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iomap: handle a post-direct I/O invalidate race in iomap_write_delalloc_release 

[ Upstream commit 7a9d43eace888a0ee6095035997bb138425844d3 ]

When direct I/O completions invalidates the page cache it holds neither the
i_rwsem nor the invalidate_lock so it can be racing with
iomap_write_delalloc_release.  If the search for the end of the region that
contains data returns the start offset we hit such a race and just need to
look for the end of the newly created hole instead.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20240910043949.3481298-2-hch@lst.de
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Christian Brauner <brauner@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
Christoph Hellwig 2024-09-10 07:39:03 +03:00 committed by Greg Kroah-Hartman
parent ad762c5204
commit 390b9e54cd
1 changed files with 9 additions and 1 deletions
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10
fs/iomap/buffered-io.c
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@ -1177,7 +1177,15 @@ static int iomap_write_delalloc_release(struct inode *inode,
error = data_end;
goto out_unlock;
}
WARN_ON_ONCE(data_end <= start_byte);
/*
* If we race with post-direct I/O invalidation of the page cache,
* there might be no data left at start_byte.
*/
if (data_end == start_byte)
continue;
WARN_ON_ONCE(data_end < start_byte);
WARN_ON_ONCE(data_end > scan_end_byte);
error = iomap_write_delalloc_scan(inode, &punch_start_byte,