[T106][ZXW-22]7520V3SCV2.01.01.02P42U09_VEC_V0.8_AP_VEC origin source commit
Change-Id: Ic6e05d89ecd62fc34f82b23dcf306c93764aec4b
diff --git a/ap/os/linux/linux-3.4.x/fs/ext4/inode.c b/ap/os/linux/linux-3.4.x/fs/ext4/inode.c
new file mode 100644
index 0000000..facf1cf
--- /dev/null
+++ b/ap/os/linux/linux-3.4.x/fs/ext4/inode.c
@@ -0,0 +1,4740 @@
+/*
+ * linux/fs/ext4/inode.c
+ *
+ * Copyright (C) 1992, 1993, 1994, 1995
+ * Remy Card (card@masi.ibp.fr)
+ * Laboratoire MASI - Institut Blaise Pascal
+ * Universite Pierre et Marie Curie (Paris VI)
+ *
+ * from
+ *
+ * linux/fs/minix/inode.c
+ *
+ * Copyright (C) 1991, 1992 Linus Torvalds
+ *
+ * 64-bit file support on 64-bit platforms by Jakub Jelinek
+ * (jj@sunsite.ms.mff.cuni.cz)
+ *
+ * Assorted race fixes, rewrite of ext4_get_block() by Al Viro, 2000
+ */
+
+#include <linux/fs.h>
+#include <linux/time.h>
+#include <linux/jbd2.h>
+#include <linux/highuid.h>
+#include <linux/pagemap.h>
+#include <linux/quotaops.h>
+#include <linux/string.h>
+#include <linux/buffer_head.h>
+#include <linux/writeback.h>
+#include <linux/pagevec.h>
+#include <linux/mpage.h>
+#include <linux/namei.h>
+#include <linux/uio.h>
+#include <linux/bio.h>
+#include <linux/workqueue.h>
+#include <linux/kernel.h>
+#include <linux/printk.h>
+#include <linux/slab.h>
+#include <linux/ratelimit.h>
+#include <linux/bitops.h>
+
+#include "ext4_jbd2.h"
+#include "xattr.h"
+#include "acl.h"
+#include "truncate.h"
+
+#include <trace/events/ext4.h>
+
+#define MPAGE_DA_EXTENT_TAIL 0x01
+
+static inline int ext4_begin_ordered_truncate(struct inode *inode,
+ loff_t new_size)
+{
+ trace_ext4_begin_ordered_truncate(inode, new_size);
+ /*
+ * If jinode is zero, then we never opened the file for
+ * writing, so there's no need to call
+ * jbd2_journal_begin_ordered_truncate() since there's no
+ * outstanding writes we need to flush.
+ */
+ if (!EXT4_I(inode)->jinode)
+ return 0;
+ return jbd2_journal_begin_ordered_truncate(EXT4_JOURNAL(inode),
+ EXT4_I(inode)->jinode,
+ new_size);
+}
+
+static void ext4_invalidatepage(struct page *page, unsigned long offset);
+static int noalloc_get_block_write(struct inode *inode, sector_t iblock,
+ struct buffer_head *bh_result, int create);
+static int ext4_set_bh_endio(struct buffer_head *bh, struct inode *inode);
+static void ext4_end_io_buffer_write(struct buffer_head *bh, int uptodate);
+static int __ext4_journalled_writepage(struct page *page, unsigned int len);
+static int ext4_bh_delay_or_unwritten(handle_t *handle, struct buffer_head *bh);
+static int ext4_discard_partial_page_buffers_no_lock(handle_t *handle,
+ struct inode *inode, struct page *page, loff_t from,
+ loff_t length, int flags);
+
+/*
+ * Test whether an inode is a fast symlink.
+ */
+static int ext4_inode_is_fast_symlink(struct inode *inode)
+{
+ int ea_blocks = EXT4_I(inode)->i_file_acl ?
+ (inode->i_sb->s_blocksize >> 9) : 0;
+
+ return (S_ISLNK(inode->i_mode) && inode->i_blocks - ea_blocks == 0);
+}
+
+/*
+ * Restart the transaction associated with *handle. This does a commit,
+ * so before we call here everything must be consistently dirtied against
+ * this transaction.
+ */
+int ext4_truncate_restart_trans(handle_t *handle, struct inode *inode,
+ int nblocks)
+{
+ int ret;
+
+ /*
+ * Drop i_data_sem to avoid deadlock with ext4_map_blocks. At this
+ * moment, get_block can be called only for blocks inside i_size since
+ * page cache has been already dropped and writes are blocked by
+ * i_mutex. So we can safely drop the i_data_sem here.
+ */
+ BUG_ON(EXT4_JOURNAL(inode) == NULL);
+ jbd_debug(2, "restarting handle %p\n", handle);
+ up_write(&EXT4_I(inode)->i_data_sem);
+ ret = ext4_journal_restart(handle, nblocks);
+ down_write(&EXT4_I(inode)->i_data_sem);
+ ext4_discard_preallocations(inode);
+
+ return ret;
+}
+
+/*
+ * Called at the last iput() if i_nlink is zero.
+ */
+void ext4_evict_inode(struct inode *inode)
+{
+ handle_t *handle;
+ int err;
+
+ trace_ext4_evict_inode(inode);
+
+ ext4_ioend_wait(inode);
+
+ if (inode->i_nlink) {
+ /*
+ * When journalling data dirty buffers are tracked only in the
+ * journal. So although mm thinks everything is clean and
+ * ready for reaping the inode might still have some pages to
+ * write in the running transaction or waiting to be
+ * checkpointed. Thus calling jbd2_journal_invalidatepage()
+ * (via truncate_inode_pages()) to discard these buffers can
+ * cause data loss. Also even if we did not discard these
+ * buffers, we would have no way to find them after the inode
+ * is reaped and thus user could see stale data if he tries to
+ * read them before the transaction is checkpointed. So be
+ * careful and force everything to disk here... We use
+ * ei->i_datasync_tid to store the newest transaction
+ * containing inode's data.
+ *
+ * Note that directories do not have this problem because they
+ * don't use page cache.
+ */
+ if (ext4_should_journal_data(inode) &&
+ (S_ISLNK(inode->i_mode) || S_ISREG(inode->i_mode)) &&
+ inode->i_ino != EXT4_JOURNAL_INO) {
+ journal_t *journal = EXT4_SB(inode->i_sb)->s_journal;
+ tid_t commit_tid = EXT4_I(inode)->i_datasync_tid;
+
+ jbd2_complete_transaction(journal, commit_tid);
+ filemap_write_and_wait(&inode->i_data);
+ }
+ truncate_inode_pages(&inode->i_data, 0);
+ goto no_delete;
+ }
+
+ if (is_bad_inode(inode))
+ goto no_delete;
+ dquot_initialize(inode);
+
+ if (ext4_should_order_data(inode))
+ ext4_begin_ordered_truncate(inode, 0);
+ truncate_inode_pages(&inode->i_data, 0);
+
+ handle = ext4_journal_start(inode, ext4_blocks_for_truncate(inode)+3);
+ if (IS_ERR(handle)) {
+ ext4_std_error(inode->i_sb, PTR_ERR(handle));
+ /*
+ * If we're going to skip the normal cleanup, we still need to
+ * make sure that the in-core orphan linked list is properly
+ * cleaned up.
+ */
+ ext4_orphan_del(NULL, inode);
+ goto no_delete;
+ }
+
+ if (IS_SYNC(inode))
+ ext4_handle_sync(handle);
+ inode->i_size = 0;
+ err = ext4_mark_inode_dirty(handle, inode);
+ if (err) {
+ ext4_warning(inode->i_sb,
+ "couldn't mark inode dirty (err %d)", err);
+ goto stop_handle;
+ }
+ if (inode->i_blocks)
+ ext4_truncate(inode);
+
+ /*
+ * ext4_ext_truncate() doesn't reserve any slop when it
+ * restarts journal transactions; therefore there may not be
+ * enough credits left in the handle to remove the inode from
+ * the orphan list and set the dtime field.
+ */
+ if (!ext4_handle_has_enough_credits(handle, 3)) {
+ err = ext4_journal_extend(handle, 3);
+ if (err > 0)
+ err = ext4_journal_restart(handle, 3);
+ if (err != 0) {
+ ext4_warning(inode->i_sb,
+ "couldn't extend journal (err %d)", err);
+ stop_handle:
+ ext4_journal_stop(handle);
+ ext4_orphan_del(NULL, inode);
+ goto no_delete;
+ }
+ }
+
+ /*
+ * Kill off the orphan record which ext4_truncate created.
+ * AKPM: I think this can be inside the above `if'.
+ * Note that ext4_orphan_del() has to be able to cope with the
+ * deletion of a non-existent orphan - this is because we don't
+ * know if ext4_truncate() actually created an orphan record.
+ * (Well, we could do this if we need to, but heck - it works)
+ */
+ ext4_orphan_del(handle, inode);
+ EXT4_I(inode)->i_dtime = get_seconds();
+
+ /*
+ * One subtle ordering requirement: if anything has gone wrong
+ * (transaction abort, IO errors, whatever), then we can still
+ * do these next steps (the fs will already have been marked as
+ * having errors), but we can't free the inode if the mark_dirty
+ * fails.
+ */
+ if (ext4_mark_inode_dirty(handle, inode))
+ /* If that failed, just do the required in-core inode clear. */
+ ext4_clear_inode(inode);
+ else
+ ext4_free_inode(handle, inode);
+ ext4_journal_stop(handle);
+ return;
+no_delete:
+ ext4_clear_inode(inode); /* We must guarantee clearing of inode... */
+}
+
+#ifdef CONFIG_QUOTA
+qsize_t *ext4_get_reserved_space(struct inode *inode)
+{
+ return &EXT4_I(inode)->i_reserved_quota;
+}
+#endif
+
+/*
+ * Calculate the number of metadata blocks need to reserve
+ * to allocate a block located at @lblock
+ */
+static int ext4_calc_metadata_amount(struct inode *inode, ext4_lblk_t lblock)
+{
+ if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))
+ return ext4_ext_calc_metadata_amount(inode, lblock);
+
+ return ext4_ind_calc_metadata_amount(inode, lblock);
+}
+
+/*
+ * Called with i_data_sem down, which is important since we can call
+ * ext4_discard_preallocations() from here.
+ */
+void ext4_da_update_reserve_space(struct inode *inode,
+ int used, int quota_claim)
+{
+ struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
+ struct ext4_inode_info *ei = EXT4_I(inode);
+
+ spin_lock(&ei->i_block_reservation_lock);
+ trace_ext4_da_update_reserve_space(inode, used, quota_claim);
+ if (unlikely(used > ei->i_reserved_data_blocks)) {
+ ext4_msg(inode->i_sb, KERN_NOTICE, "%s: ino %lu, used %d "
+ "with only %d reserved data blocks",
+ __func__, inode->i_ino, used,
+ ei->i_reserved_data_blocks);
+ WARN_ON(1);
+ used = ei->i_reserved_data_blocks;
+ }
+
+ if (unlikely(ei->i_allocated_meta_blocks > ei->i_reserved_meta_blocks)) {
+ ext4_msg(inode->i_sb, KERN_NOTICE, "%s: ino %lu, allocated %d "
+ "with only %d reserved metadata blocks\n", __func__,
+ inode->i_ino, ei->i_allocated_meta_blocks,
+ ei->i_reserved_meta_blocks);
+ WARN_ON(1);
+ ei->i_allocated_meta_blocks = ei->i_reserved_meta_blocks;
+ }
+
+ /* Update per-inode reservations */
+ ei->i_reserved_data_blocks -= used;
+ ei->i_reserved_meta_blocks -= ei->i_allocated_meta_blocks;
+ percpu_counter_sub(&sbi->s_dirtyclusters_counter,
+ used + ei->i_allocated_meta_blocks);
+ ei->i_allocated_meta_blocks = 0;
+
+ if (ei->i_reserved_data_blocks == 0) {
+ /*
+ * We can release all of the reserved metadata blocks
+ * only when we have written all of the delayed
+ * allocation blocks.
+ */
+ percpu_counter_sub(&sbi->s_dirtyclusters_counter,
+ ei->i_reserved_meta_blocks);
+ ei->i_reserved_meta_blocks = 0;
+ ei->i_da_metadata_calc_len = 0;
+ }
+ spin_unlock(&EXT4_I(inode)->i_block_reservation_lock);
+
+ /* Update quota subsystem for data blocks */
+ if (quota_claim)
+ dquot_claim_block(inode, EXT4_C2B(sbi, used));
+ else {
+ /*
+ * We did fallocate with an offset that is already delayed
+ * allocated. So on delayed allocated writeback we should
+ * not re-claim the quota for fallocated blocks.
+ */
+ dquot_release_reservation_block(inode, EXT4_C2B(sbi, used));
+ }
+
+ /*
+ * If we have done all the pending block allocations and if
+ * there aren't any writers on the inode, we can discard the
+ * inode's preallocations.
+ */
+ if ((ei->i_reserved_data_blocks == 0) &&
+ (atomic_read(&inode->i_writecount) == 0))
+ ext4_discard_preallocations(inode);
+}
+
+static int __check_block_validity(struct inode *inode, const char *func,
+ unsigned int line,
+ struct ext4_map_blocks *map)
+{
+ if (!ext4_data_block_valid(EXT4_SB(inode->i_sb), map->m_pblk,
+ map->m_len)) {
+ ext4_error_inode(inode, func, line, map->m_pblk,
+ "lblock %lu mapped to illegal pblock "
+ "(length %d)", (unsigned long) map->m_lblk,
+ map->m_len);
+ return -EIO;
+ }
+ return 0;
+}
+
+#define check_block_validity(inode, map) \
+ __check_block_validity((inode), __func__, __LINE__, (map))
+
+/*
+ * Return the number of contiguous dirty pages in a given inode
+ * starting at page frame idx.
+ */
+static pgoff_t ext4_num_dirty_pages(struct inode *inode, pgoff_t idx,
+ unsigned int max_pages)
+{
+ struct address_space *mapping = inode->i_mapping;
+ pgoff_t index;
+ struct pagevec pvec;
+ pgoff_t num = 0;
+ int i, nr_pages, done = 0;
+
+ if (max_pages == 0)
+ return 0;
+ pagevec_init(&pvec, 0);
+ while (!done) {
+ index = idx;
+ nr_pages = pagevec_lookup_tag(&pvec, mapping, &index,
+ PAGECACHE_TAG_DIRTY,
+ (pgoff_t)PAGEVEC_SIZE);
+ if (nr_pages == 0)
+ break;
+ for (i = 0; i < nr_pages; i++) {
+ struct page *page = pvec.pages[i];
+ struct buffer_head *bh, *head;
+
+ lock_page(page);
+ if (unlikely(page->mapping != mapping) ||
+ !PageDirty(page) ||
+ PageWriteback(page) ||
+ page->index != idx) {
+ done = 1;
+ unlock_page(page);
+ break;
+ }
+ if (page_has_buffers(page)) {
+ bh = head = page_buffers(page);
+ do {
+ if (!buffer_delay(bh) &&
+ !buffer_unwritten(bh))
+ done = 1;
+ bh = bh->b_this_page;
+ } while (!done && (bh != head));
+ }
+ unlock_page(page);
+ if (done)
+ break;
+ idx++;
+ num++;
+ if (num >= max_pages) {
+ done = 1;
+ break;
+ }
+ }
+ pagevec_release(&pvec);
+ }
+ return num;
+}
+
+/*
+ * Sets the BH_Da_Mapped bit on the buffer heads corresponding to the given map.
+ */
+static void set_buffers_da_mapped(struct inode *inode,
+ struct ext4_map_blocks *map)
+{
+ struct address_space *mapping = inode->i_mapping;
+ struct pagevec pvec;
+ int i, nr_pages;
+ pgoff_t index, end;
+
+ index = map->m_lblk >> (PAGE_CACHE_SHIFT - inode->i_blkbits);
+ end = (map->m_lblk + map->m_len - 1) >>
+ (PAGE_CACHE_SHIFT - inode->i_blkbits);
+
+ pagevec_init(&pvec, 0);
+ while (index <= end) {
+ nr_pages = pagevec_lookup(&pvec, mapping, index,
+ min(end - index + 1,
+ (pgoff_t)PAGEVEC_SIZE));
+ if (nr_pages == 0)
+ break;
+ for (i = 0; i < nr_pages; i++) {
+ struct page *page = pvec.pages[i];
+ struct buffer_head *bh, *head;
+
+ if (unlikely(page->mapping != mapping) ||
+ !PageDirty(page))
+ break;
+
+ if (page_has_buffers(page)) {
+ bh = head = page_buffers(page);
+ do {
+ set_buffer_da_mapped(bh);
+ bh = bh->b_this_page;
+ } while (bh != head);
+ }
+ index++;
+ }
+ pagevec_release(&pvec);
+ }
+}
+
+/*
+ * The ext4_map_blocks() function tries to look up the requested blocks,
+ * and returns if the blocks are already mapped.
+ *
+ * Otherwise it takes the write lock of the i_data_sem and allocate blocks
+ * and store the allocated blocks in the result buffer head and mark it
+ * mapped.
+ *
+ * If file type is extents based, it will call ext4_ext_map_blocks(),
+ * Otherwise, call with ext4_ind_map_blocks() to handle indirect mapping
+ * based files
+ *
+ * On success, it returns the number of blocks being mapped or allocate.
+ * if create==0 and the blocks are pre-allocated and uninitialized block,
+ * the result buffer head is unmapped. If the create ==1, it will make sure
+ * the buffer head is mapped.
+ *
+ * It returns 0 if plain look up failed (blocks have not been allocated), in
+ * that case, buffer head is unmapped
+ *
+ * It returns the error in case of allocation failure.
+ */
+int ext4_map_blocks(handle_t *handle, struct inode *inode,
+ struct ext4_map_blocks *map, int flags)
+{
+ int retval;
+
+ map->m_flags = 0;
+ ext_debug("ext4_map_blocks(): inode %lu, flag %d, max_blocks %u,"
+ "logical block %lu\n", inode->i_ino, flags, map->m_len,
+ (unsigned long) map->m_lblk);
+ /*
+ * Try to see if we can get the block without requesting a new
+ * file system block.
+ */
+ down_read((&EXT4_I(inode)->i_data_sem));
+ if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)) {
+ retval = ext4_ext_map_blocks(handle, inode, map, flags &
+ EXT4_GET_BLOCKS_KEEP_SIZE);
+ } else {
+ retval = ext4_ind_map_blocks(handle, inode, map, flags &
+ EXT4_GET_BLOCKS_KEEP_SIZE);
+ }
+ up_read((&EXT4_I(inode)->i_data_sem));
+
+ if (retval > 0 && map->m_flags & EXT4_MAP_MAPPED) {
+ int ret = check_block_validity(inode, map);
+ if (ret != 0)
+ return ret;
+ }
+
+ /* If it is only a block(s) look up */
+ if ((flags & EXT4_GET_BLOCKS_CREATE) == 0)
+ return retval;
+
+ /*
+ * Returns if the blocks have already allocated
+ *
+ * Note that if blocks have been preallocated
+ * ext4_ext_get_block() returns the create = 0
+ * with buffer head unmapped.
+ */
+ if (retval > 0 && map->m_flags & EXT4_MAP_MAPPED)
+ return retval;
+
+ /*
+ * When we call get_blocks without the create flag, the
+ * BH_Unwritten flag could have gotten set if the blocks
+ * requested were part of a uninitialized extent. We need to
+ * clear this flag now that we are committed to convert all or
+ * part of the uninitialized extent to be an initialized
+ * extent. This is because we need to avoid the combination
+ * of BH_Unwritten and BH_Mapped flags being simultaneously
+ * set on the buffer_head.
+ */
+ map->m_flags &= ~EXT4_MAP_UNWRITTEN;
+
+ /*
+ * New blocks allocate and/or writing to uninitialized extent
+ * will possibly result in updating i_data, so we take
+ * the write lock of i_data_sem, and call get_blocks()
+ * with create == 1 flag.
+ */
+ down_write((&EXT4_I(inode)->i_data_sem));
+
+ /*
+ * if the caller is from delayed allocation writeout path
+ * we have already reserved fs blocks for allocation
+ * let the underlying get_block() function know to
+ * avoid double accounting
+ */
+ if (flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE)
+ ext4_set_inode_state(inode, EXT4_STATE_DELALLOC_RESERVED);
+ /*
+ * We need to check for EXT4 here because migrate
+ * could have changed the inode type in between
+ */
+ if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)) {
+ retval = ext4_ext_map_blocks(handle, inode, map, flags);
+ } else {
+ retval = ext4_ind_map_blocks(handle, inode, map, flags);
+
+ if (retval > 0 && map->m_flags & EXT4_MAP_NEW) {
+ /*
+ * We allocated new blocks which will result in
+ * i_data's format changing. Force the migrate
+ * to fail by clearing migrate flags
+ */
+ ext4_clear_inode_state(inode, EXT4_STATE_EXT_MIGRATE);
+ }
+
+ /*
+ * Update reserved blocks/metadata blocks after successful
+ * block allocation which had been deferred till now. We don't
+ * support fallocate for non extent files. So we can update
+ * reserve space here.
+ */
+ if ((retval > 0) &&
+ (flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE))
+ ext4_da_update_reserve_space(inode, retval, 1);
+ }
+ if (flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE) {
+ ext4_clear_inode_state(inode, EXT4_STATE_DELALLOC_RESERVED);
+
+ /* If we have successfully mapped the delayed allocated blocks,
+ * set the BH_Da_Mapped bit on them. Its important to do this
+ * under the protection of i_data_sem.
+ */
+ if (retval > 0 && map->m_flags & EXT4_MAP_MAPPED)
+ set_buffers_da_mapped(inode, map);
+ }
+
+ up_write((&EXT4_I(inode)->i_data_sem));
+ if (retval > 0 && map->m_flags & EXT4_MAP_MAPPED) {
+ int ret = check_block_validity(inode, map);
+ if (ret != 0)
+ return ret;
+ }
+ return retval;
+}
+
+/* Maximum number of blocks we map for direct IO at once. */
+#define DIO_MAX_BLOCKS 4096
+
+static int _ext4_get_block(struct inode *inode, sector_t iblock,
+ struct buffer_head *bh, int flags)
+{
+ handle_t *handle = ext4_journal_current_handle();
+ struct ext4_map_blocks map;
+ int ret = 0, started = 0;
+ int dio_credits;
+
+ map.m_lblk = iblock;
+ map.m_len = bh->b_size >> inode->i_blkbits;
+
+ if (flags && !handle) {
+ /* Direct IO write... */
+ if (map.m_len > DIO_MAX_BLOCKS)
+ map.m_len = DIO_MAX_BLOCKS;
+ dio_credits = ext4_chunk_trans_blocks(inode, map.m_len);
+ handle = ext4_journal_start(inode, dio_credits);
+ if (IS_ERR(handle)) {
+ ret = PTR_ERR(handle);
+ return ret;
+ }
+ started = 1;
+ }
+
+ ret = ext4_map_blocks(handle, inode, &map, flags);
+ if (ret > 0) {
+ map_bh(bh, inode->i_sb, map.m_pblk);
+ bh->b_state = (bh->b_state & ~EXT4_MAP_FLAGS) | map.m_flags;
+ bh->b_size = inode->i_sb->s_blocksize * map.m_len;
+ ret = 0;
+ }
+ if (started)
+ ext4_journal_stop(handle);
+ return ret;
+}
+
+int ext4_get_block(struct inode *inode, sector_t iblock,
+ struct buffer_head *bh, int create)
+{
+ return _ext4_get_block(inode, iblock, bh,
+ create ? EXT4_GET_BLOCKS_CREATE : 0);
+}
+
+/*
+ * `handle' can be NULL if create is zero
+ */
+struct buffer_head *ext4_getblk(handle_t *handle, struct inode *inode,
+ ext4_lblk_t block, int create, int *errp)
+{
+ struct ext4_map_blocks map;
+ struct buffer_head *bh;
+ int fatal = 0, err;
+
+ J_ASSERT(handle != NULL || create == 0);
+
+ map.m_lblk = block;
+ map.m_len = 1;
+ err = ext4_map_blocks(handle, inode, &map,
+ create ? EXT4_GET_BLOCKS_CREATE : 0);
+
+ if (err < 0)
+ *errp = err;
+ if (err <= 0)
+ return NULL;
+ *errp = 0;
+
+ bh = sb_getblk(inode->i_sb, map.m_pblk);
+ if (!bh) {
+ *errp = -ENOMEM;
+ return NULL;
+ }
+ if (map.m_flags & EXT4_MAP_NEW) {
+ J_ASSERT(create != 0);
+ J_ASSERT(handle != NULL);
+
+ /*
+ * Now that we do not always journal data, we should
+ * keep in mind whether this should always journal the
+ * new buffer as metadata. For now, regular file
+ * writes use ext4_get_block instead, so it's not a
+ * problem.
+ */
+ lock_buffer(bh);
+ BUFFER_TRACE(bh, "call get_create_access");
+ fatal = ext4_journal_get_create_access(handle, bh);
+ if (!fatal && !buffer_uptodate(bh)) {
+ memset(bh->b_data, 0, inode->i_sb->s_blocksize);
+ set_buffer_uptodate(bh);
+ }
+ unlock_buffer(bh);
+ BUFFER_TRACE(bh, "call ext4_handle_dirty_metadata");
+ err = ext4_handle_dirty_metadata(handle, inode, bh);
+ if (!fatal)
+ fatal = err;
+ } else {
+ BUFFER_TRACE(bh, "not a new buffer");
+ }
+ if (fatal) {
+ *errp = fatal;
+ brelse(bh);
+ bh = NULL;
+ }
+ return bh;
+}
+
+struct buffer_head *ext4_bread(handle_t *handle, struct inode *inode,
+ ext4_lblk_t block, int create, int *err)
+{
+ struct buffer_head *bh;
+
+ bh = ext4_getblk(handle, inode, block, create, err);
+ if (!bh)
+ return bh;
+ if (buffer_uptodate(bh))
+ return bh;
+ ll_rw_block(READ | REQ_META | REQ_PRIO, 1, &bh);
+ wait_on_buffer(bh);
+ if (buffer_uptodate(bh))
+ return bh;
+ put_bh(bh);
+ *err = -EIO;
+ return NULL;
+}
+
+static int walk_page_buffers(handle_t *handle,
+ struct buffer_head *head,
+ unsigned from,
+ unsigned to,
+ int *partial,
+ int (*fn)(handle_t *handle,
+ struct buffer_head *bh))
+{
+ struct buffer_head *bh;
+ unsigned block_start, block_end;
+ unsigned blocksize = head->b_size;
+ int err, ret = 0;
+ struct buffer_head *next;
+
+ for (bh = head, block_start = 0;
+ ret == 0 && (bh != head || !block_start);
+ block_start = block_end, bh = next) {
+ next = bh->b_this_page;
+ block_end = block_start + blocksize;
+ if (block_end <= from || block_start >= to) {
+ if (partial && !buffer_uptodate(bh))
+ *partial = 1;
+ continue;
+ }
+ err = (*fn)(handle, bh);
+ if (!ret)
+ ret = err;
+ }
+ return ret;
+}
+
+/*
+ * To preserve ordering, it is essential that the hole instantiation and
+ * the data write be encapsulated in a single transaction. We cannot
+ * close off a transaction and start a new one between the ext4_get_block()
+ * and the commit_write(). So doing the jbd2_journal_start at the start of
+ * prepare_write() is the right place.
+ *
+ * Also, this function can nest inside ext4_writepage() ->
+ * block_write_full_page(). In that case, we *know* that ext4_writepage()
+ * has generated enough buffer credits to do the whole page. So we won't
+ * block on the journal in that case, which is good, because the caller may
+ * be PF_MEMALLOC.
+ *
+ * By accident, ext4 can be reentered when a transaction is open via
+ * quota file writes. If we were to commit the transaction while thus
+ * reentered, there can be a deadlock - we would be holding a quota
+ * lock, and the commit would never complete if another thread had a
+ * transaction open and was blocking on the quota lock - a ranking
+ * violation.
+ *
+ * So what we do is to rely on the fact that jbd2_journal_stop/journal_start
+ * will _not_ run commit under these circumstances because handle->h_ref
+ * is elevated. We'll still have enough credits for the tiny quotafile
+ * write.
+ */
+static int do_journal_get_write_access(handle_t *handle,
+ struct buffer_head *bh)
+{
+ int dirty = buffer_dirty(bh);
+ int ret;
+
+ if (!buffer_mapped(bh) || buffer_freed(bh))
+ return 0;
+ /*
+ * __block_write_begin() could have dirtied some buffers. Clean
+ * the dirty bit as jbd2_journal_get_write_access() could complain
+ * otherwise about fs integrity issues. Setting of the dirty bit
+ * by __block_write_begin() isn't a real problem here as we clear
+ * the bit before releasing a page lock and thus writeback cannot
+ * ever write the buffer.
+ */
+ if (dirty)
+ clear_buffer_dirty(bh);
+ ret = ext4_journal_get_write_access(handle, bh);
+ if (!ret && dirty)
+ ret = ext4_handle_dirty_metadata(handle, NULL, bh);
+ return ret;
+}
+
+static int ext4_get_block_write(struct inode *inode, sector_t iblock,
+ struct buffer_head *bh_result, int create);
+static int ext4_write_begin(struct file *file, struct address_space *mapping,
+ loff_t pos, unsigned len, unsigned flags,
+ struct page **pagep, void **fsdata)
+{
+ struct inode *inode = mapping->host;
+ int ret, needed_blocks;
+ handle_t *handle;
+ int retries = 0;
+ struct page *page;
+ pgoff_t index;
+ unsigned from, to;
+
+ trace_ext4_write_begin(inode, pos, len, flags);
+ /*
+ * Reserve one block more for addition to orphan list in case
+ * we allocate blocks but write fails for some reason
+ */
+ needed_blocks = ext4_writepage_trans_blocks(inode) + 1;
+ index = pos >> PAGE_CACHE_SHIFT;
+ from = pos & (PAGE_CACHE_SIZE - 1);
+ to = from + len;
+
+retry:
+ handle = ext4_journal_start(inode, needed_blocks);
+ if (IS_ERR(handle)) {
+ ret = PTR_ERR(handle);
+ goto out;
+ }
+
+ /* We cannot recurse into the filesystem as the transaction is already
+ * started */
+ flags |= AOP_FLAG_NOFS;
+
+ page = grab_cache_page_write_begin(mapping, index, flags);
+ if (!page) {
+ ext4_journal_stop(handle);
+ ret = -ENOMEM;
+ goto out;
+ }
+ *pagep = page;
+
+ if (ext4_should_dioread_nolock(inode))
+ ret = __block_write_begin(page, pos, len, ext4_get_block_write);
+ else
+ ret = __block_write_begin(page, pos, len, ext4_get_block);
+
+ if (!ret && ext4_should_journal_data(inode)) {
+ ret = walk_page_buffers(handle, page_buffers(page),
+ from, to, NULL, do_journal_get_write_access);
+ }
+
+ if (ret) {
+ unlock_page(page);
+ page_cache_release(page);
+ /*
+ * __block_write_begin may have instantiated a few blocks
+ * outside i_size. Trim these off again. Don't need
+ * i_size_read because we hold i_mutex.
+ *
+ * Add inode to orphan list in case we crash before
+ * truncate finishes
+ */
+ if (pos + len > inode->i_size && ext4_can_truncate(inode))
+ ext4_orphan_add(handle, inode);
+
+ ext4_journal_stop(handle);
+ if (pos + len > inode->i_size) {
+ ext4_truncate_failed_write(inode);
+ /*
+ * If truncate failed early the inode might
+ * still be on the orphan list; we need to
+ * make sure the inode is removed from the
+ * orphan list in that case.
+ */
+ if (inode->i_nlink)
+ ext4_orphan_del(NULL, inode);
+ }
+ }
+
+ if (ret == -ENOSPC && ext4_should_retry_alloc(inode->i_sb, &retries))
+ goto retry;
+out:
+ return ret;
+}
+
+/* For write_end() in data=journal mode */
+static int write_end_fn(handle_t *handle, struct buffer_head *bh)
+{
+ if (!buffer_mapped(bh) || buffer_freed(bh))
+ return 0;
+ set_buffer_uptodate(bh);
+ return ext4_handle_dirty_metadata(handle, NULL, bh);
+}
+
+static int ext4_generic_write_end(struct file *file,
+ struct address_space *mapping,
+ loff_t pos, unsigned len, unsigned copied,
+ struct page *page, void *fsdata)
+{
+ int i_size_changed = 0;
+ struct inode *inode = mapping->host;
+ handle_t *handle = ext4_journal_current_handle();
+
+ copied = block_write_end(file, mapping, pos, len, copied, page, fsdata);
+
+ /*
+ * No need to use i_size_read() here, the i_size
+ * cannot change under us because we hold i_mutex.
+ *
+ * But it's important to update i_size while still holding page lock:
+ * page writeout could otherwise come in and zero beyond i_size.
+ */
+ if (pos + copied > inode->i_size) {
+ i_size_write(inode, pos + copied);
+ i_size_changed = 1;
+ }
+
+ if (pos + copied > EXT4_I(inode)->i_disksize) {
+ /* We need to mark inode dirty even if
+ * new_i_size is less that inode->i_size
+ * bu greater than i_disksize.(hint delalloc)
+ */
+ ext4_update_i_disksize(inode, (pos + copied));
+ i_size_changed = 1;
+ }
+ unlock_page(page);
+ page_cache_release(page);
+
+ /*
+ * Don't mark the inode dirty under page lock. First, it unnecessarily
+ * makes the holding time of page lock longer. Second, it forces lock
+ * ordering of page lock and transaction start for journaling
+ * filesystems.
+ */
+ if (i_size_changed)
+ ext4_mark_inode_dirty(handle, inode);
+
+ return copied;
+}
+
+/*
+ * We need to pick up the new inode size which generic_commit_write gave us
+ * `file' can be NULL - eg, when called from page_symlink().
+ *
+ * ext4 never places buffers on inode->i_mapping->private_list. metadata
+ * buffers are managed internally.
+ */
+static int ext4_ordered_write_end(struct file *file,
+ struct address_space *mapping,
+ loff_t pos, unsigned len, unsigned copied,
+ struct page *page, void *fsdata)
+{
+ handle_t *handle = ext4_journal_current_handle();
+ struct inode *inode = mapping->host;
+ int ret = 0, ret2;
+
+ trace_ext4_ordered_write_end(inode, pos, len, copied);
+ ret = ext4_jbd2_file_inode(handle, inode);
+
+ if (ret == 0) {
+ ret2 = ext4_generic_write_end(file, mapping, pos, len, copied,
+ page, fsdata);
+ copied = ret2;
+ if (pos + len > inode->i_size && ext4_can_truncate(inode))
+ /* if we have allocated more blocks and copied
+ * less. We will have blocks allocated outside
+ * inode->i_size. So truncate them
+ */
+ ext4_orphan_add(handle, inode);
+ if (ret2 < 0)
+ ret = ret2;
+ } else {
+ unlock_page(page);
+ page_cache_release(page);
+ }
+
+ ret2 = ext4_journal_stop(handle);
+ if (!ret)
+ ret = ret2;
+
+ if (pos + len > inode->i_size) {
+ ext4_truncate_failed_write(inode);
+ /*
+ * If truncate failed early the inode might still be
+ * on the orphan list; we need to make sure the inode
+ * is removed from the orphan list in that case.
+ */
+ if (inode->i_nlink)
+ ext4_orphan_del(NULL, inode);
+ }
+
+
+ return ret ? ret : copied;
+}
+
+static int ext4_writeback_write_end(struct file *file,
+ struct address_space *mapping,
+ loff_t pos, unsigned len, unsigned copied,
+ struct page *page, void *fsdata)
+{
+ handle_t *handle = ext4_journal_current_handle();
+ struct inode *inode = mapping->host;
+ int ret = 0, ret2;
+
+ trace_ext4_writeback_write_end(inode, pos, len, copied);
+ ret2 = ext4_generic_write_end(file, mapping, pos, len, copied,
+ page, fsdata);
+ copied = ret2;
+ if (pos + len > inode->i_size && ext4_can_truncate(inode))
+ /* if we have allocated more blocks and copied
+ * less. We will have blocks allocated outside
+ * inode->i_size. So truncate them
+ */
+ ext4_orphan_add(handle, inode);
+
+ if (ret2 < 0)
+ ret = ret2;
+
+ ret2 = ext4_journal_stop(handle);
+ if (!ret)
+ ret = ret2;
+
+ if (pos + len > inode->i_size) {
+ ext4_truncate_failed_write(inode);
+ /*
+ * If truncate failed early the inode might still be
+ * on the orphan list; we need to make sure the inode
+ * is removed from the orphan list in that case.
+ */
+ if (inode->i_nlink)
+ ext4_orphan_del(NULL, inode);
+ }
+
+ return ret ? ret : copied;
+}
+
+static int ext4_journalled_write_end(struct file *file,
+ struct address_space *mapping,
+ loff_t pos, unsigned len, unsigned copied,
+ struct page *page, void *fsdata)
+{
+ handle_t *handle = ext4_journal_current_handle();
+ struct inode *inode = mapping->host;
+ int ret = 0, ret2;
+ int partial = 0;
+ unsigned from, to;
+ loff_t new_i_size;
+
+ trace_ext4_journalled_write_end(inode, pos, len, copied);
+ from = pos & (PAGE_CACHE_SIZE - 1);
+ to = from + len;
+
+ BUG_ON(!ext4_handle_valid(handle));
+
+ if (copied < len) {
+ if (!PageUptodate(page))
+ copied = 0;
+ page_zero_new_buffers(page, from+copied, to);
+ }
+
+ ret = walk_page_buffers(handle, page_buffers(page), from,
+ to, &partial, write_end_fn);
+ if (!partial)
+ SetPageUptodate(page);
+ new_i_size = pos + copied;
+ if (new_i_size > inode->i_size)
+ i_size_write(inode, pos+copied);
+ ext4_set_inode_state(inode, EXT4_STATE_JDATA);
+ EXT4_I(inode)->i_datasync_tid = handle->h_transaction->t_tid;
+ if (new_i_size > EXT4_I(inode)->i_disksize) {
+ ext4_update_i_disksize(inode, new_i_size);
+ ret2 = ext4_mark_inode_dirty(handle, inode);
+ if (!ret)
+ ret = ret2;
+ }
+
+ unlock_page(page);
+ page_cache_release(page);
+ if (pos + len > inode->i_size && ext4_can_truncate(inode))
+ /* if we have allocated more blocks and copied
+ * less. We will have blocks allocated outside
+ * inode->i_size. So truncate them
+ */
+ ext4_orphan_add(handle, inode);
+
+ ret2 = ext4_journal_stop(handle);
+ if (!ret)
+ ret = ret2;
+ if (pos + len > inode->i_size) {
+ ext4_truncate_failed_write(inode);
+ /*
+ * If truncate failed early the inode might still be
+ * on the orphan list; we need to make sure the inode
+ * is removed from the orphan list in that case.
+ */
+ if (inode->i_nlink)
+ ext4_orphan_del(NULL, inode);
+ }
+
+ return ret ? ret : copied;
+}
+
+/*
+ * Reserve a single cluster located at lblock
+ */
+static int ext4_da_reserve_space(struct inode *inode, ext4_lblk_t lblock)
+{
+ int retries = 0;
+ struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
+ struct ext4_inode_info *ei = EXT4_I(inode);
+ unsigned int md_needed;
+ int ret;
+ ext4_lblk_t save_last_lblock;
+ int save_len;
+
+ /*
+ * We will charge metadata quota at writeout time; this saves
+ * us from metadata over-estimation, though we may go over by
+ * a small amount in the end. Here we just reserve for data.
+ */
+ ret = dquot_reserve_block(inode, EXT4_C2B(sbi, 1));
+ if (ret)
+ return ret;
+
+ /*
+ * recalculate the amount of metadata blocks to reserve
+ * in order to allocate nrblocks
+ * worse case is one extent per block
+ */
+repeat:
+ spin_lock(&ei->i_block_reservation_lock);
+ /*
+ * ext4_calc_metadata_amount() has side effects, which we have
+ * to be prepared undo if we fail to claim space.
+ */
+ save_len = ei->i_da_metadata_calc_len;
+ save_last_lblock = ei->i_da_metadata_calc_last_lblock;
+ md_needed = EXT4_NUM_B2C(sbi,
+ ext4_calc_metadata_amount(inode, lblock));
+ trace_ext4_da_reserve_space(inode, md_needed);
+
+ /*
+ * We do still charge estimated metadata to the sb though;
+ * we cannot afford to run out of free blocks.
+ */
+ if (ext4_claim_free_clusters(sbi, md_needed + 1, 0)) {
+ ei->i_da_metadata_calc_len = save_len;
+ ei->i_da_metadata_calc_last_lblock = save_last_lblock;
+ spin_unlock(&ei->i_block_reservation_lock);
+ if (ext4_should_retry_alloc(inode->i_sb, &retries)) {
+ yield();
+ goto repeat;
+ }
+ dquot_release_reservation_block(inode, EXT4_C2B(sbi, 1));
+ return -ENOSPC;
+ }
+ ei->i_reserved_data_blocks++;
+ ei->i_reserved_meta_blocks += md_needed;
+ spin_unlock(&ei->i_block_reservation_lock);
+
+ return 0; /* success */
+}
+
+static void ext4_da_release_space(struct inode *inode, int to_free)
+{
+ struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
+ struct ext4_inode_info *ei = EXT4_I(inode);
+
+ if (!to_free)
+ return; /* Nothing to release, exit */
+
+ spin_lock(&EXT4_I(inode)->i_block_reservation_lock);
+
+ trace_ext4_da_release_space(inode, to_free);
+ if (unlikely(to_free > ei->i_reserved_data_blocks)) {
+ /*
+ * if there aren't enough reserved blocks, then the
+ * counter is messed up somewhere. Since this
+ * function is called from invalidate page, it's
+ * harmless to return without any action.
+ */
+ ext4_msg(inode->i_sb, KERN_NOTICE, "ext4_da_release_space: "
+ "ino %lu, to_free %d with only %d reserved "
+ "data blocks", inode->i_ino, to_free,
+ ei->i_reserved_data_blocks);
+ WARN_ON(1);
+ to_free = ei->i_reserved_data_blocks;
+ }
+ ei->i_reserved_data_blocks -= to_free;
+
+ if (ei->i_reserved_data_blocks == 0) {
+ /*
+ * We can release all of the reserved metadata blocks
+ * only when we have written all of the delayed
+ * allocation blocks.
+ * Note that in case of bigalloc, i_reserved_meta_blocks,
+ * i_reserved_data_blocks, etc. refer to number of clusters.
+ */
+ percpu_counter_sub(&sbi->s_dirtyclusters_counter,
+ ei->i_reserved_meta_blocks);
+ ei->i_reserved_meta_blocks = 0;
+ ei->i_da_metadata_calc_len = 0;
+ }
+
+ /* update fs dirty data blocks counter */
+ percpu_counter_sub(&sbi->s_dirtyclusters_counter, to_free);
+
+ spin_unlock(&EXT4_I(inode)->i_block_reservation_lock);
+
+ dquot_release_reservation_block(inode, EXT4_C2B(sbi, to_free));
+}
+
+static void ext4_da_page_release_reservation(struct page *page,
+ unsigned long offset)
+{
+ int to_release = 0;
+ struct buffer_head *head, *bh;
+ unsigned int curr_off = 0;
+ struct inode *inode = page->mapping->host;
+ struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
+ int num_clusters;
+
+ head = page_buffers(page);
+ bh = head;
+ do {
+ unsigned int next_off = curr_off + bh->b_size;
+
+ if ((offset <= curr_off) && (buffer_delay(bh))) {
+ to_release++;
+ clear_buffer_delay(bh);
+ clear_buffer_da_mapped(bh);
+ }
+ curr_off = next_off;
+ } while ((bh = bh->b_this_page) != head);
+
+ /* If we have released all the blocks belonging to a cluster, then we
+ * need to release the reserved space for that cluster. */
+ num_clusters = EXT4_NUM_B2C(sbi, to_release);
+ while (num_clusters > 0) {
+ ext4_fsblk_t lblk;
+ lblk = (page->index << (PAGE_CACHE_SHIFT - inode->i_blkbits)) +
+ ((num_clusters - 1) << sbi->s_cluster_bits);
+ if (sbi->s_cluster_ratio == 1 ||
+ !ext4_find_delalloc_cluster(inode, lblk, 1))
+ ext4_da_release_space(inode, 1);
+
+ num_clusters--;
+ }
+}
+
+/*
+ * Delayed allocation stuff
+ */
+
+/*
+ * mpage_da_submit_io - walks through extent of pages and try to write
+ * them with writepage() call back
+ *
+ * @mpd->inode: inode
+ * @mpd->first_page: first page of the extent
+ * @mpd->next_page: page after the last page of the extent
+ *
+ * By the time mpage_da_submit_io() is called we expect all blocks
+ * to be allocated. this may be wrong if allocation failed.
+ *
+ * As pages are already locked by write_cache_pages(), we can't use it
+ */
+static int mpage_da_submit_io(struct mpage_da_data *mpd,
+ struct ext4_map_blocks *map)
+{
+ struct pagevec pvec;
+ unsigned long index, end;
+ int ret = 0, err, nr_pages, i;
+ struct inode *inode = mpd->inode;
+ struct address_space *mapping = inode->i_mapping;
+ loff_t size = i_size_read(inode);
+ unsigned int len, block_start;
+ struct buffer_head *bh, *page_bufs = NULL;
+ int journal_data = ext4_should_journal_data(inode);
+ sector_t pblock = 0, cur_logical = 0;
+ struct ext4_io_submit io_submit;
+
+ BUG_ON(mpd->next_page <= mpd->first_page);
+ memset(&io_submit, 0, sizeof(io_submit));
+ /*
+ * We need to start from the first_page to the next_page - 1
+ * to make sure we also write the mapped dirty buffer_heads.
+ * If we look at mpd->b_blocknr we would only be looking
+ * at the currently mapped buffer_heads.
+ */
+ index = mpd->first_page;
+ end = mpd->next_page - 1;
+
+ pagevec_init(&pvec, 0);
+ while (index <= end) {
+ nr_pages = pagevec_lookup(&pvec, mapping, index, PAGEVEC_SIZE);
+ if (nr_pages == 0)
+ break;
+ for (i = 0; i < nr_pages; i++) {
+ int commit_write = 0, skip_page = 0;
+ struct page *page = pvec.pages[i];
+
+ index = page->index;
+ if (index > end)
+ break;
+
+ if (index == size >> PAGE_CACHE_SHIFT)
+ len = size & ~PAGE_CACHE_MASK;
+ else
+ len = PAGE_CACHE_SIZE;
+ if (map) {
+ cur_logical = index << (PAGE_CACHE_SHIFT -
+ inode->i_blkbits);
+ pblock = map->m_pblk + (cur_logical -
+ map->m_lblk);
+ }
+ index++;
+
+ BUG_ON(!PageLocked(page));
+ BUG_ON(PageWriteback(page));
+
+ /*
+ * If the page does not have buffers (for
+ * whatever reason), try to create them using
+ * __block_write_begin. If this fails,
+ * skip the page and move on.
+ */
+ if (!page_has_buffers(page)) {
+ if (__block_write_begin(page, 0, len,
+ noalloc_get_block_write)) {
+ skip_page:
+ unlock_page(page);
+ continue;
+ }
+ commit_write = 1;
+ }
+
+ bh = page_bufs = page_buffers(page);
+ block_start = 0;
+ do {
+ if (!bh)
+ goto skip_page;
+ if (map && (cur_logical >= map->m_lblk) &&
+ (cur_logical <= (map->m_lblk +
+ (map->m_len - 1)))) {
+ if (buffer_delay(bh)) {
+ clear_buffer_delay(bh);
+ bh->b_blocknr = pblock;
+ }
+ if (buffer_da_mapped(bh))
+ clear_buffer_da_mapped(bh);
+ if (buffer_unwritten(bh) ||
+ buffer_mapped(bh))
+ BUG_ON(bh->b_blocknr != pblock);
+ if (map->m_flags & EXT4_MAP_UNINIT)
+ set_buffer_uninit(bh);
+ clear_buffer_unwritten(bh);
+ }
+
+ /*
+ * skip page if block allocation undone and
+ * block is dirty
+ */
+ if (ext4_bh_delay_or_unwritten(NULL, bh))
+ skip_page = 1;
+ bh = bh->b_this_page;
+ block_start += bh->b_size;
+ cur_logical++;
+ pblock++;
+ } while (bh != page_bufs);
+
+ if (skip_page)
+ goto skip_page;
+
+ if (commit_write)
+ /* mark the buffer_heads as dirty & uptodate */
+ block_commit_write(page, 0, len);
+
+ clear_page_dirty_for_io(page);
+ /*
+ * Delalloc doesn't support data journalling,
+ * but eventually maybe we'll lift this
+ * restriction.
+ */
+ if (unlikely(journal_data && PageChecked(page)))
+ err = __ext4_journalled_writepage(page, len);
+ else if (test_opt(inode->i_sb, MBLK_IO_SUBMIT))
+ err = ext4_bio_write_page(&io_submit, page,
+ len, mpd->wbc);
+ else if (buffer_uninit(page_bufs)) {
+ ext4_set_bh_endio(page_bufs, inode);
+ err = block_write_full_page_endio(page,
+ noalloc_get_block_write,
+ mpd->wbc, ext4_end_io_buffer_write);
+ } else
+ err = block_write_full_page(page,
+ noalloc_get_block_write, mpd->wbc);
+
+ if (!err)
+ mpd->pages_written++;
+ /*
+ * In error case, we have to continue because
+ * remaining pages are still locked
+ */
+ if (ret == 0)
+ ret = err;
+ }
+ pagevec_release(&pvec);
+ }
+ ext4_io_submit(&io_submit);
+ return ret;
+}
+
+static void ext4_da_block_invalidatepages(struct mpage_da_data *mpd)
+{
+ int nr_pages, i;
+ pgoff_t index, end;
+ struct pagevec pvec;
+ struct inode *inode = mpd->inode;
+ struct address_space *mapping = inode->i_mapping;
+
+ index = mpd->first_page;
+ end = mpd->next_page - 1;
+
+ pagevec_init(&pvec, 0);
+ while (index <= end) {
+ nr_pages = pagevec_lookup(&pvec, mapping, index, PAGEVEC_SIZE);
+ if (nr_pages == 0)
+ break;
+ for (i = 0; i < nr_pages; i++) {
+ struct page *page = pvec.pages[i];
+ if (page->index > end)
+ break;
+ BUG_ON(!PageLocked(page));
+ BUG_ON(PageWriteback(page));
+ block_invalidatepage(page, 0);
+ ClearPageUptodate(page);
+ unlock_page(page);
+ }
+ index = pvec.pages[nr_pages - 1]->index + 1;
+ pagevec_release(&pvec);
+ }
+ return;
+}
+
+static void ext4_print_free_blocks(struct inode *inode)
+{
+ struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
+ struct super_block *sb = inode->i_sb;
+
+ ext4_msg(sb, KERN_CRIT, "Total free blocks count %lld",
+ EXT4_C2B(EXT4_SB(inode->i_sb),
+ ext4_count_free_clusters(inode->i_sb)));
+ ext4_msg(sb, KERN_CRIT, "Free/Dirty block details");
+ ext4_msg(sb, KERN_CRIT, "free_blocks=%lld",
+ (long long) EXT4_C2B(EXT4_SB(inode->i_sb),
+ percpu_counter_sum(&sbi->s_freeclusters_counter)));
+ ext4_msg(sb, KERN_CRIT, "dirty_blocks=%lld",
+ (long long) EXT4_C2B(EXT4_SB(inode->i_sb),
+ percpu_counter_sum(&sbi->s_dirtyclusters_counter)));
+ ext4_msg(sb, KERN_CRIT, "Block reservation details");
+ ext4_msg(sb, KERN_CRIT, "i_reserved_data_blocks=%u",
+ EXT4_I(inode)->i_reserved_data_blocks);
+ ext4_msg(sb, KERN_CRIT, "i_reserved_meta_blocks=%u",
+ EXT4_I(inode)->i_reserved_meta_blocks);
+ return;
+}
+
+/*
+ * mpage_da_map_and_submit - go through given space, map them
+ * if necessary, and then submit them for I/O
+ *
+ * @mpd - bh describing space
+ *
+ * The function skips space we know is already mapped to disk blocks.
+ *
+ */
+static void mpage_da_map_and_submit(struct mpage_da_data *mpd)
+{
+ int err, blks, get_blocks_flags;
+ struct ext4_map_blocks map, *mapp = NULL;
+ sector_t next = mpd->b_blocknr;
+ unsigned max_blocks = mpd->b_size >> mpd->inode->i_blkbits;
+ loff_t disksize = EXT4_I(mpd->inode)->i_disksize;
+ handle_t *handle = NULL;
+
+ /*
+ * If the blocks are mapped already, or we couldn't accumulate
+ * any blocks, then proceed immediately to the submission stage.
+ */
+ if ((mpd->b_size == 0) ||
+ ((mpd->b_state & (1 << BH_Mapped)) &&
+ !(mpd->b_state & (1 << BH_Delay)) &&
+ !(mpd->b_state & (1 << BH_Unwritten))))
+ goto submit_io;
+
+ handle = ext4_journal_current_handle();
+ BUG_ON(!handle);
+
+ /*
+ * Call ext4_map_blocks() to allocate any delayed allocation
+ * blocks, or to convert an uninitialized extent to be
+ * initialized (in the case where we have written into
+ * one or more preallocated blocks).
+ *
+ * We pass in the magic EXT4_GET_BLOCKS_DELALLOC_RESERVE to
+ * indicate that we are on the delayed allocation path. This
+ * affects functions in many different parts of the allocation
+ * call path. This flag exists primarily because we don't
+ * want to change *many* call functions, so ext4_map_blocks()
+ * will set the EXT4_STATE_DELALLOC_RESERVED flag once the
+ * inode's allocation semaphore is taken.
+ *
+ * If the blocks in questions were delalloc blocks, set
+ * EXT4_GET_BLOCKS_DELALLOC_RESERVE so the delalloc accounting
+ * variables are updated after the blocks have been allocated.
+ */
+ map.m_lblk = next;
+ map.m_len = max_blocks;
+ get_blocks_flags = EXT4_GET_BLOCKS_CREATE;
+ if (ext4_should_dioread_nolock(mpd->inode))
+ get_blocks_flags |= EXT4_GET_BLOCKS_IO_CREATE_EXT;
+ if (mpd->b_state & (1 << BH_Delay))
+ get_blocks_flags |= EXT4_GET_BLOCKS_DELALLOC_RESERVE;
+
+ blks = ext4_map_blocks(handle, mpd->inode, &map, get_blocks_flags);
+ if (blks < 0) {
+ struct super_block *sb = mpd->inode->i_sb;
+
+ err = blks;
+ /*
+ * If get block returns EAGAIN or ENOSPC and there
+ * appears to be free blocks we will just let
+ * mpage_da_submit_io() unlock all of the pages.
+ */
+ if (err == -EAGAIN)
+ goto submit_io;
+
+ if (err == -ENOSPC && ext4_count_free_clusters(sb)) {
+ mpd->retval = err;
+ goto submit_io;
+ }
+
+ /*
+ * get block failure will cause us to loop in
+ * writepages, because a_ops->writepage won't be able
+ * to make progress. The page will be redirtied by
+ * writepage and writepages will again try to write
+ * the same.
+ */
+ if (!(EXT4_SB(sb)->s_mount_flags & EXT4_MF_FS_ABORTED)) {
+ ext4_msg(sb, KERN_CRIT,
+ "delayed block allocation failed for inode %lu "
+ "at logical offset %llu with max blocks %zd "
+ "with error %d", mpd->inode->i_ino,
+ (unsigned long long) next,
+ mpd->b_size >> mpd->inode->i_blkbits, err);
+ ext4_msg(sb, KERN_CRIT,
+ "This should not happen!! Data will be lost\n");
+ if (err == -ENOSPC)
+ ext4_print_free_blocks(mpd->inode);
+ }
+ /* invalidate all the pages */
+ ext4_da_block_invalidatepages(mpd);
+
+ /* Mark this page range as having been completed */
+ mpd->io_done = 1;
+ return;
+ }
+ BUG_ON(blks == 0);
+
+ mapp = ↦
+ if (map.m_flags & EXT4_MAP_NEW) {
+ struct block_device *bdev = mpd->inode->i_sb->s_bdev;
+ int i;
+
+ for (i = 0; i < map.m_len; i++)
+ unmap_underlying_metadata(bdev, map.m_pblk + i);
+
+ if (ext4_should_order_data(mpd->inode)) {
+ err = ext4_jbd2_file_inode(handle, mpd->inode);
+ if (err) {
+ /* Only if the journal is aborted */
+ mpd->retval = err;
+ goto submit_io;
+ }
+ }
+ }
+
+ /*
+ * Update on-disk size along with block allocation.
+ */
+ disksize = ((loff_t) next + blks) << mpd->inode->i_blkbits;
+ if (disksize > i_size_read(mpd->inode))
+ disksize = i_size_read(mpd->inode);
+ if (disksize > EXT4_I(mpd->inode)->i_disksize) {
+ ext4_update_i_disksize(mpd->inode, disksize);
+ err = ext4_mark_inode_dirty(handle, mpd->inode);
+ if (err)
+ ext4_error(mpd->inode->i_sb,
+ "Failed to mark inode %lu dirty",
+ mpd->inode->i_ino);
+ }
+
+submit_io:
+ mpage_da_submit_io(mpd, mapp);
+ mpd->io_done = 1;
+}
+
+#define BH_FLAGS ((1 << BH_Uptodate) | (1 << BH_Mapped) | \
+ (1 << BH_Delay) | (1 << BH_Unwritten))
+
+/*
+ * mpage_add_bh_to_extent - try to add one more block to extent of blocks
+ *
+ * @mpd->lbh - extent of blocks
+ * @logical - logical number of the block in the file
+ * @bh - bh of the block (used to access block's state)
+ *
+ * the function is used to collect contig. blocks in same state
+ */
+static void mpage_add_bh_to_extent(struct mpage_da_data *mpd,
+ sector_t logical, size_t b_size,
+ unsigned long b_state)
+{
+ sector_t next;
+ int nrblocks = mpd->b_size >> mpd->inode->i_blkbits;
+
+ /*
+ * XXX Don't go larger than mballoc is willing to allocate
+ * This is a stopgap solution. We eventually need to fold
+ * mpage_da_submit_io() into this function and then call
+ * ext4_map_blocks() multiple times in a loop
+ */
+ if (nrblocks >= 8*1024*1024/mpd->inode->i_sb->s_blocksize)
+ goto flush_it;
+
+ /* check if thereserved journal credits might overflow */
+ if (!(ext4_test_inode_flag(mpd->inode, EXT4_INODE_EXTENTS))) {
+ if (nrblocks >= EXT4_MAX_TRANS_DATA) {
+ /*
+ * With non-extent format we are limited by the journal
+ * credit available. Total credit needed to insert
+ * nrblocks contiguous blocks is dependent on the
+ * nrblocks. So limit nrblocks.
+ */
+ goto flush_it;
+ } else if ((nrblocks + (b_size >> mpd->inode->i_blkbits)) >
+ EXT4_MAX_TRANS_DATA) {
+ /*
+ * Adding the new buffer_head would make it cross the
+ * allowed limit for which we have journal credit
+ * reserved. So limit the new bh->b_size
+ */
+ b_size = (EXT4_MAX_TRANS_DATA - nrblocks) <<
+ mpd->inode->i_blkbits;
+ /* we will do mpage_da_submit_io in the next loop */
+ }
+ }
+ /*
+ * First block in the extent
+ */
+ if (mpd->b_size == 0) {
+ mpd->b_blocknr = logical;
+ mpd->b_size = b_size;
+ mpd->b_state = b_state & BH_FLAGS;
+ return;
+ }
+
+ next = mpd->b_blocknr + nrblocks;
+ /*
+ * Can we merge the block to our big extent?
+ */
+ if (logical == next && (b_state & BH_FLAGS) == mpd->b_state) {
+ mpd->b_size += b_size;
+ return;
+ }
+
+flush_it:
+ /*
+ * We couldn't merge the block to our extent, so we
+ * need to flush current extent and start new one
+ */
+ mpage_da_map_and_submit(mpd);
+ return;
+}
+
+static int ext4_bh_delay_or_unwritten(handle_t *handle, struct buffer_head *bh)
+{
+ return (buffer_delay(bh) || buffer_unwritten(bh)) && buffer_dirty(bh);
+}
+
+/*
+ * This function is grabs code from the very beginning of
+ * ext4_map_blocks, but assumes that the caller is from delayed write
+ * time. This function looks up the requested blocks and sets the
+ * buffer delay bit under the protection of i_data_sem.
+ */
+static int ext4_da_map_blocks(struct inode *inode, sector_t iblock,
+ struct ext4_map_blocks *map,
+ struct buffer_head *bh)
+{
+ int retval;
+ sector_t invalid_block = ~((sector_t) 0xffff);
+
+ if (invalid_block < ext4_blocks_count(EXT4_SB(inode->i_sb)->s_es))
+ invalid_block = ~0;
+
+ map->m_flags = 0;
+ ext_debug("ext4_da_map_blocks(): inode %lu, max_blocks %u,"
+ "logical block %lu\n", inode->i_ino, map->m_len,
+ (unsigned long) map->m_lblk);
+ /*
+ * Try to see if we can get the block without requesting a new
+ * file system block.
+ */
+ down_read((&EXT4_I(inode)->i_data_sem));
+ if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))
+ retval = ext4_ext_map_blocks(NULL, inode, map, 0);
+ else
+ retval = ext4_ind_map_blocks(NULL, inode, map, 0);
+
+ if (retval == 0) {
+ /*
+ * XXX: __block_prepare_write() unmaps passed block,
+ * is it OK?
+ */
+ /* If the block was allocated from previously allocated cluster,
+ * then we dont need to reserve it again. */
+ if (!(map->m_flags & EXT4_MAP_FROM_CLUSTER)) {
+ retval = ext4_da_reserve_space(inode, iblock);
+ if (retval)
+ /* not enough space to reserve */
+ goto out_unlock;
+ }
+
+ /* Clear EXT4_MAP_FROM_CLUSTER flag since its purpose is served
+ * and it should not appear on the bh->b_state.
+ */
+ map->m_flags &= ~EXT4_MAP_FROM_CLUSTER;
+
+ map_bh(bh, inode->i_sb, invalid_block);
+ set_buffer_new(bh);
+ set_buffer_delay(bh);
+ }
+
+out_unlock:
+ up_read((&EXT4_I(inode)->i_data_sem));
+
+ return retval;
+}
+
+/*
+ * This is a special get_blocks_t callback which is used by
+ * ext4_da_write_begin(). It will either return mapped block or
+ * reserve space for a single block.
+ *
+ * For delayed buffer_head we have BH_Mapped, BH_New, BH_Delay set.
+ * We also have b_blocknr = -1 and b_bdev initialized properly
+ *
+ * For unwritten buffer_head we have BH_Mapped, BH_New, BH_Unwritten set.
+ * We also have b_blocknr = physicalblock mapping unwritten extent and b_bdev
+ * initialized properly.
+ */
+static int ext4_da_get_block_prep(struct inode *inode, sector_t iblock,
+ struct buffer_head *bh, int create)
+{
+ struct ext4_map_blocks map;
+ int ret = 0;
+
+ BUG_ON(create == 0);
+ BUG_ON(bh->b_size != inode->i_sb->s_blocksize);
+
+ map.m_lblk = iblock;
+ map.m_len = 1;
+
+ /*
+ * first, we need to know whether the block is allocated already
+ * preallocated blocks are unmapped but should treated
+ * the same as allocated blocks.
+ */
+ ret = ext4_da_map_blocks(inode, iblock, &map, bh);
+ if (ret <= 0)
+ return ret;
+
+ map_bh(bh, inode->i_sb, map.m_pblk);
+ bh->b_state = (bh->b_state & ~EXT4_MAP_FLAGS) | map.m_flags;
+
+ if (buffer_unwritten(bh)) {
+ /* A delayed write to unwritten bh should be marked
+ * new and mapped. Mapped ensures that we don't do
+ * get_block multiple times when we write to the same
+ * offset and new ensures that we do proper zero out
+ * for partial write.
+ */
+ set_buffer_new(bh);
+ set_buffer_mapped(bh);
+ }
+ return 0;
+}
+
+/*
+ * This function is used as a standard get_block_t calback function
+ * when there is no desire to allocate any blocks. It is used as a
+ * callback function for block_write_begin() and block_write_full_page().
+ * These functions should only try to map a single block at a time.
+ *
+ * Since this function doesn't do block allocations even if the caller
+ * requests it by passing in create=1, it is critically important that
+ * any caller checks to make sure that any buffer heads are returned
+ * by this function are either all already mapped or marked for
+ * delayed allocation before calling block_write_full_page(). Otherwise,
+ * b_blocknr could be left unitialized, and the page write functions will
+ * be taken by surprise.
+ */
+static int noalloc_get_block_write(struct inode *inode, sector_t iblock,
+ struct buffer_head *bh_result, int create)
+{
+ BUG_ON(bh_result->b_size != inode->i_sb->s_blocksize);
+ return _ext4_get_block(inode, iblock, bh_result, 0);
+}
+
+static int bget_one(handle_t *handle, struct buffer_head *bh)
+{
+ get_bh(bh);
+ return 0;
+}
+
+static int bput_one(handle_t *handle, struct buffer_head *bh)
+{
+ put_bh(bh);
+ return 0;
+}
+
+static int __ext4_journalled_writepage(struct page *page,
+ unsigned int len)
+{
+ struct address_space *mapping = page->mapping;
+ struct inode *inode = mapping->host;
+ struct buffer_head *page_bufs;
+ handle_t *handle = NULL;
+ int ret = 0;
+ int err;
+
+ ClearPageChecked(page);
+ page_bufs = page_buffers(page);
+ BUG_ON(!page_bufs);
+ walk_page_buffers(handle, page_bufs, 0, len, NULL, bget_one);
+ /*
+ * We need to release the page lock before we start the
+ * journal, so grab a reference so the page won't disappear
+ * out from under us.
+ */
+ get_page(page);
+ unlock_page(page);
+
+ handle = ext4_journal_start(inode, ext4_writepage_trans_blocks(inode));
+ if (IS_ERR(handle)) {
+ ret = PTR_ERR(handle);
+ put_page(page);
+ goto out_no_pagelock;
+ }
+
+ BUG_ON(!ext4_handle_valid(handle));
+
+ lock_page(page);
+ put_page(page);
+ if (page->mapping != mapping) {
+ /* The page got truncated from under us */
+ ext4_journal_stop(handle);
+ ret = 0;
+ goto out;
+ }
+
+ ret = walk_page_buffers(handle, page_bufs, 0, len, NULL,
+ do_journal_get_write_access);
+
+ err = walk_page_buffers(handle, page_bufs, 0, len, NULL,
+ write_end_fn);
+ if (ret == 0)
+ ret = err;
+ EXT4_I(inode)->i_datasync_tid = handle->h_transaction->t_tid;
+ err = ext4_journal_stop(handle);
+ if (!ret)
+ ret = err;
+
+ walk_page_buffers(handle, page_bufs, 0, len, NULL, bput_one);
+ ext4_set_inode_state(inode, EXT4_STATE_JDATA);
+out:
+ unlock_page(page);
+out_no_pagelock:
+ return ret;
+}
+
+static int ext4_set_bh_endio(struct buffer_head *bh, struct inode *inode);
+static void ext4_end_io_buffer_write(struct buffer_head *bh, int uptodate);
+
+/*
+ * Note that we don't need to start a transaction unless we're journaling data
+ * because we should have holes filled from ext4_page_mkwrite(). We even don't
+ * need to file the inode to the transaction's list in ordered mode because if
+ * we are writing back data added by write(), the inode is already there and if
+ * we are writing back data modified via mmap(), no one guarantees in which
+ * transaction the data will hit the disk. In case we are journaling data, we
+ * cannot start transaction directly because transaction start ranks above page
+ * lock so we have to do some magic.
+ *
+ * This function can get called via...
+ * - ext4_da_writepages after taking page lock (have journal handle)
+ * - journal_submit_inode_data_buffers (no journal handle)
+ * - shrink_page_list via pdflush (no journal handle)
+ * - grab_page_cache when doing write_begin (have journal handle)
+ *
+ * We don't do any block allocation in this function. If we have page with
+ * multiple blocks we need to write those buffer_heads that are mapped. This
+ * is important for mmaped based write. So if we do with blocksize 1K
+ * truncate(f, 1024);
+ * a = mmap(f, 0, 4096);
+ * a[0] = 'a';
+ * truncate(f, 4096);
+ * we have in the page first buffer_head mapped via page_mkwrite call back
+ * but other buffer_heads would be unmapped but dirty (dirty done via the
+ * do_wp_page). So writepage should write the first block. If we modify
+ * the mmap area beyond 1024 we will again get a page_fault and the
+ * page_mkwrite callback will do the block allocation and mark the
+ * buffer_heads mapped.
+ *
+ * We redirty the page if we have any buffer_heads that is either delay or
+ * unwritten in the page.
+ *
+ * We can get recursively called as show below.
+ *
+ * ext4_writepage() -> kmalloc() -> __alloc_pages() -> page_launder() ->
+ * ext4_writepage()
+ *
+ * But since we don't do any block allocation we should not deadlock.
+ * Page also have the dirty flag cleared so we don't get recurive page_lock.
+ */
+static int ext4_writepage(struct page *page,
+ struct writeback_control *wbc)
+{
+ int ret = 0, commit_write = 0;
+ loff_t size;
+ unsigned int len;
+ struct buffer_head *page_bufs = NULL;
+ struct inode *inode = page->mapping->host;
+
+ trace_ext4_writepage(page);
+ size = i_size_read(inode);
+ if (page->index == size >> PAGE_CACHE_SHIFT)
+ len = size & ~PAGE_CACHE_MASK;
+ else
+ len = PAGE_CACHE_SIZE;
+
+ /*
+ * If the page does not have buffers (for whatever reason),
+ * try to create them using __block_write_begin. If this
+ * fails, redirty the page and move on.
+ */
+ if (!page_has_buffers(page)) {
+ if (__block_write_begin(page, 0, len,
+ noalloc_get_block_write)) {
+ redirty_page:
+ redirty_page_for_writepage(wbc, page);
+ unlock_page(page);
+ return 0;
+ }
+ commit_write = 1;
+ }
+ page_bufs = page_buffers(page);
+ if (walk_page_buffers(NULL, page_bufs, 0, len, NULL,
+ ext4_bh_delay_or_unwritten)) {
+ /*
+ * We don't want to do block allocation, so redirty
+ * the page and return. We may reach here when we do
+ * a journal commit via journal_submit_inode_data_buffers.
+ * We can also reach here via shrink_page_list but it
+ * should never be for direct reclaim so warn if that
+ * happens
+ */
+ WARN_ON_ONCE((current->flags & (PF_MEMALLOC|PF_KSWAPD)) ==
+ PF_MEMALLOC);
+ goto redirty_page;
+ }
+ if (commit_write)
+ /* now mark the buffer_heads as dirty and uptodate */
+ block_commit_write(page, 0, len);
+
+ if (PageChecked(page) && ext4_should_journal_data(inode))
+ /*
+ * It's mmapped pagecache. Add buffers and journal it. There
+ * doesn't seem much point in redirtying the page here.
+ */
+ return __ext4_journalled_writepage(page, len);
+
+ if (buffer_uninit(page_bufs)) {
+ ext4_set_bh_endio(page_bufs, inode);
+ ret = block_write_full_page_endio(page, noalloc_get_block_write,
+ wbc, ext4_end_io_buffer_write);
+ } else
+ ret = block_write_full_page(page, noalloc_get_block_write,
+ wbc);
+
+ return ret;
+}
+
+/*
+ * This is called via ext4_da_writepages() to
+ * calculate the total number of credits to reserve to fit
+ * a single extent allocation into a single transaction,
+ * ext4_da_writpeages() will loop calling this before
+ * the block allocation.
+ */
+
+static int ext4_da_writepages_trans_blocks(struct inode *inode)
+{
+ int max_blocks = EXT4_I(inode)->i_reserved_data_blocks;
+
+ /*
+ * With non-extent format the journal credit needed to
+ * insert nrblocks contiguous block is dependent on
+ * number of contiguous block. So we will limit
+ * number of contiguous block to a sane value
+ */
+ if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)) &&
+ (max_blocks > EXT4_MAX_TRANS_DATA))
+ max_blocks = EXT4_MAX_TRANS_DATA;
+
+ return ext4_chunk_trans_blocks(inode, max_blocks);
+}
+
+/*
+ * write_cache_pages_da - walk the list of dirty pages of the given
+ * address space and accumulate pages that need writing, and call
+ * mpage_da_map_and_submit to map a single contiguous memory region
+ * and then write them.
+ */
+static int write_cache_pages_da(struct address_space *mapping,
+ struct writeback_control *wbc,
+ struct mpage_da_data *mpd,
+ pgoff_t *done_index)
+{
+ struct buffer_head *bh, *head;
+ struct inode *inode = mapping->host;
+ struct pagevec pvec;
+ unsigned int nr_pages;
+ sector_t logical;
+ pgoff_t index, end;
+ long nr_to_write = wbc->nr_to_write;
+ int i, tag, ret = 0;
+
+ memset(mpd, 0, sizeof(struct mpage_da_data));
+ mpd->wbc = wbc;
+ mpd->inode = inode;
+ pagevec_init(&pvec, 0);
+ index = wbc->range_start >> PAGE_CACHE_SHIFT;
+ end = wbc->range_end >> PAGE_CACHE_SHIFT;
+
+ if (wbc->sync_mode == WB_SYNC_ALL || wbc->tagged_writepages)
+ tag = PAGECACHE_TAG_TOWRITE;
+ else
+ tag = PAGECACHE_TAG_DIRTY;
+
+ *done_index = index;
+ while (index <= end) {
+ nr_pages = pagevec_lookup_tag(&pvec, mapping, &index, tag,
+ min(end - index, (pgoff_t)PAGEVEC_SIZE-1) + 1);
+ if (nr_pages == 0)
+ return 0;
+
+ for (i = 0; i < nr_pages; i++) {
+ struct page *page = pvec.pages[i];
+
+ /*
+ * At this point, the page may be truncated or
+ * invalidated (changing page->mapping to NULL), or
+ * even swizzled back from swapper_space to tmpfs file
+ * mapping. However, page->index will not change
+ * because we have a reference on the page.
+ */
+ if (page->index > end)
+ goto out;
+
+ *done_index = page->index + 1;
+
+ /*
+ * If we can't merge this page, and we have
+ * accumulated an contiguous region, write it
+ */
+ if ((mpd->next_page != page->index) &&
+ (mpd->next_page != mpd->first_page)) {
+ mpage_da_map_and_submit(mpd);
+ goto ret_extent_tail;
+ }
+
+ lock_page(page);
+
+ /*
+ * If the page is no longer dirty, or its
+ * mapping no longer corresponds to inode we
+ * are writing (which means it has been
+ * truncated or invalidated), or the page is
+ * already under writeback and we are not
+ * doing a data integrity writeback, skip the page
+ */
+ if (!PageDirty(page) ||
+ (PageWriteback(page) &&
+ (wbc->sync_mode == WB_SYNC_NONE)) ||
+ unlikely(page->mapping != mapping)) {
+ unlock_page(page);
+ continue;
+ }
+
+ wait_on_page_writeback(page);
+ BUG_ON(PageWriteback(page));
+
+ if (mpd->next_page != page->index)
+ mpd->first_page = page->index;
+ mpd->next_page = page->index + 1;
+ logical = (sector_t) page->index <<
+ (PAGE_CACHE_SHIFT - inode->i_blkbits);
+
+ if (!page_has_buffers(page)) {
+ mpage_add_bh_to_extent(mpd, logical,
+ PAGE_CACHE_SIZE,
+ (1 << BH_Dirty) | (1 << BH_Uptodate));
+ if (mpd->io_done)
+ goto ret_extent_tail;
+ } else {
+ /*
+ * Page with regular buffer heads,
+ * just add all dirty ones
+ */
+ head = page_buffers(page);
+ bh = head;
+ do {
+ BUG_ON(buffer_locked(bh));
+ /*
+ * We need to try to allocate
+ * unmapped blocks in the same page.
+ * Otherwise we won't make progress
+ * with the page in ext4_writepage
+ */
+ if (ext4_bh_delay_or_unwritten(NULL, bh)) {
+ mpage_add_bh_to_extent(mpd, logical,
+ bh->b_size,
+ bh->b_state);
+ if (mpd->io_done)
+ goto ret_extent_tail;
+ } else if (buffer_dirty(bh) && (buffer_mapped(bh))) {
+ /*
+ * mapped dirty buffer. We need
+ * to update the b_state
+ * because we look at b_state
+ * in mpage_da_map_blocks. We
+ * don't update b_size because
+ * if we find an unmapped
+ * buffer_head later we need to
+ * use the b_state flag of that
+ * buffer_head.
+ */
+ if (mpd->b_size == 0)
+ mpd->b_state = bh->b_state & BH_FLAGS;
+ }
+ logical++;
+ } while ((bh = bh->b_this_page) != head);
+ }
+
+ if (nr_to_write > 0) {
+ nr_to_write--;
+ if (nr_to_write == 0 &&
+ wbc->sync_mode == WB_SYNC_NONE)
+ /*
+ * We stop writing back only if we are
+ * not doing integrity sync. In case of
+ * integrity sync we have to keep going
+ * because someone may be concurrently
+ * dirtying pages, and we might have
+ * synced a lot of newly appeared dirty
+ * pages, but have not synced all of the
+ * old dirty pages.
+ */
+ goto out;
+ }
+ }
+ pagevec_release(&pvec);
+ cond_resched();
+ }
+ return 0;
+ret_extent_tail:
+ ret = MPAGE_DA_EXTENT_TAIL;
+out:
+ pagevec_release(&pvec);
+ cond_resched();
+ return ret;
+}
+
+
+static int ext4_da_writepages(struct address_space *mapping,
+ struct writeback_control *wbc)
+{
+ pgoff_t index;
+ int range_whole = 0;
+ handle_t *handle = NULL;
+ struct mpage_da_data mpd;
+ struct inode *inode = mapping->host;
+ int pages_written = 0;
+ unsigned int max_pages;
+ int range_cyclic, cycled = 1, io_done = 0;
+ int needed_blocks, ret = 0;
+ long desired_nr_to_write, nr_to_writebump = 0;
+ loff_t range_start = wbc->range_start;
+ struct ext4_sb_info *sbi = EXT4_SB(mapping->host->i_sb);
+ pgoff_t done_index = 0;
+ pgoff_t end;
+ struct blk_plug plug;
+
+ trace_ext4_da_writepages(inode, wbc);
+
+ /*
+ * No pages to write? This is mainly a kludge to avoid starting
+ * a transaction for special inodes like journal inode on last iput()
+ * because that could violate lock ordering on umount
+ */
+ if (!mapping->nrpages || !mapping_tagged(mapping, PAGECACHE_TAG_DIRTY))
+ return 0;
+
+ /*
+ * If the filesystem has aborted, it is read-only, so return
+ * right away instead of dumping stack traces later on that
+ * will obscure the real source of the problem. We test
+ * EXT4_MF_FS_ABORTED instead of sb->s_flag's MS_RDONLY because
+ * the latter could be true if the filesystem is mounted
+ * read-only, and in that case, ext4_da_writepages should
+ * *never* be called, so if that ever happens, we would want
+ * the stack trace.
+ */
+ if (unlikely(sbi->s_mount_flags & EXT4_MF_FS_ABORTED))
+ return -EROFS;
+
+ if (wbc->range_start == 0 && wbc->range_end == LLONG_MAX)
+ range_whole = 1;
+
+ range_cyclic = wbc->range_cyclic;
+ if (wbc->range_cyclic) {
+ index = mapping->writeback_index;
+ if (index)
+ cycled = 0;
+ wbc->range_start = index << PAGE_CACHE_SHIFT;
+ wbc->range_end = LLONG_MAX;
+ wbc->range_cyclic = 0;
+ end = -1;
+ } else {
+ index = wbc->range_start >> PAGE_CACHE_SHIFT;
+ end = wbc->range_end >> PAGE_CACHE_SHIFT;
+ }
+
+ /*
+ * This works around two forms of stupidity. The first is in
+ * the writeback code, which caps the maximum number of pages
+ * written to be 1024 pages. This is wrong on multiple
+ * levels; different architectues have a different page size,
+ * which changes the maximum amount of data which gets
+ * written. Secondly, 4 megabytes is way too small. XFS
+ * forces this value to be 16 megabytes by multiplying
+ * nr_to_write parameter by four, and then relies on its
+ * allocator to allocate larger extents to make them
+ * contiguous. Unfortunately this brings us to the second
+ * stupidity, which is that ext4's mballoc code only allocates
+ * at most 2048 blocks. So we force contiguous writes up to
+ * the number of dirty blocks in the inode, or
+ * sbi->max_writeback_mb_bump whichever is smaller.
+ */
+ max_pages = sbi->s_max_writeback_mb_bump << (20 - PAGE_CACHE_SHIFT);
+ if (!range_cyclic && range_whole) {
+ if (wbc->nr_to_write == LONG_MAX)
+ desired_nr_to_write = wbc->nr_to_write;
+ else
+ desired_nr_to_write = wbc->nr_to_write * 8;
+ } else
+ desired_nr_to_write = ext4_num_dirty_pages(inode, index,
+ max_pages);
+ if (desired_nr_to_write > max_pages)
+ desired_nr_to_write = max_pages;
+
+ if (wbc->nr_to_write < desired_nr_to_write) {
+ nr_to_writebump = desired_nr_to_write - wbc->nr_to_write;
+ wbc->nr_to_write = desired_nr_to_write;
+ }
+
+retry:
+ if (wbc->sync_mode == WB_SYNC_ALL || wbc->tagged_writepages)
+ tag_pages_for_writeback(mapping, index, end);
+
+ blk_start_plug(&plug);
+ while (!ret && wbc->nr_to_write > 0) {
+
+ /*
+ * we insert one extent at a time. So we need
+ * credit needed for single extent allocation.
+ * journalled mode is currently not supported
+ * by delalloc
+ */
+ BUG_ON(ext4_should_journal_data(inode));
+ needed_blocks = ext4_da_writepages_trans_blocks(inode);
+
+ /* start a new transaction*/
+ handle = ext4_journal_start(inode, needed_blocks);
+ if (IS_ERR(handle)) {
+ ret = PTR_ERR(handle);
+ ext4_msg(inode->i_sb, KERN_CRIT, "%s: jbd2_start: "
+ "%ld pages, ino %lu; err %d", __func__,
+ wbc->nr_to_write, inode->i_ino, ret);
+ blk_finish_plug(&plug);
+ goto out_writepages;
+ }
+
+ /*
+ * Now call write_cache_pages_da() to find the next
+ * contiguous region of logical blocks that need
+ * blocks to be allocated by ext4 and submit them.
+ */
+ ret = write_cache_pages_da(mapping, wbc, &mpd, &done_index);
+ /*
+ * If we have a contiguous extent of pages and we
+ * haven't done the I/O yet, map the blocks and submit
+ * them for I/O.
+ */
+ if (!mpd.io_done && mpd.next_page != mpd.first_page) {
+ mpage_da_map_and_submit(&mpd);
+ ret = MPAGE_DA_EXTENT_TAIL;
+ }
+ trace_ext4_da_write_pages(inode, &mpd);
+ wbc->nr_to_write -= mpd.pages_written;
+
+ ext4_journal_stop(handle);
+
+ if ((mpd.retval == -ENOSPC) && sbi->s_journal) {
+ /* commit the transaction which would
+ * free blocks released in the transaction
+ * and try again
+ */
+ jbd2_journal_force_commit_nested(sbi->s_journal);
+ ret = 0;
+ } else if (ret == MPAGE_DA_EXTENT_TAIL) {
+ /*
+ * Got one extent now try with rest of the pages.
+ * If mpd.retval is set -EIO, journal is aborted.
+ * So we don't need to write any more.
+ */
+ pages_written += mpd.pages_written;
+ ret = mpd.retval;
+ io_done = 1;
+ } else if (wbc->nr_to_write)
+ /*
+ * There is no more writeout needed
+ * or we requested for a noblocking writeout
+ * and we found the device congested
+ */
+ break;
+ }
+ blk_finish_plug(&plug);
+ if (!io_done && !cycled) {
+ cycled = 1;
+ index = 0;
+ wbc->range_start = index << PAGE_CACHE_SHIFT;
+ wbc->range_end = mapping->writeback_index - 1;
+ goto retry;
+ }
+
+ /* Update index */
+ wbc->range_cyclic = range_cyclic;
+ if (wbc->range_cyclic || (range_whole && wbc->nr_to_write > 0))
+ /*
+ * set the writeback_index so that range_cyclic
+ * mode will write it back later
+ */
+ mapping->writeback_index = done_index;
+
+out_writepages:
+ wbc->nr_to_write -= nr_to_writebump;
+ wbc->range_start = range_start;
+ trace_ext4_da_writepages_result(inode, wbc, ret, pages_written);
+ return ret;
+}
+
+#define FALL_BACK_TO_NONDELALLOC 1
+static int ext4_nonda_switch(struct super_block *sb)
+{
+ s64 free_blocks, dirty_blocks;
+ struct ext4_sb_info *sbi = EXT4_SB(sb);
+
+ /*
+ * switch to non delalloc mode if we are running low
+ * on free block. The free block accounting via percpu
+ * counters can get slightly wrong with percpu_counter_batch getting
+ * accumulated on each CPU without updating global counters
+ * Delalloc need an accurate free block accounting. So switch
+ * to non delalloc when we are near to error range.
+ */
+ free_blocks = EXT4_C2B(sbi,
+ percpu_counter_read_positive(&sbi->s_freeclusters_counter));
+ dirty_blocks = percpu_counter_read_positive(&sbi->s_dirtyclusters_counter);
+ /*
+ * Start pushing delalloc when 1/2 of free blocks are dirty.
+ */
+ if (dirty_blocks && (free_blocks < 2 * dirty_blocks) &&
+ !writeback_in_progress(sb->s_bdi) &&
+ down_read_trylock(&sb->s_umount)) {
+ writeback_inodes_sb(sb, WB_REASON_FS_FREE_SPACE);
+ up_read(&sb->s_umount);
+ }
+
+ if (2 * free_blocks < 3 * dirty_blocks ||
+ free_blocks < (dirty_blocks + EXT4_FREECLUSTERS_WATERMARK)) {
+ /*
+ * free block count is less than 150% of dirty blocks
+ * or free blocks is less than watermark
+ */
+ return 1;
+ }
+ return 0;
+}
+
+/* We always reserve for an inode update; the superblock could be there too */
+static int ext4_da_write_credits(struct inode *inode, loff_t pos, unsigned len)
+{
+ if (likely(EXT4_HAS_RO_COMPAT_FEATURE(inode->i_sb,
+ EXT4_FEATURE_RO_COMPAT_LARGE_FILE)))
+ return 1;
+
+ if (pos + len <= 0x7fffffffULL)
+ return 1;
+
+ /* We might need to update the superblock to set LARGE_FILE */
+ return 2;
+}
+
+static int ext4_da_write_begin(struct file *file, struct address_space *mapping,
+ loff_t pos, unsigned len, unsigned flags,
+ struct page **pagep, void **fsdata)
+{
+ int ret, retries = 0;
+ struct page *page;
+ pgoff_t index;
+ struct inode *inode = mapping->host;
+ handle_t *handle;
+
+ index = pos >> PAGE_CACHE_SHIFT;
+
+ if (ext4_nonda_switch(inode->i_sb)) {
+ *fsdata = (void *)FALL_BACK_TO_NONDELALLOC;
+ return ext4_write_begin(file, mapping, pos,
+ len, flags, pagep, fsdata);
+ }
+ *fsdata = (void *)0;
+ trace_ext4_da_write_begin(inode, pos, len, flags);
+retry:
+ /*
+ * With delayed allocation, we don't log the i_disksize update
+ * if there is delayed block allocation. But we still need
+ * to journalling the i_disksize update if writes to the end
+ * of file which has an already mapped buffer.
+ */
+ handle = ext4_journal_start(inode,
+ ext4_da_write_credits(inode, pos, len));
+ if (IS_ERR(handle)) {
+ ret = PTR_ERR(handle);
+ goto out;
+ }
+ /* We cannot recurse into the filesystem as the transaction is already
+ * started */
+ flags |= AOP_FLAG_NOFS;
+
+ page = grab_cache_page_write_begin(mapping, index, flags);
+ if (!page) {
+ ext4_journal_stop(handle);
+ ret = -ENOMEM;
+ goto out;
+ }
+ *pagep = page;
+
+ ret = __block_write_begin(page, pos, len, ext4_da_get_block_prep);
+ if (ret < 0) {
+ unlock_page(page);
+ ext4_journal_stop(handle);
+ page_cache_release(page);
+ /*
+ * block_write_begin may have instantiated a few blocks
+ * outside i_size. Trim these off again. Don't need
+ * i_size_read because we hold i_mutex.
+ */
+ if (pos + len > inode->i_size)
+ ext4_truncate_failed_write(inode);
+ }
+
+ if (ret == -ENOSPC && ext4_should_retry_alloc(inode->i_sb, &retries))
+ goto retry;
+out:
+ return ret;
+}
+
+/*
+ * Check if we should update i_disksize
+ * when write to the end of file but not require block allocation
+ */
+static int ext4_da_should_update_i_disksize(struct page *page,
+ unsigned long offset)
+{
+ struct buffer_head *bh;
+ struct inode *inode = page->mapping->host;
+ unsigned int idx;
+ int i;
+
+ bh = page_buffers(page);
+ idx = offset >> inode->i_blkbits;
+
+ for (i = 0; i < idx; i++)
+ bh = bh->b_this_page;
+
+ if (!buffer_mapped(bh) || (buffer_delay(bh)) || buffer_unwritten(bh))
+ return 0;
+ return 1;
+}
+
+static int ext4_da_write_end(struct file *file,
+ struct address_space *mapping,
+ loff_t pos, unsigned len, unsigned copied,
+ struct page *page, void *fsdata)
+{
+ struct inode *inode = mapping->host;
+ int ret = 0, ret2;
+ handle_t *handle = ext4_journal_current_handle();
+ loff_t new_i_size;
+ unsigned long start, end;
+ int write_mode = (int)(unsigned long)fsdata;
+
+ if (write_mode == FALL_BACK_TO_NONDELALLOC) {
+ switch (ext4_inode_journal_mode(inode)) {
+ case EXT4_INODE_ORDERED_DATA_MODE:
+ return ext4_ordered_write_end(file, mapping, pos,
+ len, copied, page, fsdata);
+ case EXT4_INODE_WRITEBACK_DATA_MODE:
+ return ext4_writeback_write_end(file, mapping, pos,
+ len, copied, page, fsdata);
+ default:
+ BUG();
+ }
+ }
+
+ trace_ext4_da_write_end(inode, pos, len, copied);
+ start = pos & (PAGE_CACHE_SIZE - 1);
+ end = start + copied - 1;
+
+ /*
+ * generic_write_end() will run mark_inode_dirty() if i_size
+ * changes. So let's piggyback the i_disksize mark_inode_dirty
+ * into that.
+ */
+
+ new_i_size = pos + copied;
+ if (copied && new_i_size > EXT4_I(inode)->i_disksize) {
+ if (ext4_da_should_update_i_disksize(page, end)) {
+ down_write(&EXT4_I(inode)->i_data_sem);
+ if (new_i_size > EXT4_I(inode)->i_disksize) {
+ /*
+ * Updating i_disksize when extending file
+ * without needing block allocation
+ */
+ if (ext4_should_order_data(inode))
+ ret = ext4_jbd2_file_inode(handle,
+ inode);
+
+ EXT4_I(inode)->i_disksize = new_i_size;
+ }
+ up_write(&EXT4_I(inode)->i_data_sem);
+ /* We need to mark inode dirty even if
+ * new_i_size is less that inode->i_size
+ * bu greater than i_disksize.(hint delalloc)
+ */
+ ext4_mark_inode_dirty(handle, inode);
+ }
+ }
+ ret2 = generic_write_end(file, mapping, pos, len, copied,
+ page, fsdata);
+ copied = ret2;
+ if (ret2 < 0)
+ ret = ret2;
+ ret2 = ext4_journal_stop(handle);
+ if (!ret)
+ ret = ret2;
+
+ return ret ? ret : copied;
+}
+
+static void ext4_da_invalidatepage(struct page *page, unsigned long offset)
+{
+ /*
+ * Drop reserved blocks
+ */
+ BUG_ON(!PageLocked(page));
+ if (!page_has_buffers(page))
+ goto out;
+
+ ext4_da_page_release_reservation(page, offset);
+
+out:
+ ext4_invalidatepage(page, offset);
+
+ return;
+}
+
+/*
+ * Force all delayed allocation blocks to be allocated for a given inode.
+ */
+int ext4_alloc_da_blocks(struct inode *inode)
+{
+ trace_ext4_alloc_da_blocks(inode);
+
+ if (!EXT4_I(inode)->i_reserved_data_blocks &&
+ !EXT4_I(inode)->i_reserved_meta_blocks)
+ return 0;
+
+ /*
+ * We do something simple for now. The filemap_flush() will
+ * also start triggering a write of the data blocks, which is
+ * not strictly speaking necessary (and for users of
+ * laptop_mode, not even desirable). However, to do otherwise
+ * would require replicating code paths in:
+ *
+ * ext4_da_writepages() ->
+ * write_cache_pages() ---> (via passed in callback function)
+ * __mpage_da_writepage() -->
+ * mpage_add_bh_to_extent()
+ * mpage_da_map_blocks()
+ *
+ * The problem is that write_cache_pages(), located in
+ * mm/page-writeback.c, marks pages clean in preparation for
+ * doing I/O, which is not desirable if we're not planning on
+ * doing I/O at all.
+ *
+ * We could call write_cache_pages(), and then redirty all of
+ * the pages by calling redirty_page_for_writepage() but that
+ * would be ugly in the extreme. So instead we would need to
+ * replicate parts of the code in the above functions,
+ * simplifying them because we wouldn't actually intend to
+ * write out the pages, but rather only collect contiguous
+ * logical block extents, call the multi-block allocator, and
+ * then update the buffer heads with the block allocations.
+ *
+ * For now, though, we'll cheat by calling filemap_flush(),
+ * which will map the blocks, and start the I/O, but not
+ * actually wait for the I/O to complete.
+ */
+ return filemap_flush(inode->i_mapping);
+}
+
+/*
+ * bmap() is special. It gets used by applications such as lilo and by
+ * the swapper to find the on-disk block of a specific piece of data.
+ *
+ * Naturally, this is dangerous if the block concerned is still in the
+ * journal. If somebody makes a swapfile on an ext4 data-journaling
+ * filesystem and enables swap, then they may get a nasty shock when the
+ * data getting swapped to that swapfile suddenly gets overwritten by
+ * the original zero's written out previously to the journal and
+ * awaiting writeback in the kernel's buffer cache.
+ *
+ * So, if we see any bmap calls here on a modified, data-journaled file,
+ * take extra steps to flush any blocks which might be in the cache.
+ */
+static sector_t ext4_bmap(struct address_space *mapping, sector_t block)
+{
+ struct inode *inode = mapping->host;
+ journal_t *journal;
+ int err;
+
+ if (mapping_tagged(mapping, PAGECACHE_TAG_DIRTY) &&
+ test_opt(inode->i_sb, DELALLOC)) {
+ /*
+ * With delalloc we want to sync the file
+ * so that we can make sure we allocate
+ * blocks for file
+ */
+ filemap_write_and_wait(mapping);
+ }
+
+ if (EXT4_JOURNAL(inode) &&
+ ext4_test_inode_state(inode, EXT4_STATE_JDATA)) {
+ /*
+ * This is a REALLY heavyweight approach, but the use of
+ * bmap on dirty files is expected to be extremely rare:
+ * only if we run lilo or swapon on a freshly made file
+ * do we expect this to happen.
+ *
+ * (bmap requires CAP_SYS_RAWIO so this does not
+ * represent an unprivileged user DOS attack --- we'd be
+ * in trouble if mortal users could trigger this path at
+ * will.)
+ *
+ * NB. EXT4_STATE_JDATA is not set on files other than
+ * regular files. If somebody wants to bmap a directory
+ * or symlink and gets confused because the buffer
+ * hasn't yet been flushed to disk, they deserve
+ * everything they get.
+ */
+
+ ext4_clear_inode_state(inode, EXT4_STATE_JDATA);
+ journal = EXT4_JOURNAL(inode);
+ jbd2_journal_lock_updates(journal);
+ err = jbd2_journal_flush(journal);
+ jbd2_journal_unlock_updates(journal);
+
+ if (err)
+ return 0;
+ }
+
+ return generic_block_bmap(mapping, block, ext4_get_block);
+}
+
+static int ext4_readpage(struct file *file, struct page *page)
+{
+ trace_ext4_readpage(page);
+ return mpage_readpage(page, ext4_get_block);
+}
+
+static int
+ext4_readpages(struct file *file, struct address_space *mapping,
+ struct list_head *pages, unsigned nr_pages)
+{
+ return mpage_readpages(mapping, pages, nr_pages, ext4_get_block);
+}
+
+static void ext4_invalidatepage_free_endio(struct page *page, unsigned long offset)
+{
+ struct buffer_head *head, *bh;
+ unsigned int curr_off = 0;
+
+ if (!page_has_buffers(page))
+ return;
+ head = bh = page_buffers(page);
+ do {
+ if (offset <= curr_off && test_clear_buffer_uninit(bh)
+ && bh->b_private) {
+ ext4_free_io_end(bh->b_private);
+ bh->b_private = NULL;
+ bh->b_end_io = NULL;
+ }
+ curr_off = curr_off + bh->b_size;
+ bh = bh->b_this_page;
+ } while (bh != head);
+}
+
+static void ext4_invalidatepage(struct page *page, unsigned long offset)
+{
+ journal_t *journal = EXT4_JOURNAL(page->mapping->host);
+
+ trace_ext4_invalidatepage(page, offset);
+
+ /*
+ * free any io_end structure allocated for buffers to be discarded
+ */
+ if (ext4_should_dioread_nolock(page->mapping->host))
+ ext4_invalidatepage_free_endio(page, offset);
+ /*
+ * If it's a full truncate we just forget about the pending dirtying
+ */
+ if (offset == 0)
+ ClearPageChecked(page);
+
+ if (journal)
+ jbd2_journal_invalidatepage(journal, page, offset);
+ else
+ block_invalidatepage(page, offset);
+}
+
+static int ext4_releasepage(struct page *page, gfp_t wait)
+{
+ journal_t *journal = EXT4_JOURNAL(page->mapping->host);
+
+ trace_ext4_releasepage(page);
+
+ WARN_ON(PageChecked(page));
+ if (!page_has_buffers(page))
+ return 0;
+ if (journal)
+ return jbd2_journal_try_to_free_buffers(journal, page, wait);
+ else
+ return try_to_free_buffers(page);
+}
+
+/*
+ * ext4_get_block used when preparing for a DIO write or buffer write.
+ * We allocate an uinitialized extent if blocks haven't been allocated.
+ * The extent will be converted to initialized after the IO is complete.
+ */
+static int ext4_get_block_write(struct inode *inode, sector_t iblock,
+ struct buffer_head *bh_result, int create)
+{
+ ext4_debug("ext4_get_block_write: inode %lu, create flag %d\n",
+ inode->i_ino, create);
+ return _ext4_get_block(inode, iblock, bh_result,
+ EXT4_GET_BLOCKS_IO_CREATE_EXT);
+}
+
+static void ext4_end_io_dio(struct kiocb *iocb, loff_t offset,
+ ssize_t size, void *private, int ret,
+ bool is_async)
+{
+ struct inode *inode = iocb->ki_filp->f_path.dentry->d_inode;
+ ext4_io_end_t *io_end = iocb->private;
+ struct workqueue_struct *wq;
+ unsigned long flags;
+ struct ext4_inode_info *ei;
+
+ /* if not async direct IO or dio with 0 bytes write, just return */
+ if (!io_end || !size)
+ goto out;
+
+ ext_debug("ext4_end_io_dio(): io_end 0x%p "
+ "for inode %lu, iocb 0x%p, offset %llu, size %zd\n",
+ iocb->private, io_end->inode->i_ino, iocb, offset,
+ size);
+
+ iocb->private = NULL;
+
+ /* if not aio dio with unwritten extents, just free io and return */
+ if (!(io_end->flag & EXT4_IO_END_UNWRITTEN)) {
+ ext4_free_io_end(io_end);
+out:
+ inode_dio_done(inode);
+ if (is_async)
+ aio_complete(iocb, ret, 0);
+ return;
+ }
+
+ io_end->offset = offset;
+ io_end->size = size;
+ if (is_async) {
+ io_end->iocb = iocb;
+ io_end->result = ret;
+ }
+ wq = EXT4_SB(io_end->inode->i_sb)->dio_unwritten_wq;
+
+ /* Add the io_end to per-inode completed aio dio list*/
+ ei = EXT4_I(io_end->inode);
+ spin_lock_irqsave(&ei->i_completed_io_lock, flags);
+ list_add_tail(&io_end->list, &ei->i_completed_io_list);
+ spin_unlock_irqrestore(&ei->i_completed_io_lock, flags);
+
+ /* queue the work to convert unwritten extents to written */
+ queue_work(wq, &io_end->work);
+}
+
+static void ext4_end_io_buffer_write(struct buffer_head *bh, int uptodate)
+{
+ ext4_io_end_t *io_end = bh->b_private;
+ struct workqueue_struct *wq;
+ struct inode *inode;
+ unsigned long flags;
+
+ if (!test_clear_buffer_uninit(bh) || !io_end)
+ goto out;
+
+ if (!(io_end->inode->i_sb->s_flags & MS_ACTIVE)) {
+ ext4_msg(io_end->inode->i_sb, KERN_INFO,
+ "sb umounted, discard end_io request for inode %lu",
+ io_end->inode->i_ino);
+ ext4_free_io_end(io_end);
+ goto out;
+ }
+
+ /*
+ * It may be over-defensive here to check EXT4_IO_END_UNWRITTEN now,
+ * but being more careful is always safe for the future change.
+ */
+ inode = io_end->inode;
+ ext4_set_io_unwritten_flag(inode, io_end);
+
+ /* Add the io_end to per-inode completed io list*/
+ spin_lock_irqsave(&EXT4_I(inode)->i_completed_io_lock, flags);
+ list_add_tail(&io_end->list, &EXT4_I(inode)->i_completed_io_list);
+ spin_unlock_irqrestore(&EXT4_I(inode)->i_completed_io_lock, flags);
+
+ wq = EXT4_SB(inode->i_sb)->dio_unwritten_wq;
+ /* queue the work to convert unwritten extents to written */
+ queue_work(wq, &io_end->work);
+out:
+ bh->b_private = NULL;
+ bh->b_end_io = NULL;
+ clear_buffer_uninit(bh);
+ end_buffer_async_write(bh, uptodate);
+}
+
+static int ext4_set_bh_endio(struct buffer_head *bh, struct inode *inode)
+{
+ ext4_io_end_t *io_end;
+ struct page *page = bh->b_page;
+ loff_t offset = (sector_t)page->index << PAGE_CACHE_SHIFT;
+ size_t size = bh->b_size;
+
+retry:
+ io_end = ext4_init_io_end(inode, GFP_ATOMIC);
+ if (!io_end) {
+ pr_warn_ratelimited("%s: allocation fail\n", __func__);
+ schedule();
+ goto retry;
+ }
+ io_end->offset = offset;
+ io_end->size = size;
+ /*
+ * We need to hold a reference to the page to make sure it
+ * doesn't get evicted before ext4_end_io_work() has a chance
+ * to convert the extent from written to unwritten.
+ */
+ io_end->page = page;
+ get_page(io_end->page);
+
+ bh->b_private = io_end;
+ bh->b_end_io = ext4_end_io_buffer_write;
+ return 0;
+}
+
+/*
+ * For ext4 extent files, ext4 will do direct-io write to holes,
+ * preallocated extents, and those write extend the file, no need to
+ * fall back to buffered IO.
+ *
+ * For holes, we fallocate those blocks, mark them as uninitialized
+ * If those blocks were preallocated, we mark sure they are splited, but
+ * still keep the range to write as uninitialized.
+ *
+ * The unwrritten extents will be converted to written when DIO is completed.
+ * For async direct IO, since the IO may still pending when return, we
+ * set up an end_io call back function, which will do the conversion
+ * when async direct IO completed.
+ *
+ * If the O_DIRECT write will extend the file then add this inode to the
+ * orphan list. So recovery will truncate it back to the original size
+ * if the machine crashes during the write.
+ *
+ */
+static ssize_t ext4_ext_direct_IO(int rw, struct kiocb *iocb,
+ const struct iovec *iov, loff_t offset,
+ unsigned long nr_segs)
+{
+ struct file *file = iocb->ki_filp;
+ struct inode *inode = file->f_mapping->host;
+ ssize_t ret;
+ size_t count = iov_length(iov, nr_segs);
+
+ loff_t final_size = offset + count;
+ if (rw == WRITE && final_size <= inode->i_size) {
+ /*
+ * We could direct write to holes and fallocate.
+ *
+ * Allocated blocks to fill the hole are marked as uninitialized
+ * to prevent parallel buffered read to expose the stale data
+ * before DIO complete the data IO.
+ *
+ * As to previously fallocated extents, ext4 get_block
+ * will just simply mark the buffer mapped but still
+ * keep the extents uninitialized.
+ *
+ * for non AIO case, we will convert those unwritten extents
+ * to written after return back from blockdev_direct_IO.
+ *
+ * for async DIO, the conversion needs to be defered when
+ * the IO is completed. The ext4 end_io callback function
+ * will be called to take care of the conversion work.
+ * Here for async case, we allocate an io_end structure to
+ * hook to the iocb.
+ */
+ iocb->private = NULL;
+ EXT4_I(inode)->cur_aio_dio = NULL;
+ if (!is_sync_kiocb(iocb)) {
+ ext4_io_end_t *io_end =
+ ext4_init_io_end(inode, GFP_NOFS);
+ if (!io_end)
+ return -ENOMEM;
+ io_end->flag |= EXT4_IO_END_DIRECT;
+ iocb->private = io_end;
+ /*
+ * we save the io structure for current async
+ * direct IO, so that later ext4_map_blocks()
+ * could flag the io structure whether there
+ * is a unwritten extents needs to be converted
+ * when IO is completed.
+ */
+ EXT4_I(inode)->cur_aio_dio = iocb->private;
+ }
+
+ ret = __blockdev_direct_IO(rw, iocb, inode,
+ inode->i_sb->s_bdev, iov,
+ offset, nr_segs,
+ ext4_get_block_write,
+ ext4_end_io_dio,
+ NULL,
+ DIO_LOCKING);
+ if (iocb->private)
+ EXT4_I(inode)->cur_aio_dio = NULL;
+ /*
+ * The io_end structure takes a reference to the inode,
+ * that structure needs to be destroyed and the
+ * reference to the inode need to be dropped, when IO is
+ * complete, even with 0 byte write, or failed.
+ *
+ * In the successful AIO DIO case, the io_end structure will be
+ * desctroyed and the reference to the inode will be dropped
+ * after the end_io call back function is called.
+ *
+ * In the case there is 0 byte write, or error case, since
+ * VFS direct IO won't invoke the end_io call back function,
+ * we need to free the end_io structure here.
+ */
+ if (ret != -EIOCBQUEUED && ret <= 0 && iocb->private) {
+ ext4_free_io_end(iocb->private);
+ iocb->private = NULL;
+ } else if (ret > 0 && ext4_test_inode_state(inode,
+ EXT4_STATE_DIO_UNWRITTEN)) {
+ int err;
+ /*
+ * for non AIO case, since the IO is already
+ * completed, we could do the conversion right here
+ */
+ err = ext4_convert_unwritten_extents(inode,
+ offset, ret);
+ if (err < 0)
+ ret = err;
+ ext4_clear_inode_state(inode, EXT4_STATE_DIO_UNWRITTEN);
+ }
+ return ret;
+ }
+
+ /* for write the the end of file case, we fall back to old way */
+ return ext4_ind_direct_IO(rw, iocb, iov, offset, nr_segs);
+}
+
+static ssize_t ext4_direct_IO(int rw, struct kiocb *iocb,
+ const struct iovec *iov, loff_t offset,
+ unsigned long nr_segs)
+{
+ struct file *file = iocb->ki_filp;
+ struct inode *inode = file->f_mapping->host;
+ ssize_t ret;
+
+ /*
+ * If we are doing data journalling we don't support O_DIRECT
+ */
+ if (ext4_should_journal_data(inode))
+ return 0;
+
+ trace_ext4_direct_IO_enter(inode, offset, iov_length(iov, nr_segs), rw);
+ if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))
+ ret = ext4_ext_direct_IO(rw, iocb, iov, offset, nr_segs);
+ else
+ ret = ext4_ind_direct_IO(rw, iocb, iov, offset, nr_segs);
+ trace_ext4_direct_IO_exit(inode, offset,
+ iov_length(iov, nr_segs), rw, ret);
+ return ret;
+}
+
+/*
+ * Pages can be marked dirty completely asynchronously from ext4's journalling
+ * activity. By filemap_sync_pte(), try_to_unmap_one(), etc. We cannot do
+ * much here because ->set_page_dirty is called under VFS locks. The page is
+ * not necessarily locked.
+ *
+ * We cannot just dirty the page and leave attached buffers clean, because the
+ * buffers' dirty state is "definitive". We cannot just set the buffers dirty
+ * or jbddirty because all the journalling code will explode.
+ *
+ * So what we do is to mark the page "pending dirty" and next time writepage
+ * is called, propagate that into the buffers appropriately.
+ */
+static int ext4_journalled_set_page_dirty(struct page *page)
+{
+ SetPageChecked(page);
+ return __set_page_dirty_nobuffers(page);
+}
+
+static const struct address_space_operations ext4_ordered_aops = {
+ .readpage = ext4_readpage,
+ .readpages = ext4_readpages,
+ .writepage = ext4_writepage,
+ .write_begin = ext4_write_begin,
+ .write_end = ext4_ordered_write_end,
+ .bmap = ext4_bmap,
+ .invalidatepage = ext4_invalidatepage,
+ .releasepage = ext4_releasepage,
+ .direct_IO = ext4_direct_IO,
+ .migratepage = buffer_migrate_page,
+ .is_partially_uptodate = block_is_partially_uptodate,
+ .error_remove_page = generic_error_remove_page,
+};
+
+static const struct address_space_operations ext4_writeback_aops = {
+ .readpage = ext4_readpage,
+ .readpages = ext4_readpages,
+ .writepage = ext4_writepage,
+ .write_begin = ext4_write_begin,
+ .write_end = ext4_writeback_write_end,
+ .bmap = ext4_bmap,
+ .invalidatepage = ext4_invalidatepage,
+ .releasepage = ext4_releasepage,
+ .direct_IO = ext4_direct_IO,
+ .migratepage = buffer_migrate_page,
+ .is_partially_uptodate = block_is_partially_uptodate,
+ .error_remove_page = generic_error_remove_page,
+};
+
+static const struct address_space_operations ext4_journalled_aops = {
+ .readpage = ext4_readpage,
+ .readpages = ext4_readpages,
+ .writepage = ext4_writepage,
+ .write_begin = ext4_write_begin,
+ .write_end = ext4_journalled_write_end,
+ .set_page_dirty = ext4_journalled_set_page_dirty,
+ .bmap = ext4_bmap,
+ .invalidatepage = ext4_invalidatepage,
+ .releasepage = ext4_releasepage,
+ .direct_IO = ext4_direct_IO,
+ .is_partially_uptodate = block_is_partially_uptodate,
+ .error_remove_page = generic_error_remove_page,
+};
+
+static const struct address_space_operations ext4_da_aops = {
+ .readpage = ext4_readpage,
+ .readpages = ext4_readpages,
+ .writepage = ext4_writepage,
+ .writepages = ext4_da_writepages,
+ .write_begin = ext4_da_write_begin,
+ .write_end = ext4_da_write_end,
+ .bmap = ext4_bmap,
+ .invalidatepage = ext4_da_invalidatepage,
+ .releasepage = ext4_releasepage,
+ .direct_IO = ext4_direct_IO,
+ .migratepage = buffer_migrate_page,
+ .is_partially_uptodate = block_is_partially_uptodate,
+ .error_remove_page = generic_error_remove_page,
+};
+
+void ext4_set_aops(struct inode *inode)
+{
+ switch (ext4_inode_journal_mode(inode)) {
+ case EXT4_INODE_ORDERED_DATA_MODE:
+ if (test_opt(inode->i_sb, DELALLOC))
+ inode->i_mapping->a_ops = &ext4_da_aops;
+ else
+ inode->i_mapping->a_ops = &ext4_ordered_aops;
+ break;
+ case EXT4_INODE_WRITEBACK_DATA_MODE:
+ if (test_opt(inode->i_sb, DELALLOC))
+ inode->i_mapping->a_ops = &ext4_da_aops;
+ else
+ inode->i_mapping->a_ops = &ext4_writeback_aops;
+ break;
+ case EXT4_INODE_JOURNAL_DATA_MODE:
+ inode->i_mapping->a_ops = &ext4_journalled_aops;
+ break;
+ default:
+ BUG();
+ }
+}
+
+
+/*
+ * ext4_discard_partial_page_buffers()
+ * Wrapper function for ext4_discard_partial_page_buffers_no_lock.
+ * This function finds and locks the page containing the offset
+ * "from" and passes it to ext4_discard_partial_page_buffers_no_lock.
+ * Calling functions that already have the page locked should call
+ * ext4_discard_partial_page_buffers_no_lock directly.
+ */
+int ext4_discard_partial_page_buffers(handle_t *handle,
+ struct address_space *mapping, loff_t from,
+ loff_t length, int flags)
+{
+ struct inode *inode = mapping->host;
+ struct page *page;
+ int err = 0;
+
+ page = find_or_create_page(mapping, from >> PAGE_CACHE_SHIFT,
+ mapping_gfp_mask(mapping) & ~__GFP_FS);
+ if (!page)
+ return -ENOMEM;
+
+ err = ext4_discard_partial_page_buffers_no_lock(handle, inode, page,
+ from, length, flags);
+
+ unlock_page(page);
+ page_cache_release(page);
+ return err;
+}
+
+/*
+ * ext4_discard_partial_page_buffers_no_lock()
+ * Zeros a page range of length 'length' starting from offset 'from'.
+ * Buffer heads that correspond to the block aligned regions of the
+ * zeroed range will be unmapped. Unblock aligned regions
+ * will have the corresponding buffer head mapped if needed so that
+ * that region of the page can be updated with the partial zero out.
+ *
+ * This function assumes that the page has already been locked. The
+ * The range to be discarded must be contained with in the given page.
+ * If the specified range exceeds the end of the page it will be shortened
+ * to the end of the page that corresponds to 'from'. This function is
+ * appropriate for updating a page and it buffer heads to be unmapped and
+ * zeroed for blocks that have been either released, or are going to be
+ * released.
+ *
+ * handle: The journal handle
+ * inode: The files inode
+ * page: A locked page that contains the offset "from"
+ * from: The starting byte offset (from the begining of the file)
+ * to begin discarding
+ * len: The length of bytes to discard
+ * flags: Optional flags that may be used:
+ *
+ * EXT4_DISCARD_PARTIAL_PG_ZERO_UNMAPPED
+ * Only zero the regions of the page whose buffer heads
+ * have already been unmapped. This flag is appropriate
+ * for updateing the contents of a page whose blocks may
+ * have already been released, and we only want to zero
+ * out the regions that correspond to those released blocks.
+ *
+ * Returns zero on sucess or negative on failure.
+ */
+static int ext4_discard_partial_page_buffers_no_lock(handle_t *handle,
+ struct inode *inode, struct page *page, loff_t from,
+ loff_t length, int flags)
+{
+ ext4_fsblk_t index = from >> PAGE_CACHE_SHIFT;
+ unsigned int offset = from & (PAGE_CACHE_SIZE-1);
+ unsigned int blocksize, max, pos;
+ ext4_lblk_t iblock;
+ struct buffer_head *bh;
+ int err = 0;
+
+ blocksize = inode->i_sb->s_blocksize;
+ max = PAGE_CACHE_SIZE - offset;
+
+ if (index != page->index)
+ return -EINVAL;
+
+ /*
+ * correct length if it does not fall between
+ * 'from' and the end of the page
+ */
+ if (length > max || length < 0)
+ length = max;
+
+ iblock = index << (PAGE_CACHE_SHIFT - inode->i_sb->s_blocksize_bits);
+
+ if (!page_has_buffers(page))
+ create_empty_buffers(page, blocksize, 0);
+
+ /* Find the buffer that contains "offset" */
+ bh = page_buffers(page);
+ pos = blocksize;
+ while (offset >= pos) {
+ bh = bh->b_this_page;
+ iblock++;
+ pos += blocksize;
+ }
+
+ pos = offset;
+ while (pos < offset + length) {
+ unsigned int end_of_block, range_to_discard;
+
+ err = 0;
+
+ /* The length of space left to zero and unmap */
+ range_to_discard = offset + length - pos;
+
+ /* The length of space until the end of the block */
+ end_of_block = blocksize - (pos & (blocksize-1));
+
+ /*
+ * Do not unmap or zero past end of block
+ * for this buffer head
+ */
+ if (range_to_discard > end_of_block)
+ range_to_discard = end_of_block;
+
+
+ /*
+ * Skip this buffer head if we are only zeroing unampped
+ * regions of the page
+ */
+ if (flags & EXT4_DISCARD_PARTIAL_PG_ZERO_UNMAPPED &&
+ buffer_mapped(bh))
+ goto next;
+
+ /* If the range is block aligned, unmap */
+ if (range_to_discard == blocksize) {
+ clear_buffer_dirty(bh);
+ bh->b_bdev = NULL;
+ clear_buffer_mapped(bh);
+ clear_buffer_req(bh);
+ clear_buffer_new(bh);
+ clear_buffer_delay(bh);
+ clear_buffer_unwritten(bh);
+ clear_buffer_uptodate(bh);
+ zero_user(page, pos, range_to_discard);
+ BUFFER_TRACE(bh, "Buffer discarded");
+ goto next;
+ }
+
+ /*
+ * If this block is not completely contained in the range
+ * to be discarded, then it is not going to be released. Because
+ * we need to keep this block, we need to make sure this part
+ * of the page is uptodate before we modify it by writeing
+ * partial zeros on it.
+ */
+ if (!buffer_mapped(bh)) {
+ /*
+ * Buffer head must be mapped before we can read
+ * from the block
+ */
+ BUFFER_TRACE(bh, "unmapped");
+ ext4_get_block(inode, iblock, bh, 0);
+ /* unmapped? It's a hole - nothing to do */
+ if (!buffer_mapped(bh)) {
+ BUFFER_TRACE(bh, "still unmapped");
+ goto next;
+ }
+ }
+
+ /* Ok, it's mapped. Make sure it's up-to-date */
+ if (PageUptodate(page))
+ set_buffer_uptodate(bh);
+
+ if (!buffer_uptodate(bh)) {
+ err = -EIO;
+ ll_rw_block(READ, 1, &bh);
+ wait_on_buffer(bh);
+ /* Uhhuh. Read error. Complain and punt.*/
+ if (!buffer_uptodate(bh))
+ goto next;
+ }
+
+ if (ext4_should_journal_data(inode)) {
+ BUFFER_TRACE(bh, "get write access");
+ err = ext4_journal_get_write_access(handle, bh);
+ if (err)
+ goto next;
+ }
+
+ zero_user(page, pos, range_to_discard);
+
+ err = 0;
+ if (ext4_should_journal_data(inode)) {
+ err = ext4_handle_dirty_metadata(handle, inode, bh);
+ } else
+ mark_buffer_dirty(bh);
+
+ BUFFER_TRACE(bh, "Partial buffer zeroed");
+next:
+ bh = bh->b_this_page;
+ iblock++;
+ pos += range_to_discard;
+ }
+
+ return err;
+}
+
+int ext4_can_truncate(struct inode *inode)
+{
+ if (S_ISREG(inode->i_mode))
+ return 1;
+ if (S_ISDIR(inode->i_mode))
+ return 1;
+ if (S_ISLNK(inode->i_mode))
+ return !ext4_inode_is_fast_symlink(inode);
+ return 0;
+}
+
+/*
+ * ext4_punch_hole: punches a hole in a file by releaseing the blocks
+ * associated with the given offset and length
+ *
+ * @inode: File inode
+ * @offset: The offset where the hole will begin
+ * @len: The length of the hole
+ *
+ * Returns: 0 on sucess or negative on failure
+ */
+
+int ext4_punch_hole(struct file *file, loff_t offset, loff_t length)
+{
+ struct inode *inode = file->f_path.dentry->d_inode;
+ if (!S_ISREG(inode->i_mode))
+ return -EOPNOTSUPP;
+
+ if (!ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)) {
+ /* TODO: Add support for non extent hole punching */
+ return -EOPNOTSUPP;
+ }
+
+ if (EXT4_SB(inode->i_sb)->s_cluster_ratio > 1) {
+ /* TODO: Add support for bigalloc file systems */
+ return -EOPNOTSUPP;
+ }
+
+ return ext4_ext_punch_hole(file, offset, length);
+}
+
+/*
+ * ext4_truncate()
+ *
+ * We block out ext4_get_block() block instantiations across the entire
+ * transaction, and VFS/VM ensures that ext4_truncate() cannot run
+ * simultaneously on behalf of the same inode.
+ *
+ * As we work through the truncate and commit bits of it to the journal there
+ * is one core, guiding principle: the file's tree must always be consistent on
+ * disk. We must be able to restart the truncate after a crash.
+ *
+ * The file's tree may be transiently inconsistent in memory (although it
+ * probably isn't), but whenever we close off and commit a journal transaction,
+ * the contents of (the filesystem + the journal) must be consistent and
+ * restartable. It's pretty simple, really: bottom up, right to left (although
+ * left-to-right works OK too).
+ *
+ * Note that at recovery time, journal replay occurs *before* the restart of
+ * truncate against the orphan inode list.
+ *
+ * The committed inode has the new, desired i_size (which is the same as
+ * i_disksize in this case). After a crash, ext4_orphan_cleanup() will see
+ * that this inode's truncate did not complete and it will again call
+ * ext4_truncate() to have another go. So there will be instantiated blocks
+ * to the right of the truncation point in a crashed ext4 filesystem. But
+ * that's fine - as long as they are linked from the inode, the post-crash
+ * ext4_truncate() run will find them and release them.
+ */
+void ext4_truncate(struct inode *inode)
+{
+ trace_ext4_truncate_enter(inode);
+
+ if (!ext4_can_truncate(inode))
+ return;
+
+ ext4_clear_inode_flag(inode, EXT4_INODE_EOFBLOCKS);
+
+ if (inode->i_size == 0 && !test_opt(inode->i_sb, NO_AUTO_DA_ALLOC))
+ ext4_set_inode_state(inode, EXT4_STATE_DA_ALLOC_CLOSE);
+
+ if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))
+ ext4_ext_truncate(inode);
+ else
+ ext4_ind_truncate(inode);
+
+ trace_ext4_truncate_exit(inode);
+}
+
+/*
+ * ext4_get_inode_loc returns with an extra refcount against the inode's
+ * underlying buffer_head on success. If 'in_mem' is true, we have all
+ * data in memory that is needed to recreate the on-disk version of this
+ * inode.
+ */
+static int __ext4_get_inode_loc(struct inode *inode,
+ struct ext4_iloc *iloc, int in_mem)
+{
+ struct ext4_group_desc *gdp;
+ struct buffer_head *bh;
+ struct super_block *sb = inode->i_sb;
+ ext4_fsblk_t block;
+ int inodes_per_block, inode_offset;
+
+ iloc->bh = NULL;
+ if (!ext4_valid_inum(sb, inode->i_ino))
+ return -EIO;
+
+ iloc->block_group = (inode->i_ino - 1) / EXT4_INODES_PER_GROUP(sb);
+ gdp = ext4_get_group_desc(sb, iloc->block_group, NULL);
+ if (!gdp)
+ return -EIO;
+
+ /*
+ * Figure out the offset within the block group inode table
+ */
+ inodes_per_block = EXT4_SB(sb)->s_inodes_per_block;
+ inode_offset = ((inode->i_ino - 1) %
+ EXT4_INODES_PER_GROUP(sb));
+ block = ext4_inode_table(sb, gdp) + (inode_offset / inodes_per_block);
+ iloc->offset = (inode_offset % inodes_per_block) * EXT4_INODE_SIZE(sb);
+
+ bh = sb_getblk(sb, block);
+ if (!bh)
+ return -ENOMEM;
+ if (!buffer_uptodate(bh)) {
+ lock_buffer(bh);
+
+ /*
+ * If the buffer has the write error flag, we have failed
+ * to write out another inode in the same block. In this
+ * case, we don't have to read the block because we may
+ * read the old inode data successfully.
+ */
+ if (buffer_write_io_error(bh) && !buffer_uptodate(bh))
+ set_buffer_uptodate(bh);
+
+ if (buffer_uptodate(bh)) {
+ /* someone brought it uptodate while we waited */
+ unlock_buffer(bh);
+ goto has_buffer;
+ }
+
+ /*
+ * If we have all information of the inode in memory and this
+ * is the only valid inode in the block, we need not read the
+ * block.
+ */
+ if (in_mem) {
+ struct buffer_head *bitmap_bh;
+ int i, start;
+
+ start = inode_offset & ~(inodes_per_block - 1);
+
+ /* Is the inode bitmap in cache? */
+ bitmap_bh = sb_getblk(sb, ext4_inode_bitmap(sb, gdp));
+ if (!bitmap_bh)
+ goto make_io;
+
+ /*
+ * If the inode bitmap isn't in cache then the
+ * optimisation may end up performing two reads instead
+ * of one, so skip it.
+ */
+ if (!buffer_uptodate(bitmap_bh)) {
+ brelse(bitmap_bh);
+ goto make_io;
+ }
+ for (i = start; i < start + inodes_per_block; i++) {
+ if (i == inode_offset)
+ continue;
+ if (ext4_test_bit(i, bitmap_bh->b_data))
+ break;
+ }
+ brelse(bitmap_bh);
+ if (i == start + inodes_per_block) {
+ /* all other inodes are free, so skip I/O */
+ memset(bh->b_data, 0, bh->b_size);
+ set_buffer_uptodate(bh);
+ unlock_buffer(bh);
+ goto has_buffer;
+ }
+ }
+
+make_io:
+ /*
+ * If we need to do any I/O, try to pre-readahead extra
+ * blocks from the inode table.
+ */
+ if (EXT4_SB(sb)->s_inode_readahead_blks) {
+ ext4_fsblk_t b, end, table;
+ unsigned num;
+
+ table = ext4_inode_table(sb, gdp);
+ /* s_inode_readahead_blks is always a power of 2 */
+ b = block & ~(EXT4_SB(sb)->s_inode_readahead_blks-1);
+ if (table > b)
+ b = table;
+ end = b + EXT4_SB(sb)->s_inode_readahead_blks;
+ num = EXT4_INODES_PER_GROUP(sb);
+ if (EXT4_HAS_RO_COMPAT_FEATURE(sb,
+ EXT4_FEATURE_RO_COMPAT_GDT_CSUM))
+ num -= ext4_itable_unused_count(sb, gdp);
+ table += num / inodes_per_block;
+ if (end > table)
+ end = table;
+ while (b <= end)
+ sb_breadahead(sb, b++);
+ }
+
+ /*
+ * There are other valid inodes in the buffer, this inode
+ * has in-inode xattrs, or we don't have this inode in memory.
+ * Read the block from disk.
+ */
+ trace_ext4_load_inode(inode);
+ get_bh(bh);
+ bh->b_end_io = end_buffer_read_sync;
+ submit_bh(READ | REQ_META | REQ_PRIO, bh);
+ wait_on_buffer(bh);
+ if (!buffer_uptodate(bh)) {
+ EXT4_ERROR_INODE_BLOCK(inode, block,
+ "unable to read itable block");
+ brelse(bh);
+ return -EIO;
+ }
+ }
+has_buffer:
+ iloc->bh = bh;
+ return 0;
+}
+
+int ext4_get_inode_loc(struct inode *inode, struct ext4_iloc *iloc)
+{
+ /* We have all inode data except xattrs in memory here. */
+ return __ext4_get_inode_loc(inode, iloc,
+ !ext4_test_inode_state(inode, EXT4_STATE_XATTR));
+}
+
+void ext4_set_inode_flags(struct inode *inode)
+{
+ unsigned int flags = EXT4_I(inode)->i_flags;
+ unsigned int new_fl = 0;
+
+ if (flags & EXT4_SYNC_FL)
+ new_fl |= S_SYNC;
+ if (flags & EXT4_APPEND_FL)
+ new_fl |= S_APPEND;
+ if (flags & EXT4_IMMUTABLE_FL)
+ new_fl |= S_IMMUTABLE;
+ if (flags & EXT4_NOATIME_FL)
+ new_fl |= S_NOATIME;
+ if (flags & EXT4_DIRSYNC_FL)
+ new_fl |= S_DIRSYNC;
+ set_mask_bits(&inode->i_flags,
+ S_SYNC|S_APPEND|S_IMMUTABLE|S_NOATIME|S_DIRSYNC, new_fl);
+}
+
+/* Propagate flags from i_flags to EXT4_I(inode)->i_flags */
+void ext4_get_inode_flags(struct ext4_inode_info *ei)
+{
+ unsigned int vfs_fl;
+ unsigned long old_fl, new_fl;
+
+ do {
+ vfs_fl = ei->vfs_inode.i_flags;
+ old_fl = ei->i_flags;
+ new_fl = old_fl & ~(EXT4_SYNC_FL|EXT4_APPEND_FL|
+ EXT4_IMMUTABLE_FL|EXT4_NOATIME_FL|
+ EXT4_DIRSYNC_FL);
+ if (vfs_fl & S_SYNC)
+ new_fl |= EXT4_SYNC_FL;
+ if (vfs_fl & S_APPEND)
+ new_fl |= EXT4_APPEND_FL;
+ if (vfs_fl & S_IMMUTABLE)
+ new_fl |= EXT4_IMMUTABLE_FL;
+ if (vfs_fl & S_NOATIME)
+ new_fl |= EXT4_NOATIME_FL;
+ if (vfs_fl & S_DIRSYNC)
+ new_fl |= EXT4_DIRSYNC_FL;
+ } while (cmpxchg(&ei->i_flags, old_fl, new_fl) != old_fl);
+}
+
+static blkcnt_t ext4_inode_blocks(struct ext4_inode *raw_inode,
+ struct ext4_inode_info *ei)
+{
+ blkcnt_t i_blocks ;
+ struct inode *inode = &(ei->vfs_inode);
+ struct super_block *sb = inode->i_sb;
+
+ if (EXT4_HAS_RO_COMPAT_FEATURE(sb,
+ EXT4_FEATURE_RO_COMPAT_HUGE_FILE)) {
+ /* we are using combined 48 bit field */
+ i_blocks = ((u64)le16_to_cpu(raw_inode->i_blocks_high)) << 32 |
+ le32_to_cpu(raw_inode->i_blocks_lo);
+ if (ext4_test_inode_flag(inode, EXT4_INODE_HUGE_FILE)) {
+ /* i_blocks represent file system block size */
+ return i_blocks << (inode->i_blkbits - 9);
+ } else {
+ return i_blocks;
+ }
+ } else {
+ return le32_to_cpu(raw_inode->i_blocks_lo);
+ }
+}
+
+struct inode *ext4_iget(struct super_block *sb, unsigned long ino)
+{
+ struct ext4_iloc iloc;
+ struct ext4_inode *raw_inode;
+ struct ext4_inode_info *ei;
+ struct inode *inode;
+ journal_t *journal = EXT4_SB(sb)->s_journal;
+ long ret;
+ int block;
+
+ inode = iget_locked(sb, ino);
+ if (!inode)
+ return ERR_PTR(-ENOMEM);
+ if (!(inode->i_state & I_NEW))
+ return inode;
+
+ ei = EXT4_I(inode);
+ iloc.bh = NULL;
+
+ ret = __ext4_get_inode_loc(inode, &iloc, 0);
+ if (ret < 0)
+ goto bad_inode;
+ raw_inode = ext4_raw_inode(&iloc);
+ inode->i_mode = le16_to_cpu(raw_inode->i_mode);
+ inode->i_uid = (uid_t)le16_to_cpu(raw_inode->i_uid_low);
+ inode->i_gid = (gid_t)le16_to_cpu(raw_inode->i_gid_low);
+ if (!(test_opt(inode->i_sb, NO_UID32))) {
+ inode->i_uid |= le16_to_cpu(raw_inode->i_uid_high) << 16;
+ inode->i_gid |= le16_to_cpu(raw_inode->i_gid_high) << 16;
+ }
+ set_nlink(inode, le16_to_cpu(raw_inode->i_links_count));
+
+ ext4_clear_state_flags(ei); /* Only relevant on 32-bit archs */
+ ei->i_dir_start_lookup = 0;
+ ei->i_dtime = le32_to_cpu(raw_inode->i_dtime);
+ /* We now have enough fields to check if the inode was active or not.
+ * This is needed because nfsd might try to access dead inodes
+ * the test is that same one that e2fsck uses
+ * NeilBrown 1999oct15
+ */
+ if (inode->i_nlink == 0) {
+ if (inode->i_mode == 0 ||
+ !(EXT4_SB(inode->i_sb)->s_mount_state & EXT4_ORPHAN_FS)) {
+ /* this inode is deleted */
+ ret = -ESTALE;
+ goto bad_inode;
+ }
+ /* The only unlinked inodes we let through here have
+ * valid i_mode and are being read by the orphan
+ * recovery code: that's fine, we're about to complete
+ * the process of deleting those. */
+ }
+ ei->i_flags = le32_to_cpu(raw_inode->i_flags);
+ inode->i_blocks = ext4_inode_blocks(raw_inode, ei);
+ ei->i_file_acl = le32_to_cpu(raw_inode->i_file_acl_lo);
+ if (EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_64BIT))
+ ei->i_file_acl |=
+ ((__u64)le16_to_cpu(raw_inode->i_file_acl_high)) << 32;
+ inode->i_size = ext4_isize(raw_inode);
+ ei->i_disksize = inode->i_size;
+#ifdef CONFIG_QUOTA
+ ei->i_reserved_quota = 0;
+#endif
+ inode->i_generation = le32_to_cpu(raw_inode->i_generation);
+ ei->i_block_group = iloc.block_group;
+ ei->i_last_alloc_group = ~0;
+ /*
+ * NOTE! The in-memory inode i_data array is in little-endian order
+ * even on big-endian machines: we do NOT byteswap the block numbers!
+ */
+ for (block = 0; block < EXT4_N_BLOCKS; block++)
+ ei->i_data[block] = raw_inode->i_block[block];
+ INIT_LIST_HEAD(&ei->i_orphan);
+
+ /*
+ * Set transaction id's of transactions that have to be committed
+ * to finish f[data]sync. We set them to currently running transaction
+ * as we cannot be sure that the inode or some of its metadata isn't
+ * part of the transaction - the inode could have been reclaimed and
+ * now it is reread from disk.
+ */
+ if (journal) {
+ transaction_t *transaction;
+ tid_t tid;
+
+ read_lock(&journal->j_state_lock);
+ if (journal->j_running_transaction)
+ transaction = journal->j_running_transaction;
+ else
+ transaction = journal->j_committing_transaction;
+ if (transaction)
+ tid = transaction->t_tid;
+ else
+ tid = journal->j_commit_sequence;
+ read_unlock(&journal->j_state_lock);
+ ei->i_sync_tid = tid;
+ ei->i_datasync_tid = tid;
+ }
+
+ if (EXT4_INODE_SIZE(inode->i_sb) > EXT4_GOOD_OLD_INODE_SIZE) {
+ ei->i_extra_isize = le16_to_cpu(raw_inode->i_extra_isize);
+ if (EXT4_GOOD_OLD_INODE_SIZE + ei->i_extra_isize >
+ EXT4_INODE_SIZE(inode->i_sb)) {
+ ret = -EIO;
+ goto bad_inode;
+ }
+ if (ei->i_extra_isize == 0) {
+ /* The extra space is currently unused. Use it. */
+ ei->i_extra_isize = sizeof(struct ext4_inode) -
+ EXT4_GOOD_OLD_INODE_SIZE;
+ } else {
+ __le32 *magic = (void *)raw_inode +
+ EXT4_GOOD_OLD_INODE_SIZE +
+ ei->i_extra_isize;
+ if (*magic == cpu_to_le32(EXT4_XATTR_MAGIC))
+ ext4_set_inode_state(inode, EXT4_STATE_XATTR);
+ }
+ } else
+ ei->i_extra_isize = 0;
+
+ EXT4_INODE_GET_XTIME(i_ctime, inode, raw_inode);
+ EXT4_INODE_GET_XTIME(i_mtime, inode, raw_inode);
+ EXT4_INODE_GET_XTIME(i_atime, inode, raw_inode);
+ EXT4_EINODE_GET_XTIME(i_crtime, ei, raw_inode);
+
+ inode->i_version = le32_to_cpu(raw_inode->i_disk_version);
+ if (EXT4_INODE_SIZE(inode->i_sb) > EXT4_GOOD_OLD_INODE_SIZE) {
+ if (EXT4_FITS_IN_INODE(raw_inode, ei, i_version_hi))
+ inode->i_version |=
+ (__u64)(le32_to_cpu(raw_inode->i_version_hi)) << 32;
+ }
+
+ ret = 0;
+ if (ei->i_file_acl &&
+ !ext4_data_block_valid(EXT4_SB(sb), ei->i_file_acl, 1)) {
+ EXT4_ERROR_INODE(inode, "bad extended attribute block %llu",
+ ei->i_file_acl);
+ ret = -EIO;
+ goto bad_inode;
+ } else if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)) {
+ if (S_ISREG(inode->i_mode) || S_ISDIR(inode->i_mode) ||
+ (S_ISLNK(inode->i_mode) &&
+ !ext4_inode_is_fast_symlink(inode)))
+ /* Validate extent which is part of inode */
+ ret = ext4_ext_check_inode(inode);
+ } else if (S_ISREG(inode->i_mode) || S_ISDIR(inode->i_mode) ||
+ (S_ISLNK(inode->i_mode) &&
+ !ext4_inode_is_fast_symlink(inode))) {
+ /* Validate block references which are part of inode */
+ ret = ext4_ind_check_inode(inode);
+ }
+ if (ret)
+ goto bad_inode;
+
+ if (S_ISREG(inode->i_mode)) {
+ inode->i_op = &ext4_file_inode_operations;
+ inode->i_fop = &ext4_file_operations;
+ ext4_set_aops(inode);
+ } else if (S_ISDIR(inode->i_mode)) {
+ inode->i_op = &ext4_dir_inode_operations;
+ inode->i_fop = &ext4_dir_operations;
+ } else if (S_ISLNK(inode->i_mode)) {
+ if (ext4_inode_is_fast_symlink(inode)) {
+ inode->i_op = &ext4_fast_symlink_inode_operations;
+ nd_terminate_link(ei->i_data, inode->i_size,
+ sizeof(ei->i_data) - 1);
+ } else {
+ inode->i_op = &ext4_symlink_inode_operations;
+ ext4_set_aops(inode);
+ }
+ } else if (S_ISCHR(inode->i_mode) || S_ISBLK(inode->i_mode) ||
+ S_ISFIFO(inode->i_mode) || S_ISSOCK(inode->i_mode)) {
+ inode->i_op = &ext4_special_inode_operations;
+ if (raw_inode->i_block[0])
+ init_special_inode(inode, inode->i_mode,
+ old_decode_dev(le32_to_cpu(raw_inode->i_block[0])));
+ else
+ init_special_inode(inode, inode->i_mode,
+ new_decode_dev(le32_to_cpu(raw_inode->i_block[1])));
+ } else {
+ ret = -EIO;
+ EXT4_ERROR_INODE(inode, "bogus i_mode (%o)", inode->i_mode);
+ goto bad_inode;
+ }
+ brelse(iloc.bh);
+ ext4_set_inode_flags(inode);
+ unlock_new_inode(inode);
+ return inode;
+
+bad_inode:
+ brelse(iloc.bh);
+ iget_failed(inode);
+ return ERR_PTR(ret);
+}
+
+struct inode *ext4_iget_normal(struct super_block *sb, unsigned long ino)
+{
+ if (ino < EXT4_FIRST_INO(sb) && ino != EXT4_ROOT_INO)
+ return ERR_PTR(-EIO);
+ return ext4_iget(sb, ino);
+}
+
+static int ext4_inode_blocks_set(handle_t *handle,
+ struct ext4_inode *raw_inode,
+ struct ext4_inode_info *ei)
+{
+ struct inode *inode = &(ei->vfs_inode);
+ u64 i_blocks = inode->i_blocks;
+ struct super_block *sb = inode->i_sb;
+
+ if (i_blocks <= ~0U) {
+ /*
+ * i_blocks can be represnted in a 32 bit variable
+ * as multiple of 512 bytes
+ */
+ raw_inode->i_blocks_lo = cpu_to_le32(i_blocks);
+ raw_inode->i_blocks_high = 0;
+ ext4_clear_inode_flag(inode, EXT4_INODE_HUGE_FILE);
+ return 0;
+ }
+ if (!EXT4_HAS_RO_COMPAT_FEATURE(sb, EXT4_FEATURE_RO_COMPAT_HUGE_FILE))
+ return -EFBIG;
+
+ if (i_blocks <= 0xffffffffffffULL) {
+ /*
+ * i_blocks can be represented in a 48 bit variable
+ * as multiple of 512 bytes
+ */
+ raw_inode->i_blocks_lo = cpu_to_le32(i_blocks);
+ raw_inode->i_blocks_high = cpu_to_le16(i_blocks >> 32);
+ ext4_clear_inode_flag(inode, EXT4_INODE_HUGE_FILE);
+ } else {
+ ext4_set_inode_flag(inode, EXT4_INODE_HUGE_FILE);
+ /* i_block is stored in file system block size */
+ i_blocks = i_blocks >> (inode->i_blkbits - 9);
+ raw_inode->i_blocks_lo = cpu_to_le32(i_blocks);
+ raw_inode->i_blocks_high = cpu_to_le16(i_blocks >> 32);
+ }
+ return 0;
+}
+
+/*
+ * Post the struct inode info into an on-disk inode location in the
+ * buffer-cache. This gobbles the caller's reference to the
+ * buffer_head in the inode location struct.
+ *
+ * The caller must have write access to iloc->bh.
+ */
+static int ext4_do_update_inode(handle_t *handle,
+ struct inode *inode,
+ struct ext4_iloc *iloc)
+{
+ struct ext4_inode *raw_inode = ext4_raw_inode(iloc);
+ struct ext4_inode_info *ei = EXT4_I(inode);
+ struct buffer_head *bh = iloc->bh;
+ int err = 0, rc, block;
+ int need_datasync = 0;
+
+ /* For fields not not tracking in the in-memory inode,
+ * initialise them to zero for new inodes. */
+ if (ext4_test_inode_state(inode, EXT4_STATE_NEW))
+ memset(raw_inode, 0, EXT4_SB(inode->i_sb)->s_inode_size);
+
+ ext4_get_inode_flags(ei);
+ raw_inode->i_mode = cpu_to_le16(inode->i_mode);
+ if (!(test_opt(inode->i_sb, NO_UID32))) {
+ raw_inode->i_uid_low = cpu_to_le16(low_16_bits(inode->i_uid));
+ raw_inode->i_gid_low = cpu_to_le16(low_16_bits(inode->i_gid));
+/*
+ * Fix up interoperability with old kernels. Otherwise, old inodes get
+ * re-used with the upper 16 bits of the uid/gid intact
+ */
+ if (!ei->i_dtime) {
+ raw_inode->i_uid_high =
+ cpu_to_le16(high_16_bits(inode->i_uid));
+ raw_inode->i_gid_high =
+ cpu_to_le16(high_16_bits(inode->i_gid));
+ } else {
+ raw_inode->i_uid_high = 0;
+ raw_inode->i_gid_high = 0;
+ }
+ } else {
+ raw_inode->i_uid_low =
+ cpu_to_le16(fs_high2lowuid(inode->i_uid));
+ raw_inode->i_gid_low =
+ cpu_to_le16(fs_high2lowgid(inode->i_gid));
+ raw_inode->i_uid_high = 0;
+ raw_inode->i_gid_high = 0;
+ }
+ raw_inode->i_links_count = cpu_to_le16(inode->i_nlink);
+
+ EXT4_INODE_SET_XTIME(i_ctime, inode, raw_inode);
+ EXT4_INODE_SET_XTIME(i_mtime, inode, raw_inode);
+ EXT4_INODE_SET_XTIME(i_atime, inode, raw_inode);
+ EXT4_EINODE_SET_XTIME(i_crtime, ei, raw_inode);
+
+ if (ext4_inode_blocks_set(handle, raw_inode, ei))
+ goto out_brelse;
+ raw_inode->i_dtime = cpu_to_le32(ei->i_dtime);
+ raw_inode->i_flags = cpu_to_le32(ei->i_flags & 0xFFFFFFFF);
+ if (EXT4_SB(inode->i_sb)->s_es->s_creator_os !=
+ cpu_to_le32(EXT4_OS_HURD))
+ raw_inode->i_file_acl_high =
+ cpu_to_le16(ei->i_file_acl >> 32);
+ raw_inode->i_file_acl_lo = cpu_to_le32(ei->i_file_acl);
+ if (ei->i_disksize != ext4_isize(raw_inode)) {
+ ext4_isize_set(raw_inode, ei->i_disksize);
+ need_datasync = 1;
+ }
+ if (ei->i_disksize > 0x7fffffffULL) {
+ struct super_block *sb = inode->i_sb;
+ if (!EXT4_HAS_RO_COMPAT_FEATURE(sb,
+ EXT4_FEATURE_RO_COMPAT_LARGE_FILE) ||
+ EXT4_SB(sb)->s_es->s_rev_level ==
+ cpu_to_le32(EXT4_GOOD_OLD_REV)) {
+ /* If this is the first large file
+ * created, add a flag to the superblock.
+ */
+ err = ext4_journal_get_write_access(handle,
+ EXT4_SB(sb)->s_sbh);
+ if (err)
+ goto out_brelse;
+ ext4_update_dynamic_rev(sb);
+ EXT4_SET_RO_COMPAT_FEATURE(sb,
+ EXT4_FEATURE_RO_COMPAT_LARGE_FILE);
+ ext4_handle_sync(handle);
+ err = ext4_handle_dirty_super(handle, sb);
+ }
+ }
+ raw_inode->i_generation = cpu_to_le32(inode->i_generation);
+ if (S_ISCHR(inode->i_mode) || S_ISBLK(inode->i_mode)) {
+ if (old_valid_dev(inode->i_rdev)) {
+ raw_inode->i_block[0] =
+ cpu_to_le32(old_encode_dev(inode->i_rdev));
+ raw_inode->i_block[1] = 0;
+ } else {
+ raw_inode->i_block[0] = 0;
+ raw_inode->i_block[1] =
+ cpu_to_le32(new_encode_dev(inode->i_rdev));
+ raw_inode->i_block[2] = 0;
+ }
+ } else
+ for (block = 0; block < EXT4_N_BLOCKS; block++)
+ raw_inode->i_block[block] = ei->i_data[block];
+
+ raw_inode->i_disk_version = cpu_to_le32(inode->i_version);
+ if (ei->i_extra_isize) {
+ if (EXT4_FITS_IN_INODE(raw_inode, ei, i_version_hi))
+ raw_inode->i_version_hi =
+ cpu_to_le32(inode->i_version >> 32);
+ raw_inode->i_extra_isize = cpu_to_le16(ei->i_extra_isize);
+ }
+
+ BUFFER_TRACE(bh, "call ext4_handle_dirty_metadata");
+ rc = ext4_handle_dirty_metadata(handle, NULL, bh);
+ if (!err)
+ err = rc;
+ ext4_clear_inode_state(inode, EXT4_STATE_NEW);
+
+ ext4_update_inode_fsync_trans(handle, inode, need_datasync);
+out_brelse:
+ brelse(bh);
+ ext4_std_error(inode->i_sb, err);
+ return err;
+}
+
+/*
+ * ext4_write_inode()
+ *
+ * We are called from a few places:
+ *
+ * - Within generic_file_write() for O_SYNC files.
+ * Here, there will be no transaction running. We wait for any running
+ * trasnaction to commit.
+ *
+ * - Within sys_sync(), kupdate and such.
+ * We wait on commit, if tol to.
+ *
+ * - Within prune_icache() (PF_MEMALLOC == true)
+ * Here we simply return. We can't afford to block kswapd on the
+ * journal commit.
+ *
+ * In all cases it is actually safe for us to return without doing anything,
+ * because the inode has been copied into a raw inode buffer in
+ * ext4_mark_inode_dirty(). This is a correctness thing for O_SYNC and for
+ * knfsd.
+ *
+ * Note that we are absolutely dependent upon all inode dirtiers doing the
+ * right thing: they *must* call mark_inode_dirty() after dirtying info in
+ * which we are interested.
+ *
+ * It would be a bug for them to not do this. The code:
+ *
+ * mark_inode_dirty(inode)
+ * stuff();
+ * inode->i_size = expr;
+ *
+ * is in error because a kswapd-driven write_inode() could occur while
+ * `stuff()' is running, and the new i_size will be lost. Plus the inode
+ * will no longer be on the superblock's dirty inode list.
+ */
+int ext4_write_inode(struct inode *inode, struct writeback_control *wbc)
+{
+ int err;
+
+ if (current->flags & PF_MEMALLOC)
+ return 0;
+
+ if (EXT4_SB(inode->i_sb)->s_journal) {
+ if (ext4_journal_current_handle()) {
+ jbd_debug(1, "called recursively, non-PF_MEMALLOC!\n");
+ dump_stack();
+ return -EIO;
+ }
+
+ if (wbc->sync_mode != WB_SYNC_ALL)
+ return 0;
+
+ err = ext4_force_commit(inode->i_sb);
+ } else {
+ struct ext4_iloc iloc;
+
+ err = __ext4_get_inode_loc(inode, &iloc, 0);
+ if (err)
+ return err;
+ if (wbc->sync_mode == WB_SYNC_ALL)
+ sync_dirty_buffer(iloc.bh);
+ if (buffer_req(iloc.bh) && !buffer_uptodate(iloc.bh)) {
+ EXT4_ERROR_INODE_BLOCK(inode, iloc.bh->b_blocknr,
+ "IO error syncing inode");
+ err = -EIO;
+ }
+ brelse(iloc.bh);
+ }
+ return err;
+}
+
+/*
+ * ext4_setattr()
+ *
+ * Called from notify_change.
+ *
+ * We want to trap VFS attempts to truncate the file as soon as
+ * possible. In particular, we want to make sure that when the VFS
+ * shrinks i_size, we put the inode on the orphan list and modify
+ * i_disksize immediately, so that during the subsequent flushing of
+ * dirty pages and freeing of disk blocks, we can guarantee that any
+ * commit will leave the blocks being flushed in an unused state on
+ * disk. (On recovery, the inode will get truncated and the blocks will
+ * be freed, so we have a strong guarantee that no future commit will
+ * leave these blocks visible to the user.)
+ *
+ * Another thing we have to assure is that if we are in ordered mode
+ * and inode is still attached to the committing transaction, we must
+ * we start writeout of all the dirty pages which are being truncated.
+ * This way we are sure that all the data written in the previous
+ * transaction are already on disk (truncate waits for pages under
+ * writeback).
+ *
+ * Called with inode->i_mutex down.
+ */
+int ext4_setattr(struct dentry *dentry, struct iattr *attr)
+{
+ struct inode *inode = dentry->d_inode;
+ int error, rc = 0;
+ int orphan = 0;
+ const unsigned int ia_valid = attr->ia_valid;
+
+ error = inode_change_ok(inode, attr);
+ if (error)
+ return error;
+
+ if (is_quota_modification(inode, attr))
+ dquot_initialize(inode);
+ if ((ia_valid & ATTR_UID && attr->ia_uid != inode->i_uid) ||
+ (ia_valid & ATTR_GID && attr->ia_gid != inode->i_gid)) {
+ handle_t *handle;
+
+ /* (user+group)*(old+new) structure, inode write (sb,
+ * inode block, ? - but truncate inode update has it) */
+ handle = ext4_journal_start(inode, (EXT4_MAXQUOTAS_INIT_BLOCKS(inode->i_sb)+
+ EXT4_MAXQUOTAS_DEL_BLOCKS(inode->i_sb))+3);
+ if (IS_ERR(handle)) {
+ error = PTR_ERR(handle);
+ goto err_out;
+ }
+ error = dquot_transfer(inode, attr);
+ if (error) {
+ ext4_journal_stop(handle);
+ return error;
+ }
+ /* Update corresponding info in inode so that everything is in
+ * one transaction */
+ if (attr->ia_valid & ATTR_UID)
+ inode->i_uid = attr->ia_uid;
+ if (attr->ia_valid & ATTR_GID)
+ inode->i_gid = attr->ia_gid;
+ error = ext4_mark_inode_dirty(handle, inode);
+ ext4_journal_stop(handle);
+ }
+
+ if (attr->ia_valid & ATTR_SIZE) {
+ inode_dio_wait(inode);
+
+ if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))) {
+ struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
+
+ if (attr->ia_size > sbi->s_bitmap_maxbytes)
+ return -EFBIG;
+ }
+ }
+
+ if (S_ISREG(inode->i_mode) &&
+ attr->ia_valid & ATTR_SIZE &&
+ (attr->ia_size < inode->i_size)) {
+ handle_t *handle;
+
+ handle = ext4_journal_start(inode, 3);
+ if (IS_ERR(handle)) {
+ error = PTR_ERR(handle);
+ goto err_out;
+ }
+ if (ext4_handle_valid(handle)) {
+ error = ext4_orphan_add(handle, inode);
+ orphan = 1;
+ }
+ EXT4_I(inode)->i_disksize = attr->ia_size;
+ rc = ext4_mark_inode_dirty(handle, inode);
+ if (!error)
+ error = rc;
+ ext4_journal_stop(handle);
+
+ if (ext4_should_order_data(inode)) {
+ error = ext4_begin_ordered_truncate(inode,
+ attr->ia_size);
+ if (error) {
+ /* Do as much error cleanup as possible */
+ handle = ext4_journal_start(inode, 3);
+ if (IS_ERR(handle)) {
+ ext4_orphan_del(NULL, inode);
+ goto err_out;
+ }
+ ext4_orphan_del(handle, inode);
+ orphan = 0;
+ ext4_journal_stop(handle);
+ goto err_out;
+ }
+ }
+ }
+
+ if (attr->ia_valid & ATTR_SIZE) {
+ if (attr->ia_size != i_size_read(inode))
+ truncate_setsize(inode, attr->ia_size);
+ ext4_truncate(inode);
+ }
+
+ if (!rc) {
+ setattr_copy(inode, attr);
+ mark_inode_dirty(inode);
+ }
+
+ /*
+ * If the call to ext4_truncate failed to get a transaction handle at
+ * all, we need to clean up the in-core orphan list manually.
+ */
+ if (orphan && inode->i_nlink)
+ ext4_orphan_del(NULL, inode);
+
+ if (!rc && (ia_valid & ATTR_MODE))
+ rc = ext4_acl_chmod(inode);
+
+err_out:
+ ext4_std_error(inode->i_sb, error);
+ if (!error)
+ error = rc;
+ return error;
+}
+
+int ext4_getattr(struct vfsmount *mnt, struct dentry *dentry,
+ struct kstat *stat)
+{
+ struct inode *inode;
+ unsigned long long delalloc_blocks;
+
+ inode = dentry->d_inode;
+ generic_fillattr(inode, stat);
+
+ /*
+ * We can't update i_blocks if the block allocation is delayed
+ * otherwise in the case of system crash before the real block
+ * allocation is done, we will have i_blocks inconsistent with
+ * on-disk file blocks.
+ * We always keep i_blocks updated together with real
+ * allocation. But to not confuse with user, stat
+ * will return the blocks that include the delayed allocation
+ * blocks for this file.
+ */
+ delalloc_blocks = EXT4_I(inode)->i_reserved_data_blocks;
+
+ stat->blocks += delalloc_blocks << (inode->i_sb->s_blocksize_bits-9);
+ return 0;
+}
+
+static int ext4_index_trans_blocks(struct inode *inode, int nrblocks, int chunk)
+{
+ if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)))
+ return ext4_ind_trans_blocks(inode, nrblocks, chunk);
+ return ext4_ext_index_trans_blocks(inode, nrblocks, chunk);
+}
+
+/*
+ * Account for index blocks, block groups bitmaps and block group
+ * descriptor blocks if modify datablocks and index blocks
+ * worse case, the indexs blocks spread over different block groups
+ *
+ * If datablocks are discontiguous, they are possible to spread over
+ * different block groups too. If they are contiuguous, with flexbg,
+ * they could still across block group boundary.
+ *
+ * Also account for superblock, inode, quota and xattr blocks
+ */
+static int ext4_meta_trans_blocks(struct inode *inode, int nrblocks, int chunk)
+{
+ ext4_group_t groups, ngroups = ext4_get_groups_count(inode->i_sb);
+ int gdpblocks;
+ int idxblocks;
+ int ret = 0;
+
+ /*
+ * How many index blocks need to touch to modify nrblocks?
+ * The "Chunk" flag indicating whether the nrblocks is
+ * physically contiguous on disk
+ *
+ * For Direct IO and fallocate, they calls get_block to allocate
+ * one single extent at a time, so they could set the "Chunk" flag
+ */
+ idxblocks = ext4_index_trans_blocks(inode, nrblocks, chunk);
+
+ ret = idxblocks;
+
+ /*
+ * Now let's see how many group bitmaps and group descriptors need
+ * to account
+ */
+ groups = idxblocks;
+ if (chunk)
+ groups += 1;
+ else
+ groups += nrblocks;
+
+ gdpblocks = groups;
+ if (groups > ngroups)
+ groups = ngroups;
+ if (groups > EXT4_SB(inode->i_sb)->s_gdb_count)
+ gdpblocks = EXT4_SB(inode->i_sb)->s_gdb_count;
+
+ /* bitmaps and block group descriptor blocks */
+ ret += groups + gdpblocks;
+
+ /* Blocks for super block, inode, quota and xattr blocks */
+ ret += EXT4_META_TRANS_BLOCKS(inode->i_sb);
+
+ return ret;
+}
+
+/*
+ * Calculate the total number of credits to reserve to fit
+ * the modification of a single pages into a single transaction,
+ * which may include multiple chunks of block allocations.
+ *
+ * This could be called via ext4_write_begin()
+ *
+ * We need to consider the worse case, when
+ * one new block per extent.
+ */
+int ext4_writepage_trans_blocks(struct inode *inode)
+{
+ int bpp = ext4_journal_blocks_per_page(inode);
+ int ret;
+
+ ret = ext4_meta_trans_blocks(inode, bpp, 0);
+
+ /* Account for data blocks for journalled mode */
+ if (ext4_should_journal_data(inode))
+ ret += bpp;
+ return ret;
+}
+
+/*
+ * Calculate the journal credits for a chunk of data modification.
+ *
+ * This is called from DIO, fallocate or whoever calling
+ * ext4_map_blocks() to map/allocate a chunk of contiguous disk blocks.
+ *
+ * journal buffers for data blocks are not included here, as DIO
+ * and fallocate do no need to journal data buffers.
+ */
+int ext4_chunk_trans_blocks(struct inode *inode, int nrblocks)
+{
+ return ext4_meta_trans_blocks(inode, nrblocks, 1);
+}
+
+/*
+ * The caller must have previously called ext4_reserve_inode_write().
+ * Give this, we know that the caller already has write access to iloc->bh.
+ */
+int ext4_mark_iloc_dirty(handle_t *handle,
+ struct inode *inode, struct ext4_iloc *iloc)
+{
+ int err = 0;
+
+ if (IS_I_VERSION(inode))
+ inode_inc_iversion(inode);
+
+ /* the do_update_inode consumes one bh->b_count */
+ get_bh(iloc->bh);
+
+ /* ext4_do_update_inode() does jbd2_journal_dirty_metadata */
+ err = ext4_do_update_inode(handle, inode, iloc);
+ put_bh(iloc->bh);
+ return err;
+}
+
+/*
+ * On success, We end up with an outstanding reference count against
+ * iloc->bh. This _must_ be cleaned up later.
+ */
+
+int
+ext4_reserve_inode_write(handle_t *handle, struct inode *inode,
+ struct ext4_iloc *iloc)
+{
+ int err;
+
+ err = ext4_get_inode_loc(inode, iloc);
+ if (!err) {
+ BUFFER_TRACE(iloc->bh, "get_write_access");
+ err = ext4_journal_get_write_access(handle, iloc->bh);
+ if (err) {
+ brelse(iloc->bh);
+ iloc->bh = NULL;
+ }
+ }
+ ext4_std_error(inode->i_sb, err);
+ return err;
+}
+
+/*
+ * Expand an inode by new_extra_isize bytes.
+ * Returns 0 on success or negative error number on failure.
+ */
+static int ext4_expand_extra_isize(struct inode *inode,
+ unsigned int new_extra_isize,
+ struct ext4_iloc iloc,
+ handle_t *handle)
+{
+ struct ext4_inode *raw_inode;
+ struct ext4_xattr_ibody_header *header;
+
+ if (EXT4_I(inode)->i_extra_isize >= new_extra_isize)
+ return 0;
+
+ raw_inode = ext4_raw_inode(&iloc);
+
+ header = IHDR(inode, raw_inode);
+
+ /* No extended attributes present */
+ if (!ext4_test_inode_state(inode, EXT4_STATE_XATTR) ||
+ header->h_magic != cpu_to_le32(EXT4_XATTR_MAGIC)) {
+ memset((void *)raw_inode + EXT4_GOOD_OLD_INODE_SIZE, 0,
+ new_extra_isize);
+ EXT4_I(inode)->i_extra_isize = new_extra_isize;
+ return 0;
+ }
+
+ /* try to expand with EAs present */
+ return ext4_expand_extra_isize_ea(inode, new_extra_isize,
+ raw_inode, handle);
+}
+
+/*
+ * What we do here is to mark the in-core inode as clean with respect to inode
+ * dirtiness (it may still be data-dirty).
+ * This means that the in-core inode may be reaped by prune_icache
+ * without having to perform any I/O. This is a very good thing,
+ * because *any* task may call prune_icache - even ones which
+ * have a transaction open against a different journal.
+ *
+ * Is this cheating? Not really. Sure, we haven't written the
+ * inode out, but prune_icache isn't a user-visible syncing function.
+ * Whenever the user wants stuff synced (sys_sync, sys_msync, sys_fsync)
+ * we start and wait on commits.
+ *
+ * Is this efficient/effective? Well, we're being nice to the system
+ * by cleaning up our inodes proactively so they can be reaped
+ * without I/O. But we are potentially leaving up to five seconds'
+ * worth of inodes floating about which prune_icache wants us to
+ * write out. One way to fix that would be to get prune_icache()
+ * to do a write_super() to free up some memory. It has the desired
+ * effect.
+ */
+int ext4_mark_inode_dirty(handle_t *handle, struct inode *inode)
+{
+ struct ext4_iloc iloc;
+ struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
+ static unsigned int mnt_count;
+ int err, ret;
+
+ might_sleep();
+ trace_ext4_mark_inode_dirty(inode, _RET_IP_);
+ err = ext4_reserve_inode_write(handle, inode, &iloc);
+ if (ext4_handle_valid(handle) &&
+ EXT4_I(inode)->i_extra_isize < sbi->s_want_extra_isize &&
+ !ext4_test_inode_state(inode, EXT4_STATE_NO_EXPAND)) {
+ /*
+ * We need extra buffer credits since we may write into EA block
+ * with this same handle. If journal_extend fails, then it will
+ * only result in a minor loss of functionality for that inode.
+ * If this is felt to be critical, then e2fsck should be run to
+ * force a large enough s_min_extra_isize.
+ */
+ if ((jbd2_journal_extend(handle,
+ EXT4_DATA_TRANS_BLOCKS(inode->i_sb))) == 0) {
+ ret = ext4_expand_extra_isize(inode,
+ sbi->s_want_extra_isize,
+ iloc, handle);
+ if (ret) {
+ ext4_set_inode_state(inode,
+ EXT4_STATE_NO_EXPAND);
+ if (mnt_count !=
+ le16_to_cpu(sbi->s_es->s_mnt_count)) {
+ ext4_warning(inode->i_sb,
+ "Unable to expand inode %lu. Delete"
+ " some EAs or run e2fsck.",
+ inode->i_ino);
+ mnt_count =
+ le16_to_cpu(sbi->s_es->s_mnt_count);
+ }
+ }
+ }
+ }
+ if (!err)
+ err = ext4_mark_iloc_dirty(handle, inode, &iloc);
+ return err;
+}
+
+/*
+ * ext4_dirty_inode() is called from __mark_inode_dirty()
+ *
+ * We're really interested in the case where a file is being extended.
+ * i_size has been changed by generic_commit_write() and we thus need
+ * to include the updated inode in the current transaction.
+ *
+ * Also, dquot_alloc_block() will always dirty the inode when blocks
+ * are allocated to the file.
+ *
+ * If the inode is marked synchronous, we don't honour that here - doing
+ * so would cause a commit on atime updates, which we don't bother doing.
+ * We handle synchronous inodes at the highest possible level.
+ */
+void ext4_dirty_inode(struct inode *inode, int flags)
+{
+ handle_t *handle;
+
+ handle = ext4_journal_start(inode, 2);
+ if (IS_ERR(handle))
+ goto out;
+
+ ext4_mark_inode_dirty(handle, inode);
+
+ ext4_journal_stop(handle);
+out:
+ return;
+}
+
+#if 0
+/*
+ * Bind an inode's backing buffer_head into this transaction, to prevent
+ * it from being flushed to disk early. Unlike
+ * ext4_reserve_inode_write, this leaves behind no bh reference and
+ * returns no iloc structure, so the caller needs to repeat the iloc
+ * lookup to mark the inode dirty later.
+ */
+static int ext4_pin_inode(handle_t *handle, struct inode *inode)
+{
+ struct ext4_iloc iloc;
+
+ int err = 0;
+ if (handle) {
+ err = ext4_get_inode_loc(inode, &iloc);
+ if (!err) {
+ BUFFER_TRACE(iloc.bh, "get_write_access");
+ err = jbd2_journal_get_write_access(handle, iloc.bh);
+ if (!err)
+ err = ext4_handle_dirty_metadata(handle,
+ NULL,
+ iloc.bh);
+ brelse(iloc.bh);
+ }
+ }
+ ext4_std_error(inode->i_sb, err);
+ return err;
+}
+#endif
+
+int ext4_change_inode_journal_flag(struct inode *inode, int val)
+{
+ journal_t *journal;
+ handle_t *handle;
+ int err;
+
+ /*
+ * We have to be very careful here: changing a data block's
+ * journaling status dynamically is dangerous. If we write a
+ * data block to the journal, change the status and then delete
+ * that block, we risk forgetting to revoke the old log record
+ * from the journal and so a subsequent replay can corrupt data.
+ * So, first we make sure that the journal is empty and that
+ * nobody is changing anything.
+ */
+
+ journal = EXT4_JOURNAL(inode);
+ if (!journal)
+ return 0;
+ if (is_journal_aborted(journal))
+ return -EROFS;
+ /* We have to allocate physical blocks for delalloc blocks
+ * before flushing journal. otherwise delalloc blocks can not
+ * be allocated any more. even more truncate on delalloc blocks
+ * could trigger BUG by flushing delalloc blocks in journal.
+ * There is no delalloc block in non-journal data mode.
+ */
+ if (val && test_opt(inode->i_sb, DELALLOC)) {
+ err = ext4_alloc_da_blocks(inode);
+ if (err < 0)
+ return err;
+ }
+
+ jbd2_journal_lock_updates(journal);
+
+ /*
+ * OK, there are no updates running now, and all cached data is
+ * synced to disk. We are now in a completely consistent state
+ * which doesn't have anything in the journal, and we know that
+ * no filesystem updates are running, so it is safe to modify
+ * the inode's in-core data-journaling state flag now.
+ */
+
+ if (val)
+ ext4_set_inode_flag(inode, EXT4_INODE_JOURNAL_DATA);
+ else {
+ jbd2_journal_flush(journal);
+ ext4_clear_inode_flag(inode, EXT4_INODE_JOURNAL_DATA);
+ }
+ ext4_set_aops(inode);
+
+ jbd2_journal_unlock_updates(journal);
+
+ /* Finally we can mark the inode as dirty. */
+
+ handle = ext4_journal_start(inode, 1);
+ if (IS_ERR(handle))
+ return PTR_ERR(handle);
+
+ err = ext4_mark_inode_dirty(handle, inode);
+ ext4_handle_sync(handle);
+ ext4_journal_stop(handle);
+ ext4_std_error(inode->i_sb, err);
+
+ return err;
+}
+
+static int ext4_bh_unmapped(handle_t *handle, struct buffer_head *bh)
+{
+ return !buffer_mapped(bh);
+}
+
+int ext4_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf)
+{
+ struct page *page = vmf->page;
+ loff_t size;
+ unsigned long len;
+ int ret;
+ struct file *file = vma->vm_file;
+ struct inode *inode = file->f_path.dentry->d_inode;
+ struct address_space *mapping = inode->i_mapping;
+ handle_t *handle;
+ get_block_t *get_block;
+ int retries = 0;
+
+ /*
+ * This check is racy but catches the common case. We rely on
+ * __block_page_mkwrite() to do a reliable check.
+ */
+ vfs_check_frozen(inode->i_sb, SB_FREEZE_WRITE);
+ /* Delalloc case is easy... */
+ if (test_opt(inode->i_sb, DELALLOC) &&
+ !ext4_should_journal_data(inode) &&
+ !ext4_nonda_switch(inode->i_sb)) {
+ do {
+ ret = __block_page_mkwrite(vma, vmf,
+ ext4_da_get_block_prep);
+ } while (ret == -ENOSPC &&
+ ext4_should_retry_alloc(inode->i_sb, &retries));
+ goto out_ret;
+ }
+
+ lock_page(page);
+ size = i_size_read(inode);
+ /* Page got truncated from under us? */
+ if (page->mapping != mapping || page_offset(page) > size) {
+ unlock_page(page);
+ ret = VM_FAULT_NOPAGE;
+ goto out;
+ }
+
+ if (page->index == size >> PAGE_CACHE_SHIFT)
+ len = size & ~PAGE_CACHE_MASK;
+ else
+ len = PAGE_CACHE_SIZE;
+ /*
+ * Return if we have all the buffers mapped. This avoids the need to do
+ * journal_start/journal_stop which can block and take a long time
+ */
+ if (page_has_buffers(page)) {
+ if (!walk_page_buffers(NULL, page_buffers(page), 0, len, NULL,
+ ext4_bh_unmapped)) {
+ /* Wait so that we don't change page under IO */
+ wait_on_page_writeback(page);
+ ret = VM_FAULT_LOCKED;
+ goto out;
+ }
+ }
+ unlock_page(page);
+ /* OK, we need to fill the hole... */
+ if (ext4_should_dioread_nolock(inode))
+ get_block = ext4_get_block_write;
+ else
+ get_block = ext4_get_block;
+retry_alloc:
+ handle = ext4_journal_start(inode, ext4_writepage_trans_blocks(inode));
+ if (IS_ERR(handle)) {
+ ret = VM_FAULT_SIGBUS;
+ goto out;
+ }
+ ret = __block_page_mkwrite(vma, vmf, get_block);
+ if (!ret && ext4_should_journal_data(inode)) {
+ if (walk_page_buffers(handle, page_buffers(page), 0,
+ PAGE_CACHE_SIZE, NULL, do_journal_get_write_access)) {
+ unlock_page(page);
+ ret = VM_FAULT_SIGBUS;
+ ext4_journal_stop(handle);
+ goto out;
+ }
+ ext4_set_inode_state(inode, EXT4_STATE_JDATA);
+ }
+ ext4_journal_stop(handle);
+ if (ret == -ENOSPC && ext4_should_retry_alloc(inode->i_sb, &retries))
+ goto retry_alloc;
+out_ret:
+ ret = block_page_mkwrite_return(ret);
+out:
+ return ret;
+}