ext4: use core vfs llseek code for dir seeks
Use the new functionality in generic_file_llseek_size() to
accept a custom EOF position, and un-cut-and-paste all the
vfs llseek code from ext4.
Also fix up comments on ext4_llseek() to reflect reality.
Signed-off-by: Eric Sandeen <sandeen@redaht.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/fs/ext4/dir.c b/fs/ext4/dir.c
index aa39e60..8e07d2a 100644
--- a/fs/ext4/dir.c
+++ b/fs/ext4/dir.c
@@ -324,74 +324,27 @@
/*
- * ext4_dir_llseek() based on generic_file_llseek() to handle both
- * non-htree and htree directories, where the "offset" is in terms
- * of the filename hash value instead of the byte offset.
+ * ext4_dir_llseek() calls generic_file_llseek_size to handle htree
+ * directories, where the "offset" is in terms of the filename hash
+ * value instead of the byte offset.
*
- * NOTE: offsets obtained *before* ext4_set_inode_flag(dir, EXT4_INODE_INDEX)
- * will be invalid once the directory was converted into a dx directory
+ * Because we may return a 64-bit hash that is well beyond offset limits,
+ * we need to pass the max hash as the maximum allowable offset in
+ * the htree directory case.
+ *
+ * For non-htree, ext4_llseek already chooses the proper max offset.
*/
loff_t ext4_dir_llseek(struct file *file, loff_t offset, int origin)
{
struct inode *inode = file->f_mapping->host;
- loff_t ret = -EINVAL;
int dx_dir = is_dx_dir(inode);
+ loff_t htree_max = ext4_get_htree_eof(file);
- mutex_lock(&inode->i_mutex);
-
- /* NOTE: relative offsets with dx directories might not work
- * as expected, as it is difficult to figure out the
- * correct offset between dx hashes */
-
- switch (origin) {
- case SEEK_END:
- if (unlikely(offset > 0))
- goto out_err; /* not supported for directories */
-
- /* so only negative offsets are left, does that have a
- * meaning for directories at all? */
- if (dx_dir)
- offset += ext4_get_htree_eof(file);
- else
- offset += inode->i_size;
- break;
- case SEEK_CUR:
- /*
- * Here we special-case the lseek(fd, 0, SEEK_CUR)
- * position-querying operation. Avoid rewriting the "same"
- * f_pos value back to the file because a concurrent read(),
- * write() or lseek() might have altered it
- */
- if (offset == 0) {
- offset = file->f_pos;
- goto out_ok;
- }
-
- offset += file->f_pos;
- break;
- }
-
- if (unlikely(offset < 0))
- goto out_err;
-
- if (!dx_dir) {
- if (offset > inode->i_sb->s_maxbytes)
- goto out_err;
- } else if (offset > ext4_get_htree_eof(file))
- goto out_err;
-
- /* Special lock needed here? */
- if (offset != file->f_pos) {
- file->f_pos = offset;
- file->f_version = 0;
- }
-
-out_ok:
- ret = offset;
-out_err:
- mutex_unlock(&inode->i_mutex);
-
- return ret;
+ if (likely(dx_dir))
+ return generic_file_llseek_size(file, offset, origin,
+ htree_max, htree_max);
+ else
+ return ext4_llseek(file, offset, origin);
}
/*
diff --git a/fs/ext4/file.c b/fs/ext4/file.c
index f3dadd0..782eecb 100644
--- a/fs/ext4/file.c
+++ b/fs/ext4/file.c
@@ -211,9 +211,9 @@
}
/*
- * ext4_llseek() copied from generic_file_llseek() to handle both
- * block-mapped and extent-mapped maxbytes values. This should
- * otherwise be identical with generic_file_llseek().
+ * ext4_llseek() handles both block-mapped and extent-mapped maxbytes values
+ * by calling generic_file_llseek_size() with the appropriate maxbytes
+ * value for each.
*/
loff_t ext4_llseek(struct file *file, loff_t offset, int origin)
{