ASR_BASE
Change-Id: Icf3719cc0afe3eeb3edc7fa80a2eb5199ca9dda1
diff --git a/marvell/linux/fs/libfs.c b/marvell/linux/fs/libfs.c
new file mode 100644
index 0000000..78476f1
--- /dev/null
+++ b/marvell/linux/fs/libfs.c
@@ -0,0 +1,1463 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * fs/libfs.c
+ * Library for filesystems writers.
+ */
+
+#include <linux/blkdev.h>
+#include <linux/export.h>
+#include <linux/pagemap.h>
+#include <linux/slab.h>
+#include <linux/cred.h>
+#include <linux/mount.h>
+#include <linux/vfs.h>
+#include <linux/quotaops.h>
+#include <linux/mutex.h>
+#include <linux/namei.h>
+#include <linux/exportfs.h>
+#include <linux/writeback.h>
+#include <linux/buffer_head.h> /* sync_mapping_buffers */
+#include <linux/fs_context.h>
+#include <linux/pseudo_fs.h>
+#include <linux/unicode.h>
+#include <linux/fscrypt.h>
+
+#include <linux/uaccess.h>
+
+#include "internal.h"
+
+int simple_getattr(const struct path *path, struct kstat *stat,
+ u32 request_mask, unsigned int query_flags)
+{
+ struct inode *inode = d_inode(path->dentry);
+ generic_fillattr(inode, stat);
+ stat->blocks = inode->i_mapping->nrpages << (PAGE_SHIFT - 9);
+ return 0;
+}
+EXPORT_SYMBOL(simple_getattr);
+
+int simple_statfs(struct dentry *dentry, struct kstatfs *buf)
+{
+ buf->f_type = dentry->d_sb->s_magic;
+ buf->f_bsize = PAGE_SIZE;
+ buf->f_namelen = NAME_MAX;
+ return 0;
+}
+EXPORT_SYMBOL(simple_statfs);
+
+/*
+ * Retaining negative dentries for an in-memory filesystem just wastes
+ * memory and lookup time: arrange for them to be deleted immediately.
+ */
+int always_delete_dentry(const struct dentry *dentry)
+{
+ return 1;
+}
+EXPORT_SYMBOL(always_delete_dentry);
+
+const struct dentry_operations simple_dentry_operations = {
+ .d_delete = always_delete_dentry,
+};
+EXPORT_SYMBOL(simple_dentry_operations);
+
+/*
+ * Lookup the data. This is trivial - if the dentry didn't already
+ * exist, we know it is negative. Set d_op to delete negative dentries.
+ */
+struct dentry *simple_lookup(struct inode *dir, struct dentry *dentry, unsigned int flags)
+{
+ if (dentry->d_name.len > NAME_MAX)
+ return ERR_PTR(-ENAMETOOLONG);
+ if (!dentry->d_sb->s_d_op)
+ d_set_d_op(dentry, &simple_dentry_operations);
+ d_add(dentry, NULL);
+ return NULL;
+}
+EXPORT_SYMBOL(simple_lookup);
+
+int dcache_dir_open(struct inode *inode, struct file *file)
+{
+ file->private_data = d_alloc_cursor(file->f_path.dentry);
+
+ return file->private_data ? 0 : -ENOMEM;
+}
+EXPORT_SYMBOL(dcache_dir_open);
+
+int dcache_dir_close(struct inode *inode, struct file *file)
+{
+ dput(file->private_data);
+ return 0;
+}
+EXPORT_SYMBOL(dcache_dir_close);
+
+/* parent is locked at least shared */
+/*
+ * Returns an element of siblings' list.
+ * We are looking for <count>th positive after <p>; if
+ * found, dentry is grabbed and returned to caller.
+ * If no such element exists, NULL is returned.
+ */
+static struct dentry *scan_positives(struct dentry *cursor,
+ struct list_head *p,
+ loff_t count,
+ struct dentry *last)
+{
+ struct dentry *dentry = cursor->d_parent, *found = NULL;
+
+ spin_lock(&dentry->d_lock);
+ while ((p = p->next) != &dentry->d_subdirs) {
+ struct dentry *d = list_entry(p, struct dentry, d_child);
+ // we must at least skip cursors, to avoid livelocks
+ if (d->d_flags & DCACHE_DENTRY_CURSOR)
+ continue;
+ if (simple_positive(d) && !--count) {
+ spin_lock_nested(&d->d_lock, DENTRY_D_LOCK_NESTED);
+ if (simple_positive(d))
+ found = dget_dlock(d);
+ spin_unlock(&d->d_lock);
+ if (likely(found))
+ break;
+ count = 1;
+ }
+ if (need_resched()) {
+ list_move(&cursor->d_child, p);
+ p = &cursor->d_child;
+ spin_unlock(&dentry->d_lock);
+ cond_resched();
+ spin_lock(&dentry->d_lock);
+ }
+ }
+ spin_unlock(&dentry->d_lock);
+ dput(last);
+ return found;
+}
+
+loff_t dcache_dir_lseek(struct file *file, loff_t offset, int whence)
+{
+ struct dentry *dentry = file->f_path.dentry;
+ switch (whence) {
+ case 1:
+ offset += file->f_pos;
+ /* fall through */
+ case 0:
+ if (offset >= 0)
+ break;
+ /* fall through */
+ default:
+ return -EINVAL;
+ }
+ if (offset != file->f_pos) {
+ struct dentry *cursor = file->private_data;
+ struct dentry *to = NULL;
+
+ inode_lock_shared(dentry->d_inode);
+
+ if (offset > 2)
+ to = scan_positives(cursor, &dentry->d_subdirs,
+ offset - 2, NULL);
+ spin_lock(&dentry->d_lock);
+ if (to)
+ list_move(&cursor->d_child, &to->d_child);
+ else
+ list_del_init(&cursor->d_child);
+ spin_unlock(&dentry->d_lock);
+ dput(to);
+
+ file->f_pos = offset;
+
+ inode_unlock_shared(dentry->d_inode);
+ }
+ return offset;
+}
+EXPORT_SYMBOL(dcache_dir_lseek);
+
+/* Relationship between i_mode and the DT_xxx types */
+static inline unsigned char dt_type(struct inode *inode)
+{
+ return (inode->i_mode >> 12) & 15;
+}
+
+/*
+ * Directory is locked and all positive dentries in it are safe, since
+ * for ramfs-type trees they can't go away without unlink() or rmdir(),
+ * both impossible due to the lock on directory.
+ */
+
+int dcache_readdir(struct file *file, struct dir_context *ctx)
+{
+ struct dentry *dentry = file->f_path.dentry;
+ struct dentry *cursor = file->private_data;
+ struct list_head *anchor = &dentry->d_subdirs;
+ struct dentry *next = NULL;
+ struct list_head *p;
+
+ if (!dir_emit_dots(file, ctx))
+ return 0;
+
+ if (ctx->pos == 2)
+ p = anchor;
+ else if (!list_empty(&cursor->d_child))
+ p = &cursor->d_child;
+ else
+ return 0;
+
+ while ((next = scan_positives(cursor, p, 1, next)) != NULL) {
+ if (!dir_emit(ctx, next->d_name.name, next->d_name.len,
+ d_inode(next)->i_ino, dt_type(d_inode(next))))
+ break;
+ ctx->pos++;
+ p = &next->d_child;
+ }
+ spin_lock(&dentry->d_lock);
+ if (next)
+ list_move_tail(&cursor->d_child, &next->d_child);
+ else
+ list_del_init(&cursor->d_child);
+ spin_unlock(&dentry->d_lock);
+ dput(next);
+
+ return 0;
+}
+EXPORT_SYMBOL(dcache_readdir);
+
+ssize_t generic_read_dir(struct file *filp, char __user *buf, size_t siz, loff_t *ppos)
+{
+ return -EISDIR;
+}
+EXPORT_SYMBOL(generic_read_dir);
+
+const struct file_operations simple_dir_operations = {
+ .open = dcache_dir_open,
+ .release = dcache_dir_close,
+ .llseek = dcache_dir_lseek,
+ .read = generic_read_dir,
+ .iterate_shared = dcache_readdir,
+ .fsync = noop_fsync,
+};
+EXPORT_SYMBOL(simple_dir_operations);
+
+const struct inode_operations simple_dir_inode_operations = {
+ .lookup = simple_lookup,
+};
+EXPORT_SYMBOL(simple_dir_inode_operations);
+
+static const struct super_operations simple_super_operations = {
+ .statfs = simple_statfs,
+};
+
+static int pseudo_fs_fill_super(struct super_block *s, struct fs_context *fc)
+{
+ struct pseudo_fs_context *ctx = fc->fs_private;
+ struct inode *root;
+
+ s->s_maxbytes = MAX_LFS_FILESIZE;
+ s->s_blocksize = PAGE_SIZE;
+ s->s_blocksize_bits = PAGE_SHIFT;
+ s->s_magic = ctx->magic;
+ s->s_op = ctx->ops ?: &simple_super_operations;
+ s->s_xattr = ctx->xattr;
+ s->s_time_gran = 1;
+ root = new_inode(s);
+ if (!root)
+ return -ENOMEM;
+
+ /*
+ * since this is the first inode, make it number 1. New inodes created
+ * after this must take care not to collide with it (by passing
+ * max_reserved of 1 to iunique).
+ */
+ root->i_ino = 1;
+ root->i_mode = S_IFDIR | S_IRUSR | S_IWUSR;
+ root->i_atime = root->i_mtime = root->i_ctime = current_time(root);
+ s->s_root = d_make_root(root);
+ if (!s->s_root)
+ return -ENOMEM;
+ s->s_d_op = ctx->dops;
+ return 0;
+}
+
+static int pseudo_fs_get_tree(struct fs_context *fc)
+{
+ return get_tree_nodev(fc, pseudo_fs_fill_super);
+}
+
+static void pseudo_fs_free(struct fs_context *fc)
+{
+ kfree(fc->fs_private);
+}
+
+static const struct fs_context_operations pseudo_fs_context_ops = {
+ .free = pseudo_fs_free,
+ .get_tree = pseudo_fs_get_tree,
+};
+
+/*
+ * Common helper for pseudo-filesystems (sockfs, pipefs, bdev - stuff that
+ * will never be mountable)
+ */
+struct pseudo_fs_context *init_pseudo(struct fs_context *fc,
+ unsigned long magic)
+{
+ struct pseudo_fs_context *ctx;
+
+ ctx = kzalloc(sizeof(struct pseudo_fs_context), GFP_KERNEL);
+ if (likely(ctx)) {
+ ctx->magic = magic;
+ fc->fs_private = ctx;
+ fc->ops = &pseudo_fs_context_ops;
+ fc->sb_flags |= SB_NOUSER;
+ fc->global = true;
+ }
+ return ctx;
+}
+EXPORT_SYMBOL(init_pseudo);
+
+int simple_open(struct inode *inode, struct file *file)
+{
+ if (inode->i_private)
+ file->private_data = inode->i_private;
+ return 0;
+}
+EXPORT_SYMBOL(simple_open);
+
+int simple_link(struct dentry *old_dentry, struct inode *dir, struct dentry *dentry)
+{
+ struct inode *inode = d_inode(old_dentry);
+
+ inode->i_ctime = dir->i_ctime = dir->i_mtime = current_time(inode);
+ inc_nlink(inode);
+ ihold(inode);
+ dget(dentry);
+ d_instantiate(dentry, inode);
+ return 0;
+}
+EXPORT_SYMBOL(simple_link);
+
+int simple_empty(struct dentry *dentry)
+{
+ struct dentry *child;
+ int ret = 0;
+
+ spin_lock(&dentry->d_lock);
+ list_for_each_entry(child, &dentry->d_subdirs, d_child) {
+ spin_lock_nested(&child->d_lock, DENTRY_D_LOCK_NESTED);
+ if (simple_positive(child)) {
+ spin_unlock(&child->d_lock);
+ goto out;
+ }
+ spin_unlock(&child->d_lock);
+ }
+ ret = 1;
+out:
+ spin_unlock(&dentry->d_lock);
+ return ret;
+}
+EXPORT_SYMBOL(simple_empty);
+
+int simple_unlink(struct inode *dir, struct dentry *dentry)
+{
+ struct inode *inode = d_inode(dentry);
+
+ inode->i_ctime = dir->i_ctime = dir->i_mtime = current_time(inode);
+ drop_nlink(inode);
+ dput(dentry);
+ return 0;
+}
+EXPORT_SYMBOL(simple_unlink);
+
+int simple_rmdir(struct inode *dir, struct dentry *dentry)
+{
+ if (!simple_empty(dentry))
+ return -ENOTEMPTY;
+
+ drop_nlink(d_inode(dentry));
+ simple_unlink(dir, dentry);
+ drop_nlink(dir);
+ return 0;
+}
+EXPORT_SYMBOL(simple_rmdir);
+
+int simple_rename(struct inode *old_dir, struct dentry *old_dentry,
+ struct inode *new_dir, struct dentry *new_dentry,
+ unsigned int flags)
+{
+ struct inode *inode = d_inode(old_dentry);
+ int they_are_dirs = d_is_dir(old_dentry);
+
+ if (flags & ~RENAME_NOREPLACE)
+ return -EINVAL;
+
+ if (!simple_empty(new_dentry))
+ return -ENOTEMPTY;
+
+ if (d_really_is_positive(new_dentry)) {
+ simple_unlink(new_dir, new_dentry);
+ if (they_are_dirs) {
+ drop_nlink(d_inode(new_dentry));
+ drop_nlink(old_dir);
+ }
+ } else if (they_are_dirs) {
+ drop_nlink(old_dir);
+ inc_nlink(new_dir);
+ }
+
+ old_dir->i_ctime = old_dir->i_mtime = new_dir->i_ctime =
+ new_dir->i_mtime = inode->i_ctime = current_time(old_dir);
+
+ return 0;
+}
+EXPORT_SYMBOL(simple_rename);
+
+/**
+ * simple_setattr - setattr for simple filesystem
+ * @dentry: dentry
+ * @iattr: iattr structure
+ *
+ * Returns 0 on success, -error on failure.
+ *
+ * simple_setattr is a simple ->setattr implementation without a proper
+ * implementation of size changes.
+ *
+ * It can either be used for in-memory filesystems or special files
+ * on simple regular filesystems. Anything that needs to change on-disk
+ * or wire state on size changes needs its own setattr method.
+ */
+int simple_setattr(struct dentry *dentry, struct iattr *iattr)
+{
+ struct inode *inode = d_inode(dentry);
+ int error;
+
+ error = setattr_prepare(dentry, iattr);
+ if (error)
+ return error;
+
+ if (iattr->ia_valid & ATTR_SIZE)
+ truncate_setsize(inode, iattr->ia_size);
+ setattr_copy(inode, iattr);
+ mark_inode_dirty(inode);
+ return 0;
+}
+EXPORT_SYMBOL(simple_setattr);
+
+int simple_readpage(struct file *file, struct page *page)
+{
+ clear_highpage(page);
+ flush_dcache_page(page);
+ SetPageUptodate(page);
+ unlock_page(page);
+ return 0;
+}
+EXPORT_SYMBOL(simple_readpage);
+
+int simple_write_begin(struct file *file, struct address_space *mapping,
+ loff_t pos, unsigned len, unsigned flags,
+ struct page **pagep, void **fsdata)
+{
+ struct page *page;
+ pgoff_t index;
+
+ index = pos >> PAGE_SHIFT;
+
+ page = grab_cache_page_write_begin(mapping, index, flags);
+ if (!page)
+ return -ENOMEM;
+
+ *pagep = page;
+
+ if (!PageUptodate(page) && (len != PAGE_SIZE)) {
+ unsigned from = pos & (PAGE_SIZE - 1);
+
+ zero_user_segments(page, 0, from, from + len, PAGE_SIZE);
+ }
+ return 0;
+}
+EXPORT_SYMBOL(simple_write_begin);
+
+/**
+ * simple_write_end - .write_end helper for non-block-device FSes
+ * @file: See .write_end of address_space_operations
+ * @mapping: "
+ * @pos: "
+ * @len: "
+ * @copied: "
+ * @page: "
+ * @fsdata: "
+ *
+ * simple_write_end does the minimum needed for updating a page after writing is
+ * done. It has the same API signature as the .write_end of
+ * address_space_operations vector. So it can just be set onto .write_end for
+ * FSes that don't need any other processing. i_mutex is assumed to be held.
+ * Block based filesystems should use generic_write_end().
+ * NOTE: Even though i_size might get updated by this function, mark_inode_dirty
+ * is not called, so a filesystem that actually does store data in .write_inode
+ * should extend on what's done here with a call to mark_inode_dirty() in the
+ * case that i_size has changed.
+ *
+ * Use *ONLY* with simple_readpage()
+ */
+int simple_write_end(struct file *file, struct address_space *mapping,
+ loff_t pos, unsigned len, unsigned copied,
+ struct page *page, void *fsdata)
+{
+ struct inode *inode = page->mapping->host;
+ loff_t last_pos = pos + copied;
+
+ /* zero the stale part of the page if we did a short copy */
+ if (!PageUptodate(page)) {
+ if (copied < len) {
+ unsigned from = pos & (PAGE_SIZE - 1);
+
+ zero_user(page, from + copied, len - copied);
+ }
+ SetPageUptodate(page);
+ }
+ /*
+ * No need to use i_size_read() here, the i_size
+ * cannot change under us because we hold the i_mutex.
+ */
+ if (last_pos > inode->i_size)
+ i_size_write(inode, last_pos);
+
+ set_page_dirty(page);
+ unlock_page(page);
+ put_page(page);
+
+ return copied;
+}
+EXPORT_SYMBOL(simple_write_end);
+
+/*
+ * the inodes created here are not hashed. If you use iunique to generate
+ * unique inode values later for this filesystem, then you must take care
+ * to pass it an appropriate max_reserved value to avoid collisions.
+ */
+int simple_fill_super(struct super_block *s, unsigned long magic,
+ const struct tree_descr *files)
+{
+ struct inode *inode;
+ struct dentry *root;
+ struct dentry *dentry;
+ int i;
+
+ s->s_blocksize = PAGE_SIZE;
+ s->s_blocksize_bits = PAGE_SHIFT;
+ s->s_magic = magic;
+ s->s_op = &simple_super_operations;
+ s->s_time_gran = 1;
+
+ inode = new_inode(s);
+ if (!inode)
+ return -ENOMEM;
+ /*
+ * because the root inode is 1, the files array must not contain an
+ * entry at index 1
+ */
+ inode->i_ino = 1;
+ inode->i_mode = S_IFDIR | 0755;
+ inode->i_atime = inode->i_mtime = inode->i_ctime = current_time(inode);
+ inode->i_op = &simple_dir_inode_operations;
+ inode->i_fop = &simple_dir_operations;
+ set_nlink(inode, 2);
+ root = d_make_root(inode);
+ if (!root)
+ return -ENOMEM;
+ for (i = 0; !files->name || files->name[0]; i++, files++) {
+ if (!files->name)
+ continue;
+
+ /* warn if it tries to conflict with the root inode */
+ if (unlikely(i == 1))
+ printk(KERN_WARNING "%s: %s passed in a files array"
+ "with an index of 1!\n", __func__,
+ s->s_type->name);
+
+ dentry = d_alloc_name(root, files->name);
+ if (!dentry)
+ goto out;
+ inode = new_inode(s);
+ if (!inode) {
+ dput(dentry);
+ goto out;
+ }
+ inode->i_mode = S_IFREG | files->mode;
+ inode->i_atime = inode->i_mtime = inode->i_ctime = current_time(inode);
+ inode->i_fop = files->ops;
+ inode->i_ino = i;
+ d_add(dentry, inode);
+ }
+ s->s_root = root;
+ return 0;
+out:
+ d_genocide(root);
+ shrink_dcache_parent(root);
+ dput(root);
+ return -ENOMEM;
+}
+EXPORT_SYMBOL(simple_fill_super);
+
+static DEFINE_SPINLOCK(pin_fs_lock);
+
+int simple_pin_fs(struct file_system_type *type, struct vfsmount **mount, int *count)
+{
+ struct vfsmount *mnt = NULL;
+ spin_lock(&pin_fs_lock);
+ if (unlikely(!*mount)) {
+ spin_unlock(&pin_fs_lock);
+ mnt = vfs_kern_mount(type, SB_KERNMOUNT, type->name, NULL);
+ if (IS_ERR(mnt))
+ return PTR_ERR(mnt);
+ spin_lock(&pin_fs_lock);
+ if (!*mount)
+ *mount = mnt;
+ }
+ mntget(*mount);
+ ++*count;
+ spin_unlock(&pin_fs_lock);
+ mntput(mnt);
+ return 0;
+}
+EXPORT_SYMBOL(simple_pin_fs);
+
+void simple_release_fs(struct vfsmount **mount, int *count)
+{
+ struct vfsmount *mnt;
+ spin_lock(&pin_fs_lock);
+ mnt = *mount;
+ if (!--*count)
+ *mount = NULL;
+ spin_unlock(&pin_fs_lock);
+ mntput(mnt);
+}
+EXPORT_SYMBOL(simple_release_fs);
+
+/**
+ * simple_read_from_buffer - copy data from the buffer to user space
+ * @to: the user space buffer to read to
+ * @count: the maximum number of bytes to read
+ * @ppos: the current position in the buffer
+ * @from: the buffer to read from
+ * @available: the size of the buffer
+ *
+ * The simple_read_from_buffer() function reads up to @count bytes from the
+ * buffer @from at offset @ppos into the user space address starting at @to.
+ *
+ * On success, the number of bytes read is returned and the offset @ppos is
+ * advanced by this number, or negative value is returned on error.
+ **/
+ssize_t simple_read_from_buffer(void __user *to, size_t count, loff_t *ppos,
+ const void *from, size_t available)
+{
+ loff_t pos = *ppos;
+ size_t ret;
+
+ if (pos < 0)
+ return -EINVAL;
+ if (pos >= available || !count)
+ return 0;
+ if (count > available - pos)
+ count = available - pos;
+ ret = copy_to_user(to, from + pos, count);
+ if (ret == count)
+ return -EFAULT;
+ count -= ret;
+ *ppos = pos + count;
+ return count;
+}
+EXPORT_SYMBOL(simple_read_from_buffer);
+
+/**
+ * simple_write_to_buffer - copy data from user space to the buffer
+ * @to: the buffer to write to
+ * @available: the size of the buffer
+ * @ppos: the current position in the buffer
+ * @from: the user space buffer to read from
+ * @count: the maximum number of bytes to read
+ *
+ * The simple_write_to_buffer() function reads up to @count bytes from the user
+ * space address starting at @from into the buffer @to at offset @ppos.
+ *
+ * On success, the number of bytes written is returned and the offset @ppos is
+ * advanced by this number, or negative value is returned on error.
+ **/
+ssize_t simple_write_to_buffer(void *to, size_t available, loff_t *ppos,
+ const void __user *from, size_t count)
+{
+ loff_t pos = *ppos;
+ size_t res;
+
+ if (pos < 0)
+ return -EINVAL;
+ if (pos >= available || !count)
+ return 0;
+ if (count > available - pos)
+ count = available - pos;
+ res = copy_from_user(to + pos, from, count);
+ if (res == count)
+ return -EFAULT;
+ count -= res;
+ *ppos = pos + count;
+ return count;
+}
+EXPORT_SYMBOL(simple_write_to_buffer);
+
+/**
+ * memory_read_from_buffer - copy data from the buffer
+ * @to: the kernel space buffer to read to
+ * @count: the maximum number of bytes to read
+ * @ppos: the current position in the buffer
+ * @from: the buffer to read from
+ * @available: the size of the buffer
+ *
+ * The memory_read_from_buffer() function reads up to @count bytes from the
+ * buffer @from at offset @ppos into the kernel space address starting at @to.
+ *
+ * On success, the number of bytes read is returned and the offset @ppos is
+ * advanced by this number, or negative value is returned on error.
+ **/
+ssize_t memory_read_from_buffer(void *to, size_t count, loff_t *ppos,
+ const void *from, size_t available)
+{
+ loff_t pos = *ppos;
+
+ if (pos < 0)
+ return -EINVAL;
+ if (pos >= available)
+ return 0;
+ if (count > available - pos)
+ count = available - pos;
+ memcpy(to, from + pos, count);
+ *ppos = pos + count;
+
+ return count;
+}
+EXPORT_SYMBOL(memory_read_from_buffer);
+
+/*
+ * Transaction based IO.
+ * The file expects a single write which triggers the transaction, and then
+ * possibly a read which collects the result - which is stored in a
+ * file-local buffer.
+ */
+
+void simple_transaction_set(struct file *file, size_t n)
+{
+ struct simple_transaction_argresp *ar = file->private_data;
+
+ BUG_ON(n > SIMPLE_TRANSACTION_LIMIT);
+
+ /*
+ * The barrier ensures that ar->size will really remain zero until
+ * ar->data is ready for reading.
+ */
+ smp_mb();
+ ar->size = n;
+}
+EXPORT_SYMBOL(simple_transaction_set);
+
+char *simple_transaction_get(struct file *file, const char __user *buf, size_t size)
+{
+ struct simple_transaction_argresp *ar;
+ static DEFINE_SPINLOCK(simple_transaction_lock);
+
+ if (size > SIMPLE_TRANSACTION_LIMIT - 1)
+ return ERR_PTR(-EFBIG);
+
+ ar = (struct simple_transaction_argresp *)get_zeroed_page(GFP_KERNEL);
+ if (!ar)
+ return ERR_PTR(-ENOMEM);
+
+ spin_lock(&simple_transaction_lock);
+
+ /* only one write allowed per open */
+ if (file->private_data) {
+ spin_unlock(&simple_transaction_lock);
+ free_page((unsigned long)ar);
+ return ERR_PTR(-EBUSY);
+ }
+
+ file->private_data = ar;
+
+ spin_unlock(&simple_transaction_lock);
+
+ if (copy_from_user(ar->data, buf, size))
+ return ERR_PTR(-EFAULT);
+
+ return ar->data;
+}
+EXPORT_SYMBOL(simple_transaction_get);
+
+ssize_t simple_transaction_read(struct file *file, char __user *buf, size_t size, loff_t *pos)
+{
+ struct simple_transaction_argresp *ar = file->private_data;
+
+ if (!ar)
+ return 0;
+ return simple_read_from_buffer(buf, size, pos, ar->data, ar->size);
+}
+EXPORT_SYMBOL(simple_transaction_read);
+
+int simple_transaction_release(struct inode *inode, struct file *file)
+{
+ free_page((unsigned long)file->private_data);
+ return 0;
+}
+EXPORT_SYMBOL(simple_transaction_release);
+
+/* Simple attribute files */
+
+struct simple_attr {
+ int (*get)(void *, u64 *);
+ int (*set)(void *, u64);
+ char get_buf[24]; /* enough to store a u64 and "\n\0" */
+ char set_buf[24];
+ void *data;
+ const char *fmt; /* format for read operation */
+ struct mutex mutex; /* protects access to these buffers */
+};
+
+/* simple_attr_open is called by an actual attribute open file operation
+ * to set the attribute specific access operations. */
+int simple_attr_open(struct inode *inode, struct file *file,
+ int (*get)(void *, u64 *), int (*set)(void *, u64),
+ const char *fmt)
+{
+ struct simple_attr *attr;
+
+ attr = kzalloc(sizeof(*attr), GFP_KERNEL);
+ if (!attr)
+ return -ENOMEM;
+
+ attr->get = get;
+ attr->set = set;
+ attr->data = inode->i_private;
+ attr->fmt = fmt;
+ mutex_init(&attr->mutex);
+
+ file->private_data = attr;
+
+ return nonseekable_open(inode, file);
+}
+EXPORT_SYMBOL_GPL(simple_attr_open);
+
+int simple_attr_release(struct inode *inode, struct file *file)
+{
+ kfree(file->private_data);
+ return 0;
+}
+EXPORT_SYMBOL_GPL(simple_attr_release); /* GPL-only? This? Really? */
+
+/* read from the buffer that is filled with the get function */
+ssize_t simple_attr_read(struct file *file, char __user *buf,
+ size_t len, loff_t *ppos)
+{
+ struct simple_attr *attr;
+ size_t size;
+ ssize_t ret;
+
+ attr = file->private_data;
+
+ if (!attr->get)
+ return -EACCES;
+
+ ret = mutex_lock_interruptible(&attr->mutex);
+ if (ret)
+ return ret;
+
+ if (*ppos && attr->get_buf[0]) {
+ /* continued read */
+ size = strlen(attr->get_buf);
+ } else {
+ /* first read */
+ u64 val;
+ ret = attr->get(attr->data, &val);
+ if (ret)
+ goto out;
+
+ size = scnprintf(attr->get_buf, sizeof(attr->get_buf),
+ attr->fmt, (unsigned long long)val);
+ }
+
+ ret = simple_read_from_buffer(buf, len, ppos, attr->get_buf, size);
+out:
+ mutex_unlock(&attr->mutex);
+ return ret;
+}
+EXPORT_SYMBOL_GPL(simple_attr_read);
+
+/* interpret the buffer as a number to call the set function with */
+static ssize_t simple_attr_write_xsigned(struct file *file, const char __user *buf,
+ size_t len, loff_t *ppos, bool is_signed)
+{
+ struct simple_attr *attr;
+ unsigned long long val;
+ size_t size;
+ ssize_t ret;
+
+ attr = file->private_data;
+ if (!attr->set)
+ return -EACCES;
+
+ ret = mutex_lock_interruptible(&attr->mutex);
+ if (ret)
+ return ret;
+
+ ret = -EFAULT;
+ size = min(sizeof(attr->set_buf) - 1, len);
+ if (copy_from_user(attr->set_buf, buf, size))
+ goto out;
+
+ attr->set_buf[size] = '\0';
+ if (is_signed)
+ ret = kstrtoll(attr->set_buf, 0, &val);
+ else
+ ret = kstrtoull(attr->set_buf, 0, &val);
+ if (ret)
+ goto out;
+ ret = attr->set(attr->data, val);
+ if (ret == 0)
+ ret = len; /* on success, claim we got the whole input */
+out:
+ mutex_unlock(&attr->mutex);
+ return ret;
+}
+
+ssize_t simple_attr_write(struct file *file, const char __user *buf,
+ size_t len, loff_t *ppos)
+{
+ return simple_attr_write_xsigned(file, buf, len, ppos, false);
+}
+EXPORT_SYMBOL_GPL(simple_attr_write);
+
+ssize_t simple_attr_write_signed(struct file *file, const char __user *buf,
+ size_t len, loff_t *ppos)
+{
+ return simple_attr_write_xsigned(file, buf, len, ppos, true);
+}
+EXPORT_SYMBOL_GPL(simple_attr_write_signed);
+
+/**
+ * generic_fh_to_dentry - generic helper for the fh_to_dentry export operation
+ * @sb: filesystem to do the file handle conversion on
+ * @fid: file handle to convert
+ * @fh_len: length of the file handle in bytes
+ * @fh_type: type of file handle
+ * @get_inode: filesystem callback to retrieve inode
+ *
+ * This function decodes @fid as long as it has one of the well-known
+ * Linux filehandle types and calls @get_inode on it to retrieve the
+ * inode for the object specified in the file handle.
+ */
+struct dentry *generic_fh_to_dentry(struct super_block *sb, struct fid *fid,
+ int fh_len, int fh_type, struct inode *(*get_inode)
+ (struct super_block *sb, u64 ino, u32 gen))
+{
+ struct inode *inode = NULL;
+
+ if (fh_len < 2)
+ return NULL;
+
+ switch (fh_type) {
+ case FILEID_INO32_GEN:
+ case FILEID_INO32_GEN_PARENT:
+ inode = get_inode(sb, fid->i32.ino, fid->i32.gen);
+ break;
+ }
+
+ return d_obtain_alias(inode);
+}
+EXPORT_SYMBOL_GPL(generic_fh_to_dentry);
+
+/**
+ * generic_fh_to_parent - generic helper for the fh_to_parent export operation
+ * @sb: filesystem to do the file handle conversion on
+ * @fid: file handle to convert
+ * @fh_len: length of the file handle in bytes
+ * @fh_type: type of file handle
+ * @get_inode: filesystem callback to retrieve inode
+ *
+ * This function decodes @fid as long as it has one of the well-known
+ * Linux filehandle types and calls @get_inode on it to retrieve the
+ * inode for the _parent_ object specified in the file handle if it
+ * is specified in the file handle, or NULL otherwise.
+ */
+struct dentry *generic_fh_to_parent(struct super_block *sb, struct fid *fid,
+ int fh_len, int fh_type, struct inode *(*get_inode)
+ (struct super_block *sb, u64 ino, u32 gen))
+{
+ struct inode *inode = NULL;
+
+ if (fh_len <= 2)
+ return NULL;
+
+ switch (fh_type) {
+ case FILEID_INO32_GEN_PARENT:
+ inode = get_inode(sb, fid->i32.parent_ino,
+ (fh_len > 3 ? fid->i32.parent_gen : 0));
+ break;
+ }
+
+ return d_obtain_alias(inode);
+}
+EXPORT_SYMBOL_GPL(generic_fh_to_parent);
+
+/**
+ * __generic_file_fsync - generic fsync implementation for simple filesystems
+ *
+ * @file: file to synchronize
+ * @start: start offset in bytes
+ * @end: end offset in bytes (inclusive)
+ * @datasync: only synchronize essential metadata if true
+ *
+ * This is a generic implementation of the fsync method for simple
+ * filesystems which track all non-inode metadata in the buffers list
+ * hanging off the address_space structure.
+ */
+int __generic_file_fsync(struct file *file, loff_t start, loff_t end,
+ int datasync)
+{
+ struct inode *inode = file->f_mapping->host;
+ int err;
+ int ret;
+
+ err = file_write_and_wait_range(file, start, end);
+ if (err)
+ return err;
+
+ inode_lock(inode);
+ ret = sync_mapping_buffers(inode->i_mapping);
+ if (!(inode->i_state & I_DIRTY_ALL))
+ goto out;
+ if (datasync && !(inode->i_state & I_DIRTY_DATASYNC))
+ goto out;
+
+ err = sync_inode_metadata(inode, 1);
+ if (ret == 0)
+ ret = err;
+
+out:
+ inode_unlock(inode);
+ /* check and advance again to catch errors after syncing out buffers */
+ err = file_check_and_advance_wb_err(file);
+ if (ret == 0)
+ ret = err;
+ return ret;
+}
+EXPORT_SYMBOL(__generic_file_fsync);
+
+/**
+ * generic_file_fsync - generic fsync implementation for simple filesystems
+ * with flush
+ * @file: file to synchronize
+ * @start: start offset in bytes
+ * @end: end offset in bytes (inclusive)
+ * @datasync: only synchronize essential metadata if true
+ *
+ */
+
+int generic_file_fsync(struct file *file, loff_t start, loff_t end,
+ int datasync)
+{
+ struct inode *inode = file->f_mapping->host;
+ int err;
+
+ err = __generic_file_fsync(file, start, end, datasync);
+ if (err)
+ return err;
+ return blkdev_issue_flush(inode->i_sb->s_bdev, GFP_KERNEL, NULL);
+}
+EXPORT_SYMBOL(generic_file_fsync);
+
+/**
+ * generic_check_addressable - Check addressability of file system
+ * @blocksize_bits: log of file system block size
+ * @num_blocks: number of blocks in file system
+ *
+ * Determine whether a file system with @num_blocks blocks (and a
+ * block size of 2**@blocksize_bits) is addressable by the sector_t
+ * and page cache of the system. Return 0 if so and -EFBIG otherwise.
+ */
+int generic_check_addressable(unsigned blocksize_bits, u64 num_blocks)
+{
+ u64 last_fs_block = num_blocks - 1;
+ u64 last_fs_page =
+ last_fs_block >> (PAGE_SHIFT - blocksize_bits);
+
+ if (unlikely(num_blocks == 0))
+ return 0;
+
+ if ((blocksize_bits < 9) || (blocksize_bits > PAGE_SHIFT))
+ return -EINVAL;
+
+ if ((last_fs_block > (sector_t)(~0ULL) >> (blocksize_bits - 9)) ||
+ (last_fs_page > (pgoff_t)(~0ULL))) {
+ return -EFBIG;
+ }
+ return 0;
+}
+EXPORT_SYMBOL(generic_check_addressable);
+
+/*
+ * No-op implementation of ->fsync for in-memory filesystems.
+ */
+int noop_fsync(struct file *file, loff_t start, loff_t end, int datasync)
+{
+ return 0;
+}
+EXPORT_SYMBOL(noop_fsync);
+
+int noop_set_page_dirty(struct page *page)
+{
+ /*
+ * Unlike __set_page_dirty_no_writeback that handles dirty page
+ * tracking in the page object, dax does all dirty tracking in
+ * the inode address_space in response to mkwrite faults. In the
+ * dax case we only need to worry about potentially dirty CPU
+ * caches, not dirty page cache pages to write back.
+ *
+ * This callback is defined to prevent fallback to
+ * __set_page_dirty_buffers() in set_page_dirty().
+ */
+ return 0;
+}
+EXPORT_SYMBOL_GPL(noop_set_page_dirty);
+
+void noop_invalidatepage(struct page *page, unsigned int offset,
+ unsigned int length)
+{
+ /*
+ * There is no page cache to invalidate in the dax case, however
+ * we need this callback defined to prevent falling back to
+ * block_invalidatepage() in do_invalidatepage().
+ */
+}
+EXPORT_SYMBOL_GPL(noop_invalidatepage);
+
+ssize_t noop_direct_IO(struct kiocb *iocb, struct iov_iter *iter)
+{
+ /*
+ * iomap based filesystems support direct I/O without need for
+ * this callback. However, it still needs to be set in
+ * inode->a_ops so that open/fcntl know that direct I/O is
+ * generally supported.
+ */
+ return -EINVAL;
+}
+EXPORT_SYMBOL_GPL(noop_direct_IO);
+
+/* Because kfree isn't assignment-compatible with void(void*) ;-/ */
+void kfree_link(void *p)
+{
+ kfree(p);
+}
+EXPORT_SYMBOL(kfree_link);
+
+/*
+ * nop .set_page_dirty method so that people can use .page_mkwrite on
+ * anon inodes.
+ */
+static int anon_set_page_dirty(struct page *page)
+{
+ return 0;
+};
+
+struct inode *alloc_anon_inode(struct super_block *s)
+{
+ static const struct address_space_operations anon_aops = {
+ .set_page_dirty = anon_set_page_dirty,
+ };
+ struct inode *inode = new_inode_pseudo(s);
+
+ if (!inode)
+ return ERR_PTR(-ENOMEM);
+
+ inode->i_ino = get_next_ino();
+ inode->i_mapping->a_ops = &anon_aops;
+
+ /*
+ * Mark the inode dirty from the very beginning,
+ * that way it will never be moved to the dirty
+ * list because mark_inode_dirty() will think
+ * that it already _is_ on the dirty list.
+ */
+ inode->i_state = I_DIRTY;
+ inode->i_mode = S_IRUSR | S_IWUSR;
+ inode->i_uid = current_fsuid();
+ inode->i_gid = current_fsgid();
+ inode->i_flags |= S_PRIVATE;
+ inode->i_atime = inode->i_mtime = inode->i_ctime = current_time(inode);
+ return inode;
+}
+EXPORT_SYMBOL(alloc_anon_inode);
+
+/**
+ * simple_nosetlease - generic helper for prohibiting leases
+ * @filp: file pointer
+ * @arg: type of lease to obtain
+ * @flp: new lease supplied for insertion
+ * @priv: private data for lm_setup operation
+ *
+ * Generic helper for filesystems that do not wish to allow leases to be set.
+ * All arguments are ignored and it just returns -EINVAL.
+ */
+int
+simple_nosetlease(struct file *filp, long arg, struct file_lock **flp,
+ void **priv)
+{
+ return -EINVAL;
+}
+EXPORT_SYMBOL(simple_nosetlease);
+
+/**
+ * simple_get_link - generic helper to get the target of "fast" symlinks
+ * @dentry: not used here
+ * @inode: the symlink inode
+ * @done: not used here
+ *
+ * Generic helper for filesystems to use for symlink inodes where a pointer to
+ * the symlink target is stored in ->i_link. NOTE: this isn't normally called,
+ * since as an optimization the path lookup code uses any non-NULL ->i_link
+ * directly, without calling ->get_link(). But ->get_link() still must be set,
+ * to mark the inode_operations as being for a symlink.
+ *
+ * Return: the symlink target
+ */
+const char *simple_get_link(struct dentry *dentry, struct inode *inode,
+ struct delayed_call *done)
+{
+ return inode->i_link;
+}
+EXPORT_SYMBOL(simple_get_link);
+
+const struct inode_operations simple_symlink_inode_operations = {
+ .get_link = simple_get_link,
+};
+EXPORT_SYMBOL(simple_symlink_inode_operations);
+
+/*
+ * Operations for a permanently empty directory.
+ */
+static struct dentry *empty_dir_lookup(struct inode *dir, struct dentry *dentry, unsigned int flags)
+{
+ return ERR_PTR(-ENOENT);
+}
+
+static int empty_dir_getattr(const struct path *path, struct kstat *stat,
+ u32 request_mask, unsigned int query_flags)
+{
+ struct inode *inode = d_inode(path->dentry);
+ generic_fillattr(inode, stat);
+ return 0;
+}
+
+static int empty_dir_setattr(struct dentry *dentry, struct iattr *attr)
+{
+ return -EPERM;
+}
+
+static ssize_t empty_dir_listxattr(struct dentry *dentry, char *list, size_t size)
+{
+ return -EOPNOTSUPP;
+}
+
+static const struct inode_operations empty_dir_inode_operations = {
+ .lookup = empty_dir_lookup,
+ .permission = generic_permission,
+ .setattr = empty_dir_setattr,
+ .getattr = empty_dir_getattr,
+ .listxattr = empty_dir_listxattr,
+};
+
+static loff_t empty_dir_llseek(struct file *file, loff_t offset, int whence)
+{
+ /* An empty directory has two entries . and .. at offsets 0 and 1 */
+ return generic_file_llseek_size(file, offset, whence, 2, 2);
+}
+
+static int empty_dir_readdir(struct file *file, struct dir_context *ctx)
+{
+ dir_emit_dots(file, ctx);
+ return 0;
+}
+
+static const struct file_operations empty_dir_operations = {
+ .llseek = empty_dir_llseek,
+ .read = generic_read_dir,
+ .iterate_shared = empty_dir_readdir,
+ .fsync = noop_fsync,
+};
+
+
+void make_empty_dir_inode(struct inode *inode)
+{
+ set_nlink(inode, 2);
+ inode->i_mode = S_IFDIR | S_IRUGO | S_IXUGO;
+ inode->i_uid = GLOBAL_ROOT_UID;
+ inode->i_gid = GLOBAL_ROOT_GID;
+ inode->i_rdev = 0;
+ inode->i_size = 0;
+ inode->i_blkbits = PAGE_SHIFT;
+ inode->i_blocks = 0;
+
+ inode->i_op = &empty_dir_inode_operations;
+ inode->i_opflags &= ~IOP_XATTR;
+ inode->i_fop = &empty_dir_operations;
+}
+
+bool is_empty_dir_inode(struct inode *inode)
+{
+ return (inode->i_fop == &empty_dir_operations) &&
+ (inode->i_op == &empty_dir_inode_operations);
+}
+
+#ifdef CONFIG_UNICODE
+/*
+ * Determine if the name of a dentry should be casefolded.
+ *
+ * Return: if names will need casefolding
+ */
+static bool needs_casefold(const struct inode *dir)
+{
+ return IS_CASEFOLDED(dir) && dir->i_sb->s_encoding;
+}
+
+/**
+ * generic_ci_d_compare - generic d_compare implementation for casefolding filesystems
+ * @dentry: dentry whose name we are checking against
+ * @len: len of name of dentry
+ * @str: str pointer to name of dentry
+ * @name: Name to compare against
+ *
+ * Return: 0 if names match, 1 if mismatch, or -ERRNO
+ */
+static int generic_ci_d_compare(const struct dentry *dentry, unsigned int len,
+ const char *str, const struct qstr *name)
+{
+ const struct dentry *parent = READ_ONCE(dentry->d_parent);
+ const struct inode *dir = READ_ONCE(parent->d_inode);
+ const struct super_block *sb = dentry->d_sb;
+ const struct unicode_map *um = sb->s_encoding;
+ struct qstr qstr = QSTR_INIT(str, len);
+ char strbuf[DNAME_INLINE_LEN];
+ int ret;
+
+ if (!dir || !needs_casefold(dir))
+ goto fallback;
+ /*
+ * If the dentry name is stored in-line, then it may be concurrently
+ * modified by a rename. If this happens, the VFS will eventually retry
+ * the lookup, so it doesn't matter what ->d_compare() returns.
+ * However, it's unsafe to call utf8_strncasecmp() with an unstable
+ * string. Therefore, we have to copy the name into a temporary buffer.
+ */
+ if (len <= DNAME_INLINE_LEN - 1) {
+ memcpy(strbuf, str, len);
+ strbuf[len] = 0;
+ qstr.name = strbuf;
+ /* prevent compiler from optimizing out the temporary buffer */
+ barrier();
+ }
+ ret = utf8_strncasecmp(um, name, &qstr);
+ if (ret >= 0)
+ return ret;
+
+ if (sb_has_strict_encoding(sb))
+ return -EINVAL;
+fallback:
+ if (len != name->len)
+ return 1;
+ return !!memcmp(str, name->name, len);
+}
+
+/**
+ * generic_ci_d_hash - generic d_hash implementation for casefolding filesystems
+ * @dentry: dentry of the parent directory
+ * @str: qstr of name whose hash we should fill in
+ *
+ * Return: 0 if hash was successful or unchanged, and -EINVAL on error
+ */
+static int generic_ci_d_hash(const struct dentry *dentry, struct qstr *str)
+{
+ const struct inode *dir = READ_ONCE(dentry->d_inode);
+ struct super_block *sb = dentry->d_sb;
+ const struct unicode_map *um = sb->s_encoding;
+ int ret = 0;
+
+ if (!dir || !needs_casefold(dir))
+ return 0;
+
+ ret = utf8_casefold_hash(um, dentry, str);
+ if (ret < 0 && sb_has_strict_encoding(sb))
+ return -EINVAL;
+ return 0;
+}
+
+static const struct dentry_operations generic_ci_dentry_ops = {
+ .d_hash = generic_ci_d_hash,
+ .d_compare = generic_ci_d_compare,
+};
+#endif
+
+#ifdef CONFIG_FS_ENCRYPTION
+static const struct dentry_operations generic_encrypted_dentry_ops = {
+ .d_revalidate = fscrypt_d_revalidate,
+};
+#endif
+
+#if defined(CONFIG_FS_ENCRYPTION) && defined(CONFIG_UNICODE)
+static const struct dentry_operations generic_encrypted_ci_dentry_ops = {
+ .d_hash = generic_ci_d_hash,
+ .d_compare = generic_ci_d_compare,
+ .d_revalidate = fscrypt_d_revalidate,
+};
+#endif
+
+/**
+ * generic_set_encrypted_ci_d_ops - helper for setting d_ops for given dentry
+ * @dentry: dentry to set ops on
+ *
+ * Casefolded directories need d_hash and d_compare set, so that the dentries
+ * contained in them are handled case-insensitively. Note that these operations
+ * are needed on the parent directory rather than on the dentries in it, and
+ * while the casefolding flag can be toggled on and off on an empty directory,
+ * dentry_operations can't be changed later. As a result, if the filesystem has
+ * casefolding support enabled at all, we have to give all dentries the
+ * casefolding operations even if their inode doesn't have the casefolding flag
+ * currently (and thus the casefolding ops would be no-ops for now).
+ *
+ * Encryption works differently in that the only dentry operation it needs is
+ * d_revalidate, which it only needs on dentries that have the no-key name flag.
+ * The no-key flag can't be set "later", so we don't have to worry about that.
+ *
+ * Finally, to maximize compatibility with overlayfs (which isn't compatible
+ * with certain dentry operations) and to avoid taking an unnecessary
+ * performance hit, we use custom dentry_operations for each possible
+ * combination rather than always installing all operations.
+ */
+void generic_set_encrypted_ci_d_ops(struct dentry *dentry)
+{
+#ifdef CONFIG_FS_ENCRYPTION
+ bool needs_encrypt_ops = dentry->d_flags & DCACHE_NOKEY_NAME;
+#endif
+#ifdef CONFIG_UNICODE
+ bool needs_ci_ops = dentry->d_sb->s_encoding;
+#endif
+#if defined(CONFIG_FS_ENCRYPTION) && defined(CONFIG_UNICODE)
+ if (needs_encrypt_ops && needs_ci_ops) {
+ d_set_d_op(dentry, &generic_encrypted_ci_dentry_ops);
+ return;
+ }
+#endif
+#ifdef CONFIG_FS_ENCRYPTION
+ if (needs_encrypt_ops) {
+ d_set_d_op(dentry, &generic_encrypted_dentry_ops);
+ return;
+ }
+#endif
+#ifdef CONFIG_UNICODE
+ if (needs_ci_ops) {
+ d_set_d_op(dentry, &generic_ci_dentry_ops);
+ return;
+ }
+#endif
+}
+EXPORT_SYMBOL(generic_set_encrypted_ci_d_ops);