We have this unclear comment at find_extent_clone() about extents starting
at a file offset greater than or equals to the i_size of the inode. It's
not really informative and it's misleading, since it mentions the author
found such extents with snapshots and large files.
Such extents are a result of fallocate with FALLOC_FL_KEEP_SIZE and there
is no relation to snapshots or large files (all write paths update the
i_size before inserting a new file extent item). So update the comment to
be precise about it and why we don't bother looking for clone sources in
that case.
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
int compressed;
u32 i;
- if (data_offset >= ino_size) {
- /*
- * There may be extents that lie behind the file's size.
- * I at least had this in combination with snapshotting while
- * writing large files.
- */
+ /*
+ * With fallocate we can get prealloc extents beyond the inode's i_size,
+ * so we don't do anything here because clone operations can not clone
+ * to a range beyond i_size without increasing the i_size of the
+ * destination inode.
+ */
+ if (data_offset >= ino_size)
return 0;
- }
fi = btrfs_item_ptr(eb, path->slots[0], struct btrfs_file_extent_item);
extent_type = btrfs_file_extent_type(eb, fi);