Commit a099b09a authored by Wei Gao's avatar Wei Gao Committed by Jan Kara
Browse files

ext2: Handle fiemap on empty files to prevent EINVAL 

Previously, ext2_fiemap would unconditionally apply "len = min_t(u64, len,
i_size_read(inode));", When inode->i_size was 0 (for an empty file), this
would reduce the requested len to 0. Passing len = 0 to iomap_fiemap could
then result in an -EINVAL error, even for valid queries on empty files.

Link: https://github.com/linux-test-project/ltp/issues/1246


Signed-off-by: default avatarWei Gao <wegao@suse.com>
Signed-off-by: default avatarJan Kara <jack@suse.cz>
Link: https://patch.msgid.link/20250613152402.3432135-1-wegao@suse.com
parent 27605c8c

fs/ext2/inode.c

+11 −1
Original line number Diff line number Diff line
@@ -895,9 +895,19 @@ int ext2_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo, 
		u64 start, u64 len)

{

	int ret;

	loff_t i_size;



	inode_lock(inode);

	len = min_t(u64, len, i_size_read(inode));

	i_size = i_size_read(inode);

	/*

	 * iomap_fiemap() returns EINVAL for 0 length. Make sure we don't trim

	 * length to 0 but still trim the range as much as possible since

	 * ext2_get_blocks() iterates unmapped space block by block which is

	 * slow.

	 */

	if (i_size == 0)

		i_size = 1;

	len = min_t(u64, len, i_size);

	ret = iomap_fiemap(inode, fieinfo, start, len, &ext2_iomap_ops);

	inode_unlock(inode);