Unverified Commit 7a9d43ea authored by Christoph Hellwig's avatar Christoph Hellwig Committed by Christian Brauner
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iomap: handle a post-direct I/O invalidate race in iomap_write_delalloc_release 



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: default avatarChristoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20240910043949.3481298-2-hch@lst.de


Reviewed-by: default avatarDarrick J. Wong <djwong@kernel.org>
Signed-off-by: default avatarChristian Brauner <brauner@kernel.org>
parent b1daf3f8

fs/iomap/buffered-io.c

+9 −1
Original line number Diff line number Diff line
@@ -1242,7 +1242,15 @@ 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,