From 7f4d01f36a3ac16f539f0fd3839de5d58fa4940f Mon Sep 17 00:00:00 2001 From: Brian Foster Date: Tue, 8 Aug 2017 18:21:52 -0700 Subject: [PATCH] xfs: add log item pinning error injection tag Add an error injection tag to force log items in the AIL to the pinned state. This option can be used by test infrastructure to induce head behind tail conditions. Specifically, this is intended to be used by xfstests to reproduce log recovery problems after failed/corrupted log writes overwrite the last good tail LSN in the log. When enabled, AIL push attempts see log items in the AIL in the pinned state. This stalls metadata writeback and thus prevents the current tail of the log from moving forward. When disabled, subsequent AIL pushes observe the log items in their appropriate state and filesystem operation continues as normal. Signed-off-by: Brian Foster Reviewed-by: Darrick J. Wong Signed-off-by: Darrick J. Wong --- fs/xfs/xfs_error.c | 3 +++ fs/xfs/xfs_error.h | 4 +++- fs/xfs/xfs_trans_ail.c | 17 ++++++++++++++++- 3 files changed, 22 insertions(+), 2 deletions(-) diff --git a/fs/xfs/xfs_error.c b/fs/xfs/xfs_error.c index 2f4feb959bfb..bd786a9ac2c3 100644 --- a/fs/xfs/xfs_error.c +++ b/fs/xfs/xfs_error.c @@ -57,6 +57,7 @@ static unsigned int xfs_errortag_random_default[] = { XFS_RANDOM_AG_RESV_CRITICAL, XFS_RANDOM_DROP_WRITES, XFS_RANDOM_LOG_BAD_CRC, + XFS_RANDOM_LOG_ITEM_PIN, }; struct xfs_errortag_attr { @@ -161,6 +162,7 @@ XFS_ERRORTAG_ATTR_RW(bmap_finish_one, XFS_ERRTAG_BMAP_FINISH_ONE); XFS_ERRORTAG_ATTR_RW(ag_resv_critical, XFS_ERRTAG_AG_RESV_CRITICAL); XFS_ERRORTAG_ATTR_RW(drop_writes, XFS_ERRTAG_DROP_WRITES); XFS_ERRORTAG_ATTR_RW(log_bad_crc, XFS_ERRTAG_LOG_BAD_CRC); +XFS_ERRORTAG_ATTR_RW(log_item_pin, XFS_ERRTAG_LOG_ITEM_PIN); static struct attribute *xfs_errortag_attrs[] = { XFS_ERRORTAG_ATTR_LIST(noerror), @@ -193,6 +195,7 @@ static struct attribute *xfs_errortag_attrs[] = { XFS_ERRORTAG_ATTR_LIST(ag_resv_critical), XFS_ERRORTAG_ATTR_LIST(drop_writes), XFS_ERRORTAG_ATTR_LIST(log_bad_crc), + XFS_ERRORTAG_ATTR_LIST(log_item_pin), NULL, }; diff --git a/fs/xfs/xfs_error.h b/fs/xfs/xfs_error.h index 7577be5f09bc..7c4bef3bddb7 100644 --- a/fs/xfs/xfs_error.h +++ b/fs/xfs/xfs_error.h @@ -106,7 +106,8 @@ extern void xfs_verifier_error(struct xfs_buf *bp); */ #define XFS_ERRTAG_DROP_WRITES 28 #define XFS_ERRTAG_LOG_BAD_CRC 29 -#define XFS_ERRTAG_MAX 30 +#define XFS_ERRTAG_LOG_ITEM_PIN 30 +#define XFS_ERRTAG_MAX 31 /* * Random factors for above tags, 1 means always, 2 means 1/2 time, etc. @@ -141,6 +142,7 @@ extern void xfs_verifier_error(struct xfs_buf *bp); #define XFS_RANDOM_AG_RESV_CRITICAL 4 #define XFS_RANDOM_DROP_WRITES 1 #define XFS_RANDOM_LOG_BAD_CRC 1 +#define XFS_RANDOM_LOG_ITEM_PIN 1 #ifdef DEBUG extern int xfs_errortag_init(struct xfs_mount *mp); diff --git a/fs/xfs/xfs_trans_ail.c b/fs/xfs/xfs_trans_ail.c index 70f5ab017323..354368a906e5 100644 --- a/fs/xfs/xfs_trans_ail.c +++ b/fs/xfs/xfs_trans_ail.c @@ -325,6 +325,21 @@ xfs_ail_delete( xfs_trans_ail_cursor_clear(ailp, lip); } +static inline uint +xfsaild_push_item( + struct xfs_ail *ailp, + struct xfs_log_item *lip) +{ + /* + * If log item pinning is enabled, skip the push and track the item as + * pinned. This can help induce head-behind-tail conditions. + */ + if (XFS_TEST_ERROR(false, ailp->xa_mount, XFS_ERRTAG_LOG_ITEM_PIN)) + return XFS_ITEM_PINNED; + + return lip->li_ops->iop_push(lip, &ailp->xa_buf_list); +} + static long xfsaild_push( struct xfs_ail *ailp) @@ -382,7 +397,7 @@ xfsaild_push( * rely on the AIL cursor implementation to be able to deal with * the dropped lock. */ - lock_result = lip->li_ops->iop_push(lip, &ailp->xa_buf_list); + lock_result = xfsaild_push_item(ailp, lip); switch (lock_result) { case XFS_ITEM_SUCCESS: XFS_STATS_INC(mp, xs_push_ail_success);