Commit 07eae0fa authored by Christoph Hellwig's avatar Christoph Hellwig Committed by Carlos Maiolino
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xfs: check for dead buffers in xfs_buf_find_insert 



Commit 32dd4f9c ("xfs: remove a superflous hash lookup when inserting
new buffers") converted xfs_buf_find_insert to use
rhashtable_lookup_get_insert_fast and thus an operation that returns the
existing buffer when an insert would duplicate the hash key.  But this
code path misses the check for a buffer with a reference count of zero,
which could lead to reusing an about to be freed buffer.  Fix this by
using the same atomic_inc_not_zero pattern as xfs_buf_insert.

Fixes: 32dd4f9c ("xfs: remove a superflous hash lookup when inserting new buffers")
Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
Reviewed-by: default avatarDave Chinner <dchinner@redhat.com>
Reviewed-by: default avatarDarrick J. Wong <djwong@kernel.org>
Cc: stable@vger.kernel.org # v6.0
Signed-off-by: default avatarCarlos Maiolino <cem@kernel.org>
parent 4e35be63

fs/xfs/xfs_buf.c

+1 −2
Original line number Diff line number Diff line
@@ -655,9 +655,8 @@ xfs_buf_find_insert( 
		spin_unlock(&bch->bc_lock);

		goto out_free_buf;

	}

	if (bp) {

	if (bp && atomic_inc_not_zero(&bp->b_hold)) {

		/* found an existing buffer */

		atomic_inc(&bp->b_hold);

		spin_unlock(&bch->bc_lock);

		error = xfs_buf_find_lock(bp, flags);

		if (error)