xfs: reorder iunlink remove operation in xfs_ifree
[ Upstream commit 9a5280b3 ] The O_TMPFILE creation implementation creates a specific order of operations for inode allocation/freeing and unlinked list modification. Currently both are serialised by the AGI, so the order doesn't strictly matter as long as the are both in the same transaction. However, if we want to move the unlinked list insertions largely out from under the AGI lock, then we have to be concerned about the order in which we do unlinked list modification operations. O_TMPFILE creation tells us this order is inode allocation/free, then unlinked list modification. Change xfs_ifree() to use this same ordering on unlinked list removal. This way we always guarantee that when we enter the iunlinked list removal code from this path, we already have the AGI locked and we don't have to worry about lock nesting AGI reads inside unlink list locks because it's already locked and attached to the transaction. We can do this safely as the inode freeing and unlinked list removal are done in the same transaction and hence are atomic operations with respect to log recovery. Reported-by:Frank Hofmann <fhofmann@cloudflare.com> Fixes: 298f7bec ("xfs: pin inode backing buffer to the inode log item") Signed-off-by:
Dave Chinner <dchinner@redhat.com> Reviewed-by:
Darrick J. Wong <darrick.wong@oracle.com> Signed-off-by:
Dave Chinner <david@fromorbit.com> Signed-off-by:
Leah Rumancik <leah.rumancik@gmail.com> Acked-by:
Darrick J. Wong <djwong@kernel.org> Signed-off-by:
Greg Kroah-Hartman <gregkh@linuxfoundation.org>
parent
28c7ef86
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