diff options
author | Darrick J. Wong <djwong@kernel.org> | 2021-07-09 11:05:48 -0700 |
---|---|---|
committer | Darrick J. Wong <djwong@kernel.org> | 2021-08-25 22:25:59 -0700 |
commit | 4cf18001845083e35676c913ddcc7ae41b914b64 (patch) | |
tree | d08c99508a485e9787d43603e0f13c879fa0d90c | |
parent | 176fd00779949a9f87cfc7f157f78eb86c6c0d84 (diff) |
xfs: clear log incompat feature bits when the log is idlelog-use-incompat-features_2021-08-25
When there are no ongoing transactions and the log contents have been
checkpointed back into the filesystem, the log performs 'covering',
which is to say that it log a dummy transaction to record the fact that
the tail has caught up with the head. This is a good time to clear log
incompat feature flags, because they are flags that are temporarily set
to limit the range of kernels that can replay a dirty log.
Since it's possible that some other higher level thread is about to
start logging items protected by a log incompat flag, we create a rwsem
so that upper level threads can coordinate this with the log. It would
probably be more performant to use a percpu rwsem, but the ability to
/try/ taking the write lock during covering is critical, and percpu
rwsems do not provide that.
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
-rw-r--r-- | fs/xfs/xfs_log.c | 49 | ||||
-rw-r--r-- | fs/xfs/xfs_log.h | 3 | ||||
-rw-r--r-- | fs/xfs/xfs_log_priv.h | 3 |
3 files changed, 55 insertions, 0 deletions
diff --git a/fs/xfs/xfs_log.c b/fs/xfs/xfs_log.c index c70161efe6bb..3cf265c5374e 100644 --- a/fs/xfs/xfs_log.c +++ b/fs/xfs/xfs_log.c @@ -1363,6 +1363,32 @@ xfs_log_work_queue( } /* + * Clear the log incompat flags if we have the opportunity. + * + * This only happens if we're about to log the second dummy transaction as part + * of covering the log and we can get the log incompat feature usage lock. + */ +static inline void +xlog_clear_incompat( + struct xlog *log) +{ + struct xfs_mount *mp = log->l_mp; + + if (!xfs_sb_has_incompat_log_feature(&mp->m_sb, + XFS_SB_FEAT_INCOMPAT_LOG_ALL)) + return; + + if (log->l_covered_state != XLOG_STATE_COVER_DONE2) + return; + + if (!down_write_trylock(&log->l_incompat_users)) + return; + + xfs_clear_incompat_log_features(mp); + up_write(&log->l_incompat_users); +} + +/* * Every sync period we need to unpin all items in the AIL and push them to * disk. If there is nothing dirty, then we might need to cover the log to * indicate that the filesystem is idle. @@ -1388,6 +1414,7 @@ xfs_log_worker( * synchronously log the superblock instead to ensure the * superblock is immediately unpinned and can be written back. */ + xlog_clear_incompat(log); xfs_sync_sb(mp, true); } else xfs_log_force(mp, 0); @@ -1475,6 +1502,8 @@ xlog_alloc_log( } log->l_sectBBsize = 1 << log2_size; + init_rwsem(&log->l_incompat_users); + xlog_get_iclog_buffer_size(mp, log); spin_lock_init(&log->l_icloglock); @@ -3974,3 +4003,23 @@ xfs_log_in_recovery( return log->l_flags & XLOG_ACTIVE_RECOVERY; } + +/* + * Notify the log that we're about to start using a feature that is protected + * by a log incompat feature flag. This will prevent log covering from + * clearing those flags. + */ +void +xlog_use_incompat_feat( + struct xlog *log) +{ + down_read(&log->l_incompat_users); +} + +/* Notify the log that we've finished using log incompat features. */ +void +xlog_drop_incompat_feat( + struct xlog *log) +{ + up_read(&log->l_incompat_users); +} diff --git a/fs/xfs/xfs_log.h b/fs/xfs/xfs_log.h index 813b972e9788..b274fb9dcd8d 100644 --- a/fs/xfs/xfs_log.h +++ b/fs/xfs/xfs_log.h @@ -142,4 +142,7 @@ bool xfs_log_in_recovery(struct xfs_mount *); xfs_lsn_t xlog_grant_push_threshold(struct xlog *log, int need_bytes); +void xlog_use_incompat_feat(struct xlog *log); +void xlog_drop_incompat_feat(struct xlog *log); + #endif /* __XFS_LOG_H__ */ diff --git a/fs/xfs/xfs_log_priv.h b/fs/xfs/xfs_log_priv.h index f3e79a45d60a..6953f86f866c 100644 --- a/fs/xfs/xfs_log_priv.h +++ b/fs/xfs/xfs_log_priv.h @@ -456,6 +456,9 @@ struct xlog { xfs_lsn_t l_recovery_lsn; uint32_t l_iclog_roundoff;/* padding roundoff */ + + /* Users of log incompat features should take a read lock. */ + struct rw_semaphore l_incompat_users; }; #define XLOG_BUF_CANCEL_BUCKET(log, blkno) \ |