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ext2: Handle fiemap on empty files to prevent EINVAL

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[ Upstream commit a099b09a3342a0b28ea330e405501b5b4d0424b4 ]

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: Wei Gao <wegao@suse.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Link: https://patch.msgid.link/20250613152402.3432135-1-wegao@suse.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
Wei Gao
2025-06-13 11:18:38 -04:00
committed by Greg Kroah-Hartman
parent 6c7fadac6c
commit 327276cb8a
1 changed files with 11 additions and 1 deletions
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12
fs/ext2/inode.c
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@@ -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);