}
/*
- * First stage of freeze - no more writers will make progress now we are here,
+ * When remounting a filesystem read-only or freezing the filesystem, we have
+ * two phases to execute. This first phase is syncing the data before we
+ * quiesce the filesystem, and the second is flushing all the inodes out after
+ * we've waited for all the transactions created by the first phase to
+ * complete. The second phase ensures that the inodes are written to their
+ * location on disk rather than just existing in transactions in the log. This
+ * means after a quiesce there is no log replay required to write the inodes to
+ * disk (this is the main difference between a sync and a quiesce).
+ */
+/*
+ * First stage of freeze - no writers will make progress now we are here,
* so we flush delwri and delalloc buffers here, then wait for all I/O to
* complete. Data is frozen at that point. Metadata is not frozen,
- * transactions can still occur here so don't bother flushing the buftarg (i.e
- * SYNC_QUIESCE) because it'll just get dirty again.
+ * transactions can still occur here so don't bother flushing the buftarg
+ * because it'll just get dirty again.
*/
int
xfs_quiesce_data(
xfs_sync_inodes(mp, SYNC_DELWRI|SYNC_WAIT|SYNC_IOWAIT);
XFS_QM_DQSYNC(mp, SYNC_WAIT);
- /* write superblock and hoover shutdown errors */
+ /* write superblock and hoover up shutdown errors */
error = xfs_sync_fsdata(mp, 0);
- /* flush devices */
- XFS_bflush(mp->m_ddev_targp);
+ /* flush data-only devices */
if (mp->m_rtdev_targp)
XFS_bflush(mp->m_rtdev_targp);
return error;
}
-/*
- * xfs_sync flushes any pending I/O to file system vfsp.
- *
- * This routine is called by vfs_sync() to make sure that things make it
- * out to disk eventually, on sync() system calls to flush out everything,
- * and when the file system is unmounted. For the vfs_sync() case, all
- * we really need to do is sync out the log to make all of our meta-data
- * updates permanent (except for timestamps). For calls from pflushd(),
- * dirty pages are kept moving by calling pdflush() on the inodes
- * containing them. We also flush the inodes that we can lock without
- * sleeping and the superblock if we can lock it without sleeping from
- * vfs_sync() so that items at the tail of the log are always moving out.
- *
- * Flags:
- * SYNC_BDFLUSH - We're being called from vfs_sync() so we don't want
- * to sleep if we can help it. All we really need
- * to do is ensure that the log is synced at least
- * periodically. We also push the inodes and
- * superblock if we can lock them without sleeping
- * and they are not pinned.
- * SYNC_ATTR - We need to flush the inodes. Now handled by direct calls
- * to xfs_sync_inodes().
- * SYNC_WAIT - All the flushes that take place in this call should
- * be synchronous.
- * SYNC_DELWRI - This tells us to push dirty pages associated with
- * inodes. SYNC_WAIT and SYNC_BDFLUSH are used to
- * determine if they should be flushed sync, async, or
- * delwri.
- * SYNC_FSDATA - This indicates that the caller would like to make
- * sure the superblock is safe on disk. We can ensure
- * this by simply making sure the log gets flushed
- * if SYNC_BDFLUSH is set, and by actually writing it
- * out otherwise.
- * SYNC_IOWAIT - The caller wants us to wait for all data I/O to complete
- * before we return (including direct I/O). Forms the drain
- * side of the write barrier needed to safely quiesce the
- * filesystem.
- *
- */
-int
-xfs_sync(
- xfs_mount_t *mp,
- int flags)
-{
- int error;
- int last_error = 0;
- uint log_flags = XFS_LOG_FORCE;
-
- ASSERT(!(flags & SYNC_ATTR));
-
- /*
- * Get the Quota Manager to flush the dquots.
- *
- * If XFS quota support is not enabled or this filesystem
- * instance does not use quotas XFS_QM_DQSYNC will always
- * return zero.
- */
- error = XFS_QM_DQSYNC(mp, flags);
- if (error) {
- /*
- * If we got an IO error, we will be shutting down.
- * So, there's nothing more for us to do here.
- */
- ASSERT(error != EIO || XFS_FORCED_SHUTDOWN(mp));
- if (XFS_FORCED_SHUTDOWN(mp))
- return XFS_ERROR(error);
- }
-
- if (flags & SYNC_IOWAIT)
- xfs_filestream_flush(mp);
-
- /*
- * Sync out the log. This ensures that the log is periodically
- * flushed even if there is not enough activity to fill it up.
- */
- if (flags & SYNC_WAIT)
- log_flags |= XFS_LOG_SYNC;
-
- xfs_log_force(mp, (xfs_lsn_t)0, log_flags);
-
- if (flags & SYNC_DELWRI) {
- if (flags & SYNC_BDFLUSH)
- xfs_finish_reclaim_all(mp, 1, XFS_IFLUSH_DELWRI_ELSE_ASYNC);
- else
- error = xfs_sync_inodes(mp, flags);
- /*
- * Flushing out dirty data above probably generated more
- * log activity, so if this isn't vfs_sync() then flush
- * the log again.
- */
- xfs_log_force(mp, 0, log_flags);
- }
-
- if (flags & SYNC_FSDATA) {
- error = xfs_sync_fsdata(mp, flags);
- if (error)
- last_error = error;
- }
-
- /*
- * Now check to see if the log needs a "dummy" transaction.
- */
- if (!(flags & SYNC_REMOUNT) && xfs_log_need_covered(mp)) {
- error = xfs_commit_dummy_trans(mp, log_flags);
- if (error)
- return error;
- }
-
- return XFS_ERROR(last_error);
-}
-
/*
* Enqueue a work item to be picked up by the vfs xfssyncd thread.
* Doing this has two advantages:
} bhv_vfs_sync_work_t;
#define SYNC_ATTR 0x0001 /* sync attributes */
-#define SYNC_DELWRI 0x0004 /* look at delayed writes */
-#define SYNC_WAIT 0x0008 /* wait for i/o to complete */
-#define SYNC_BDFLUSH 0x0010 /* BDFLUSH is calling -- don't block */
-#define SYNC_FSDATA 0x0020 /* flush fs data (e.g. superblocks) */
-#define SYNC_REFCACHE 0x0040 /* prune some of the nfs ref cache */
-#define SYNC_REMOUNT 0x0080 /* remount readonly, no dummy LRs */
-#define SYNC_IOWAIT 0x0100 /* wait for all I/O to complete */
-
-/*
- * When remounting a filesystem read-only or freezing the filesystem,
- * we have two phases to execute. This first phase is syncing the data
- * before we quiesce the fielsystem, and the second is flushing all the
- * inodes out after we've waited for all the transactions created by
- * the first phase to complete. The second phase uses SYNC_INODE_QUIESCE
- * to ensure that the inodes are written to their location on disk
- * rather than just existing in transactions in the log. This means
- * after a quiesce there is no log replay required to write the inodes
- * to disk (this is the main difference between a sync and a quiesce).
- */
-#define SYNC_DATA_QUIESCE (SYNC_DELWRI|SYNC_FSDATA|SYNC_WAIT|SYNC_IOWAIT)
+#define SYNC_DELWRI 0x0002 /* look at delayed writes */
+#define SYNC_WAIT 0x0004 /* wait for i/o to complete */
+#define SYNC_BDFLUSH 0x0008 /* BDFLUSH is calling -- don't block */
+#define SYNC_IOWAIT 0x0010 /* wait for all I/O to complete */
int xfs_syncd_init(struct xfs_mount *mp);
void xfs_syncd_stop(struct xfs_mount *mp);
-int xfs_sync(struct xfs_mount *mp, int flags);
int xfs_sync_inodes(struct xfs_mount *mp, int flags);
int xfs_sync_fsdata(struct xfs_mount *mp, int flags);
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