if ((ret < 0 && ret != -EAGAIN) || !ret)
+ goto out;
+
+ /*
+ * Ok we had -EAGAIN which means we didn't have space to insert and
+ * inline extent ref, so just update the reference count and add a
+ * normal backref.
+ */
+ leaf = path->nodes[0];
+ btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
+ item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
+ refs = btrfs_extent_refs(leaf, item);
+ btrfs_set_extent_refs(leaf, item, refs + refs_to_add);
+ if (extent_op)
+ __run_delayed_extent_op(extent_op, leaf, item);
+
+ btrfs_mark_buffer_dirty(leaf);
+ btrfs_release_path(path);
+
+ path->reada = READA_FORWARD;
+ path->leave_spinning = 1;
+ /* now insert the actual backref */
+ ret = insert_extent_backref(trans, path, bytenr, parent, root_objectid,
+ owner, offset, refs_to_add);
+ if (ret)
+ btrfs_abort_transaction(trans, ret);
+out:
+ btrfs_free_path(path);
+ return ret;
+}
+
+static int run_delayed_data_ref(struct btrfs_trans_handle *trans,
+ struct btrfs_delayed_ref_node *node,
+ struct btrfs_delayed_extent_op *extent_op,
+ int insert_reserved)
+{
+ int ret = 0;
+ struct btrfs_delayed_data_ref *ref;
+ struct btrfs_key ins;
+ u64 parent = 0;
+ u64 ref_root = 0;
+ u64 flags = 0;
+
+ ins.objectid = node->bytenr;
+ ins.offset = node->num_bytes;
+ ins.type = BTRFS_EXTENT_ITEM_KEY;
+
+ ref = btrfs_delayed_node_to_data_ref(node);
+ trace_run_delayed_data_ref(trans->fs_info, node, ref, node->action);
+
+ if (node->type == BTRFS_SHARED_DATA_REF_KEY)
+ parent = ref->parent;
+ ref_root = ref->root;
+
+ if (node->action == BTRFS_ADD_DELAYED_REF && insert_reserved) {
+ if (extent_op)
+ flags |= extent_op->flags_to_set;
+ ret = alloc_reserved_file_extent(trans, parent, ref_root,
+ flags, ref->objectid,
+ ref->offset, &ins,
+ node->ref_mod);
+ } else if (node->action == BTRFS_ADD_DELAYED_REF) {
+ ret = __btrfs_inc_extent_ref(trans, node, parent, ref_root,
+ ref->objectid, ref->offset,
+ node->ref_mod, extent_op);
+ } else if (node->action == BTRFS_DROP_DELAYED_REF) {
+ ret = __btrfs_free_extent(trans, node, parent,
+ ref_root, ref->objectid,
+ ref->offset, node->ref_mod,
+ extent_op);
+ } else {
+ BUG();
+ }
+ return ret;
+}
+
+static void __run_delayed_extent_op(struct btrfs_delayed_extent_op *extent_op,
+ struct extent_buffer *leaf,
+ struct btrfs_extent_item *ei)
+{
+ u64 flags = btrfs_extent_flags(leaf, ei);
+ if (extent_op->update_flags) {
+ flags |= extent_op->flags_to_set;
+ btrfs_set_extent_flags(leaf, ei, flags);
+ }
+
+ if (extent_op->update_key) {
+ struct btrfs_tree_block_info *bi;
+ BUG_ON(!(flags & BTRFS_EXTENT_FLAG_TREE_BLOCK));
+ bi = (struct btrfs_tree_block_info *)(ei + 1);
+ btrfs_set_tree_block_key(leaf, bi, &extent_op->key);
+ }
+}
+
+static int run_delayed_extent_op(struct btrfs_trans_handle *trans,
+ struct btrfs_delayed_ref_head *head,
+ struct btrfs_delayed_extent_op *extent_op)
+{
+ struct btrfs_fs_info *fs_info = trans->fs_info;
+ struct btrfs_key key;
+ struct btrfs_path *path;
+ struct btrfs_extent_item *ei;
+ struct extent_buffer *leaf;
+ u32 item_size;
+ int ret;
+ int err = 0;
+ int metadata = !extent_op->is_data;
+
+ if (TRANS_ABORTED(trans))
+ return 0;
+
+ if (metadata && !btrfs_fs_incompat(fs_info, SKINNY_METADATA))
+ metadata = 0;
+
+ path = btrfs_alloc_path();
+ if (!path)
+ return -ENOMEM;
+
+ key.objectid = head->bytenr;
+
+ if (metadata) {
+ key.type = BTRFS_METADATA_ITEM_KEY;
+ key.offset = extent_op->level;
+ } else {
+ key.type = BTRFS_EXTENT_ITEM_KEY;
+ key.offset = head->num_bytes;
+ }
+
+again:
+ path->reada = READA_FORWARD;
+ path->leave_spinning = 1;
+ ret = btrfs_search_slot(trans, fs_info->extent_root, &key, path, 0, 1);
+ if (ret < 0) {
+ err = ret;
+ goto out;
+ }
+ if (ret > 0) {
+ if (metadata) {
+ if (path->slots[0] > 0) {
+ path->slots[0]--;
+ btrfs_item_key_to_cpu(path->nodes[0], &key,
+ path->slots[0]);
+ if (key.objectid == head->bytenr &&
+ key.type == BTRFS_EXTENT_ITEM_KEY &&
+ key.offset == head->num_bytes)
+ ret = 0;
+ }
+ if (ret > 0) {
+ btrfs_release_path(path);
+ metadata = 0;
+
+ key.objectid = head->bytenr;
+ key.offset = head->num_bytes;
+ key.type = BTRFS_EXTENT_ITEM_KEY;
+ goto again;
+ }
+ } else {
+ err = -EIO;
+ goto out;
+ }
+ }
+
+ leaf = path->nodes[0];
+ item_size = btrfs_item_size_nr(leaf, path->slots[0]);
+
+ if (unlikely(item_size < sizeof(*ei))) {
+ err = -EINVAL;
+ btrfs_print_v0_err(fs_info);
+ btrfs_abort_transaction(trans, err);
+ goto out;
+ }
+
+ ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
+ __run_delayed_extent_op(extent_op, leaf, ei);
+
+ btrfs_mark_buffer_dirty(leaf);
+out:
+ btrfs_free_path(path);
+ return err;
+}
+
+static int run_delayed_tree_ref(struct btrfs_trans_handle *trans,
+ struct btrfs_delayed_ref_node *node,
+ struct btrfs_delayed_extent_op *extent_op,
+ int insert_reserved)
+{
+ int ret = 0;
+ struct btrfs_delayed_tree_ref *ref;
+ u64 parent = 0;
+ u64 ref_root = 0;
+
+ ref = btrfs_delayed_node_to_tree_ref(node);
+ trace_run_delayed_tree_ref(trans->fs_info, node, ref, node->action);
+
+ if (node->type == BTRFS_SHARED_BLOCK_REF_KEY)
+ parent = ref->parent;
+ ref_root = ref->root;
+
+ if (unlikely(node->ref_mod != 1)) {
+ btrfs_err(trans->fs_info,
+ "btree block %llu has %d references rather than 1: action %d ref_root %llu parent %llu",
+ node->bytenr, node->ref_mod, node->action, ref_root,
+ parent);
+ return -EUCLEAN;
+ }
+ if (node->action == BTRFS_ADD_DELAYED_REF && insert_reserved) {
+ BUG_ON(!extent_op || !extent_op->update_flags);
+ ret = alloc_reserved_tree_block(trans, node, extent_op);
+ } else if (node->action == BTRFS_ADD_DELAYED_REF) {
+ ret = __btrfs_inc_extent_ref(trans, node, parent, ref_root,
+ ref->level, 0, 1, extent_op);
+ } else if (node->action == BTRFS_DROP_DELAYED_REF) {
+ ret = __btrfs_free_extent(trans, node, parent, ref_root,
+ ref->level, 0, 1, extent_op);
+ } else {
+ BUG();
+ }
+ return ret;
+}
+
+/* helper function to actually process a single delayed ref entry */
+static int run_one_delayed_ref(struct btrfs_trans_handle *trans,
+ struct btrfs_delayed_ref_node *node,
+ struct btrfs_delayed_extent_op *extent_op,
+ int insert_reserved)
+{
+ int ret = 0;
+
+ if (TRANS_ABORTED(trans)) {
+ if (insert_reserved)
+ btrfs_pin_extent(trans->fs_info, node->bytenr,
+ node->num_bytes, 1);
+ return 0;
+ }
+
+ if (node->type == BTRFS_TREE_BLOCK_REF_KEY ||
+ node->type == BTRFS_SHARED_BLOCK_REF_KEY)
+ ret = run_delayed_tree_ref(trans, node, extent_op,
+ insert_reserved);
+ else if (node->type == BTRFS_EXTENT_DATA_REF_KEY ||
+ node->type == BTRFS_SHARED_DATA_REF_KEY)
+ ret = run_delayed_data_ref(trans, node, extent_op,
+ insert_reserved);
+ else
+ BUG();
+ if (ret && insert_reserved)
+ btrfs_pin_extent(trans->fs_info, node->bytenr,
+ node->num_bytes, 1);
+ return ret;
+}
+
+static inline struct btrfs_delayed_ref_node *
+select_delayed_ref(struct btrfs_delayed_ref_head *head)
+{
+ struct btrfs_delayed_ref_node *ref;
+
+ if (RB_EMPTY_ROOT(&head->ref_tree.rb_root))
+ return NULL;
+
+ /*
+ * Select a delayed ref of type BTRFS_ADD_DELAYED_REF first.
+ * This is to prevent a ref count from going down to zero, which deletes
+ * the extent item from the extent tree, when there still are references
+ * to add, which would fail because they would not find the extent item.
+ */
+ if (!list_empty(&head->ref_add_list))
+ return list_first_entry(&head->ref_add_list,
+ struct btrfs_delayed_ref_node, add_list);
+
+ ref = rb_entry(rb_first_cached(&head->ref_tree),
+ struct btrfs_delayed_ref_node, ref_node);
+ ASSERT(list_empty(&ref->add_list));
+ return ref;
+}
+
+static void unselect_delayed_ref_head(struct btrfs_delayed_ref_root *delayed_refs,
+ struct btrfs_delayed_ref_head *head)
+{
+ spin_lock(&delayed_refs->lock);
+ head->processing = 0;
+ delayed_refs->num_heads_ready++;
+ spin_unlock(&delayed_refs->lock);
+ btrfs_delayed_ref_unlock(head);
+}
+
+static struct btrfs_delayed_extent_op *cleanup_extent_op(
+ struct btrfs_delayed_ref_head *head)
+{
+ struct btrfs_delayed_extent_op *extent_op = head->extent_op;
+
+ if (!extent_op)
+ return NULL;
+
+ if (head->must_insert_reserved) {
+ head->extent_op = NULL;
+ btrfs_free_delayed_extent_op(extent_op);
+ return NULL;
+ }
+ return extent_op;
+}
+
+static int run_and_cleanup_extent_op(struct btrfs_trans_handle *trans,
+ struct btrfs_delayed_ref_head *head)
+{
+ struct btrfs_delayed_extent_op *extent_op;
+ int ret;
+
+ extent_op = cleanup_extent_op(head);
+ if (!extent_op)
+ return 0;
+ head->extent_op = NULL;
+ spin_unlock(&head->lock);
+ ret = run_delayed_extent_op(trans, head, extent_op);
+ btrfs_free_delayed_extent_op(extent_op);
+ return ret ? ret : 1;
+}
+
+void btrfs_cleanup_ref_head_accounting(struct btrfs_fs_info *fs_info,
+ struct btrfs_delayed_ref_root *delayed_refs,
+ struct btrfs_delayed_ref_head *head)
+{
+ int nr_items = 1; /* Dropping this ref head update. */
+
+ if (head->total_ref_mod < 0) {
+ struct btrfs_space_info *space_info;
+ u64 flags;
+
+ if (head->is_data)
+ flags = BTRFS_BLOCK_GROUP_DATA;
+ else if (head->is_system)
+ flags = BTRFS_BLOCK_GROUP_SYSTEM;
+ else
+ flags = BTRFS_BLOCK_GROUP_METADATA;
+ space_info = btrfs_find_space_info(fs_info, flags);
+ ASSERT(space_info);
+ percpu_counter_add_batch(&space_info->total_bytes_pinned,
+ -head->num_bytes,
+ BTRFS_TOTAL_BYTES_PINNED_BATCH);
+
+ /*
+ * We had csum deletions accounted for in our delayed refs rsv,
+ * we need to drop the csum leaves for this update from our
+ * delayed_refs_rsv.
+ */
+ if (head->is_data) {
+ spin_lock(&delayed_refs->lock);
+ delayed_refs->pending_csums -= head->num_bytes;
+ spin_unlock(&delayed_refs->lock);
+ nr_items += btrfs_csum_bytes_to_leaves(fs_info,
+ head->num_bytes);
+ }
+ }
+
+ btrfs_delayed_refs_rsv_release(fs_info, nr_items);
+}
+
+static int cleanup_ref_head(struct btrfs_trans_handle *trans,
+ struct btrfs_delayed_ref_head *head)
+{
+
+ struct btrfs_fs_info *fs_info = trans->fs_info;
+ struct btrfs_delayed_ref_root *delayed_refs;
+ int ret;
+
+ delayed_refs = &trans->transaction->delayed_refs;
+
+ ret = run_and_cleanup_extent_op(trans, head);
+ if (ret < 0) {
+ unselect_delayed_ref_head(delayed_refs, head);
+ btrfs_debug(fs_info, "run_delayed_extent_op returned %d", ret);
+ return ret;
+ } else if (ret) {
+ return ret;
+ }
+
+ /*
+ * Need to drop our head ref lock and re-acquire the delayed ref lock
+ * and then re-check to make sure nobody got added.
+ */
+ spin_unlock(&head->lock);
+ spin_lock(&delayed_refs->lock);
+ spin_lock(&head->lock);
+ if (!RB_EMPTY_ROOT(&head->ref_tree.rb_root) || head->extent_op) {
+ spin_unlock(&head->lock);
+ spin_unlock(&delayed_refs->lock);
+ return 1;
+ }
+ btrfs_delete_ref_head(delayed_refs, head);
+ spin_unlock(&head->lock);
+ spin_unlock(&delayed_refs->lock);
+
+ if (head->must_insert_reserved) {
+ btrfs_pin_extent(fs_info, head->bytenr,
+ head->num_bytes, 1);
+ if (head->is_data) {
+ ret = btrfs_del_csums(trans, fs_info->csum_root,
+ head->bytenr, head->num_bytes);
+ }
+ }
+
+ btrfs_cleanup_ref_head_accounting(fs_info, delayed_refs, head);
+
+ trace_run_delayed_ref_head(fs_info, head, 0);
+ btrfs_delayed_ref_unlock(head);
+ btrfs_put_delayed_ref_head(head);
+ return ret;
+}
+
+static struct btrfs_delayed_ref_head *btrfs_obtain_ref_head(
+ struct btrfs_trans_handle *trans)
+{
+ struct btrfs_delayed_ref_root *delayed_refs =
+ &trans->transaction->delayed_refs;
+ struct btrfs_delayed_ref_head *head = NULL;
+ int ret;
+
+ spin_lock(&delayed_refs->lock);
+ head = btrfs_select_ref_head(delayed_refs);
+ if (!head) {
+ spin_unlock(&delayed_refs->lock);
+ return head;
+ }
+
+ /*
+ * Grab the lock that says we are going to process all the refs for
+ * this head
+ */
+ ret = btrfs_delayed_ref_lock(delayed_refs, head);
+ spin_unlock(&delayed_refs->lock);
+
+ /*
+ * We may have dropped the spin lock to get the head mutex lock, and
+ * that might have given someone else time to free the head. If that's
+ * true, it has been removed from our list and we can move on.
+ */
+ if (ret == -EAGAIN)
+ head = ERR_PTR(-EAGAIN);
+
+ return head;
+}
+
+static int btrfs_run_delayed_refs_for_head(struct btrfs_trans_handle *trans,
+ struct btrfs_delayed_ref_head *locked_ref,
+ unsigned long *run_refs)
+{
+ struct btrfs_fs_info *fs_info = trans->fs_info;
+ struct btrfs_delayed_ref_root *delayed_refs;
+ struct btrfs_delayed_extent_op *extent_op;
+ struct btrfs_delayed_ref_node *ref;
+ int must_insert_reserved = 0;
+ int ret;
+
+ delayed_refs = &trans->transaction->delayed_refs;
+
+ lockdep_assert_held(&locked_ref->mutex);
+ lockdep_assert_held(&locked_ref->lock);
+
+ while ((ref = select_delayed_ref(locked_ref))) {
+ if (ref->seq &&
+ btrfs_check_delayed_seq(fs_info, ref->seq)) {
+ spin_unlock(&locked_ref->lock);
+ unselect_delayed_ref_head(delayed_refs, locked_ref);
+ return -EAGAIN;
+ }
+
+ (*run_refs)++;
+ ref->in_tree = 0;
+ rb_erase_cached(&ref->ref_node, &locked_ref->ref_tree);
+ RB_CLEAR_NODE(&ref->ref_node);
+ if (!list_empty(&ref->add_list))
+ list_del(&ref->add_list);
+ /*
+ * When we play the delayed ref, also correct the ref_mod on
+ * head
+ */
+ switch (ref->action) {
+ case BTRFS_ADD_DELAYED_REF:
+ case BTRFS_ADD_DELAYED_EXTENT:
+ locked_ref->ref_mod -= ref->ref_mod;
+ break;
+ case BTRFS_DROP_DELAYED_REF:
+ locked_ref->ref_mod += ref->ref_mod;
+ break;
+ default:
+ WARN_ON(1);
+ }
+ atomic_dec(&delayed_refs->num_entries);
+
+ /*
+ * Record the must_insert_reserved flag before we drop the
+ * spin lock.
+ */
+ must_insert_reserved = locked_ref->must_insert_reserved;
+ locked_ref->must_insert_reserved = 0;
+
+ extent_op = locked_ref->extent_op;
+ locked_ref->extent_op = NULL;
+ spin_unlock(&locked_ref->lock);
+
+ ret = run_one_delayed_ref(trans, ref, extent_op,
+ must_insert_reserved);
+
+ btrfs_free_delayed_extent_op(extent_op);
+ if (ret) {
+ unselect_delayed_ref_head(delayed_refs, locked_ref);
+ btrfs_put_delayed_ref(ref);
+ btrfs_debug(fs_info, "run_one_delayed_ref returned %d",
+ ret);
+ return ret;
+ }
+
+ btrfs_put_delayed_ref(ref);
+ cond_resched();
+
+ spin_lock(&locked_ref->lock);
+ btrfs_merge_delayed_refs(trans, delayed_refs, locked_ref);
+ }
+
+ return 0;
+}
+
+/*
+ * Returns 0 on success or if called with an already aborted transaction.
+ * Returns -ENOMEM or -EIO on failure and will abort the transaction.
+ */
+static noinline int __btrfs_run_delayed_refs(struct btrfs_trans_handle *trans,
+ unsigned long nr)
+{
+ struct btrfs_fs_info *fs_info = trans->fs_info;
+ struct btrfs_delayed_ref_root *delayed_refs;
+ struct btrfs_delayed_ref_head *locked_ref = NULL;
+ ktime_t start = ktime_get();
+ int ret;
+ unsigned long count = 0;
+ unsigned long actual_count = 0;
+
+ delayed_refs = &trans->transaction->delayed_refs;
+ do {
+ if (!locked_ref) {
+ locked_ref = btrfs_obtain_ref_head(trans);
+ if (IS_ERR_OR_NULL(locked_ref)) {
+ if (PTR_ERR(locked_ref) == -EAGAIN) {
+ continue;
+ } else {
+ break;
+ }
+ }
+ count++;
+ }
+ /*
+ * We need to try and merge add/drops of the same ref since we
+ * can run into issues with relocate dropping the implicit ref
+ * and then it being added back again before the drop can
+ * finish. If we merged anything we need to re-loop so we can
+ * get a good ref.
+ * Or we can get node references of the same type that weren't
+ * merged when created due to bumps in the tree mod seq, and
+ * we need to merge them to prevent adding an inline extent
+ * backref before dropping it (triggering a BUG_ON at
+ * insert_inline_extent_backref()).
+ */
+ spin_lock(&locked_ref->lock);
+ btrfs_merge_delayed_refs(trans, delayed_refs, locked_ref);
+
+ ret = btrfs_run_delayed_refs_for_head(trans, locked_ref,
+ &actual_count);
+ if (ret < 0 && ret != -EAGAIN) {
+ /*
+ * Error, btrfs_run_delayed_refs_for_head already
+ * unlocked everything so just bail out
+ */
+ return ret;
+ } else if (!ret) {
+ /*
+ * Success, perform the usual cleanup of a processed
+ * head
+ */
+ ret = cleanup_ref_head(trans, locked_ref);
+ if (ret > 0 ) {
+ /* We dropped our lock, we need to loop. */
+ ret = 0;
+ continue;
+ } else if (ret) {
+ return ret;
+ }
+ }
+
+ /*
+ * Either success case or btrfs_run_delayed_refs_for_head
+ * returned -EAGAIN, meaning we need to select another head
+ */
+
+ locked_ref = NULL;
+ cond_resched();
+ } while ((nr != -1 && count < nr) || locked_ref);
+
+ /*
+ * We don't want to include ref heads since we can have empty ref heads
+ * and those will drastically skew our runtime down since we just do
+ * accounting, no actual extent tree updates.
+ */
+ if (actual_count > 0) {
+ u64 runtime = ktime_to_ns(ktime_sub(ktime_get(), start));
+ u64 avg;
+
+ /*
+ * We weigh the current average higher than our current runtime
+ * to avoid large swings in the average.
+ */
+ spin_lock(&delayed_refs->lock);
+ avg = fs_info->avg_delayed_ref_runtime * 3 + runtime;
+ fs_info->avg_delayed_ref_runtime = avg >> 2; /* div by 4 */
+ spin_unlock(&delayed_refs->lock);
+ }
+ return 0;
+}
+
+#ifdef SCRAMBLE_DELAYED_REFS
+/*
+ * Normally delayed refs get processed in ascending bytenr order. This
+ * correlates in most cases to the order added. To expose dependencies on this
+ * order, we start to process the tree in the middle instead of the beginning
+ */
+static u64 find_middle(struct rb_root *root)
+{
+ struct rb_node *n = root->rb_node;
+ struct btrfs_delayed_ref_node *entry;
+ int alt = 1;
+ u64 middle;
+ u64 first = 0, last = 0;
+
+ n = rb_first(root);
+ if (n) {
+ entry = rb_entry(n, struct btrfs_delayed_ref_node, rb_node);
+ first = entry->bytenr;
+ }
+ n = rb_last(root);
+ if (n) {
+ entry = rb_entry(n, struct btrfs_delayed_ref_node, rb_node);
+ last = entry->bytenr;
+ }
+ n = root->rb_node;
+
+ while (n) {
+ entry = rb_entry(n, struct btrfs_delayed_ref_node, rb_node);
+ WARN_ON(!entry->in_tree);
+
+ middle = entry->bytenr;
+
+ if (alt)
+ n = n->rb_left;
+ else
+ n = n->rb_right;
+
+ alt = 1 - alt;
+ }
+ return middle;
+}
+#endif
+
+static inline u64 heads_to_leaves(struct btrfs_fs_info *fs_info, u64 heads)
+{
+ u64 num_bytes;
+
+ num_bytes = heads * (sizeof(struct btrfs_extent_item) +
+ sizeof(struct btrfs_extent_inline_ref));
+ if (!btrfs_fs_incompat(fs_info, SKINNY_METADATA))
+ num_bytes += heads * sizeof(struct btrfs_tree_block_info);
+
+ /*
+ * We don't ever fill up leaves all the way so multiply by 2 just to be
+ * closer to what we're really going to want to use.
+ */
+ return div_u64(num_bytes, BTRFS_LEAF_DATA_SIZE(fs_info));
+}
+
+/*
+ * Takes the number of bytes to be csumm'ed and figures out how many leaves it
+ * would require to store the csums for that many bytes.
+ */
+u64 btrfs_csum_bytes_to_leaves(struct btrfs_fs_info *fs_info, u64 csum_bytes)
+{
+ u64 csum_size;
+ u64 num_csums_per_leaf;
+ u64 num_csums;
+
+ csum_size = BTRFS_MAX_ITEM_SIZE(fs_info);
+ num_csums_per_leaf = div64_u64(csum_size,
+ (u64)btrfs_super_csum_size(fs_info->super_copy));
+ num_csums = div64_u64(csum_bytes, fs_info->sectorsize);
+ num_csums += num_csums_per_leaf - 1;
+ num_csums = div64_u64(num_csums, num_csums_per_leaf);
+ return num_csums;
+}
+
+/*
+ * this starts processing the delayed reference count updates and
+ * extent insertions we have queued up so far. count can be
+ * 0, which means to process everything in the tree at the start
+ * of the run (but not newly added entries), or it can be some target
+ * number you'd like to process.
+ *
+ * Returns 0 on success or if called with an aborted transaction
+ * Returns <0 on error and aborts the transaction
+ */
+int btrfs_run_delayed_refs(struct btrfs_trans_handle *trans,
+ unsigned long count)
+{
+ struct btrfs_fs_info *fs_info = trans->fs_info;
+ struct rb_node *node;
+ struct btrfs_delayed_ref_root *delayed_refs;
+ struct btrfs_delayed_ref_head *head;
+ int ret;
+ int run_all = count == (unsigned long)-1;
+
+ /* We'll clean this up in btrfs_cleanup_transaction */
+ if (TRANS_ABORTED(trans))
+ return 0;
+
+ if (test_bit(BTRFS_FS_CREATING_FREE_SPACE_TREE, &fs_info->flags))
+ return 0;
+
+ delayed_refs = &trans->transaction->delayed_refs;
+ if (count == 0)
+ count = atomic_read(&delayed_refs->num_entries) * 2;
+
+again:
+#ifdef SCRAMBLE_DELAYED_REFS
+ delayed_refs->run_delayed_start = find_middle(&delayed_refs->root);
+#endif
+ ret = __btrfs_run_delayed_refs(trans, count);
+ if (ret < 0) {
+ btrfs_abort_transaction(trans, ret);
+ return ret;
+ }
+
+ if (run_all) {
+ btrfs_create_pending_block_groups(trans);
+
+ spin_lock(&delayed_refs->lock);
+ node = rb_first_cached(&delayed_refs->href_root);
+ if (!node) {
+ spin_unlock(&delayed_refs->lock);
+ goto out;
+ }
+ head = rb_entry(node, struct btrfs_delayed_ref_head,
+ href_node);
+ refcount_inc(&head->refs);
+ spin_unlock(&delayed_refs->lock);
+
+ /* Mutex was contended, block until it's released and retry. */
+ mutex_lock(&head->mutex);
+ mutex_unlock(&head->mutex);
+
+ btrfs_put_delayed_ref_head(head);
+ cond_resched();
+ goto again;
+ }
+out:
+ return 0;
+}
+
+int btrfs_set_disk_extent_flags(struct btrfs_trans_handle *trans,
+ u64 bytenr, u64 num_bytes, u64 flags,
+ int level, int is_data)
+{
+ struct btrfs_delayed_extent_op *extent_op;
+ int ret;
+
+ extent_op = btrfs_alloc_delayed_extent_op();
+ if (!extent_op)
+ return -ENOMEM;
+
+ extent_op->flags_to_set = flags;
+ extent_op->update_flags = true;
+ extent_op->update_key = false;
+ extent_op->is_data = is_data ? true : false;
+ extent_op->level = level;
+
+ ret = btrfs_add_delayed_extent_op(trans, bytenr, num_bytes, extent_op);
+ if (ret)
+ btrfs_free_delayed_extent_op(extent_op);
+ return ret;
+}
+
+static noinline int check_delayed_ref(struct btrfs_root *root,
+ struct btrfs_path *path,
+ u64 objectid, u64 offset, u64 bytenr)
+{
+ struct btrfs_delayed_ref_head *head;
+ struct btrfs_delayed_ref_node *ref;
+ struct btrfs_delayed_data_ref *data_ref;
+ struct btrfs_delayed_ref_root *delayed_refs;
+ struct btrfs_transaction *cur_trans;
+ struct rb_node *node;
+ int ret = 0;
+
+ spin_lock(&root->fs_info->trans_lock);
+ cur_trans = root->fs_info->running_transaction;
+ if (cur_trans)
+ refcount_inc(&cur_trans->use_count);
+ spin_unlock(&root->fs_info->trans_lock);
+ if (!cur_trans)
+ return 0;
+
+ delayed_refs = &cur_trans->delayed_refs;
+ spin_lock(&delayed_refs->lock);
+ head = btrfs_find_delayed_ref_head(delayed_refs, bytenr);
+ if (!head) {
+ spin_unlock(&delayed_refs->lock);
+ btrfs_put_transaction(cur_trans);
+ return 0;
+ }
+
+ if (!mutex_trylock(&head->mutex)) {
+ refcount_inc(&head->refs);
+ spin_unlock(&delayed_refs->lock);
+
+ btrfs_release_path(path);
+
+ /*
+ * Mutex was contended, block until it's released and let
+ * caller try again
+ */
+ mutex_lock(&head->mutex);
+ mutex_unlock(&head->mutex);
+ btrfs_put_delayed_ref_head(head);
+ btrfs_put_transaction(cur_trans);
+ return -EAGAIN;
+ }
+ spin_unlock(&delayed_refs->lock);
+
+ spin_lock(&head->lock);
+ /*
+ * XXX: We should replace this with a proper search function in the
+ * future.
+ */
+ for (node = rb_first_cached(&head->ref_tree); node;
+ node = rb_next(node)) {
+ ref = rb_entry(node, struct btrfs_delayed_ref_node, ref_node);
+ /* If it's a shared ref we know a cross reference exists */
+ if (ref->type != BTRFS_EXTENT_DATA_REF_KEY) {
+ ret = 1;
+ break;
+ }
+
+ data_ref = btrfs_delayed_node_to_data_ref(ref);
+
+ /*
+ * If our ref doesn't match the one we're currently looking at
+ * then we have a cross reference.
+ */
+ if (data_ref->root != root->root_key.objectid ||
+ data_ref->objectid != objectid ||
+ data_ref->offset != offset) {
+ ret = 1;
+ break;
+ }
+ }
+ spin_unlock(&head->lock);
+ mutex_unlock(&head->mutex);
+ btrfs_put_transaction(cur_trans);
+ return ret;
+}
+
+static noinline int check_committed_ref(struct btrfs_root *root,
+ struct btrfs_path *path,
+ u64 objectid, u64 offset, u64 bytenr,
+ bool strict)
+{
+ struct btrfs_fs_info *fs_info = root->fs_info;
+ struct btrfs_root *extent_root = fs_info->extent_root;
+ struct extent_buffer *leaf;
+ struct btrfs_extent_data_ref *ref;
+ struct btrfs_extent_inline_ref *iref;
+ struct btrfs_extent_item *ei;
+ struct btrfs_key key;
+ u32 item_size;
+ int type;
+ int ret;
+
+ key.objectid = bytenr;
+ key.offset = (u64)-1;
+ key.type = BTRFS_EXTENT_ITEM_KEY;
+
+ ret = btrfs_search_slot(NULL, extent_root, &key, path, 0, 0);
+ if (ret < 0)
+ goto out;
+ BUG_ON(ret == 0); /* Corruption */
+
+ ret = -ENOENT;
+ if (path->slots[0] == 0)
+ goto out;
+
+ path->slots[0]--;
+ leaf = path->nodes[0];
+ btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
+
+ if (key.objectid != bytenr || key.type != BTRFS_EXTENT_ITEM_KEY)
+ goto out;
+
+ ret = 1;
+ item_size = btrfs_item_size_nr(leaf, path->slots[0]);
+ ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
+
+ /* If extent item has more than 1 inline ref then it's shared */
+ if (item_size != sizeof(*ei) +
+ btrfs_extent_inline_ref_size(BTRFS_EXTENT_DATA_REF_KEY))
+ goto out;
+
+ /*
+ * If extent created before last snapshot => it's shared unless the
+ * snapshot has been deleted. Use the heuristic if strict is false.
+ */
+ if (!strict &&
+ (btrfs_extent_generation(leaf, ei) <=
+ btrfs_root_last_snapshot(&root->root_item)))
+ goto out;
+
+ iref = (struct btrfs_extent_inline_ref *)(ei + 1);
+
+ /* If this extent has SHARED_DATA_REF then it's shared */
+ type = btrfs_get_extent_inline_ref_type(leaf, iref, BTRFS_REF_TYPE_DATA);
+ if (type != BTRFS_EXTENT_DATA_REF_KEY)
+ goto out;
+
+ ref = (struct btrfs_extent_data_ref *)(&iref->offset);
+ if (btrfs_extent_refs(leaf, ei) !=
+ btrfs_extent_data_ref_count(leaf, ref) ||
+ btrfs_extent_data_ref_root(leaf, ref) !=
+ root->root_key.objectid ||
+ btrfs_extent_data_ref_objectid(leaf, ref) != objectid ||
+ btrfs_extent_data_ref_offset(leaf, ref) != offset)
+ goto out;
+
+ ret = 0;
+out:
+ return ret;
+}
+
+int btrfs_cross_ref_exist(struct btrfs_root *root, u64 objectid, u64 offset,
+ u64 bytenr, bool strict)
+{
+ struct btrfs_path *path;
+ int ret;
+
+ path = btrfs_alloc_path();
+ if (!path)
+ return -ENOMEM;
+
+ do {
+ ret = check_committed_ref(root, path, objectid,
+ offset, bytenr, strict);
+ if (ret && ret != -ENOENT)
+ goto out;
+
+ ret = check_delayed_ref(root, path, objectid, offset, bytenr);
+ } while (ret == -EAGAIN);
+
+out:
+ btrfs_free_path(path);
+ if (root->root_key.objectid == BTRFS_DATA_RELOC_TREE_OBJECTID)
+ WARN_ON(ret > 0);
+ return ret;
+}
+
+static int __btrfs_mod_ref(struct btrfs_trans_handle *trans,
+ struct btrfs_root *root,
+ struct extent_buffer *buf,
+ int full_backref, int inc)
+{
+ struct btrfs_fs_info *fs_info = root->fs_info;
+ u64 bytenr;
+ u64 num_bytes;
+ u64 parent;
+ u64 ref_root;
+ u32 nritems;
+ struct btrfs_key key;
+ struct btrfs_file_extent_item *fi;
+ struct btrfs_ref generic_ref = { 0 };
+ bool for_reloc = btrfs_header_flag(buf, BTRFS_HEADER_FLAG_RELOC);
+ int i;
+ int action;
+ int level;
+ int ret = 0;
+
+ if (btrfs_is_testing(fs_info))
+ return 0;
+
+ ref_root = btrfs_header_owner(buf);
+ nritems = btrfs_header_nritems(buf);
+ level = btrfs_header_level(buf);
+
+ if (!test_bit(BTRFS_ROOT_REF_COWS, &root->state) && level == 0)
+ return 0;
+
+ if (full_backref)
+ parent = buf->start;
+ else
+ parent = 0;
+ if (inc)
+ action = BTRFS_ADD_DELAYED_REF;
+ else
+ action = BTRFS_DROP_DELAYED_REF;
+
+ for (i = 0; i < nritems; i++) {
+ if (level == 0) {
+ btrfs_item_key_to_cpu(buf, &key, i);
+ if (key.type != BTRFS_EXTENT_DATA_KEY)
+ continue;
+ fi = btrfs_item_ptr(buf, i,
+ struct btrfs_file_extent_item);
+ if (btrfs_file_extent_type(buf, fi) ==
+ BTRFS_FILE_EXTENT_INLINE)
+ continue;
+ bytenr = btrfs_file_extent_disk_bytenr(buf, fi);
+ if (bytenr == 0)
+ continue;
+
+ num_bytes = btrfs_file_extent_disk_num_bytes(buf, fi);
+ key.offset -= btrfs_file_extent_offset(buf, fi);
+ btrfs_init_generic_ref(&generic_ref, action, bytenr,
+ num_bytes, parent);
+ generic_ref.real_root = root->root_key.objectid;
+ btrfs_init_data_ref(&generic_ref, ref_root, key.objectid,
+ key.offset);
+ generic_ref.skip_qgroup = for_reloc;
+ if (inc)
+ ret = btrfs_inc_extent_ref(trans, &generic_ref);
+ else
+ ret = btrfs_free_extent(trans, &generic_ref);
+ if (ret)
+ goto fail;
+ } else {
+ bytenr = btrfs_node_blockptr(buf, i);
+ num_bytes = fs_info->nodesize;
+ btrfs_init_generic_ref(&generic_ref, action, bytenr,
+ num_bytes, parent);
+ generic_ref.real_root = root->root_key.objectid;
+ btrfs_init_tree_ref(&generic_ref, level - 1, ref_root);
+ generic_ref.skip_qgroup = for_reloc;
+ if (inc)
+ ret = btrfs_inc_extent_ref(trans, &generic_ref);
+ else
+ ret = btrfs_free_extent(trans, &generic_ref);
+ if (ret)
+ goto fail;
+ }
+ }
+ return 0;
+fail:
+ return ret;
+}
+
+int btrfs_inc_ref(struct btrfs_trans_handle *trans, struct btrfs_root *root,
+ struct extent_buffer *buf, int full_backref)
+{
+ return __btrfs_mod_ref(trans, root, buf, full_backref, 1);
+}
+
+int btrfs_dec_ref(struct btrfs_trans_handle *trans, struct btrfs_root *root,
+ struct extent_buffer *buf, int full_backref)
+{
+ return __btrfs_mod_ref(trans, root, buf, full_backref, 0);
+}
+
+int btrfs_extent_readonly(struct btrfs_fs_info *fs_info, u64 bytenr)
+{
+ struct btrfs_block_group_cache *block_group;
+ int readonly = 0;
+
+ block_group = btrfs_lookup_block_group(fs_info, bytenr);
+ if (!block_group || block_group->ro)
+ readonly = 1;
+ if (block_group)
+ btrfs_put_block_group(block_group);
+ return readonly;
+}
+
+static u64 get_alloc_profile_by_root(struct btrfs_root *root, int data)
+{
+ struct btrfs_fs_info *fs_info = root->fs_info;
+ u64 flags;
+ u64 ret;
+
+ if (data)
+ flags = BTRFS_BLOCK_GROUP_DATA;
+ else if (root == fs_info->chunk_root)
+ flags = BTRFS_BLOCK_GROUP_SYSTEM;
+ else
+ flags = BTRFS_BLOCK_GROUP_METADATA;
+
+ ret = btrfs_get_alloc_profile(fs_info, flags);
+ return ret;
+}
+
+static u64 first_logical_byte(struct btrfs_fs_info *fs_info, u64 search_start)
+{
+ struct btrfs_block_group_cache *cache;
+ u64 bytenr;
+
+ spin_lock(&fs_info->block_group_cache_lock);
+ bytenr = fs_info->first_logical_byte;
+ spin_unlock(&fs_info->block_group_cache_lock);
+
+ if (bytenr < (u64)-1)
+ return bytenr;
+
+ cache = btrfs_lookup_first_block_group(fs_info, search_start);
+ if (!cache)
+ return 0;
+
+ bytenr = cache->key.objectid;
+ btrfs_put_block_group(cache);
+
+ return bytenr;
+}
+
+static int pin_down_extent(struct btrfs_block_group_cache *cache,
+ u64 bytenr, u64 num_bytes, int reserved)
+{
+ struct btrfs_fs_info *fs_info = cache->fs_info;
+
+ spin_lock(&cache->space_info->lock);
+ spin_lock(&cache->lock);
+ cache->pinned += num_bytes;
+ btrfs_space_info_update_bytes_pinned(fs_info, cache->space_info,
+ num_bytes);
+ if (reserved) {
+ cache->reserved -= num_bytes;
+ cache->space_info->bytes_reserved -= num_bytes;
+ }
+ spin_unlock(&cache->lock);
+ spin_unlock(&cache->space_info->lock);
+
+ percpu_counter_add_batch(&cache->space_info->total_bytes_pinned,
+ num_bytes, BTRFS_TOTAL_BYTES_PINNED_BATCH);
+ set_extent_dirty(fs_info->pinned_extents, bytenr,
+ bytenr + num_bytes - 1, GFP_NOFS | __GFP_NOFAIL);
+ return 0;
+}
+
+/*
+ * this function must be called within transaction
+ */
+int btrfs_pin_extent(struct btrfs_fs_info *fs_info,
+ u64 bytenr, u64 num_bytes, int reserved)
+{
+ struct btrfs_block_group_cache *cache;
+
+ cache = btrfs_lookup_block_group(fs_info, bytenr);
+ BUG_ON(!cache); /* Logic error */
+
+ pin_down_extent(cache, bytenr, num_bytes, reserved);
+
+ btrfs_put_block_group(cache);
+ return 0;
+}
+
+/*
+ * this function must be called within transaction
+ */
+int btrfs_pin_extent_for_log_replay(struct btrfs_fs_info *fs_info,
+ u64 bytenr, u64 num_bytes)
+{
+ struct btrfs_block_group_cache *cache;
+ int ret;
+
+ cache = btrfs_lookup_block_group(fs_info, bytenr);
+ if (!cache)
+ return -EINVAL;
+
+ /*
+ * pull in the free space cache (if any) so that our pin
+ * removes the free space from the cache. We have load_only set
+ * to one because the slow code to read in the free extents does check
+ * the pinned extents.
+ */
+ btrfs_cache_block_group(cache, 1);
+
+ pin_down_extent(cache, bytenr, num_bytes, 0);
+
+ /* remove us from the free space cache (if we're there at all) */
+ ret = btrfs_remove_free_space(cache, bytenr, num_bytes);
+ btrfs_put_block_group(cache);
+ return ret;
+}
+
+static int __exclude_logged_extent(struct btrfs_fs_info *fs_info,
+ u64 start, u64 num_bytes)
+{
+ int ret;
+ struct btrfs_block_group_cache *block_group;
+ struct btrfs_caching_control *caching_ctl;
+
+ block_group = btrfs_lookup_block_group(fs_info, start);
+ if (!block_group)
+ return -EINVAL;
+
+ btrfs_cache_block_group(block_group, 0);
+ caching_ctl = btrfs_get_caching_control(block_group);
+
+ if (!caching_ctl) {
+ /* Logic error */
+ BUG_ON(!btrfs_block_group_cache_done(block_group));
+ ret = btrfs_remove_free_space(block_group, start, num_bytes);
+ } else {
+ mutex_lock(&caching_ctl->mutex);
+
+ if (start >= caching_ctl->progress) {
+ ret = btrfs_add_excluded_extent(fs_info, start,
+ num_bytes);
+ } else if (start + num_bytes <= caching_ctl->progress) {
+ ret = btrfs_remove_free_space(block_group,
+ start, num_bytes);
+ } else {
+ num_bytes = caching_ctl->progress - start;
+ ret = btrfs_remove_free_space(block_group,
+ start, num_bytes);
+ if (ret)
+ goto out_lock;
+
+ num_bytes = (start + num_bytes) -
+ caching_ctl->progress;
+ start = caching_ctl->progress;
+ ret = btrfs_add_excluded_extent(fs_info, start,
+ num_bytes);
+ }
+out_lock:
+ mutex_unlock(&caching_ctl->mutex);
+ btrfs_put_caching_control(caching_ctl);
+ }
+ btrfs_put_block_group(block_group);
+ return ret;
+}
+
+int btrfs_exclude_logged_extents(struct extent_buffer *eb)
+{
+ struct btrfs_fs_info *fs_info = eb->fs_info;
+ struct btrfs_file_extent_item *item;
+ struct btrfs_key key;
+ int found_type;
+ int i;
+ int ret = 0;
+
+ if (!btrfs_fs_incompat(fs_info, MIXED_GROUPS))
+ return 0;
+
+ for (i = 0; i < btrfs_header_nritems(eb); i++) {
+ btrfs_item_key_to_cpu(eb, &key, i);
+ if (key.type != BTRFS_EXTENT_DATA_KEY)
+ continue;
+ item = btrfs_item_ptr(eb, i, struct btrfs_file_extent_item);
+ found_type = btrfs_file_extent_type(eb, item);
+ if (found_type == BTRFS_FILE_EXTENT_INLINE)
+ continue;
+ if (btrfs_file_extent_disk_bytenr(eb, item) == 0)
+ continue;
+ key.objectid = btrfs_file_extent_disk_bytenr(eb, item);
+ key.offset = btrfs_file_extent_disk_num_bytes(eb, item);
+ ret = __exclude_logged_extent(fs_info, key.objectid, key.offset);
+ if (ret)
+ break;
+ }
+
+ return ret;
+}
+
+static void
+btrfs_inc_block_group_reservations(struct btrfs_block_group_cache *bg)
+{
+ atomic_inc(&bg->reservations);
+}
+
+void btrfs_prepare_extent_commit(struct btrfs_fs_info *fs_info)
+{
+ struct btrfs_caching_control *next;
+ struct btrfs_caching_control *caching_ctl;
+ struct btrfs_block_group_cache *cache;
+
+ down_write(&fs_info->commit_root_sem);
+
+ list_for_each_entry_safe(caching_ctl, next,
+ &fs_info->caching_block_groups, list) {
+ cache = caching_ctl->block_group;
+ if (btrfs_block_group_cache_done(cache)) {
+ cache->last_byte_to_unpin = (u64)-1;
+ list_del_init(&caching_ctl->list);
+ btrfs_put_caching_control(caching_ctl);
+ } else {
+ cache->last_byte_to_unpin = caching_ctl->progress;
+ }
+ }
+
+ if (fs_info->pinned_extents == &fs_info->freed_extents[0])
+ fs_info->pinned_extents = &fs_info->freed_extents[1];
+ else
+ fs_info->pinned_extents = &fs_info->freed_extents[0];
+
+ up_write(&fs_info->commit_root_sem);
+
+ btrfs_update_global_block_rsv(fs_info);
+}
+
+/*
+ * Returns the free cluster for the given space info and sets empty_cluster to
+ * what it should be based on the mount options.
+ */
+static struct btrfs_free_cluster *
+fetch_cluster_info(struct btrfs_fs_info *fs_info,
+ struct btrfs_space_info *space_info, u64 *empty_cluster)
+{
+ struct btrfs_free_cluster *ret = NULL;
+
+ *empty_cluster = 0;
+ if (btrfs_mixed_space_info(space_info))
+ return ret;
+
+ if (space_info->flags & BTRFS_BLOCK_GROUP_METADATA) {
+ ret = &fs_info->meta_alloc_cluster;
+ if (btrfs_test_opt(fs_info, SSD))
+ *empty_cluster = SZ_2M;
+ else
+ *empty_cluster = SZ_64K;
+ } else if ((space_info->flags & BTRFS_BLOCK_GROUP_DATA) &&
+ btrfs_test_opt(fs_info, SSD_SPREAD)) {
+ *empty_cluster = SZ_2M;
+ ret = &fs_info->data_alloc_cluster;
+ }
+
+ return ret;
+}
+
+static int unpin_extent_range(struct btrfs_fs_info *fs_info,
+ u64 start, u64 end,
+ const bool return_free_space)
+{
+ struct btrfs_block_group_cache *cache = NULL;
+ struct btrfs_space_info *space_info;
+ struct btrfs_block_rsv *global_rsv = &fs_info->global_block_rsv;
+ struct btrfs_free_cluster *cluster = NULL;
+ u64 len;
+ u64 total_unpinned = 0;
+ u64 empty_cluster = 0;
+ bool readonly;
+
+ while (start <= end) {
+ readonly = false;
+ if (!cache ||
+ start >= cache->key.objectid + cache->key.offset) {
+ if (cache)
+ btrfs_put_block_group(cache);
+ total_unpinned = 0;
+ cache = btrfs_lookup_block_group(fs_info, start);
+ BUG_ON(!cache); /* Logic error */
+
+ cluster = fetch_cluster_info(fs_info,
+ cache->space_info,
+ &empty_cluster);
+ empty_cluster <<= 1;
+ }
+
+ len = cache->key.objectid + cache->key.offset - start;
+ len = min(len, end + 1 - start);
+
+ if (start < cache->last_byte_to_unpin && return_free_space) {
+ u64 add_len = min(len, cache->last_byte_to_unpin - start);
+
+ btrfs_add_free_space(cache, start, add_len);
+ }
+
+ start += len;
+ total_unpinned += len;
+ space_info = cache->space_info;
+
+ /*
+ * If this space cluster has been marked as fragmented and we've
+ * unpinned enough in this block group to potentially allow a
+ * cluster to be created inside of it go ahead and clear the
+ * fragmented check.
+ */
+ if (cluster && cluster->fragmented &&
+ total_unpinned > empty_cluster) {
+ spin_lock(&cluster->lock);
+ cluster->fragmented = 0;
+ spin_unlock(&cluster->lock);
+ }
+
+ spin_lock(&space_info->lock);
+ spin_lock(&cache->lock);
+ cache->pinned -= len;
+ btrfs_space_info_update_bytes_pinned(fs_info, space_info, -len);
+ space_info->max_extent_size = 0;
+ percpu_counter_add_batch(&space_info->total_bytes_pinned,
+ -len, BTRFS_TOTAL_BYTES_PINNED_BATCH);
+ if (cache->ro) {
+ space_info->bytes_readonly += len;
+ readonly = true;
+ }
+ spin_unlock(&cache->lock);
+ if (!readonly && return_free_space &&
+ global_rsv->space_info == space_info) {
+ u64 to_add = len;
+
+ spin_lock(&global_rsv->lock);
+ if (!global_rsv->full) {
+ to_add = min(len, global_rsv->size -
+ global_rsv->reserved);
+ global_rsv->reserved += to_add;
+ btrfs_space_info_update_bytes_may_use(fs_info,
+ space_info, to_add);
+ if (global_rsv->reserved >= global_rsv->size)
+ global_rsv->full = 1;
+ len -= to_add;
+ }
+ spin_unlock(&global_rsv->lock);
+ /* Add to any tickets we may have */
+ if (len)
+ btrfs_try_granting_tickets(fs_info,
+ space_info);
+ }
+ spin_unlock(&space_info->lock);
+ }
+
+ if (cache)
+ btrfs_put_block_group(cache);
+ return 0;
+}
+
+int btrfs_finish_extent_commit(struct btrfs_trans_handle *trans)
+{
+ struct btrfs_fs_info *fs_info = trans->fs_info;
+ struct btrfs_block_group_cache *block_group, *tmp;
+ struct list_head *deleted_bgs;
+ struct extent_io_tree *unpin;
+ u64 start;
+ u64 end;
+ int ret;
+
+ if (fs_info->pinned_extents == &fs_info->freed_extents[0])
+ unpin = &fs_info->freed_extents[1];
+ else
+ unpin = &fs_info->freed_extents[0];
+
+ while (!TRANS_ABORTED(trans)) {
+ struct extent_state *cached_state = NULL;
+
+ mutex_lock(&fs_info->unused_bg_unpin_mutex);
+ ret = find_first_extent_bit(unpin, 0, &start, &end,
+ EXTENT_DIRTY, &cached_state);
+ if (ret) {
+ mutex_unlock(&fs_info->unused_bg_unpin_mutex);
+ break;
+ }
+
+ if (btrfs_test_opt(fs_info, DISCARD))
+ ret = btrfs_discard_extent(fs_info, start,
+ end + 1 - start, NULL);
+
+ clear_extent_dirty(unpin, start, end, &cached_state);
+ unpin_extent_range(fs_info, start, end, true);
+ mutex_unlock(&fs_info->unused_bg_unpin_mutex);
+ free_extent_state(cached_state);
+ cond_resched();
+ }
+
+ /*
+ * Transaction is finished. We don't need the lock anymore. We
+ * do need to clean up the block groups in case of a transaction
+ * abort.
+ */
+ deleted_bgs = &trans->transaction->deleted_bgs;
+ list_for_each_entry_safe(block_group, tmp, deleted_bgs, bg_list) {
+ u64 trimmed = 0;
+
+ ret = -EROFS;
+ if (!TRANS_ABORTED(trans))
+ ret = btrfs_discard_extent(fs_info,
+ block_group->key.objectid,
+ block_group->key.offset,
+ &trimmed);
+
+ list_del_init(&block_group->bg_list);
+ btrfs_put_block_group_trimming(block_group);
+ btrfs_put_block_group(block_group);
+
+ if (ret) {
+ const char *errstr = btrfs_decode_error(ret);
+ btrfs_warn(fs_info,
+ "discard failed while removing blockgroup: errno=%d %s",
+ ret, errstr);
+ }
+ }
+
+ return 0;
+}
+
+static int __btrfs_free_extent(struct btrfs_trans_handle *trans,
+ struct btrfs_delayed_ref_node *node, u64 parent,
+ u64 root_objectid, u64 owner_objectid,
+ u64 owner_offset, int refs_to_drop,
+ struct btrfs_delayed_extent_op *extent_op)
+{
+ struct btrfs_fs_info *info = trans->fs_info;
+ struct btrfs_key key;
+ struct btrfs_path *path;
+ struct btrfs_root *extent_root = info->extent_root;
+ struct extent_buffer *leaf;
+ struct btrfs_extent_item *ei;
+ struct btrfs_extent_inline_ref *iref;
+ int ret;
+ int is_data;
+ int extent_slot = 0;
+ int found_extent = 0;
+ int num_to_del = 1;
+ u32 item_size;
+ u64 refs;
+ u64 bytenr = node->bytenr;
+ u64 num_bytes = node->num_bytes;
+ int last_ref = 0;
+ bool skinny_metadata = btrfs_fs_incompat(info, SKINNY_METADATA);
+
+ path = btrfs_alloc_path();
+ if (!path)
+ return -ENOMEM;
+
+ path->reada = READA_FORWARD;
+ path->leave_spinning = 1;
+
+ is_data = owner_objectid >= BTRFS_FIRST_FREE_OBJECTID;
+ BUG_ON(!is_data && refs_to_drop != 1);
+
+ if (is_data)
+ skinny_metadata = false;
+
+ ret = lookup_extent_backref(trans, path, &iref, bytenr, num_bytes,
+ parent, root_objectid, owner_objectid,
+ owner_offset);
+ if (ret == 0) {
+ extent_slot = path->slots[0];
+ while (extent_slot >= 0) {
+ btrfs_item_key_to_cpu(path->nodes[0], &key,
+ extent_slot);
+ if (key.objectid != bytenr)
+ break;
+ if (key.type == BTRFS_EXTENT_ITEM_KEY &&
+ key.offset == num_bytes) {
+ found_extent = 1;
+ break;
+ }
+ if (key.type == BTRFS_METADATA_ITEM_KEY &&
+ key.offset == owner_objectid) {
+ found_extent = 1;
+ break;
+ }
+ if (path->slots[0] - extent_slot > 5)
+ break;
+ extent_slot--;
+ }
+
+ if (!found_extent) {
+ BUG_ON(iref);
+ ret = remove_extent_backref(trans, path, NULL,
+ refs_to_drop,
+ is_data, &last_ref);
+ if (ret) {
+ btrfs_abort_transaction(trans, ret);
+ goto out;
+ }
+ btrfs_release_path(path);
+ path->leave_spinning = 1;
+
+ key.objectid = bytenr;
+ key.type = BTRFS_EXTENT_ITEM_KEY;
+ key.offset = num_bytes;
+
+ if (!is_data && skinny_metadata) {
+ key.type = BTRFS_METADATA_ITEM_KEY;
+ key.offset = owner_objectid;
+ }
+
+ ret = btrfs_search_slot(trans, extent_root,
+ &key, path, -1, 1);
+ if (ret > 0 && skinny_metadata && path->slots[0]) {
+ /*
+ * Couldn't find our skinny metadata item,
+ * see if we have ye olde extent item.
+ */
+ path->slots[0]--;
+ btrfs_item_key_to_cpu(path->nodes[0], &key,
+ path->slots[0]);
+ if (key.objectid == bytenr &&
+ key.type == BTRFS_EXTENT_ITEM_KEY &&
+ key.offset == num_bytes)
+ ret = 0;
+ }
+
+ if (ret > 0 && skinny_metadata) {
+ skinny_metadata = false;
+ key.objectid = bytenr;
+ key.type = BTRFS_EXTENT_ITEM_KEY;
+ key.offset = num_bytes;
+ btrfs_release_path(path);
+ ret = btrfs_search_slot(trans, extent_root,
+ &key, path, -1, 1);
+ }
+
+ if (ret) {
+ btrfs_err(info,
+ "umm, got %d back from search, was looking for %llu",
+ ret, bytenr);
+ if (ret > 0)
+ btrfs_print_leaf(path->nodes[0]);
+ }
+ if (ret < 0) {
+ btrfs_abort_transaction(trans, ret);
+ goto out;
+ }
+ extent_slot = path->slots[0];
+ }
+ } else if (WARN_ON(ret == -ENOENT)) {
+ btrfs_print_leaf(path->nodes[0]);
+ btrfs_err(info,
+ "unable to find ref byte nr %llu parent %llu root %llu owner %llu offset %llu",
+ bytenr, parent, root_objectid, owner_objectid,
+ owner_offset);
+ btrfs_abort_transaction(trans, ret);
+ goto out;
+ } else {
+ btrfs_abort_transaction(trans, ret);
+ goto out;
+ }
+
+ leaf = path->nodes[0];
+ item_size = btrfs_item_size_nr(leaf, extent_slot);
+ if (unlikely(item_size < sizeof(*ei))) {
+ ret = -EINVAL;
+ btrfs_print_v0_err(info);
+ btrfs_abort_transaction(trans, ret);
+ goto out;
+ }
+ ei = btrfs_item_ptr(leaf, extent_slot,
+ struct btrfs_extent_item);
+ if (owner_objectid < BTRFS_FIRST_FREE_OBJECTID &&
+ key.type == BTRFS_EXTENT_ITEM_KEY) {
+ struct btrfs_tree_block_info *bi;
+ BUG_ON(item_size < sizeof(*ei) + sizeof(*bi));
+ bi = (struct btrfs_tree_block_info *)(ei + 1);
+ WARN_ON(owner_objectid != btrfs_tree_block_level(leaf, bi));
+ }
+
+ refs = btrfs_extent_refs(leaf, ei);
+ if (refs < refs_to_drop) {
+ btrfs_err(info,
+ "trying to drop %d refs but we only have %Lu for bytenr %Lu",
+ refs_to_drop, refs, bytenr);
+ ret = -EINVAL;
+ btrfs_abort_transaction(trans, ret);
+ goto out;
+ }
+ refs -= refs_to_drop;
+
+ if (refs > 0) {
+ if (extent_op)
+ __run_delayed_extent_op(extent_op, leaf, ei);
+ /*
+ * In the case of inline back ref, reference count will
+ * be updated by remove_extent_backref
+ */
+ if (iref) {
+ BUG_ON(!found_extent);
+ } else {
+ btrfs_set_extent_refs(leaf, ei, refs);
+ btrfs_mark_buffer_dirty(leaf);
+ }
+ if (found_extent) {
+ ret = remove_extent_backref(trans, path, iref,
+ refs_to_drop, is_data,
+ &last_ref);
+ if (ret) {
+ btrfs_abort_transaction(trans, ret);
+ goto out;
+ }
+ }
+ } else {
+ if (found_extent) {
+ BUG_ON(is_data && refs_to_drop !=
+ extent_data_ref_count(path, iref));
+ if (iref) {
+ BUG_ON(path->slots[0] != extent_slot);
+ } else {
+ BUG_ON(path->slots[0] != extent_slot + 1);
+ path->slots[0] = extent_slot;
+ num_to_del = 2;
+ }
+ }
+
+ last_ref = 1;
+ ret = btrfs_del_items(trans, extent_root, path, path->slots[0],
+ num_to_del);
+ if (ret) {
+ btrfs_abort_transaction(trans, ret);
+ goto out;
+ }
+ btrfs_release_path(path);
+
+ if (is_data) {
+ ret = btrfs_del_csums(trans, info->csum_root, bytenr,
+ num_bytes);
+ if (ret) {
+ btrfs_abort_transaction(trans, ret);
+ goto out;
+ }
+ }
+
+ ret = add_to_free_space_tree(trans, bytenr, num_bytes);
+ if (ret) {
+ btrfs_abort_transaction(trans, ret);
+ goto out;
+ }
+
+ ret = btrfs_update_block_group(trans, bytenr, num_bytes, 0);
+ if (ret) {
+ btrfs_abort_transaction(trans, ret);
+ goto out;
+ }
+ }
+ btrfs_release_path(path);
+
+out:
+ btrfs_free_path(path);
+ return ret;
+}
+
+/*
+ * when we free an block, it is possible (and likely) that we free the last
+ * delayed ref for that extent as well. This searches the delayed ref tree for
+ * a given extent, and if there are no other delayed refs to be processed, it
+ * removes it from the tree.
+ */
+static noinline int check_ref_cleanup(struct btrfs_trans_handle *trans,
+ u64 bytenr)
+{
+ struct btrfs_delayed_ref_head *head;
+ struct btrfs_delayed_ref_root *delayed_refs;
+ int ret = 0;
+
+ delayed_refs = &trans->transaction->delayed_refs;
+ spin_lock(&delayed_refs->lock);
+ head = btrfs_find_delayed_ref_head(delayed_refs, bytenr);
+ if (!head)
+ goto out_delayed_unlock;
+
+ spin_lock(&head->lock);
+ if (!RB_EMPTY_ROOT(&head->ref_tree.rb_root))
+ goto out;
+
+ if (cleanup_extent_op(head) != NULL)
+ goto out;
+
+ /*
+ * waiting for the lock here would deadlock. If someone else has it
+ * locked they are already in the process of dropping it anyway
+ */
+ if (!mutex_trylock(&head->mutex))
+ goto out;
+
+ btrfs_delete_ref_head(delayed_refs, head);
+ head->processing = 0;
+
+ spin_unlock(&head->lock);
+ spin_unlock(&delayed_refs->lock);
+
+ BUG_ON(head->extent_op);
+ if (head->must_insert_reserved)
+ ret = 1;
+
+ btrfs_cleanup_ref_head_accounting(trans->fs_info, delayed_refs, head);
+ mutex_unlock(&head->mutex);
+ btrfs_put_delayed_ref_head(head);
+ return ret;
+out:
+ spin_unlock(&head->lock);
+
+out_delayed_unlock:
+ spin_unlock(&delayed_refs->lock);
+ return 0;
+}
+
+void btrfs_free_tree_block(struct btrfs_trans_handle *trans,
+ struct btrfs_root *root,
+ struct extent_buffer *buf,
+ u64 parent, int last_ref)
+{
+ struct btrfs_fs_info *fs_info = root->fs_info;
+ struct btrfs_ref generic_ref = { 0 };
+ int pin = 1;
+ int ret;
+
+ btrfs_init_generic_ref(&generic_ref, BTRFS_DROP_DELAYED_REF,
+ buf->start, buf->len, parent);
+ btrfs_init_tree_ref(&generic_ref, btrfs_header_level(buf),
+ root->root_key.objectid);
+
+ if (root->root_key.objectid != BTRFS_TREE_LOG_OBJECTID) {
+ int old_ref_mod, new_ref_mod;
+
+ btrfs_ref_tree_mod(fs_info, &generic_ref);
+ ret = btrfs_add_delayed_tree_ref(trans, &generic_ref, NULL,
+ &old_ref_mod, &new_ref_mod);
+ BUG_ON(ret); /* -ENOMEM */
+ pin = old_ref_mod >= 0 && new_ref_mod < 0;
+ }
+
+ if (last_ref && btrfs_header_generation(buf) == trans->transid) {
+ struct btrfs_block_group_cache *cache;
+
+ if (root->root_key.objectid != BTRFS_TREE_LOG_OBJECTID) {
+ ret = check_ref_cleanup(trans, buf->start);
+ if (!ret)
+ goto out;
+ }
+
+ pin = 0;
+ cache = btrfs_lookup_block_group(fs_info, buf->start);
+
+ if (btrfs_header_flag(buf, BTRFS_HEADER_FLAG_WRITTEN)) {
+ pin_down_extent(cache, buf->start, buf->len, 1);
+ btrfs_put_block_group(cache);
+ goto out;
+ }
+
+ WARN_ON(test_bit(EXTENT_BUFFER_DIRTY, &buf->bflags));
+
+ btrfs_add_free_space(cache, buf->start, buf->len);
+ btrfs_free_reserved_bytes(cache, buf->len, 0);
+ btrfs_put_block_group(cache);
+ trace_btrfs_reserved_extent_free(fs_info, buf->start, buf->len);
+ }
+out:
+ if (pin)
+ add_pinned_bytes(fs_info, &generic_ref);
+
+ if (last_ref) {
+ /*
+ * Deleting the buffer, clear the corrupt flag since it doesn't
+ * matter anymore.
+ */
+ clear_bit(EXTENT_BUFFER_CORRUPT, &buf->bflags);
+ }
+}
+
+/* Can return -ENOMEM */
+int btrfs_free_extent(struct btrfs_trans_handle *trans, struct btrfs_ref *ref)
+{
+ struct btrfs_fs_info *fs_info = trans->fs_info;
+ int old_ref_mod, new_ref_mod;
+ int ret;
+
+ if (btrfs_is_testing(fs_info))
+ return 0;
+
+ /*
+ * tree log blocks never actually go into the extent allocation
+ * tree, just update pinning info and exit early.
+ */
+ if ((ref->type == BTRFS_REF_METADATA &&
+ ref->tree_ref.root == BTRFS_TREE_LOG_OBJECTID) ||
+ (ref->type == BTRFS_REF_DATA &&
+ ref->data_ref.ref_root == BTRFS_TREE_LOG_OBJECTID)) {
+ /* unlocks the pinned mutex */
+ btrfs_pin_extent(fs_info, ref->bytenr, ref->len, 1);
+ old_ref_mod = new_ref_mod = 0;
+ ret = 0;
+ } else if (ref->type == BTRFS_REF_METADATA) {
+ ret = btrfs_add_delayed_tree_ref(trans, ref, NULL,
+ &old_ref_mod, &new_ref_mod);
+ } else {
+ ret = btrfs_add_delayed_data_ref(trans, ref, 0,
+ &old_ref_mod, &new_ref_mod);
+ }
+
+ if (!((ref->type == BTRFS_REF_METADATA &&
+ ref->tree_ref.root == BTRFS_TREE_LOG_OBJECTID) ||
+ (ref->type == BTRFS_REF_DATA &&
+ ref->data_ref.ref_root == BTRFS_TREE_LOG_OBJECTID)))
+ btrfs_ref_tree_mod(fs_info, ref);
+
+ if (ret == 0 && old_ref_mod >= 0 && new_ref_mod < 0)
+ add_pinned_bytes(fs_info, ref);
+
+ return ret;
+}
+
+enum btrfs_loop_type {
+ LOOP_CACHING_NOWAIT,
+ LOOP_CACHING_WAIT,
+ LOOP_ALLOC_CHUNK,
+ LOOP_NO_EMPTY_SIZE,
+};
+
+static inline void
+btrfs_lock_block_group(struct btrfs_block_group_cache *cache,
+ int delalloc)
+{
+ if (delalloc)
+ down_read(&cache->data_rwsem);
+}
+
+static inline void
+btrfs_grab_block_group(struct btrfs_block_group_cache *cache,
+ int delalloc)
+{
+ btrfs_get_block_group(cache);
+ if (delalloc)
+ down_read(&cache->data_rwsem);
+}
+
+static struct btrfs_block_group_cache *
+btrfs_lock_cluster(struct btrfs_block_group_cache *block_group,
+ struct btrfs_free_cluster *cluster,
+ int delalloc)
+{
+ struct btrfs_block_group_cache *used_bg = NULL;
+
+ spin_lock(&cluster->refill_lock);
+ while (1) {
+ used_bg = cluster->block_group;
+ if (!used_bg)
+ return NULL;
+
+ if (used_bg == block_group)
+ return used_bg;
+
+ btrfs_get_block_group(used_bg);
+
+ if (!delalloc)
+ return used_bg;
+
+ if (down_read_trylock(&used_bg->data_rwsem))
+ return used_bg;
+
+ spin_unlock(&cluster->refill_lock);
+
+ /* We should only have one-level nested. */
+ down_read_nested(&used_bg->data_rwsem, SINGLE_DEPTH_NESTING);
+
+ spin_lock(&cluster->refill_lock);
+ if (used_bg == cluster->block_group)
+ return used_bg;
+
+ up_read(&used_bg->data_rwsem);
+ btrfs_put_block_group(used_bg);
+ }
+}
+
+static inline void
+btrfs_release_block_group(struct btrfs_block_group_cache *cache,
+ int delalloc)
+{
+ if (delalloc)
+ up_read(&cache->data_rwsem);
+ btrfs_put_block_group(cache);
+}
+
+/*
+ * Structure used internally for find_free_extent() function. Wraps needed
+ * parameters.
+ */
+struct find_free_extent_ctl {
+ /* Basic allocation info */
+ u64 ram_bytes;
+ u64 num_bytes;
+ u64 empty_size;
+ u64 flags;
+ int delalloc;
+
+ /* Where to start the search inside the bg */
+ u64 search_start;
+
+ /* For clustered allocation */
+ u64 empty_cluster;
+
+ bool have_caching_bg;
+ bool orig_have_caching_bg;
+
+ /* RAID index, converted from flags */
+ int index;
+
+ /*
+ * Current loop number, check find_free_extent_update_loop() for details
+ */
+ int loop;
+
+ /*
+ * Whether we're refilling a cluster, if true we need to re-search
+ * current block group but don't try to refill the cluster again.
+ */
+ bool retry_clustered;
+
+ /*
+ * Whether we're updating free space cache, if true we need to re-search
+ * current block group but don't try updating free space cache again.
+ */
+ bool retry_unclustered;
+
+ /* If current block group is cached */
+ int cached;
+
+ /* Max contiguous hole found */
+ u64 max_extent_size;
+
+ /* Total free space from free space cache, not always contiguous */
+ u64 total_free_space;
+
+ /* Found result */
+ u64 found_offset;
+};
+
+
+/*
+ * Helper function for find_free_extent().
+ *
+ * Return -ENOENT to inform caller that we need fallback to unclustered mode.
+ * Return -EAGAIN to inform caller that we need to re-search this block group
+ * Return >0 to inform caller that we find nothing
+ * Return 0 means we have found a location and set ffe_ctl->found_offset.
+ */
+static int find_free_extent_clustered(struct btrfs_block_group_cache *bg,
+ struct btrfs_free_cluster *last_ptr,
+ struct find_free_extent_ctl *ffe_ctl,
+ struct btrfs_block_group_cache **cluster_bg_ret)
+{
+ struct btrfs_block_group_cache *cluster_bg;
+ u64 aligned_cluster;
+ u64 offset;
+ int ret;
+
+ cluster_bg = btrfs_lock_cluster(bg, last_ptr, ffe_ctl->delalloc);
+ if (!cluster_bg)
+ goto refill_cluster;
+ if (cluster_bg != bg && (cluster_bg->ro ||
+ !block_group_bits(cluster_bg, ffe_ctl->flags)))
+ goto release_cluster;
+
+ offset = btrfs_alloc_from_cluster(cluster_bg, last_ptr,
+ ffe_ctl->num_bytes, cluster_bg->key.objectid,
+ &ffe_ctl->max_extent_size);
+ if (offset) {
+ /* We have a block, we're done */
+ spin_unlock(&last_ptr->refill_lock);
+ trace_btrfs_reserve_extent_cluster(cluster_bg,
+ ffe_ctl->search_start, ffe_ctl->num_bytes);
+ *cluster_bg_ret = cluster_bg;
+ ffe_ctl->found_offset = offset;
+ return 0;
+ }
+ WARN_ON(last_ptr->block_group != cluster_bg);
+
+release_cluster:
+ /*
+ * If we are on LOOP_NO_EMPTY_SIZE, we can't set up a new clusters, so
+ * lets just skip it and let the allocator find whatever block it can
+ * find. If we reach this point, we will have tried the cluster
+ * allocator plenty of times and not have found anything, so we are
+ * likely way too fragmented for the clustering stuff to find anything.
+ *
+ * However, if the cluster is taken from the current block group,
+ * release the cluster first, so that we stand a better chance of
+ * succeeding in the unclustered allocation.
+ */
+ if (ffe_ctl->loop >= LOOP_NO_EMPTY_SIZE && cluster_bg != bg) {
+ spin_unlock(&last_ptr->refill_lock);
+ btrfs_release_block_group(cluster_bg, ffe_ctl->delalloc);
+ return -ENOENT;
+ }
+
+ /* This cluster didn't work out, free it and start over */
+ btrfs_return_cluster_to_free_space(NULL, last_ptr);
+
+ if (cluster_bg != bg)
+ btrfs_release_block_group(cluster_bg, ffe_ctl->delalloc);
+
+refill_cluster:
+ if (ffe_ctl->loop >= LOOP_NO_EMPTY_SIZE) {
+ spin_unlock(&last_ptr->refill_lock);
+ return -ENOENT;
+ }
+
+ aligned_cluster = max_t(u64,
+ ffe_ctl->empty_cluster + ffe_ctl->empty_size,
+ bg->full_stripe_len);
+ ret = btrfs_find_space_cluster(bg, last_ptr, ffe_ctl->search_start,
+ ffe_ctl->num_bytes, aligned_cluster);
+ if (ret == 0) {
+ /* Now pull our allocation out of this cluster */
+ offset = btrfs_alloc_from_cluster(bg, last_ptr,
+ ffe_ctl->num_bytes, ffe_ctl->search_start,
+ &ffe_ctl->max_extent_size);
+ if (offset) {
+ /* We found one, proceed */
+ spin_unlock(&last_ptr->refill_lock);
+ trace_btrfs_reserve_extent_cluster(bg,
+ ffe_ctl->search_start,
+ ffe_ctl->num_bytes);
+ ffe_ctl->found_offset = offset;
+ return 0;
+ }
+ } else if (!ffe_ctl->cached && ffe_ctl->loop > LOOP_CACHING_NOWAIT &&
+ !ffe_ctl->retry_clustered) {
+ spin_unlock(&last_ptr->refill_lock);
+
+ ffe_ctl->retry_clustered = true;
+ btrfs_wait_block_group_cache_progress(bg, ffe_ctl->num_bytes +
+ ffe_ctl->empty_cluster + ffe_ctl->empty_size);
+ return -EAGAIN;
+ }
+ /*
+ * At this point we either didn't find a cluster or we weren't able to
+ * allocate a block from our cluster. Free the cluster we've been
+ * trying to use, and go to the next block group.
+ */
+ btrfs_return_cluster_to_free_space(NULL, last_ptr);
+ spin_unlock(&last_ptr->refill_lock);
+ return 1;
+}
+
+/*
+ * Return >0 to inform caller that we find nothing
+ * Return 0 when we found an free extent and set ffe_ctrl->found_offset
+ * Return -EAGAIN to inform caller that we need to re-search this block group
+ */
+static int find_free_extent_unclustered(struct btrfs_block_group_cache *bg,
+ struct btrfs_free_cluster *last_ptr,
+ struct find_free_extent_ctl *ffe_ctl)
+{
+ u64 offset;
+
+ /*
+ * We are doing an unclustered allocation, set the fragmented flag so
+ * we don't bother trying to setup a cluster again until we get more
+ * space.
+ */
+ if (unlikely(last_ptr)) {
+ spin_lock(&last_ptr->lock);
+ last_ptr->fragmented = 1;
+ spin_unlock(&last_ptr->lock);
+ }
+ if (ffe_ctl->cached) {
+ struct btrfs_free_space_ctl *free_space_ctl;
+
+ free_space_ctl = bg->free_space_ctl;
+ spin_lock(&free_space_ctl->tree_lock);
+ if (free_space_ctl->free_space <
+ ffe_ctl->num_bytes + ffe_ctl->empty_cluster +
+ ffe_ctl->empty_size) {
+ ffe_ctl->total_free_space = max_t(u64,
+ ffe_ctl->total_free_space,
+ free_space_ctl->free_space);
+ spin_unlock(&free_space_ctl->tree_lock);
+ return 1;
+ }
+ spin_unlock(&free_space_ctl->tree_lock);
+ }
+
+ offset = btrfs_find_space_for_alloc(bg, ffe_ctl->search_start,
+ ffe_ctl->num_bytes, ffe_ctl->empty_size,
+ &ffe_ctl->max_extent_size);
+
+ /*
+ * If we didn't find a chunk, and we haven't failed on this block group
+ * before, and this block group is in the middle of caching and we are
+ * ok with waiting, then go ahead and wait for progress to be made, and
+ * set @retry_unclustered to true.
+ *
+ * If @retry_unclustered is true then we've already waited on this
+ * block group once and should move on to the next block group.
+ */
+ if (!offset && !ffe_ctl->retry_unclustered && !ffe_ctl->cached &&
+ ffe_ctl->loop > LOOP_CACHING_NOWAIT) {
+ btrfs_wait_block_group_cache_progress(bg, ffe_ctl->num_bytes +
+ ffe_ctl->empty_size);
+ ffe_ctl->retry_unclustered = true;
+ return -EAGAIN;
+ } else if (!offset) {
+ return 1;
+ }
+ ffe_ctl->found_offset = offset;
+ return 0;
+}
+
+/*
+ * Return >0 means caller needs to re-search for free extent
+ * Return 0 means we have the needed free extent.
+ * Return <0 means we failed to locate any free extent.
+ */
+static int find_free_extent_update_loop(struct btrfs_fs_info *fs_info,
+ struct btrfs_free_cluster *last_ptr,
+ struct btrfs_key *ins,
+ struct find_free_extent_ctl *ffe_ctl,
+ int full_search, bool use_cluster)
+{
+ struct btrfs_root *root = fs_info->extent_root;
+ int ret;
+
+ if ((ffe_ctl->loop == LOOP_CACHING_NOWAIT) &&
+ ffe_ctl->have_caching_bg && !ffe_ctl->orig_have_caching_bg)
+ ffe_ctl->orig_have_caching_bg = true;
+
+ if (!ins->objectid && ffe_ctl->loop >= LOOP_CACHING_WAIT &&
+ ffe_ctl->have_caching_bg)
+ return 1;
+
+ if (!ins->objectid && ++(ffe_ctl->index) < BTRFS_NR_RAID_TYPES)
+ return 1;
+
+ if (ins->objectid) {
+ if (!use_cluster && last_ptr) {
+ spin_lock(&last_ptr->lock);
+ last_ptr->window_start = ins->objectid;
+ spin_unlock(&last_ptr->lock);
+ }
+ return 0;
+ }
+
+ /*
+ * LOOP_CACHING_NOWAIT, search partially cached block groups, kicking
+ * caching kthreads as we move along
+ * LOOP_CACHING_WAIT, search everything, and wait if our bg is caching
+ * LOOP_ALLOC_CHUNK, force a chunk allocation and try again
+ * LOOP_NO_EMPTY_SIZE, set empty_size and empty_cluster to 0 and try
+ * again
+ */
+ if (ffe_ctl->loop < LOOP_NO_EMPTY_SIZE) {
+ ffe_ctl->index = 0;
+ if (ffe_ctl->loop == LOOP_CACHING_NOWAIT) {
+ /*
+ * We want to skip the LOOP_CACHING_WAIT step if we
+ * don't have any uncached bgs and we've already done a
+ * full search through.
+ */
+ if (ffe_ctl->orig_have_caching_bg || !full_search)
+ ffe_ctl->loop = LOOP_CACHING_WAIT;
+ else
+ ffe_ctl->loop = LOOP_ALLOC_CHUNK;
+ } else {
+ ffe_ctl->loop++;
+ }
+
+ if (ffe_ctl->loop == LOOP_ALLOC_CHUNK) {
+ struct btrfs_trans_handle *trans;
+ int exist = 0;
+
+ trans = current->journal_info;
+ if (trans)
+ exist = 1;
+ else
+ trans = btrfs_join_transaction(root);
+
+ if (IS_ERR(trans)) {
+ ret = PTR_ERR(trans);
+ return ret;
+ }
+
+ ret = btrfs_chunk_alloc(trans, ffe_ctl->flags,
+ CHUNK_ALLOC_FORCE);
+
+ /*
+ * If we can't allocate a new chunk we've already looped
+ * through at least once, move on to the NO_EMPTY_SIZE
+ * case.
+ */
+ if (ret == -ENOSPC)
+ ffe_ctl->loop = LOOP_NO_EMPTY_SIZE;
+
+ /* Do not bail out on ENOSPC since we can do more. */
+ if (ret < 0 && ret != -ENOSPC)
+ btrfs_abort_transaction(trans, ret);
+ else
+ ret = 0;
+ if (!exist)
+ btrfs_end_transaction(trans);
+ if (ret)
+ return ret;
+ }
+
+ if (ffe_ctl->loop == LOOP_NO_EMPTY_SIZE) {
+ /*
+ * Don't loop again if we already have no empty_size and
+ * no empty_cluster.
+ */
+ if (ffe_ctl->empty_size == 0 &&
+ ffe_ctl->empty_cluster == 0)
+ return -ENOSPC;
+ ffe_ctl->empty_size = 0;
+ ffe_ctl->empty_cluster = 0;
+ }
+ return 1;
+ }
+ return -ENOSPC;
+}
+
+/*
+ * walks the btree of allocated extents and find a hole of a given size.
+ * The key ins is changed to record the hole:
+ * ins->objectid == start position
+ * ins->flags = BTRFS_EXTENT_ITEM_KEY
+ * ins->offset == the size of the hole.
+ * Any available blocks before search_start are skipped.
+ *
+ * If there is no suitable free space, we will record the max size of
+ * the free space extent currently.
+ *
+ * The overall logic and call chain:
+ *
+ * find_free_extent()
+ * |- Iterate through all block groups
+ * | |- Get a valid block group
+ * | |- Try to do clustered allocation in that block group
+ * | |- Try to do unclustered allocation in that block group
+ * | |- Check if the result is valid
+ * | | |- If valid, then exit
+ * | |- Jump to next block group
+ * |
+ * |- Push harder to find free extents
+ * |- If not found, re-iterate all block groups
+ */
+static noinline int find_free_extent(struct btrfs_root *root,
+ u64 ram_bytes, u64 num_bytes, u64 empty_size,
+ u64 hint_byte, struct btrfs_key *ins,
+ u64 flags, int delalloc)
+{
+ struct btrfs_fs_info *fs_info = root->fs_info;
+ int ret = 0;
+ int cache_block_group_error = 0;
+ struct btrfs_free_cluster *last_ptr = NULL;
+ struct btrfs_block_group_cache *block_group = NULL;
+ struct find_free_extent_ctl ffe_ctl = {0};
+ struct btrfs_space_info *space_info;
+ bool use_cluster = true;
+ bool full_search = false;
+
+ WARN_ON(num_bytes < fs_info->sectorsize);
+
+ ffe_ctl.ram_bytes = ram_bytes;
+ ffe_ctl.num_bytes = num_bytes;
+ ffe_ctl.empty_size = empty_size;
+ ffe_ctl.flags = flags;
+ ffe_ctl.search_start = 0;
+ ffe_ctl.retry_clustered = false;
+ ffe_ctl.retry_unclustered = false;
+ ffe_ctl.delalloc = delalloc;
+ ffe_ctl.index = btrfs_bg_flags_to_raid_index(flags);
+ ffe_ctl.have_caching_bg = false;
+ ffe_ctl.orig_have_caching_bg = false;
+ ffe_ctl.found_offset = 0;
+
+ ins->type = BTRFS_EXTENT_ITEM_KEY;
+ ins->objectid = 0;
+ ins->offset = 0;
+
+ trace_find_free_extent(root, num_bytes, empty_size, flags);
+
+ space_info = btrfs_find_space_info(fs_info, flags);
+ if (!space_info) {
+ btrfs_err(fs_info, "No space info for %llu", flags);
+ return -ENOSPC;
+ }
+
+ /*
+ * If our free space is heavily fragmented we may not be able to make
+ * big contiguous allocations, so instead of doing the expensive search
+ * for free space, simply return ENOSPC with our max_extent_size so we
+ * can go ahead and search for a more manageable chunk.
+ *
+ * If our max_extent_size is large enough for our allocation simply
+ * disable clustering since we will likely not be able to find enough
+ * space to create a cluster and induce latency trying.
+ */
+ if (unlikely(space_info->max_extent_size)) {
+ spin_lock(&space_info->lock);
+ if (space_info->max_extent_size &&
+ num_bytes > space_info->max_extent_size) {
+ ins->offset = space_info->max_extent_size;
+ spin_unlock(&space_info->lock);
+ return -ENOSPC;
+ } else if (space_info->max_extent_size) {
+ use_cluster = false;
+ }
+ spin_unlock(&space_info->lock);
+ }
+
+ last_ptr = fetch_cluster_info(fs_info, space_info,
+ &ffe_ctl.empty_cluster);
+ if (last_ptr) {
+ spin_lock(&last_ptr->lock);
+ if (last_ptr->block_group)
+ hint_byte = last_ptr->window_start;
+ if (last_ptr->fragmented) {
+ /*
+ * We still set window_start so we can keep track of the
+ * last place we found an allocation to try and save
+ * some time.
+ */
+ hint_byte = last_ptr->window_start;
+ use_cluster = false;
+ }
+ spin_unlock(&last_ptr->lock);
+ }
+
+ ffe_ctl.search_start = max(ffe_ctl.search_start,
+ first_logical_byte(fs_info, 0));
+ ffe_ctl.search_start = max(ffe_ctl.search_start, hint_byte);
+ if (ffe_ctl.search_start == hint_byte) {
+ block_group = btrfs_lookup_block_group(fs_info,
+ ffe_ctl.search_start);
+ /*
+ * we don't want to use the block group if it doesn't match our
+ * allocation bits, or if its not cached.
+ *
+ * However if we are re-searching with an ideal block group
+ * picked out then we don't care that the block group is cached.
+ */
+ if (block_group && block_group_bits(block_group, flags) &&
+ block_group->cached != BTRFS_CACHE_NO) {
+ down_read(&space_info->groups_sem);
+ if (list_empty(&block_group->list) ||
+ block_group->ro) {
+ /*
+ * someone is removing this block group,
+ * we can't jump into the have_block_group
+ * target because our list pointers are not
+ * valid
+ */
+ btrfs_put_block_group(block_group);
+ up_read(&space_info->groups_sem);
+ } else {
+ ffe_ctl.index = btrfs_bg_flags_to_raid_index(
+ block_group->flags);
+ btrfs_lock_block_group(block_group, delalloc);
+ goto have_block_group;
+ }
+ } else if (block_group) {
+ btrfs_put_block_group(block_group);
+ }
+ }
+search:
+ ffe_ctl.have_caching_bg = false;
+ if (ffe_ctl.index == btrfs_bg_flags_to_raid_index(flags) ||
+ ffe_ctl.index == 0)
+ full_search = true;
+ down_read(&space_info->groups_sem);
+ list_for_each_entry(block_group,
+ &space_info->block_groups[ffe_ctl.index], list) {
+ /* If the block group is read-only, we can skip it entirely. */
+ if (unlikely(block_group->ro))
+ continue;
+
+ btrfs_grab_block_group(block_group, delalloc);
+ ffe_ctl.search_start = block_group->key.objectid;
+
+ /*
+ * this can happen if we end up cycling through all the
+ * raid types, but we want to make sure we only allocate
+ * for the proper type.
+ */
+ if (!block_group_bits(block_group, flags)) {
+ u64 extra = BTRFS_BLOCK_GROUP_DUP |
+ BTRFS_BLOCK_GROUP_RAID1_MASK |
+ BTRFS_BLOCK_GROUP_RAID56_MASK |
+ BTRFS_BLOCK_GROUP_RAID10;
+
+ /*
+ * if they asked for extra copies and this block group
+ * doesn't provide them, bail. This does allow us to
+ * fill raid0 from raid1.
+ */
+ if ((flags & extra) && !(block_group->flags & extra))
+ goto loop;
+
+ /*
+ * This block group has different flags than we want.
+ * It's possible that we have MIXED_GROUP flag but no
+ * block group is mixed. Just skip such block group.
+ */
+ btrfs_release_block_group(block_group, delalloc);
+ continue;
+ }
+
+have_block_group:
+ ffe_ctl.cached = btrfs_block_group_cache_done(block_group);
+ if (unlikely(!ffe_ctl.cached)) {
+ ffe_ctl.have_caching_bg = true;
+ ret = btrfs_cache_block_group(block_group, 0);
+
+ /*
+ * If we get ENOMEM here or something else we want to
+ * try other block groups, because it may not be fatal.
+ * However if we can't find anything else we need to
+ * save our return here so that we return the actual
+ * error that caused problems, not ENOSPC.
+ */
+ if (ret < 0) {
+ if (!cache_block_group_error)
+ cache_block_group_error = ret;
+ ret = 0;
+ goto loop;
+ }
+ ret = 0;
+ }
+
+ if (unlikely(block_group->cached == BTRFS_CACHE_ERROR)) {
+ if (!cache_block_group_error)
+ cache_block_group_error = -EIO;
+ goto loop;
+ }
+
+ /*
+ * Ok we want to try and use the cluster allocator, so
+ * lets look there
+ */
+ if (last_ptr && use_cluster) {
+ struct btrfs_block_group_cache *cluster_bg = NULL;
+
+ ret = find_free_extent_clustered(block_group, last_ptr,
+ &ffe_ctl, &cluster_bg);
+
+ if (ret == 0) {
+ if (cluster_bg && cluster_bg != block_group) {
+ btrfs_release_block_group(block_group,
+ delalloc);
+ block_group = cluster_bg;
+ }
+ goto checks;
+ } else if (ret == -EAGAIN) {
+ goto have_block_group;
+ } else if (ret > 0) {
+ goto loop;
+ }
+ /* ret == -ENOENT case falls through */
+ }
+
+ ret = find_free_extent_unclustered(block_group, last_ptr,
+ &ffe_ctl);
+ if (ret == -EAGAIN)
+ goto have_block_group;
+ else if (ret > 0)
+ goto loop;
+ /* ret == 0 case falls through */
+checks:
+ ffe_ctl.search_start = round_up(ffe_ctl.found_offset,
+ fs_info->stripesize);
+
+ /* move on to the next group */
+ if (ffe_ctl.search_start + num_bytes >
+ block_group->key.objectid + block_group->key.offset) {
+ btrfs_add_free_space(block_group, ffe_ctl.found_offset,
+ num_bytes);
+ goto loop;
+ }
+
+ if (ffe_ctl.found_offset < ffe_ctl.search_start)
+ btrfs_add_free_space(block_group, ffe_ctl.found_offset,
+ ffe_ctl.search_start - ffe_ctl.found_offset);
+
+ ret = btrfs_add_reserved_bytes(block_group, ram_bytes,
+ num_bytes, delalloc);
+ if (ret == -EAGAIN) {
+ btrfs_add_free_space(block_group, ffe_ctl.found_offset,
+ num_bytes);
+ goto loop;
+ }
+ btrfs_inc_block_group_reservations(block_group);
+
+ /* we are all good, lets return */
+ ins->objectid = ffe_ctl.search_start;
+ ins->offset = num_bytes;
+
+ trace_btrfs_reserve_extent(block_group, ffe_ctl.search_start,
+ num_bytes);
+ btrfs_release_block_group(block_group, delalloc);
+ break;
+loop:
+ ffe_ctl.retry_clustered = false;
+ ffe_ctl.retry_unclustered = false;
+ BUG_ON(btrfs_bg_flags_to_raid_index(block_group->flags) !=
+ ffe_ctl.index);
+ btrfs_release_block_group(block_group, delalloc);
+ cond_resched();
+ }
+ up_read(&space_info->groups_sem);
+
+ ret = find_free_extent_update_loop(fs_info, last_ptr, ins, &ffe_ctl,
+ full_search, use_cluster);
+ if (ret > 0)
+ goto search;
+
+ if (ret == -ENOSPC && !cache_block_group_error) {
+ /*
+ * Use ffe_ctl->total_free_space as fallback if we can't find
+ * any contiguous hole.
+ */
+ if (!ffe_ctl.max_extent_size)
+ ffe_ctl.max_extent_size = ffe_ctl.total_free_space;
+ spin_lock(&space_info->lock);
+ space_info->max_extent_size = ffe_ctl.max_extent_size;
+ spin_unlock(&space_info->lock);
+ ins->offset = ffe_ctl.max_extent_size;
+ } else if (ret == -ENOSPC) {
+ ret = cache_block_group_error;
+ }
+ return ret;
+}
+
+/*
+ * btrfs_reserve_extent - entry point to the extent allocator. Tries to find a
+ * hole that is at least as big as @num_bytes.
+ *
+ * @root - The root that will contain this extent
+ *
+ * @ram_bytes - The amount of space in ram that @num_bytes take. This
+ * is used for accounting purposes. This value differs
+ * from @num_bytes only in the case of compressed extents.
+ *
+ * @num_bytes - Number of bytes to allocate on-disk.
+ *
+ * @min_alloc_size - Indicates the minimum amount of space that the
+ * allocator should try to satisfy. In some cases
+ * @num_bytes may be larger than what is required and if
+ * the filesystem is fragmented then allocation fails.
+ * However, the presence of @min_alloc_size gives a
+ * chance to try and satisfy the smaller allocation.
+ *
+ * @empty_size - A hint that you plan on doing more COW. This is the
+ * size in bytes the allocator should try to find free
+ * next to the block it returns. This is just a hint and
+ * may be ignored by the allocator.
+ *
+ * @hint_byte - Hint to the allocator to start searching above the byte
+ * address passed. It might be ignored.
+ *
+ * @ins - This key is modified to record the found hole. It will
+ * have the following values:
+ * ins->objectid == start position
+ * ins->flags = BTRFS_EXTENT_ITEM_KEY
+ * ins->offset == the size of the hole.
+ *
+ * @is_data - Boolean flag indicating whether an extent is
+ * allocated for data (true) or metadata (false)
+ *
+ * @delalloc - Boolean flag indicating whether this allocation is for
+ * delalloc or not. If 'true' data_rwsem of block groups
+ * is going to be acquired.
+ *
+ *
+ * Returns 0 when an allocation succeeded or < 0 when an error occurred. In
+ * case -ENOSPC is returned then @ins->offset will contain the size of the
+ * largest available hole the allocator managed to find.
+ */
+int btrfs_reserve_extent(struct btrfs_root *root, u64 ram_bytes,
+ u64 num_bytes, u64 min_alloc_size,
+ u64 empty_size, u64 hint_byte,
+ struct btrfs_key *ins, int is_data, int delalloc)
+{
+ struct btrfs_fs_info *fs_info = root->fs_info;
+ bool final_tried = num_bytes == min_alloc_size;
+ u64 flags;
+ int ret;
+
+ flags = get_alloc_profile_by_root(root, is_data);
+again:
+ WARN_ON(num_bytes < fs_info->sectorsize);
+ ret = find_free_extent(root, ram_bytes, num_bytes, empty_size,
+ hint_byte, ins, flags, delalloc);
+ if (!ret && !is_data) {
+ btrfs_dec_block_group_reservations(fs_info, ins->objectid);
+ } else if (ret == -ENOSPC) {
+ if (!final_tried && ins->offset) {
+ num_bytes = min(num_bytes >> 1, ins->offset);
+ num_bytes = round_down(num_bytes,
+ fs_info->sectorsize);
+ num_bytes = max(num_bytes, min_alloc_size);
+ ram_bytes = num_bytes;
+ if (num_bytes == min_alloc_size)
+ final_tried = true;
+ goto again;
+ } else if (btrfs_test_opt(fs_info, ENOSPC_DEBUG)) {
+ struct btrfs_space_info *sinfo;
+
+ sinfo = btrfs_find_space_info(fs_info, flags);
+ btrfs_err(fs_info,
+ "allocation failed flags %llu, wanted %llu",
+ flags, num_bytes);
+ if (sinfo)
+ btrfs_dump_space_info(fs_info, sinfo,
+ num_bytes, 1);
+ }
+ }
+
+ return ret;
+}
+
+static int __btrfs_free_reserved_extent(struct btrfs_fs_info *fs_info,
+ u64 start, u64 len,
+ int pin, int delalloc)
+{
+ struct btrfs_block_group_cache *cache;
+ int ret = 0;
+
+ cache = btrfs_lookup_block_group(fs_info, start);
+ if (!cache) {
+ btrfs_err(fs_info, "Unable to find block group for %llu",
+ start);
+ return -ENOSPC;
+ }
+
+ if (pin)
+ pin_down_extent(cache, start, len, 1);
+ else {
+ if (btrfs_test_opt(fs_info, DISCARD))
+ ret = btrfs_discard_extent(fs_info, start, len, NULL);
+ btrfs_add_free_space(cache, start, len);
+ btrfs_free_reserved_bytes(cache, len, delalloc);
+ trace_btrfs_reserved_extent_free(fs_info, start, len);
+ }
+
+ btrfs_put_block_group(cache);
+ return ret;
+}
+
+int btrfs_free_reserved_extent(struct btrfs_fs_info *fs_info,
+ u64 start, u64 len, int delalloc)
+{
+ return __btrfs_free_reserved_extent(fs_info, start, len, 0, delalloc);
+}
+
+int btrfs_free_and_pin_reserved_extent(struct btrfs_fs_info *fs_info,
+ u64 start, u64 len)
+{
+ return __btrfs_free_reserved_extent(fs_info, start, len, 1, 0);
+}
+
+static int alloc_reserved_file_extent(struct btrfs_trans_handle *trans,
+ u64 parent, u64 root_objectid,
+ u64 flags, u64 owner, u64 offset,
+ struct btrfs_key *ins, int ref_mod)
+{
+ struct btrfs_fs_info *fs_info = trans->fs_info;
+ int ret;
+ struct btrfs_extent_item *extent_item;
+ struct btrfs_extent_inline_ref *iref;
+ struct btrfs_path *path;
+ struct extent_buffer *leaf;
+ int type;
+ u32 size;
+
+ if (parent > 0)
+ type = BTRFS_SHARED_DATA_REF_KEY;
+ else
+ type = BTRFS_EXTENT_DATA_REF_KEY;
+
+ size = sizeof(*extent_item) + btrfs_extent_inline_ref_size(type);
+
+ path = btrfs_alloc_path();
+ if (!path)
+ return -ENOMEM;
+
+ path->leave_spinning = 1;
+ ret = btrfs_insert_empty_item(trans, fs_info->extent_root, path,
+ ins, size);
+ if (ret) {
+ btrfs_free_path(path);
+ return ret;
+ }
+
+ leaf = path->nodes[0];
+ extent_item = btrfs_item_ptr(leaf, path->slots[0],
+ struct btrfs_extent_item);
+ btrfs_set_extent_refs(leaf, extent_item, ref_mod);
+ btrfs_set_extent_generation(leaf, extent_item, trans->transid);
+ btrfs_set_extent_flags(leaf, extent_item,
+ flags | BTRFS_EXTENT_FLAG_DATA);
+
+ iref = (struct btrfs_extent_inline_ref *)(extent_item + 1);
+ btrfs_set_extent_inline_ref_type(leaf, iref, type);
+ if (parent > 0) {
+ struct btrfs_shared_data_ref *ref;
+ ref = (struct btrfs_shared_data_ref *)(iref + 1);
+ btrfs_set_extent_inline_ref_offset(leaf, iref, parent);
+ btrfs_set_shared_data_ref_count(leaf, ref, ref_mod);
+ } else {
+ struct btrfs_extent_data_ref *ref;
+ ref = (struct btrfs_extent_data_ref *)(&iref->offset);
+ btrfs_set_extent_data_ref_root(leaf, ref, root_objectid);
+ btrfs_set_extent_data_ref_objectid(leaf, ref, owner);
+ btrfs_set_extent_data_ref_offset(leaf, ref, offset);
+ btrfs_set_extent_data_ref_count(leaf, ref, ref_mod);
+ }
+
+ btrfs_mark_buffer_dirty(path->nodes[0]);
+ btrfs_free_path(path);
+
+ ret = remove_from_free_space_tree(trans, ins->objectid, ins->offset);
+ if (ret)
+ return ret;
+
+ ret = btrfs_update_block_group(trans, ins->objectid, ins->offset, 1);
+ if (ret) { /* -ENOENT, logic error */
+ btrfs_err(fs_info, "update block group failed for %llu %llu",
+ ins->objectid, ins->offset);
+ BUG();
+ }
+ trace_btrfs_reserved_extent_alloc(fs_info, ins->objectid, ins->offset);
+ return ret;
+}
+
+static int alloc_reserved_tree_block(struct btrfs_trans_handle *trans,
+ struct btrfs_delayed_ref_node *node,
+ struct btrfs_delayed_extent_op *extent_op)
+{
+ struct btrfs_fs_info *fs_info = trans->fs_info;
+ int ret;
+ struct btrfs_extent_item *extent_item;
+ struct btrfs_key extent_key;
+ struct btrfs_tree_block_info *block_info;
+ struct btrfs_extent_inline_ref *iref;
+ struct btrfs_path *path;
+ struct extent_buffer *leaf;
+ struct btrfs_delayed_tree_ref *ref;
+ u32 size = sizeof(*extent_item) + sizeof(*iref);
+ u64 num_bytes;
+ u64 flags = extent_op->flags_to_set;
+ bool skinny_metadata = btrfs_fs_incompat(fs_info, SKINNY_METADATA);
+
+ ref = btrfs_delayed_node_to_tree_ref(node);
+
+ extent_key.objectid = node->bytenr;
+ if (skinny_metadata) {
+ extent_key.offset = ref->level;
+ extent_key.type = BTRFS_METADATA_ITEM_KEY;
+ num_bytes = fs_info->nodesize;
+ } else {
+ extent_key.offset = node->num_bytes;
+ extent_key.type = BTRFS_EXTENT_ITEM_KEY;
+ size += sizeof(*block_info);
+ num_bytes = node->num_bytes;
+ }
+
+ path = btrfs_alloc_path();
+ if (!path)
+ return -ENOMEM;
+
+ path->leave_spinning = 1;
+ ret = btrfs_insert_empty_item(trans, fs_info->extent_root, path,
+ &extent_key, size);
+ if (ret) {
+ btrfs_free_path(path);
+ return ret;
+ }
+
+ leaf = path->nodes[0];
+ extent_item = btrfs_item_ptr(leaf, path->slots[0],
+ struct btrfs_extent_item);
+ btrfs_set_extent_refs(leaf, extent_item, 1);
+ btrfs_set_extent_generation(leaf, extent_item, trans->transid);
+ btrfs_set_extent_flags(leaf, extent_item,
+ flags | BTRFS_EXTENT_FLAG_TREE_BLOCK);
+
+ if (skinny_metadata) {
+ iref = (struct btrfs_extent_inline_ref *)(extent_item + 1);
+ } else {
+ block_info = (struct btrfs_tree_block_info *)(extent_item + 1);
+ btrfs_set_tree_block_key(leaf, block_info, &extent_op->key);
+ btrfs_set_tree_block_level(leaf, block_info, ref->level);
+ iref = (struct btrfs_extent_inline_ref *)(block_info + 1);
+ }
+
+ if (node->type == BTRFS_SHARED_BLOCK_REF_KEY) {
+ BUG_ON(!(flags & BTRFS_BLOCK_FLAG_FULL_BACKREF));
+ btrfs_set_extent_inline_ref_type(leaf, iref,
+ BTRFS_SHARED_BLOCK_REF_KEY);
+ btrfs_set_extent_inline_ref_offset(leaf, iref, ref->parent);
+ } else {
+ btrfs_set_extent_inline_ref_type(leaf, iref,
+ BTRFS_TREE_BLOCK_REF_KEY);
+ btrfs_set_extent_inline_ref_offset(leaf, iref, ref->root);
+ }
+
+ btrfs_mark_buffer_dirty(leaf);
+ btrfs_free_path(path);
+
+ ret = remove_from_free_space_tree(trans, extent_key.objectid,
+ num_bytes);
+ if (ret)
+ return ret;
+
+ ret = btrfs_update_block_group(trans, extent_key.objectid,
+ fs_info->nodesize, 1);
+ if (ret) { /* -ENOENT, logic error */
+ btrfs_err(fs_info, "update block group failed for %llu %llu",
+ extent_key.objectid, extent_key.offset);
+ BUG();
+ }
+
+ trace_btrfs_reserved_extent_alloc(fs_info, extent_key.objectid,
+ fs_info->nodesize);
+ return ret;
+}
+
+int btrfs_alloc_reserved_file_extent(struct btrfs_trans_handle *trans,
+ struct btrfs_root *root, u64 owner,
+ u64 offset, u64 ram_bytes,
+ struct btrfs_key *ins)
+{
+ struct btrfs_ref generic_ref = { 0 };
+ int ret;
+
+ BUG_ON(root->root_key.objectid == BTRFS_TREE_LOG_OBJECTID);
+
+ btrfs_init_generic_ref(&generic_ref, BTRFS_ADD_DELAYED_EXTENT,
+ ins->objectid, ins->offset, 0);
+ btrfs_init_data_ref(&generic_ref, root->root_key.objectid, owner, offset);
+ btrfs_ref_tree_mod(root->fs_info, &generic_ref);
+ ret = btrfs_add_delayed_data_ref(trans, &generic_ref,
+ ram_bytes, NULL, NULL);
+ return ret;
+}
+
+/*
+ * this is used by the tree logging recovery code. It records that
+ * an extent has been allocated and makes sure to clear the free
+ * space cache bits as well
+ */
+int btrfs_alloc_logged_file_extent(struct btrfs_trans_handle *trans,
+ u64 root_objectid, u64 owner, u64 offset,
+ struct btrfs_key *ins)
+{
+ struct btrfs_fs_info *fs_info = trans->fs_info;
+ int ret;
+ struct btrfs_block_group_cache *block_group;
+ struct btrfs_space_info *space_info;
+
+ /*
+ * Mixed block groups will exclude before processing the log so we only
+ * need to do the exclude dance if this fs isn't mixed.
+ */
+ if (!btrfs_fs_incompat(fs_info, MIXED_GROUPS)) {
+ ret = __exclude_logged_extent(fs_info, ins->objectid,
+ ins->offset);
+ if (ret)
+ return ret;
+ }
+
+ block_group = btrfs_lookup_block_group(fs_info, ins->objectid);
+ if (!block_group)
+ return -EINVAL;
+
+ space_info = block_group->space_info;
+ spin_lock(&space_info->lock);
+ spin_lock(&block_group->lock);
+ space_info->bytes_reserved += ins->offset;
+ block_group->reserved += ins->offset;
+ spin_unlock(&block_group->lock);
+ spin_unlock(&space_info->lock);
+
+ ret = alloc_reserved_file_extent(trans, 0, root_objectid, 0, owner,
+ offset, ins, 1);
+ if (ret)
+ btrfs_pin_extent(fs_info, ins->objectid, ins->offset, 1);
+ btrfs_put_block_group(block_group);
+ return ret;
+}
+
+static struct extent_buffer *
+btrfs_init_new_buffer(struct btrfs_trans_handle *trans, struct btrfs_root *root,
+ u64 bytenr, int level, u64 owner)
+{
+ struct btrfs_fs_info *fs_info = root->fs_info;
+ struct extent_buffer *buf;
+
+ buf = btrfs_find_create_tree_block(fs_info, bytenr);
+ if (IS_ERR(buf))
+ return buf;
+
+ /*
+ * Extra safety check in case the extent tree is corrupted and extent
+ * allocator chooses to use a tree block which is already used and
+ * locked.
+ */
+ if (buf->lock_owner == current->pid) {
+ btrfs_err_rl(fs_info,
+"tree block %llu owner %llu already locked by pid=%d, extent tree corruption detected",
+ buf->start, btrfs_header_owner(buf), current->pid);
+ free_extent_buffer(buf);
+ return ERR_PTR(-EUCLEAN);
+ }
+
+ btrfs_set_buffer_lockdep_class(owner, buf, level);
+ btrfs_tree_lock(buf);
+ btrfs_clean_tree_block(buf);
+ clear_bit(EXTENT_BUFFER_STALE, &buf->bflags);
+
+ btrfs_set_lock_blocking_write(buf);
+ set_extent_buffer_uptodate(buf);
+
+ memzero_extent_buffer(buf, 0, sizeof(struct btrfs_header));
+ btrfs_set_header_level(buf, level);
+ btrfs_set_header_bytenr(buf, buf->start);
+ btrfs_set_header_generation(buf, trans->transid);
+ btrfs_set_header_backref_rev(buf, BTRFS_MIXED_BACKREF_REV);
+ btrfs_set_header_owner(buf, owner);
+ write_extent_buffer_fsid(buf, fs_info->fs_devices->metadata_uuid);
+ write_extent_buffer_chunk_tree_uuid(buf, fs_info->chunk_tree_uuid);
+ if (root->root_key.objectid == BTRFS_TREE_LOG_OBJECTID) {
+ buf->log_index = root->log_transid % 2;
+ /*
+ * we allow two log transactions at a time, use different
+ * EXTENT bit to differentiate dirty pages.
+ */
+ if (buf->log_index == 0)
+ set_extent_dirty(&root->dirty_log_pages, buf->start,
+ buf->start + buf->len - 1, GFP_NOFS);
+ else
+ set_extent_new(&root->dirty_log_pages, buf->start,
+ buf->start + buf->len - 1);
+ } else {
+ buf->log_index = -1;
+ set_extent_dirty(&trans->transaction->dirty_pages, buf->start,
+ buf->start + buf->len - 1, GFP_NOFS);
+ }
+ trans->dirty = true;
+ /* this returns a buffer locked for blocking */
+ return buf;
+}
+
+/*
+ * finds a free extent and does all the dirty work required for allocation
+ * returns the tree buffer or an ERR_PTR on error.
+ */
+struct extent_buffer *btrfs_alloc_tree_block(struct btrfs_trans_handle *trans,
+ struct btrfs_root *root,
+ u64 parent, u64 root_objectid,
+ const struct btrfs_disk_key *key,
+ int level, u64 hint,
+ u64 empty_size)
+{
+ struct btrfs_fs_info *fs_info = root->fs_info;
+ struct btrfs_key ins;
+ struct btrfs_block_rsv *block_rsv;
+ struct extent_buffer *buf;
+ struct btrfs_delayed_extent_op *extent_op;
+ struct btrfs_ref generic_ref = { 0 };
+ u64 flags = 0;
+ int ret;
+ u32 blocksize = fs_info->nodesize;
+ bool skinny_metadata = btrfs_fs_incompat(fs_info, SKINNY_METADATA);
+
+#ifdef CONFIG_BTRFS_FS_RUN_SANITY_TESTS
+ if (btrfs_is_testing(fs_info)) {
+ buf = btrfs_init_new_buffer(trans, root, root->alloc_bytenr,
+ level, root_objectid);
+ if (!IS_ERR(buf))
+ root->alloc_bytenr += blocksize;
+ return buf;
+ }
+#endif
+
+ block_rsv = btrfs_use_block_rsv(trans, root, blocksize);
+ if (IS_ERR(block_rsv))
+ return ERR_CAST(block_rsv);
+
+ ret = btrfs_reserve_extent(root, blocksize, blocksize, blocksize,
+ empty_size, hint, &ins, 0, 0);
+ if (ret)
+ goto out_unuse;
+
+ buf = btrfs_init_new_buffer(trans, root, ins.objectid, level,
+ root_objectid);
+ if (IS_ERR(buf)) {
+ ret = PTR_ERR(buf);
+ goto out_free_reserved;
+ }
+
+ if (root_objectid == BTRFS_TREE_RELOC_OBJECTID) {
+ if (parent == 0)
+ parent = ins.objectid;
+ flags |= BTRFS_BLOCK_FLAG_FULL_BACKREF;
+ } else
+ BUG_ON(parent > 0);
+
+ if (root_objectid != BTRFS_TREE_LOG_OBJECTID) {
+ extent_op = btrfs_alloc_delayed_extent_op();
+ if (!extent_op) {
+ ret = -ENOMEM;
+ goto out_free_buf;
+ }
+ if (key)
+ memcpy(&extent_op->key, key, sizeof(extent_op->key));
+ else
+ memset(&extent_op->key, 0, sizeof(extent_op->key));
+ extent_op->flags_to_set = flags;
+ extent_op->update_key = skinny_metadata ? false : true;
+ extent_op->update_flags = true;
+ extent_op->is_data = false;
+ extent_op->level = level;
+
+ btrfs_init_generic_ref(&generic_ref, BTRFS_ADD_DELAYED_EXTENT,
+ ins.objectid, ins.offset, parent);
+ generic_ref.real_root = root->root_key.objectid;
+ btrfs_init_tree_ref(&generic_ref, level, root_objectid);
+ btrfs_ref_tree_mod(fs_info, &generic_ref);
+ ret = btrfs_add_delayed_tree_ref(trans, &generic_ref,
+ extent_op, NULL, NULL);
+ if (ret)
+ goto out_free_delayed;
+ }
+ return buf;
+
+out_free_delayed:
+ btrfs_free_delayed_extent_op(extent_op);
+out_free_buf:
+ btrfs_tree_unlock(buf);
+ free_extent_buffer(buf);
+out_free_reserved:
+ btrfs_free_reserved_extent(fs_info, ins.objectid, ins.offset, 0);
+out_unuse:
+ btrfs_unuse_block_rsv(fs_info, block_rsv, blocksize);
+ return ERR_PTR(ret);
+}
+
+struct walk_control {
+ u64 refs[BTRFS_MAX_LEVEL];
+ u64 flags[BTRFS_MAX_LEVEL];
+ struct btrfs_key update_progress;
+ struct btrfs_key drop_progress;
+ int drop_level;
+ int stage;
+ int level;
+ int shared_level;
+ int update_ref;
+ int keep_locks;
+ int reada_slot;
+ int reada_count;
+ int restarted;
+};
+
+#define DROP_REFERENCE 1
+#define UPDATE_BACKREF 2
+
+static noinline void reada_walk_down(struct btrfs_trans_handle *trans,
+ struct btrfs_root *root,
+ struct walk_control *wc,
+ struct btrfs_path *path)
+{
+ struct btrfs_fs_info *fs_info = root->fs_info;
+ u64 bytenr;
+ u64 generation;
+ u64 refs;
+ u64 flags;
+ u32 nritems;
+ struct btrfs_key key;
+ struct extent_buffer *eb;
+ int ret;
+ int slot;
+ int nread = 0;
+
+ if (path->slots[wc->level] < wc->reada_slot) {
+ wc->reada_count = wc->reada_count * 2 / 3;
+ wc->reada_count = max(wc->reada_count, 2);
+ } else {
+ wc->reada_count = wc->reada_count * 3 / 2;
+ wc->reada_count = min_t(int, wc->reada_count,
+ BTRFS_NODEPTRS_PER_BLOCK(fs_info));
+ }
+
+ eb = path->nodes[wc->level];
+ nritems = btrfs_header_nritems(eb);
+
+ for (slot = path->slots[wc->level]; slot < nritems; slot++) {
+ if (nread >= wc->reada_count)
+ break;
+
+ cond_resched();
+ bytenr = btrfs_node_blockptr(eb, slot);
+ generation = btrfs_node_ptr_generation(eb, slot);
+
+ if (slot == path->slots[wc->level])
+ goto reada;
+
+ if (wc->stage == UPDATE_BACKREF &&
+ generation <= root->root_key.offset)
+ continue;
+
+ /* We don't lock the tree block, it's OK to be racy here */
+ ret = btrfs_lookup_extent_info(trans, fs_info, bytenr,
+ wc->level - 1, 1, &refs,
+ &flags);
+ /* We don't care about errors in readahead. */
+ if (ret < 0)
+ continue;
+
+ /*
+ * This could be racey, it's conceivable that we raced and end
+ * up with a bogus refs count, if that's the case just skip, if
+ * we are actually corrupt we will notice when we look up
+ * everything again with our locks.
+ */
+ if (refs == 0)
+ continue;
+
+ if (wc->stage == DROP_REFERENCE) {
+ if (refs == 1)
+ goto reada;
+
+ if (wc->level == 1 &&
+ (flags & BTRFS_BLOCK_FLAG_FULL_BACKREF))
+ continue;
+ if (!wc->update_ref ||
+ generation <= root->root_key.offset)
+ continue;
+ btrfs_node_key_to_cpu(eb, &key, slot);
+ ret = btrfs_comp_cpu_keys(&key,
+ &wc->update_progress);
+ if (ret < 0)
+ continue;
+ } else {
+ if (wc->level == 1 &&
+ (flags & BTRFS_BLOCK_FLAG_FULL_BACKREF))
+ continue;
+ }
+reada:
+ readahead_tree_block(fs_info, bytenr);
+ nread++;
+ }
+ wc->reada_slot = slot;
+}
+
+/*
+ * helper to process tree block while walking down the tree.
+ *
+ * when wc->stage == UPDATE_BACKREF, this function updates
+ * back refs for pointers in the block.
+ *
+ * NOTE: return value 1 means we should stop walking down.
+ */
+static noinline int walk_down_proc(struct btrfs_trans_handle *trans,
+ struct btrfs_root *root,
+ struct btrfs_path *path,
+ struct walk_control *wc, int lookup_info)
+{
+ struct btrfs_fs_info *fs_info = root->fs_info;
+ int level = wc->level;
+ struct extent_buffer *eb = path->nodes[level];
+ u64 flag = BTRFS_BLOCK_FLAG_FULL_BACKREF;
+ int ret;
+
+ if (wc->stage == UPDATE_BACKREF &&
+ btrfs_header_owner(eb) != root->root_key.objectid)
+ return 1;
+
+ /*
+ * when reference count of tree block is 1, it won't increase
+ * again. once full backref flag is set, we never clear it.
+ */
+ if (lookup_info &&
+ ((wc->stage == DROP_REFERENCE && wc->refs[level] != 1) ||
+ (wc->stage == UPDATE_BACKREF && !(wc->flags[level] & flag)))) {
+ ASSERT(path->locks[level]);
+ ret = btrfs_lookup_extent_info(trans, fs_info,
+ eb->start, level, 1,
+ &wc->refs[level],
+ &wc->flags[level]);
+ BUG_ON(ret == -ENOMEM);
+ if (ret)
+ return ret;
+ if (unlikely(wc->refs[level] == 0)) {
+ btrfs_err(fs_info, "bytenr %llu has 0 references, expect > 0",
+ eb->start);
+ return -EUCLEAN;
+ }
+ }
+
+ if (wc->stage == DROP_REFERENCE) {
+ if (wc->refs[level] > 1)
+ return 1;
+
+ if (path->locks[level] && !wc->keep_locks) {
+ btrfs_tree_unlock_rw(eb, path->locks[level]);
+ path->locks[level] = 0;
+ }
+ return 0;
+ }
+
+ /* wc->stage == UPDATE_BACKREF */
+ if (!(wc->flags[level] & flag)) {
+ ASSERT(path->locks[level]);
+ ret = btrfs_inc_ref(trans, root, eb, 1);
+ BUG_ON(ret); /* -ENOMEM */
+ ret = btrfs_dec_ref(trans, root, eb, 0);
+ BUG_ON(ret); /* -ENOMEM */
+ ret = btrfs_set_disk_extent_flags(trans, eb->start,
+ eb->len, flag,
+ btrfs_header_level(eb), 0);
+ BUG_ON(ret); /* -ENOMEM */
+ wc->flags[level] |= flag;
+ }
+
+ /*
+ * the block is shared by multiple trees, so it's not good to
+ * keep the tree lock
+ */
+ if (path->locks[level] && level > 0) {
+ btrfs_tree_unlock_rw(eb, path->locks[level]);
+ path->locks[level] = 0;
+ }
+ return 0;
+}
+
+/*
+ * This is used to verify a ref exists for this root to deal with a bug where we
+ * would have a drop_progress key that hadn't been updated properly.
+ */
+static int check_ref_exists(struct btrfs_trans_handle *trans,
+ struct btrfs_root *root, u64 bytenr, u64 parent,
+ int level)
+{
+ struct btrfs_path *path;
+ struct btrfs_extent_inline_ref *iref;
+ int ret;
+
+ path = btrfs_alloc_path();
+ if (!path)
+ return -ENOMEM;
+
+ ret = lookup_extent_backref(trans, path, &iref, bytenr,
+ root->fs_info->nodesize, parent,
+ root->root_key.objectid, level, 0);
+ btrfs_free_path(path);
+ if (ret == -ENOENT)
+ return 0;
+ if (ret < 0)
+ return ret;
+ return 1;
+}
+
+/*
+ * helper to process tree block pointer.
+ *
+ * when wc->stage == DROP_REFERENCE, this function checks
+ * reference count of the block pointed to. if the block
+ * is shared and we need update back refs for the subtree
+ * rooted at the block, this function changes wc->stage to
+ * UPDATE_BACKREF. if the block is shared and there is no
+ * need to update back, this function drops the reference
+ * to the block.
+ *
+ * NOTE: return value 1 means we should stop walking down.
+ */
+static noinline int do_walk_down(struct btrfs_trans_handle *trans,
+ struct btrfs_root *root,
+ struct btrfs_path *path,
+ struct walk_control *wc, int *lookup_info)
+{
+ struct btrfs_fs_info *fs_info = root->fs_info;
+ u64 bytenr;
+ u64 generation;
+ u64 parent;
+ struct btrfs_key key;
+ struct btrfs_key first_key;
+ struct btrfs_ref ref = { 0 };
+ struct extent_buffer *next;
+ int level = wc->level;
+ int reada = 0;
+ int ret = 0;
+ bool need_account = false;
+
+ generation = btrfs_node_ptr_generation(path->nodes[level],
+ path->slots[level]);
+ /*
+ * if the lower level block was created before the snapshot
+ * was created, we know there is no need to update back refs
+ * for the subtree
+ */
+ if (wc->stage == UPDATE_BACKREF &&
+ generation <= root->root_key.offset) {
+ *lookup_info = 1;
+ return 1;
+ }
+
+ bytenr = btrfs_node_blockptr(path->nodes[level], path->slots[level]);
+ btrfs_node_key_to_cpu(path->nodes[level], &first_key,
+ path->slots[level]);
+
+ next = find_extent_buffer(fs_info, bytenr);
+ if (!next) {
+ next = btrfs_find_create_tree_block(fs_info, bytenr);
+ if (IS_ERR(next))
+ return PTR_ERR(next);
+
+ btrfs_set_buffer_lockdep_class(root->root_key.objectid, next,
+ level - 1);
+ reada = 1;
+ }
+ btrfs_tree_lock(next);
+ btrfs_set_lock_blocking_write(next);
+
+ ret = btrfs_lookup_extent_info(trans, fs_info, bytenr, level - 1, 1,
+ &wc->refs[level - 1],
+ &wc->flags[level - 1]);
+ if (ret < 0)
+ goto out_unlock;
+
+ if (unlikely(wc->refs[level - 1] == 0)) {
+ btrfs_err(fs_info, "bytenr %llu has 0 references, expect > 0",
+ bytenr);
+ ret = -EUCLEAN;
+ goto out_unlock;
+ }
+ *lookup_info = 0;
+
+ if (wc->stage == DROP_REFERENCE) {
+ if (wc->refs[level - 1] > 1) {
+ need_account = true;
+ if (level == 1 &&
+ (wc->flags[0] & BTRFS_BLOCK_FLAG_FULL_BACKREF))
+ goto skip;
+
+ if (!wc->update_ref ||
+ generation <= root->root_key.offset)
+ goto skip;
+
+ btrfs_node_key_to_cpu(path->nodes[level], &key,
+ path->slots[level]);
+ ret = btrfs_comp_cpu_keys(&key, &wc->update_progress);
+ if (ret < 0)
+ goto skip;
+
+ wc->stage = UPDATE_BACKREF;
+ wc->shared_level = level - 1;
+ }
+ } else {
+ if (level == 1 &&
+ (wc->flags[0] & BTRFS_BLOCK_FLAG_FULL_BACKREF))
+ goto skip;
+ }
+
+ if (!btrfs_buffer_uptodate(next, generation, 0)) {
+ btrfs_tree_unlock(next);
+ free_extent_buffer(next);
+ next = NULL;
+ *lookup_info = 1;
+ }
+
+ if (!next) {
+ if (reada && level == 1)
+ reada_walk_down(trans, root, wc, path);
+ next = read_tree_block(fs_info, bytenr, generation, level - 1,
+ &first_key);
+ if (IS_ERR(next)) {
+ return PTR_ERR(next);
+ } else if (!extent_buffer_uptodate(next)) {
+ free_extent_buffer(next);
+ return -EIO;
+ }
+ btrfs_tree_lock(next);
+ btrfs_set_lock_blocking_write(next);
+ }
+
+ level--;
+ ASSERT(level == btrfs_header_level(next));
+ if (level != btrfs_header_level(next)) {
+ btrfs_err(root->fs_info, "mismatched level");
+ ret = -EIO;
+ goto out_unlock;
+ }
+ path->nodes[level] = next;
+ path->slots[level] = 0;
+ path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
+ wc->level = level;
+ if (wc->level == 1)
+ wc->reada_slot = 0;
+ return 0;
+skip:
+ wc->refs[level - 1] = 0;
+ wc->flags[level - 1] = 0;
+ if (wc->stage == DROP_REFERENCE) {
+ if (wc->flags[level] & BTRFS_BLOCK_FLAG_FULL_BACKREF) {
+ parent = path->nodes[level]->start;
+ } else {
+ ASSERT(root->root_key.objectid ==
+ btrfs_header_owner(path->nodes[level]));
+ if (root->root_key.objectid !=
+ btrfs_header_owner(path->nodes[level])) {
+ btrfs_err(root->fs_info,
+ "mismatched block owner");
+ ret = -EIO;
+ goto out_unlock;
+ }
+ parent = 0;
+ }
+
+ /*
+ * If we had a drop_progress we need to verify the refs are set
+ * as expected. If we find our ref then we know that from here
+ * on out everything should be correct, and we can clear the
+ * ->restarted flag.
+ */
+ if (wc->restarted) {
+ ret = check_ref_exists(trans, root, bytenr, parent,
+ level - 1);
+ if (ret < 0)
+ goto out_unlock;
+ if (ret == 0)
+ goto no_delete;
+ ret = 0;
+ wc->restarted = 0;
+ }
+
+ /*
+ * Reloc tree doesn't contribute to qgroup numbers, and we have
+ * already accounted them at merge time (replace_path),
+ * thus we could skip expensive subtree trace here.
+ */
+ if (root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID &&
+ need_account) {
+ ret = btrfs_qgroup_trace_subtree(trans, next,
+ generation, level - 1);
+ if (ret) {
+ btrfs_err_rl(fs_info,
+ "Error %d accounting shared subtree. Quota is out of sync, rescan required.",
+ ret);
+ }
+ }
+
+ /*
+ * We need to update the next key in our walk control so we can
+ * update the drop_progress key accordingly. We don't care if
+ * find_next_key doesn't find a key because that means we're at
+ * the end and are going to clean up now.
+ */
+ wc->drop_level = level;
+ find_next_key(path, level, &wc->drop_progress);
+
+ btrfs_init_generic_ref(&ref, BTRFS_DROP_DELAYED_REF, bytenr,
+ fs_info->nodesize, parent);
+ btrfs_init_tree_ref(&ref, level - 1, root->root_key.objectid);
+ ret = btrfs_free_extent(trans, &ref);
+ if (ret)
+ goto out_unlock;
+ }
+no_delete:
+ *lookup_info = 1;
+ ret = 1;
+
+out_unlock:
+ btrfs_tree_unlock(next);
+ free_extent_buffer(next);
+
+ return ret;
+}
+
+/*
+ * helper to process tree block while walking up the tree.
+ *
+ * when wc->stage == DROP_REFERENCE, this function drops
+ * reference count on the block.
+ *
+ * when wc->stage == UPDATE_BACKREF, this function changes
+ * wc->stage back to DROP_REFERENCE if we changed wc->stage
+ * to UPDATE_BACKREF previously while processing the block.
+ *
+ * NOTE: return value 1 means we should stop walking up.
+ */
+static noinline int walk_up_proc(struct btrfs_trans_handle *trans,
+ struct btrfs_root *root,
+ struct btrfs_path *path,
+ struct walk_control *wc)
+{
+ struct btrfs_fs_info *fs_info = root->fs_info;
+ int ret;
+ int level = wc->level;
+ struct extent_buffer *eb = path->nodes[level];
+ u64 parent = 0;
+
+ if (wc->stage == UPDATE_BACKREF) {
+ BUG_ON(wc->shared_level < level);
+ if (level < wc->shared_level)
+ goto out;
+
+ ret = find_next_key(path, level + 1, &wc->update_progress);
+ if (ret > 0)
+ wc->update_ref = 0;
+
+ wc->stage = DROP_REFERENCE;
+ wc->shared_level = -1;
+ path->slots[level] = 0;
+
+ /*
+ * check reference count again if the block isn't locked.
+ * we should start walking down the tree again if reference
+ * count is one.
+ */
+ if (!path->locks[level]) {
+ BUG_ON(level == 0);
+ btrfs_tree_lock(eb);
+ btrfs_set_lock_blocking_write(eb);
+ path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
+
+ ret = btrfs_lookup_extent_info(trans, fs_info,
+ eb->start, level, 1,
+ &wc->refs[level],
+ &wc->flags[level]);
+ if (ret < 0) {
+ btrfs_tree_unlock_rw(eb, path->locks[level]);
+ path->locks[level] = 0;
+ return ret;
+ }
+ if (unlikely(wc->refs[level] == 0)) {
+ btrfs_tree_unlock_rw(eb, path->locks[level]);
+ btrfs_err(fs_info, "bytenr %llu has 0 references, expect > 0",
+ eb->start);
+ return -EUCLEAN;
+ }
+ if (wc->refs[level] == 1) {
+ btrfs_tree_unlock_rw(eb, path->locks[level]);
+ path->locks[level] = 0;
+ return 1;
+ }
+ }
+ }
+
+ /* wc->stage == DROP_REFERENCE */
+ BUG_ON(wc->refs[level] > 1 && !path->locks[level]);
+
+ if (wc->refs[level] == 1) {
+ if (level == 0) {
+ if (wc->flags[level] & BTRFS_BLOCK_FLAG_FULL_BACKREF)
+ ret = btrfs_dec_ref(trans, root, eb, 1);
+ else
+ ret = btrfs_dec_ref(trans, root, eb, 0);
+ BUG_ON(ret); /* -ENOMEM */
+ if (is_fstree(root->root_key.objectid)) {
+ ret = btrfs_qgroup_trace_leaf_items(trans, eb);
+ if (ret) {
+ btrfs_err_rl(fs_info,
+ "error %d accounting leaf items, quota is out of sync, rescan required",
+ ret);
+ }
+ }
+ }
+ /* make block locked assertion in btrfs_clean_tree_block happy */
+ if (!path->locks[level] &&
+ btrfs_header_generation(eb) == trans->transid) {
+ btrfs_tree_lock(eb);
+ btrfs_set_lock_blocking_write(eb);
+ path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
+ }
+ btrfs_clean_tree_block(eb);
+ }
+
+ if (eb == root->node) {
+ if (wc->flags[level] & BTRFS_BLOCK_FLAG_FULL_BACKREF)
+ parent = eb->start;
+ else if (root->root_key.objectid != btrfs_header_owner(eb))
+ goto owner_mismatch;
+ } else {
+ if (wc->flags[level + 1] & BTRFS_BLOCK_FLAG_FULL_BACKREF)
+ parent = path->nodes[level + 1]->start;
+ else if (root->root_key.objectid !=
+ btrfs_header_owner(path->nodes[level + 1]))
+ goto owner_mismatch;
+ }
+
+ btrfs_free_tree_block(trans, root, eb, parent, wc->refs[level] == 1);
+out:
+ wc->refs[level] = 0;
+ wc->flags[level] = 0;
+ return 0;
+
+owner_mismatch:
+ btrfs_err_rl(fs_info, "unexpected tree owner, have %llu expect %llu",
+ btrfs_header_owner(eb), root->root_key.objectid);
+ return -EUCLEAN;
+}
+
+static noinline int walk_down_tree(struct btrfs_trans_handle *trans,
+ struct btrfs_root *root,
+ struct btrfs_path *path,
+ struct walk_control *wc)
+{
+ int level = wc->level;
+ int lookup_info = 1;
+ int ret;
+
+ while (level >= 0) {
+ ret = walk_down_proc(trans, root, path, wc, lookup_info);
+ if (ret > 0)
+ break;
+
+ if (level == 0)
+ break;
+
+ if (path->slots[level] >=
+ btrfs_header_nritems(path->nodes[level]))
+ break;
+
+ ret = do_walk_down(trans, root, path, wc, &lookup_info);
+ if (ret > 0) {
+ path->slots[level]++;
+ continue;
+ } else if (ret < 0)
+ return ret;
+ level = wc->level;
+ }
+ return 0;
+}
+
+static noinline int walk_up_tree(struct btrfs_trans_handle *trans,
+ struct btrfs_root *root,
+ struct btrfs_path *path,
+ struct walk_control *wc, int max_level)
+{
+ int level = wc->level;
+ int ret;
+
+ path->slots[level] = btrfs_header_nritems(path->nodes[level]);
+ while (level < max_level && path->nodes[level]) {
+ wc->level = level;
+ if (path->slots[level] + 1 <
+ btrfs_header_nritems(path->nodes[level])) {
+ path->slots[level]++;
+ return 0;
+ } else {
+ ret = walk_up_proc(trans, root, path, wc);
+ if (ret > 0)
+ return 0;
+ if (ret < 0)
+ return ret;
+
+ if (path->locks[level]) {
+ btrfs_tree_unlock_rw(path->nodes[level],
+ path->locks[level]);
+ path->locks[level] = 0;
+ }
+ free_extent_buffer(path->nodes[level]);
+ path->nodes[level] = NULL;
+ level++;
+ }
+ }
+ return 1;
+}
+
+/*
+ * drop a subvolume tree.
+ *
+ * this function traverses the tree freeing any blocks that only
+ * referenced by the tree.
+ *
+ * when a shared tree block is found. this function decreases its
+ * reference count by one. if update_ref is true, this function
+ * also make sure backrefs for the shared block and all lower level
+ * blocks are properly updated.
+ *
+ * If called with for_reloc == 0, may exit early with -EAGAIN
+ */
+int btrfs_drop_snapshot(struct btrfs_root *root,
+ struct btrfs_block_rsv *block_rsv, int update_ref,
+ int for_reloc)
+{
+ struct btrfs_fs_info *fs_info = root->fs_info;
+ struct btrfs_path *path;
+ struct btrfs_trans_handle *trans;
+ struct btrfs_root *tree_root = fs_info->tree_root;
+ struct btrfs_root_item *root_item = &root->root_item;
+ struct walk_control *wc;
+ struct btrfs_key key;
+ int err = 0;
+ int ret;
+ int level;
+ bool root_dropped = false;
+
+ btrfs_debug(fs_info, "Drop subvolume %llu", root->root_key.objectid);
+
+ path = btrfs_alloc_path();
+ if (!path) {
+ err = -ENOMEM;
+ goto out;
+ }
+
+ wc = kzalloc(sizeof(*wc), GFP_NOFS);
+ if (!wc) {
+ btrfs_free_path(path);
+ err = -ENOMEM;
+ goto out;
+ }
+
+ /*
+ * Use join to avoid potential EINTR from transaction start. See
+ * wait_reserve_ticket and the whole reservation callchain.
+ */
+ if (for_reloc)
+ trans = btrfs_join_transaction(tree_root);
+ else
+ trans = btrfs_start_transaction(tree_root, 0);
+ if (IS_ERR(trans)) {
+ err = PTR_ERR(trans);
+ goto out_free;
+ }
+
+ err = btrfs_run_delayed_items(trans);
+ if (err)
+ goto out_end_trans;
+
+ if (block_rsv)
+ trans->block_rsv = block_rsv;
+
+ /*
+ * This will help us catch people modifying the fs tree while we're
+ * dropping it. It is unsafe to mess with the fs tree while it's being
+ * dropped as we unlock the root node and parent nodes as we walk down
+ * the tree, assuming nothing will change. If something does change
+ * then we'll have stale information and drop references to blocks we've
+ * already dropped.
+ */
+ set_bit(BTRFS_ROOT_DELETING, &root->state);
+ if (btrfs_disk_key_objectid(&root_item->drop_progress) == 0) {
+ level = btrfs_header_level(root->node);
+ path->nodes[level] = btrfs_lock_root_node(root);
+ btrfs_set_lock_blocking_write(path->nodes[level]);
+ path->slots[level] = 0;
+ path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
+ memset(&wc->update_progress, 0,
+ sizeof(wc->update_progress));
+ } else {
+ btrfs_disk_key_to_cpu(&key, &root_item->drop_progress);
+ memcpy(&wc->update_progress, &key,
+ sizeof(wc->update_progress));
+
+ level = root_item->drop_level;
+ BUG_ON(level == 0);
+ path->lowest_level = level;
+ ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
+ path->lowest_level = 0;
+ if (ret < 0) {
+ err = ret;
+ goto out_end_trans;
+ }
+ WARN_ON(ret > 0);
+
+ /*
+ * unlock our path, this is safe because only this
+ * function is allowed to delete this snapshot
+ */
+ btrfs_unlock_up_safe(path, 0);
+
+ level = btrfs_header_level(root->node);
+ while (1) {
+ btrfs_tree_lock(path->nodes[level]);
+ btrfs_set_lock_blocking_write(path->nodes[level]);
+ path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
+
+ ret = btrfs_lookup_extent_info(trans, fs_info,
+ path->nodes[level]->start,
+ level, 1, &wc->refs[level],
+ &wc->flags[level]);
+ if (ret < 0) {
+ err = ret;
+ goto out_end_trans;
+ }
+ BUG_ON(wc->refs[level] == 0);
+
+ if (level == root_item->drop_level)
+ break;
+
+ btrfs_tree_unlock(path->nodes[level]);
+ path->locks[level] = 0;
+ WARN_ON(wc->refs[level] != 1);
+ level--;
+ }
+ }
+
+ wc->restarted = test_bit(BTRFS_ROOT_DEAD_TREE, &root->state);
+ wc->level = level;
+ wc->shared_level = -1;
+ wc->stage = DROP_REFERENCE;
+ wc->update_ref = update_ref;
+ wc->keep_locks = 0;
+ wc->reada_count = BTRFS_NODEPTRS_PER_BLOCK(fs_info);
+
+ while (1) {
+
+ ret = walk_down_tree(trans, root, path, wc);
+ if (ret < 0) {
+ err = ret;
+ break;
+ }
+
+ ret = walk_up_tree(trans, root, path, wc, BTRFS_MAX_LEVEL);
+ if (ret < 0) {
+ err = ret;
+ break;
+ }
+
+ if (ret > 0) {
+ BUG_ON(wc->stage != DROP_REFERENCE);
+ break;
+ }
+
+ if (wc->stage == DROP_REFERENCE) {
+ wc->drop_level = wc->level;
+ btrfs_node_key_to_cpu(path->nodes[wc->drop_level],
+ &wc->drop_progress,
+ path->slots[wc->drop_level]);
+ }
+ btrfs_cpu_key_to_disk(&root_item->drop_progress,
+ &wc->drop_progress);
+ root_item->drop_level = wc->drop_level;
+
+ BUG_ON(wc->level == 0);
+ if (btrfs_should_end_transaction(trans) ||
+ (!for_reloc && btrfs_need_cleaner_sleep(fs_info))) {
+ ret = btrfs_update_root(trans, tree_root,
+ &root->root_key,
+ root_item);
+ if (ret) {
+ btrfs_abort_transaction(trans, ret);
+ err = ret;
+ goto out_end_trans;
+ }
+
+ btrfs_end_transaction_throttle(trans);
+ if (!for_reloc && btrfs_need_cleaner_sleep(fs_info)) {
+ btrfs_debug(fs_info,
+ "drop snapshot early exit");
+ err = -EAGAIN;
+ goto out_free;
+ }
+
+ /*
+ * Use join to avoid potential EINTR from transaction
+ * start. See wait_reserve_ticket and the whole
+ * reservation callchain.
+ */
+ if (for_reloc)
+ trans = btrfs_join_transaction(tree_root);
+ else
+ trans = btrfs_start_transaction(tree_root, 0);
+ if (IS_ERR(trans)) {
+ err = PTR_ERR(trans);
+ goto out_free;
+ }
+ if (block_rsv)
+ trans->block_rsv = block_rsv;
+ }
+ }
+ btrfs_release_path(path);
+ if (err)
+ goto out_end_trans;
+
+ ret = btrfs_del_root(trans, &root->root_key);
+ if (ret) {
+ btrfs_abort_transaction(trans, ret);
+ err = ret;
+ goto out_end_trans;
+ }
+
+ if (root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID) {
+ ret = btrfs_find_root(tree_root, &root->root_key, path,
+ NULL, NULL);
+ if (ret < 0) {
+ btrfs_abort_transaction(trans, ret);
+ err = ret;
+ goto out_end_trans;
+ } else if (ret > 0) {
+ /* if we fail to delete the orphan item this time
+ * around, it'll get picked up the next time.
+ *
+ * The most common failure here is just -ENOENT.
+ */
+ btrfs_del_orphan_item(trans, tree_root,
+ root->root_key.objectid);
+ }
+ }
+
+ if (test_bit(BTRFS_ROOT_IN_RADIX, &root->state)) {
+ btrfs_add_dropped_root(trans, root);
+ } else {
+ free_extent_buffer(root->node);
+ free_extent_buffer(root->commit_root);
+ btrfs_put_fs_root(root);
+ }
+ root_dropped = true;
+out_end_trans:
+ btrfs_end_transaction_throttle(trans);
+out_free:
+ kfree(wc);
+ btrfs_free_path(path);
+out:
+ /*
+ * So if we need to stop dropping the snapshot for whatever reason we
+ * need to make sure to add it back to the dead root list so that we
+ * keep trying to do the work later. This also cleans up roots if we
+ * don't have it in the radix (like when we recover after a power fail
+ * or unmount) so we don't leak memory.
+ */
+ if (!for_reloc && !root_dropped)
+ btrfs_add_dead_root(root);
+ return err;
+}
+
+/*
+ * drop subtree rooted at tree block 'node'.
+ *
+ * NOTE: this function will unlock and release tree block 'node'
+ * only used by relocation code
+ */
+int btrfs_drop_subtree(struct btrfs_trans_handle *trans,
+ struct btrfs_root *root,
+ struct extent_buffer *node,
+ struct extent_buffer *parent)
+{
+ struct btrfs_fs_info *fs_info = root->fs_info;
+ struct btrfs_path *path;
+ struct walk_control *wc;
+ int level;
+ int parent_level;
+ int ret = 0;
+ int wret;
+
+ BUG_ON(root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID);
+
+ path = btrfs_alloc_path();
+ if (!path)
+ return -ENOMEM;
+
+ wc = kzalloc(sizeof(*wc), GFP_NOFS);
+ if (!wc) {
+ btrfs_free_path(path);
+ return -ENOMEM;
+ }
+
+ btrfs_assert_tree_locked(parent);
+ parent_level = btrfs_header_level(parent);
+ extent_buffer_get(parent);
+ path->nodes[parent_level] = parent;
+ path->slots[parent_level] = btrfs_header_nritems(parent);
+
+ btrfs_assert_tree_locked(node);
+ level = btrfs_header_level(node);
+ path->nodes[level] = node;
+ path->slots[level] = 0;
+ path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
+
+ wc->refs[parent_level] = 1;
+ wc->flags[parent_level] = BTRFS_BLOCK_FLAG_FULL_BACKREF;
+ wc->level = level;
+ wc->shared_level = -1;
+ wc->stage = DROP_REFERENCE;
+ wc->update_ref = 0;
+ wc->keep_locks = 1;
+ wc->reada_count = BTRFS_NODEPTRS_PER_BLOCK(fs_info);
+
+ while (1) {
+ wret = walk_down_tree(trans, root, path, wc);
+ if (wret < 0) {
+ ret = wret;
+ break;
+ }
+
+ wret = walk_up_tree(trans, root, path, wc, parent_level);
+ if (wret < 0)
+ ret = wret;
+ if (wret != 0)
+ break;
+ }
+
+ kfree(wc);
+ btrfs_free_path(path);
+ return ret;
+}
+
+/*
+ * helper to account the unused space of all the readonly block group in the
+ * space_info. takes mirrors into account.
+ */
+u64 btrfs_account_ro_block_groups_free_space(struct btrfs_space_info *sinfo)
+{
+ struct btrfs_block_group_cache *block_group;
+ u64 free_bytes = 0;
+ int factor;
+
+ /* It's df, we don't care if it's racy */
+ if (list_empty(&sinfo->ro_bgs))
+ return 0;
+
+ spin_lock(&sinfo->lock);
+ list_for_each_entry(block_group, &sinfo->ro_bgs, ro_list) {
+ spin_lock(&block_group->lock);
+
+ if (!block_group->ro) {
+ spin_unlock(&block_group->lock);
+ continue;
+ }
+
+ factor = btrfs_bg_type_to_factor(block_group->flags);
+ free_bytes += (block_group->key.offset -
+ btrfs_block_group_used(&block_group->item)) *
+ factor;
+
+ spin_unlock(&block_group->lock);
+ }
+ spin_unlock(&sinfo->lock);
+
+ return free_bytes;
+}
+
+int btrfs_error_unpin_extent_range(struct btrfs_fs_info *fs_info,
+ u64 start, u64 end)
+{
+ return unpin_extent_range(fs_info, start, end, false);
+}
+
+/*
+ * It used to be that old block groups would be left around forever.
+ * Iterating over them would be enough to trim unused space. Since we
+ * now automatically remove them, we also need to iterate over unallocated
+ * space.
+ *
+ * We don't want a transaction for this since the discard may take a
+ * substantial amount of time. We don't require that a transaction be
+ * running, but we do need to take a running transaction into account
+ * to ensure that we're not discarding chunks that were released or
+ * allocated in the current transaction.
+ *
+ * Holding the chunks lock will prevent other threads from allocating
+ * or releasing chunks, but it won't prevent a running transaction
+ * from committing and releasing the memory that the pending chunks
+ * list head uses. For that, we need to take a reference to the
+ * transaction and hold the commit root sem. We only need to hold
+ * it while performing the free space search since we have already
+ * held back allocations.
+ */
+static int btrfs_trim_free_extents(struct btrfs_device *device, u64 *trimmed)
+{
+ u64 start = SZ_1M, len = 0, end = 0;
+ int ret;
+
+ *trimmed = 0;
+
+ /* Discard not supported = nothing to do. */
+ if (!blk_queue_discard(bdev_get_queue(device->bdev)))
+ return 0;
+
+ /* Not writable = nothing to do. */
+ if (!test_bit(BTRFS_DEV_STATE_WRITEABLE, &device->dev_state))
+ return 0;
+
+ /* No free space = nothing to do. */
+ if (device->total_bytes <= device->bytes_used)
+ return 0;
+
+ ret = 0;
+
+ while (1) {
+ struct btrfs_fs_info *fs_info = device->fs_info;
+ u64 bytes;
+
+ ret = mutex_lock_interruptible(&fs_info->chunk_mutex);
+ if (ret)
+ break;
+
+ find_first_clear_extent_bit(&device->alloc_state, start,
+ &start, &end,
+ CHUNK_TRIMMED | CHUNK_ALLOCATED);
+
+ /* Check if there are any CHUNK_* bits left */
+ if (start > device->total_bytes) {
+ WARN_ON(IS_ENABLED(CONFIG_BTRFS_DEBUG));
+ btrfs_warn_in_rcu(fs_info,
+"ignoring attempt to trim beyond device size: offset %llu length %llu device %s device size %llu",
+ start, end - start + 1,
+ rcu_str_deref(device->name),
+ device->total_bytes);
+ mutex_unlock(&fs_info->chunk_mutex);
+ ret = 0;
+ break;
+ }
+
+ /* Ensure we skip the reserved area in the first 1M */
+ start = max_t(u64, start, SZ_1M);
+
+ /*
+ * If find_first_clear_extent_bit find a range that spans the
+ * end of the device it will set end to -1, in this case it's up
+ * to the caller to trim the value to the size of the device.
+ */
+ end = min(end, device->total_bytes - 1);
+
+ len = end - start + 1;
+
+ /* We didn't find any extents */
+ if (!len) {
+ mutex_unlock(&fs_info->chunk_mutex);
+ ret = 0;
+ break;
+ }
+
+ ret = btrfs_issue_discard(device->bdev, start, len,
+ &bytes);
+ if (!ret)
+ set_extent_bits(&device->alloc_state, start,
+ start + bytes - 1,
+ CHUNK_TRIMMED);
+ mutex_unlock(&fs_info->chunk_mutex);
+
+ if (ret)
+ break;
+
+ start += len;
+ *trimmed += bytes;
+
+ if (fatal_signal_pending(current)) {
+ ret = -ERESTARTSYS;
+ break;
+ }
+
+ cond_resched();
+ }
+
+ return ret;
+}
+
+/*
+ * Trim the whole filesystem by:
+ * 1) trimming the free space in each block group
+ * 2) trimming the unallocated space on each device
+ *
+ * This will also continue trimming even if a block group or device encounters
+ * an error. The return value will be the last error, or 0 if nothing bad
+ * happens.
+ */
+int btrfs_trim_fs(struct btrfs_fs_info *fs_info, struct fstrim_range *range)
+{
+ struct btrfs_block_group_cache *cache = NULL;
+ struct btrfs_device *device;
+ struct list_head *devices;
+ u64 group_trimmed;
+ u64 range_end = U64_MAX;
+ u64 start;
+ u64 end;
+ u64 trimmed = 0;
+ u64 bg_failed = 0;
+ u64 dev_failed = 0;
+ int bg_ret = 0;
+ int dev_ret = 0;
+ int ret = 0;
+
+ /*
+ * Check range overflow if range->len is set.
+ * The default range->len is U64_MAX.
+ */
+ if (range->len != U64_MAX &&
+ check_add_overflow(range->start, range->len, &range_end))
+ return -EINVAL;
+
+ cache = btrfs_lookup_first_block_group(fs_info, range->start);
+ for (; cache; cache = btrfs_next_block_group(cache)) {
+ if (cache->key.objectid >= range_end) {
+ btrfs_put_block_group(cache);
+ break;
+ }
+
+ start = max(range->start, cache->key.objectid);
+ end = min(range_end, cache->key.objectid + cache->key.offset);
+
+ if (end - start >= range->minlen) {
+ if (!btrfs_block_group_cache_done(cache)) {
+ ret = btrfs_cache_block_group(cache, 0);
+ if (ret) {
+ bg_failed++;
+ bg_ret = ret;
+ continue;
+ }
+ ret = btrfs_wait_block_group_cache_done(cache);
+ if (ret) {
+ bg_failed++;
+ bg_ret = ret;
+ continue;
+ }
+ }
+ ret = btrfs_trim_block_group(cache,
+ &group_trimmed,
+ start,
+ end,
+ range->minlen);
+
+ trimmed += group_trimmed;
+ if (ret) {
+ bg_failed++;
+ bg_ret = ret;
+ continue;
+ }
+ }
+ }
+
+ if (bg_failed)
+ btrfs_warn(fs_info,
+ "failed to trim %llu block group(s), last error %d",
+ bg_failed, bg_ret);
+ mutex_lock(&fs_info->fs_devices->device_list_mutex);
+ devices = &fs_info->fs_devices->devices;
+ list_for_each_entry(device, devices, dev_list) {
+ if (test_bit(BTRFS_DEV_STATE_MISSING, &device->dev_state))
+ continue;
+
+ ret = btrfs_trim_free_extents(device, &group_trimmed);
+ if (ret) {
+ dev_failed++;
+ dev_ret = ret;
+ break;
+ }
+
+ trimmed += group_trimmed;
+ }
+ mutex_unlock(&fs_info->fs_devices->device_list_mutex);
+
+ if (dev_failed)
+ btrfs_warn(fs_info,
+ "failed to trim %llu device(s), last error %d",
+ dev_failed, dev_ret);
+ range->len = trimmed;
+ if (bg_ret)
+ return bg_ret;
+ return dev_ret;
+}
+
+/*
+ * btrfs_{start,end}_write_no_snapshotting() are similar to
+ * mnt_{want,drop}_write(), they are used to prevent some tasks from writing
+ * data into the page cache through nocow before the subvolume is snapshoted,
+ * but flush the data into disk after the snapshot creation, or to prevent
+ * operations while snapshotting is ongoing and that cause the snapshot to be
+ * inconsistent (writes followed by expanding truncates for example).
+ */
+void btrfs_end_write_no_snapshotting(struct btrfs_root *root)
+{
+ percpu_counter_dec(&root->subv_writers->counter);
+ cond_wake_up(&root->subv_writers->wait);
+}
+
+int btrfs_start_write_no_snapshotting(struct btrfs_root *root)
+{
+ if (atomic_read(&root->will_be_snapshotted))
+ return 0;
+
+ percpu_counter_inc(&root->subv_writers->counter);
+ /*
+ * Make sure counter is updated before we check for snapshot creation.
+ */
+ smp_mb();
+ if (atomic_read(&root->will_be_snapshotted)) {
+ btrfs_end_write_no_snapshotting(root);
+ return 0;
+ }
+ return 1;
+}
+
+void btrfs_wait_for_snapshot_creation(struct btrfs_root *root)
+{
+ while (true) {
+ int ret;
+
+ ret = btrfs_start_write_no_snapshotting(root);
+ if (ret)
+ break;
+ wait_var_event(&root->will_be_snapshotted,
+ !atomic_read(&root->will_be_snapshotted));
+ }
+}