diff options
Diffstat (limited to 'kernel/fs/xfs/xfs_log_priv.h')
| -rw-r--r-- | kernel/fs/xfs/xfs_log_priv.h | 55 |
1 files changed, 54 insertions, 1 deletions
diff --git a/kernel/fs/xfs/xfs_log_priv.h b/kernel/fs/xfs/xfs_log_priv.h index db7cbdeb2..8daba7491 100644 --- a/kernel/fs/xfs/xfs_log_priv.h +++ b/kernel/fs/xfs/xfs_log_priv.h @@ -409,7 +409,7 @@ struct xlog { /* The following field are used for debugging; need to hold icloglock */ #ifdef DEBUG - char *l_iclog_bak[XLOG_MAX_ICLOGS]; + void *l_iclog_bak[XLOG_MAX_ICLOGS]; #endif }; @@ -426,6 +426,8 @@ xlog_recover( extern int xlog_recover_finish( struct xlog *log); +extern int +xlog_recover_cancel(struct xlog *); extern __le32 xlog_cksum(struct xlog *log, struct xlog_rec_header *rhead, char *dp, int size); @@ -558,4 +560,55 @@ static inline void xlog_wait(wait_queue_head_t *wq, spinlock_t *lock) remove_wait_queue(wq, &wait); } +/* + * The LSN is valid so long as it is behind the current LSN. If it isn't, this + * means that the next log record that includes this metadata could have a + * smaller LSN. In turn, this means that the modification in the log would not + * replay. + */ +static inline bool +xlog_valid_lsn( + struct xlog *log, + xfs_lsn_t lsn) +{ + int cur_cycle; + int cur_block; + bool valid = true; + + /* + * First, sample the current lsn without locking to avoid added + * contention from metadata I/O. The current cycle and block are updated + * (in xlog_state_switch_iclogs()) and read here in a particular order + * to avoid false negatives (e.g., thinking the metadata LSN is valid + * when it is not). + * + * The current block is always rewound before the cycle is bumped in + * xlog_state_switch_iclogs() to ensure the current LSN is never seen in + * a transiently forward state. Instead, we can see the LSN in a + * transiently behind state if we happen to race with a cycle wrap. + */ + cur_cycle = ACCESS_ONCE(log->l_curr_cycle); + smp_rmb(); + cur_block = ACCESS_ONCE(log->l_curr_block); + + if ((CYCLE_LSN(lsn) > cur_cycle) || + (CYCLE_LSN(lsn) == cur_cycle && BLOCK_LSN(lsn) > cur_block)) { + /* + * If the metadata LSN appears invalid, it's possible the check + * above raced with a wrap to the next log cycle. Grab the lock + * to check for sure. + */ + spin_lock(&log->l_icloglock); + cur_cycle = log->l_curr_cycle; + cur_block = log->l_curr_block; + spin_unlock(&log->l_icloglock); + + if ((CYCLE_LSN(lsn) > cur_cycle) || + (CYCLE_LSN(lsn) == cur_cycle && BLOCK_LSN(lsn) > cur_block)) + valid = false; + } + + return valid; +} + #endif /* __XFS_LOG_PRIV_H__ */ |