From: "Darrick J. Wong" djwong@kernel.org
commit 3f113c2739b1b068854c7ffed635c2bd790d1492 upstream.
When scrub is trying to iget an inode, ensure that it won't end up deadlocked on a cycle in the inode btree by using an empty transaction to store all the buffers.
Signed-off-by: Darrick J. Wong djwong@kernel.org Reviewed-by: Dave Chinner dchinner@redhat.com Reviewed-by: Christoph Hellwig hch@lst.de Signed-off-by: Catherine Hoang catherine.hoang@oracle.com Acked-by: Darrick J. Wong djwong@kernel.org --- fs/xfs/scrub/common.c | 6 ++++-- fs/xfs/scrub/common.h | 25 +++++++++++++++++++++++++ fs/xfs/scrub/inode.c | 4 ++-- 3 files changed, 31 insertions(+), 4 deletions(-)
diff --git a/fs/xfs/scrub/common.c b/fs/xfs/scrub/common.c index de24532fe083..23944fcc1a6c 100644 --- a/fs/xfs/scrub/common.c +++ b/fs/xfs/scrub/common.c @@ -733,6 +733,8 @@ xchk_iget( xfs_ino_t inum, struct xfs_inode **ipp) { + ASSERT(sc->tp != NULL); + return xfs_iget(sc->mp, sc->tp, inum, XFS_IGET_UNTRUSTED, 0, ipp); }
@@ -882,8 +884,8 @@ xchk_iget_for_scrubbing( if (!xfs_verify_ino(sc->mp, sc->sm->sm_ino)) return -ENOENT;
- /* Try a regular untrusted iget. */ - error = xchk_iget(sc, sc->sm->sm_ino, &ip); + /* Try a safe untrusted iget. */ + error = xchk_iget_safe(sc, sc->sm->sm_ino, &ip); if (!error) return xchk_install_handle_inode(sc, ip); if (error == -ENOENT) diff --git a/fs/xfs/scrub/common.h b/fs/xfs/scrub/common.h index cabdc0e16838..c83cf9e5b55f 100644 --- a/fs/xfs/scrub/common.h +++ b/fs/xfs/scrub/common.h @@ -151,12 +151,37 @@ void xchk_iunlock(struct xfs_scrub *sc, unsigned int ilock_flags);
void xchk_buffer_recheck(struct xfs_scrub *sc, struct xfs_buf *bp);
+/* + * Grab the inode at @inum. The caller must have created a scrub transaction + * so that we can confirm the inumber by walking the inobt and not deadlock on + * a loop in the inobt. + */ int xchk_iget(struct xfs_scrub *sc, xfs_ino_t inum, struct xfs_inode **ipp); int xchk_iget_agi(struct xfs_scrub *sc, xfs_ino_t inum, struct xfs_buf **agi_bpp, struct xfs_inode **ipp); void xchk_irele(struct xfs_scrub *sc, struct xfs_inode *ip); int xchk_install_handle_inode(struct xfs_scrub *sc, struct xfs_inode *ip);
+/* + * Safe version of (untrusted) xchk_iget that uses an empty transaction to + * avoid deadlocking on loops in the inobt. This should only be used in a + * scrub or repair setup routine, and only prior to grabbing a transaction. + */ +static inline int +xchk_iget_safe(struct xfs_scrub *sc, xfs_ino_t inum, struct xfs_inode **ipp) +{ + int error; + + ASSERT(sc->tp == NULL); + + error = xchk_trans_alloc(sc, 0); + if (error) + return error; + error = xchk_iget(sc, inum, ipp); + xchk_trans_cancel(sc); + return error; +} + /* * Don't bother cross-referencing if we already found corruption or cross * referencing discrepancies. diff --git a/fs/xfs/scrub/inode.c b/fs/xfs/scrub/inode.c index 59d7912fb75f..74b1ebb40a4c 100644 --- a/fs/xfs/scrub/inode.c +++ b/fs/xfs/scrub/inode.c @@ -94,8 +94,8 @@ xchk_setup_inode( if (!xfs_verify_ino(sc->mp, sc->sm->sm_ino)) return -ENOENT;
- /* Try a regular untrusted iget. */ - error = xchk_iget(sc, sc->sm->sm_ino, &ip); + /* Try a safe untrusted iget. */ + error = xchk_iget_safe(sc, sc->sm->sm_ino, &ip); if (!error) return xchk_install_handle_iscrub(sc, ip); if (error == -ENOENT)