Re: [PATCH 9/7] xfs: remove SYNC_BDFLUSH

Eric Sandeen
2009-06-05T20:45:08Z

Christoph Hellwig wrote:
> SYNC_BDFLUSH is a leftover from IRIX and rather misnamed for todays
> code. Make xfs_sync_fsdata and xfs_dq_sync use the SYNC_TRYLOCK flag
> for not blocking on logs just as the inode sync code already does.
>
> For xfs_sync_fsdata it's a trivial 1:1 replacement, but for xfs_qm_sync
> I use the opportunity to decouple the non-blocking lock case from the
> different flushing modes, similar to the inode sync code.
>
>
> Signed-off-by: Christoph Hellwig <hch@lst.de>

Reviewed-by: Eric Sandeen <sandeen@sandeen.net>

> Index: xfs/fs/xfs/linux-2.6/xfs_sync.c
> ===================================================================
> --- xfs.orig/fs/xfs/linux-2.6/xfs_sync.c 2009-05-27 13:02:57.426938830 +0200
> +++ xfs/fs/xfs/linux-2.6/xfs_sync.c 2009-05-27 13:07:53.227939055 +0200
> @@ -350,7 +350,7 @@ xfs_sync_fsdata(
> * If this is xfssyncd() then only sync the superblock if we can
> * lock it without sleeping and it is not pinned.
> */
> - if (flags & SYNC_BDFLUSH) {
> + if (flags & SYNC_TRYLOCK) {
> ASSERT(!(flags & SYNC_WAIT));
>
> bp = xfs_getsb(mp, XFS_BUF_TRYLOCK);
> @@ -415,7 +415,7 @@ xfs_quiesce_data(
>
> /* push non-blocking */
> xfs_sync_data(mp, 0);
> - xfs_qm_sync(mp, SYNC_BDFLUSH);
> + xfs_qm_sync(mp, SYNC_TRYLOCK);
> xfs_filestream_flush(mp);
>
> /* push and block */
> @@ -565,8 +565,8 @@ xfs_sync_worker(
> xfs_log_force(mp, (xfs_lsn_t)0, XFS_LOG_FORCE);
> xfs_reclaim_inodes(mp, XFS_IFLUSH_DELWRI_ELSE_ASYNC);
> /* dgc: errors ignored here */
> - error = xfs_qm_sync(mp, SYNC_BDFLUSH);
> - error = xfs_sync_fsdata(mp, SYNC_BDFLUSH);
> + error = xfs_qm_sync(mp, SYNC_TRYLOCK);
> + error = xfs_sync_fsdata(mp, SYNC_TRYLOCK);
> if (xfs_log_need_covered(mp))
> error = xfs_commit_dummy_trans(mp, XFS_LOG_FORCE);
> }
> Index: xfs/fs/xfs/quota/xfs_qm.c
> ===================================================================
> --- xfs.orig/fs/xfs/quota/xfs_qm.c 2009-05-27 13:04:00.607842293 +0200
> +++ xfs/fs/xfs/quota/xfs_qm.c 2009-05-27 13:10:21.688940102 +0200
> @@ -905,11 +905,6 @@ xfs_qm_dqdetach(
> }
> }
>
> -/*
> - * This is called to sync quotas. We can be told to use non-blocking
> - * semantics by either the SYNC_BDFLUSH flag or the absence of the
> - * SYNC_WAIT flag.
> - */
> int
> xfs_qm_sync(
> xfs_mount_t *mp,
> @@ -918,17 +913,13 @@ xfs_qm_sync(
> int recl, restarts;
> xfs_dquot_t *dqp;
> uint flush_flags;
> - boolean_t nowait;
> int error;
>
> if (!XFS_IS_QUOTA_RUNNING(mp) || !XFS_IS_QUOTA_ON(mp))
> return 0;
>
> + flush_flags = (flags & SYNC_WAIT) ? XFS_QMOPT_SYNC : XFS_QMOPT_DELWRI;
> restarts = 0;
> - /*
> - * We won't block unless we are asked to.
> - */
> - nowait = (boolean_t)(flags & SYNC_BDFLUSH || (flags & SYNC_WAIT) == 0);
>
> again:
> xfs_qm_mplist_lock(mp);
> @@ -948,18 +939,10 @@ xfs_qm_sync(
> * don't 'seem' to be dirty. ie. don't acquire dqlock.
> * This is very similar to what xfs_sync does with inodes.
> */
> - if (flags & SYNC_BDFLUSH) {
> - if (! XFS_DQ_IS_DIRTY(dqp))
> + if (flags & SYNC_TRYLOCK) {
> + if (!XFS_DQ_IS_DIRTY(dqp))
> continue;
> - }
> -
> - if (nowait) {
> - /*
> - * Try to acquire the dquot lock. We are NOT out of
> - * lock order, but we just don't want to wait for this
> - * lock, unless somebody wanted us to.
> - */
> - if (! xfs_qm_dqlock_nowait(dqp))
> + if (!xfs_qm_dqlock_nowait(dqp))
> continue;
> } else {
> xfs_dqlock(dqp);
> @@ -976,7 +959,7 @@ xfs_qm_sync(
> /* XXX a sentinel would be better */
> recl = XFS_QI_MPLRECLAIMS(mp);
> if (!xfs_dqflock_nowait(dqp)) {
> - if (nowait) {
> + if (flags & SYNC_TRYLOCK) {
> xfs_dqunlock(dqp);
> continue;
> }
> @@ -994,7 +977,6 @@ xfs_qm_sync(
> * Let go of the mplist lock. We don't want to hold it
> * across a disk write
> */
> - flush_flags = (nowait) ? XFS_QMOPT_DELWRI : XFS_QMOPT_SYNC;
> xfs_qm_mplist_unlock(mp);
> xfs_dqtrace_entry(dqp, "XQM_SYNC: DQFLUSH");
> error = xfs_qm_dqflush(dqp, flush_flags);
> Index: xfs/fs/xfs/linux-2.6/xfs_sync.h
> ===================================================================
> --- xfs.orig/fs/xfs/linux-2.6/xfs_sync.h 2009-05-27 13:07:58.997814418 +0200
> +++ xfs/fs/xfs/linux-2.6/xfs_sync.h 2009-05-27 13:08:19.922972203 +0200
> @@ -29,9 +29,8 @@ typedef struct xfs_sync_work {
> struct completion *w_completion;
> } xfs_sync_work_t;
>
> -#define SYNC_WAIT 0x0004 /* wait for i/o to complete */
> -#define SYNC_BDFLUSH 0x0008 /* BDFLUSH is calling -- don't block */
> -#define SYNC_TRYLOCK 0x0020 /* only try to lock inodes */
> +#define SYNC_WAIT 0x0001 /* wait for i/o to complete */
> +#define SYNC_TRYLOCK 0x0002 /* only try to lock inodes */
>
> int xfs_syncd_init(struct xfs_mount *mp);
> void xfs_syncd_stop(struct xfs_mount *mp);
>
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