* avoid taking the iolock in fsync unless actually needed v2 @ 2021-01-22 16:46 Christoph Hellwig 2021-01-22 16:46 ` [PATCH 1/2] xfs: refactor xfs_file_fsync Christoph Hellwig 2021-01-22 16:46 ` [PATCH 2/2] xfs: reduce ilock acquisitions in xfs_file_fsync Christoph Hellwig 0 siblings, 2 replies; 12+ messages in thread From: Christoph Hellwig @ 2021-01-22 16:46 UTC (permalink / raw) To: linux-xfs Hi all, this series avoids taking the iolock in fsync if there is no dirty metadata. Changes since v1: - add a comment explaining the ipincount check ^ permalink raw reply [flat|nested] 12+ messages in thread
* [PATCH 1/2] xfs: refactor xfs_file_fsync 2021-01-22 16:46 avoid taking the iolock in fsync unless actually needed v2 Christoph Hellwig @ 2021-01-22 16:46 ` Christoph Hellwig 2021-01-22 21:08 ` Dave Chinner 2021-01-22 16:46 ` [PATCH 2/2] xfs: reduce ilock acquisitions in xfs_file_fsync Christoph Hellwig 1 sibling, 1 reply; 12+ messages in thread From: Christoph Hellwig @ 2021-01-22 16:46 UTC (permalink / raw) To: linux-xfs; +Cc: Brian Foster Factor out the log syncing logic into two helpers to make the code easier to read and more maintainable. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Brian Foster <bfoster@redhat.com> --- fs/xfs/xfs_file.c | 81 +++++++++++++++++++++++++++++------------------ 1 file changed, 50 insertions(+), 31 deletions(-) diff --git a/fs/xfs/xfs_file.c b/fs/xfs/xfs_file.c index 39695b59dfcc92..588232c77f11e0 100644 --- a/fs/xfs/xfs_file.c +++ b/fs/xfs/xfs_file.c @@ -118,6 +118,54 @@ xfs_dir_fsync( return xfs_log_force_inode(ip); } +static xfs_lsn_t +xfs_fsync_lsn( + struct xfs_inode *ip, + bool datasync) +{ + if (!xfs_ipincount(ip)) + return 0; + if (datasync && !(ip->i_itemp->ili_fsync_fields & ~XFS_ILOG_TIMESTAMP)) + return 0; + return ip->i_itemp->ili_last_lsn; +} + +/* + * All metadata updates are logged, which means that we just have to flush the + * log up to the latest LSN that touched the inode. + * + * If we have concurrent fsync/fdatasync() calls, we need them to all block on + * the log force before we clear the ili_fsync_fields field. This ensures that + * we don't get a racing sync operation that does not wait for the metadata to + * hit the journal before returning. If we race with clearing ili_fsync_fields, + * then all that will happen is the log force will do nothing as the lsn will + * already be on disk. We can't race with setting ili_fsync_fields because that + * is done under XFS_ILOCK_EXCL, and that can't happen because we hold the lock + * shared until after the ili_fsync_fields is cleared. + */ +static int +xfs_fsync_flush_log( + struct xfs_inode *ip, + bool datasync, + int *log_flushed) +{ + int error = 0; + xfs_lsn_t lsn; + + xfs_ilock(ip, XFS_ILOCK_SHARED); + lsn = xfs_fsync_lsn(ip, datasync); + if (lsn) { + error = xfs_log_force_lsn(ip->i_mount, lsn, XFS_LOG_SYNC, + log_flushed); + + spin_lock(&ip->i_itemp->ili_lock); + ip->i_itemp->ili_fsync_fields = 0; + spin_unlock(&ip->i_itemp->ili_lock); + } + xfs_iunlock(ip, XFS_ILOCK_SHARED); + return error; +} + STATIC int xfs_file_fsync( struct file *file, @@ -125,13 +173,10 @@ xfs_file_fsync( loff_t end, int datasync) { - struct inode *inode = file->f_mapping->host; - struct xfs_inode *ip = XFS_I(inode); - struct xfs_inode_log_item *iip = ip->i_itemp; + struct xfs_inode *ip = XFS_I(file->f_mapping->host); struct xfs_mount *mp = ip->i_mount; int error = 0; int log_flushed = 0; - xfs_lsn_t lsn = 0; trace_xfs_file_fsync(ip); @@ -155,33 +200,7 @@ xfs_file_fsync( else if (mp->m_logdev_targp != mp->m_ddev_targp) xfs_blkdev_issue_flush(mp->m_ddev_targp); - /* - * All metadata updates are logged, which means that we just have to - * flush the log up to the latest LSN that touched the inode. If we have - * concurrent fsync/fdatasync() calls, we need them to all block on the - * log force before we clear the ili_fsync_fields field. This ensures - * that we don't get a racing sync operation that does not wait for the - * metadata to hit the journal before returning. If we race with - * clearing the ili_fsync_fields, then all that will happen is the log - * force will do nothing as the lsn will already be on disk. We can't - * race with setting ili_fsync_fields because that is done under - * XFS_ILOCK_EXCL, and that can't happen because we hold the lock shared - * until after the ili_fsync_fields is cleared. - */ - xfs_ilock(ip, XFS_ILOCK_SHARED); - if (xfs_ipincount(ip)) { - if (!datasync || - (iip->ili_fsync_fields & ~XFS_ILOG_TIMESTAMP)) - lsn = iip->ili_last_lsn; - } - - if (lsn) { - error = xfs_log_force_lsn(mp, lsn, XFS_LOG_SYNC, &log_flushed); - spin_lock(&iip->ili_lock); - iip->ili_fsync_fields = 0; - spin_unlock(&iip->ili_lock); - } - xfs_iunlock(ip, XFS_ILOCK_SHARED); + error = xfs_fsync_flush_log(ip, datasync, &log_flushed); /* * If we only have a single device, and the log force about was -- 2.29.2 ^ permalink raw reply related [flat|nested] 12+ messages in thread
* Re: [PATCH 1/2] xfs: refactor xfs_file_fsync 2021-01-22 16:46 ` [PATCH 1/2] xfs: refactor xfs_file_fsync Christoph Hellwig @ 2021-01-22 21:08 ` Dave Chinner 0 siblings, 0 replies; 12+ messages in thread From: Dave Chinner @ 2021-01-22 21:08 UTC (permalink / raw) To: Christoph Hellwig; +Cc: linux-xfs, Brian Foster On Fri, Jan 22, 2021 at 05:46:42PM +0100, Christoph Hellwig wrote: > Factor out the log syncing logic into two helpers to make the code easier > to read and more maintainable. > > Signed-off-by: Christoph Hellwig <hch@lst.de> > Reviewed-by: Brian Foster <bfoster@redhat.com> LGTM. Reviewed-by: Dave Chinner <dchinner@redhat.com> -- Dave Chinner david@fromorbit.com ^ permalink raw reply [flat|nested] 12+ messages in thread
* [PATCH 2/2] xfs: reduce ilock acquisitions in xfs_file_fsync 2021-01-22 16:46 avoid taking the iolock in fsync unless actually needed v2 Christoph Hellwig 2021-01-22 16:46 ` [PATCH 1/2] xfs: refactor xfs_file_fsync Christoph Hellwig @ 2021-01-22 16:46 ` Christoph Hellwig 2021-01-22 21:08 ` Dave Chinner 2021-01-25 13:16 ` Brian Foster 1 sibling, 2 replies; 12+ messages in thread From: Christoph Hellwig @ 2021-01-22 16:46 UTC (permalink / raw) To: linux-xfs If the inode is not pinned by the time fsync is called we don't need the ilock to protect against concurrent clearing of ili_fsync_fields as the inode won't need a log flush or clearing of these fields. Not taking the iolock allows for full concurrency of fsync and thus O_DSYNC completions with io_uring/aio write submissions. Signed-off-by: Christoph Hellwig <hch@lst.de> --- fs/xfs/xfs_file.c | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-) diff --git a/fs/xfs/xfs_file.c b/fs/xfs/xfs_file.c index 588232c77f11e0..ffe2d7c37e26cd 100644 --- a/fs/xfs/xfs_file.c +++ b/fs/xfs/xfs_file.c @@ -200,7 +200,14 @@ xfs_file_fsync( else if (mp->m_logdev_targp != mp->m_ddev_targp) xfs_blkdev_issue_flush(mp->m_ddev_targp); - error = xfs_fsync_flush_log(ip, datasync, &log_flushed); + /* + * Any inode that has dirty modifications in the log is pinned. The + * racy check here for a pinned inode while not catch modifications + * that happen concurrently to the fsync call, but fsync semantics + * only require to sync previously completed I/O. + */ + if (xfs_ipincount(ip)) + error = xfs_fsync_flush_log(ip, datasync, &log_flushed); /* * If we only have a single device, and the log force about was -- 2.29.2 ^ permalink raw reply related [flat|nested] 12+ messages in thread
* Re: [PATCH 2/2] xfs: reduce ilock acquisitions in xfs_file_fsync 2021-01-22 16:46 ` [PATCH 2/2] xfs: reduce ilock acquisitions in xfs_file_fsync Christoph Hellwig @ 2021-01-22 21:08 ` Dave Chinner 2021-01-23 6:41 ` Christoph Hellwig 2021-01-25 13:16 ` Brian Foster 1 sibling, 1 reply; 12+ messages in thread From: Dave Chinner @ 2021-01-22 21:08 UTC (permalink / raw) To: Christoph Hellwig; +Cc: linux-xfs On Fri, Jan 22, 2021 at 05:46:43PM +0100, Christoph Hellwig wrote: > If the inode is not pinned by the time fsync is called we don't need the > ilock to protect against concurrent clearing of ili_fsync_fields as the > inode won't need a log flush or clearing of these fields. Not taking > the iolock allows for full concurrency of fsync and thus O_DSYNC > completions with io_uring/aio write submissions. > > Signed-off-by: Christoph Hellwig <hch@lst.de> Code looks good, so Reviewed-by: Dave Chinner <dchinner@redhat.com> But it makes me wonder... That is, we already elide the call to generic_write_sync() in direct IO in the case that the device supports FUA and it's a pure overwrite with no dirty metadata on the inode. Hence for a lot of storage and AIO/io_uring+DIO w/ O_DSYNC workloads we're already eliding this fsync-based lock cycle. In the case where we can't do a REQ_FUA IO because it is not supported by the device, then don't we really only need a cache flush at IO completion rather than the full generic_write_sync() call path? That would provide this optimisation to all the filesystems using iomap_dio_rw(), not just XFS.... In fact, I wonder if we need to do anything other than just use REQ_FUA unconditionally in iomap for this situation, as the block layer will translate REQ_FUA to a write+post-flush if the device doesn't support FUA writes directly. You're thoughts on that, Christoph? Cheers, Dave. -- Dave Chinner david@fromorbit.com ^ permalink raw reply [flat|nested] 12+ messages in thread
* Re: [PATCH 2/2] xfs: reduce ilock acquisitions in xfs_file_fsync 2021-01-22 21:08 ` Dave Chinner @ 2021-01-23 6:41 ` Christoph Hellwig 2021-01-26 6:56 ` Christoph Hellwig 0 siblings, 1 reply; 12+ messages in thread From: Christoph Hellwig @ 2021-01-23 6:41 UTC (permalink / raw) To: Dave Chinner; +Cc: Christoph Hellwig, linux-xfs On Sat, Jan 23, 2021 at 08:08:01AM +1100, Dave Chinner wrote: > That is, we already elide the call to generic_write_sync() in direct > IO in the case that the device supports FUA and it's a pure > overwrite with no dirty metadata on the inode. Hence for a lot of > storage and AIO/io_uring+DIO w/ O_DSYNC workloads we're already > eliding this fsync-based lock cycle. > > In the case where we can't do a REQ_FUA IO because it is not > supported by the device, then don't we really only need a cache > flush at IO completion rather than the full generic_write_sync() > call path? That would provide this optimisation to all the > filesystems using iomap_dio_rw(), not just XFS.... > > In fact, I wonder if we need to do anything other than just use > REQ_FUA unconditionally in iomap for this situation, as the block > layer will translate REQ_FUA to a write+post-flush if the device > doesn't support FUA writes directly. > > You're thoughts on that, Christoph? For the pure overwrite O_DIRECT + O_DSYNC case we'd get away with just a flush. And using REQ_FUA will get us there, so it might be worth a try. ^ permalink raw reply [flat|nested] 12+ messages in thread
* Re: [PATCH 2/2] xfs: reduce ilock acquisitions in xfs_file_fsync 2021-01-23 6:41 ` Christoph Hellwig @ 2021-01-26 6:56 ` Christoph Hellwig 0 siblings, 0 replies; 12+ messages in thread From: Christoph Hellwig @ 2021-01-26 6:56 UTC (permalink / raw) To: Dave Chinner; +Cc: Christoph Hellwig, linux-xfs On Sat, Jan 23, 2021 at 07:41:39AM +0100, Christoph Hellwig wrote: > > In fact, I wonder if we need to do anything other than just use > > REQ_FUA unconditionally in iomap for this situation, as the block > > layer will translate REQ_FUA to a write+post-flush if the device > > doesn't support FUA writes directly. > > > > You're thoughts on that, Christoph? > > For the pure overwrite O_DIRECT + O_DSYNC case we'd get away with just > a flush. And using REQ_FUA will get us there, so it might be worth > a try. And looking at this a little more, while just using REQ_FUA would work it would be rather suboptimal for many cases, as the block layer flush state machine would do a flush for every bio. So for each O_DIRECT + O_DSYNC write that generates more than one bio we'd grow extra flushes. ^ permalink raw reply [flat|nested] 12+ messages in thread
* Re: [PATCH 2/2] xfs: reduce ilock acquisitions in xfs_file_fsync 2021-01-22 16:46 ` [PATCH 2/2] xfs: reduce ilock acquisitions in xfs_file_fsync Christoph Hellwig 2021-01-22 21:08 ` Dave Chinner @ 2021-01-25 13:16 ` Brian Foster 2021-01-28 8:00 ` Christoph Hellwig 1 sibling, 1 reply; 12+ messages in thread From: Brian Foster @ 2021-01-25 13:16 UTC (permalink / raw) To: Christoph Hellwig; +Cc: linux-xfs On Fri, Jan 22, 2021 at 05:46:43PM +0100, Christoph Hellwig wrote: > If the inode is not pinned by the time fsync is called we don't need the > ilock to protect against concurrent clearing of ili_fsync_fields as the > inode won't need a log flush or clearing of these fields. Not taking > the iolock allows for full concurrency of fsync and thus O_DSYNC > completions with io_uring/aio write submissions. > > Signed-off-by: Christoph Hellwig <hch@lst.de> > --- > fs/xfs/xfs_file.c | 9 ++++++++- > 1 file changed, 8 insertions(+), 1 deletion(-) > > diff --git a/fs/xfs/xfs_file.c b/fs/xfs/xfs_file.c > index 588232c77f11e0..ffe2d7c37e26cd 100644 > --- a/fs/xfs/xfs_file.c > +++ b/fs/xfs/xfs_file.c > @@ -200,7 +200,14 @@ xfs_file_fsync( > else if (mp->m_logdev_targp != mp->m_ddev_targp) > xfs_blkdev_issue_flush(mp->m_ddev_targp); > > - error = xfs_fsync_flush_log(ip, datasync, &log_flushed); > + /* > + * Any inode that has dirty modifications in the log is pinned. The > + * racy check here for a pinned inode while not catch modifications s/while/will/ ? Otherwise looks good: Reviewed-by: Brian Foster <bfoster@redhat.com> > + * that happen concurrently to the fsync call, but fsync semantics > + * only require to sync previously completed I/O. > + */ > + if (xfs_ipincount(ip)) > + error = xfs_fsync_flush_log(ip, datasync, &log_flushed); > > /* > * If we only have a single device, and the log force about was > -- > 2.29.2 > ^ permalink raw reply [flat|nested] 12+ messages in thread
* Re: [PATCH 2/2] xfs: reduce ilock acquisitions in xfs_file_fsync 2021-01-25 13:16 ` Brian Foster @ 2021-01-28 8:00 ` Christoph Hellwig 0 siblings, 0 replies; 12+ messages in thread From: Christoph Hellwig @ 2021-01-28 8:00 UTC (permalink / raw) To: Brian Foster; +Cc: Christoph Hellwig, linux-xfs On Mon, Jan 25, 2021 at 08:16:18AM -0500, Brian Foster wrote: > > - error = xfs_fsync_flush_log(ip, datasync, &log_flushed); > > + /* > > + * Any inode that has dirty modifications in the log is pinned. The > > + * racy check here for a pinned inode while not catch modifications > > s/while/will/ ? Yes. Darrick, can you fix this up when applying the patch, or do you want me to resend? ^ permalink raw reply [flat|nested] 12+ messages in thread
* avoid taking the iolock in fsync unless actually needed @ 2021-01-11 16:15 Christoph Hellwig 2021-01-11 16:15 ` [PATCH 1/2] xfs: refactor xfs_file_fsync Christoph Hellwig 0 siblings, 1 reply; 12+ messages in thread From: Christoph Hellwig @ 2021-01-11 16:15 UTC (permalink / raw) To: linux-xfs Hi all, this series avoids taking the iolock in fsync if there is no dirty metadata. ^ permalink raw reply [flat|nested] 12+ messages in thread
* [PATCH 1/2] xfs: refactor xfs_file_fsync 2021-01-11 16:15 avoid taking the iolock in fsync unless actually needed Christoph Hellwig @ 2021-01-11 16:15 ` Christoph Hellwig 2021-01-12 15:33 ` Brian Foster 0 siblings, 1 reply; 12+ messages in thread From: Christoph Hellwig @ 2021-01-11 16:15 UTC (permalink / raw) To: linux-xfs Factor out the log syncing logic into two helpers to make the code easier to read and more maintainable. Signed-off-by: Christoph Hellwig <hch@lst.de> --- fs/xfs/xfs_file.c | 81 +++++++++++++++++++++++++++++------------------ 1 file changed, 50 insertions(+), 31 deletions(-) diff --git a/fs/xfs/xfs_file.c b/fs/xfs/xfs_file.c index 5b0f93f738372d..414d856e2e755a 100644 --- a/fs/xfs/xfs_file.c +++ b/fs/xfs/xfs_file.c @@ -118,6 +118,54 @@ xfs_dir_fsync( return xfs_log_force_inode(ip); } +static xfs_lsn_t +xfs_fsync_lsn( + struct xfs_inode *ip, + bool datasync) +{ + if (!xfs_ipincount(ip)) + return 0; + if (datasync && !(ip->i_itemp->ili_fsync_fields & ~XFS_ILOG_TIMESTAMP)) + return 0; + return ip->i_itemp->ili_last_lsn; +} + +/* + * All metadata updates are logged, which means that we just have to flush the + * log up to the latest LSN that touched the inode. + * + * If we have concurrent fsync/fdatasync() calls, we need them to all block on + * the log force before we clear the ili_fsync_fields field. This ensures that + * we don't get a racing sync operation that does not wait for the metadata to + * hit the journal before returning. If we race with clearing ili_fsync_fields, + * then all that will happen is the log force will do nothing as the lsn will + * already be on disk. We can't race with setting ili_fsync_fields because that + * is done under XFS_ILOCK_EXCL, and that can't happen because we hold the lock + * shared until after the ili_fsync_fields is cleared. + */ +static int +xfs_fsync_flush_log( + struct xfs_inode *ip, + bool datasync, + int *log_flushed) +{ + int error = 0; + xfs_lsn_t lsn; + + xfs_ilock(ip, XFS_ILOCK_SHARED); + lsn = xfs_fsync_lsn(ip, datasync); + if (lsn) { + error = xfs_log_force_lsn(ip->i_mount, lsn, XFS_LOG_SYNC, + log_flushed); + + spin_lock(&ip->i_itemp->ili_lock); + ip->i_itemp->ili_fsync_fields = 0; + spin_unlock(&ip->i_itemp->ili_lock); + } + xfs_iunlock(ip, XFS_ILOCK_SHARED); + return error; +} + STATIC int xfs_file_fsync( struct file *file, @@ -125,13 +173,10 @@ xfs_file_fsync( loff_t end, int datasync) { - struct inode *inode = file->f_mapping->host; - struct xfs_inode *ip = XFS_I(inode); - struct xfs_inode_log_item *iip = ip->i_itemp; + struct xfs_inode *ip = XFS_I(file->f_mapping->host); struct xfs_mount *mp = ip->i_mount; int error = 0; int log_flushed = 0; - xfs_lsn_t lsn = 0; trace_xfs_file_fsync(ip); @@ -155,33 +200,7 @@ xfs_file_fsync( else if (mp->m_logdev_targp != mp->m_ddev_targp) xfs_blkdev_issue_flush(mp->m_ddev_targp); - /* - * All metadata updates are logged, which means that we just have to - * flush the log up to the latest LSN that touched the inode. If we have - * concurrent fsync/fdatasync() calls, we need them to all block on the - * log force before we clear the ili_fsync_fields field. This ensures - * that we don't get a racing sync operation that does not wait for the - * metadata to hit the journal before returning. If we race with - * clearing the ili_fsync_fields, then all that will happen is the log - * force will do nothing as the lsn will already be on disk. We can't - * race with setting ili_fsync_fields because that is done under - * XFS_ILOCK_EXCL, and that can't happen because we hold the lock shared - * until after the ili_fsync_fields is cleared. - */ - xfs_ilock(ip, XFS_ILOCK_SHARED); - if (xfs_ipincount(ip)) { - if (!datasync || - (iip->ili_fsync_fields & ~XFS_ILOG_TIMESTAMP)) - lsn = iip->ili_last_lsn; - } - - if (lsn) { - error = xfs_log_force_lsn(mp, lsn, XFS_LOG_SYNC, &log_flushed); - spin_lock(&iip->ili_lock); - iip->ili_fsync_fields = 0; - spin_unlock(&iip->ili_lock); - } - xfs_iunlock(ip, XFS_ILOCK_SHARED); + error = xfs_fsync_flush_log(ip, datasync, &log_flushed); /* * If we only have a single device, and the log force about was -- 2.29.2 ^ permalink raw reply related [flat|nested] 12+ messages in thread
* Re: [PATCH 1/2] xfs: refactor xfs_file_fsync 2021-01-11 16:15 ` [PATCH 1/2] xfs: refactor xfs_file_fsync Christoph Hellwig @ 2021-01-12 15:33 ` Brian Foster 2021-01-12 17:12 ` Christoph Hellwig 0 siblings, 1 reply; 12+ messages in thread From: Brian Foster @ 2021-01-12 15:33 UTC (permalink / raw) To: Christoph Hellwig; +Cc: linux-xfs On Mon, Jan 11, 2021 at 05:15:43PM +0100, Christoph Hellwig wrote: > Factor out the log syncing logic into two helpers to make the code easier > to read and more maintainable. > > Signed-off-by: Christoph Hellwig <hch@lst.de> > --- Looks fine, though it might be nice to find some commonality with xfs_log_force_inode(): Reviewed-by: Brian Foster <bfoster@redhat.com> > fs/xfs/xfs_file.c | 81 +++++++++++++++++++++++++++++------------------ > 1 file changed, 50 insertions(+), 31 deletions(-) > > diff --git a/fs/xfs/xfs_file.c b/fs/xfs/xfs_file.c > index 5b0f93f738372d..414d856e2e755a 100644 > --- a/fs/xfs/xfs_file.c > +++ b/fs/xfs/xfs_file.c > @@ -118,6 +118,54 @@ xfs_dir_fsync( > return xfs_log_force_inode(ip); > } > > +static xfs_lsn_t > +xfs_fsync_lsn( > + struct xfs_inode *ip, > + bool datasync) > +{ > + if (!xfs_ipincount(ip)) > + return 0; > + if (datasync && !(ip->i_itemp->ili_fsync_fields & ~XFS_ILOG_TIMESTAMP)) > + return 0; > + return ip->i_itemp->ili_last_lsn; > +} > + > +/* > + * All metadata updates are logged, which means that we just have to flush the > + * log up to the latest LSN that touched the inode. > + * > + * If we have concurrent fsync/fdatasync() calls, we need them to all block on > + * the log force before we clear the ili_fsync_fields field. This ensures that > + * we don't get a racing sync operation that does not wait for the metadata to > + * hit the journal before returning. If we race with clearing ili_fsync_fields, > + * then all that will happen is the log force will do nothing as the lsn will > + * already be on disk. We can't race with setting ili_fsync_fields because that > + * is done under XFS_ILOCK_EXCL, and that can't happen because we hold the lock > + * shared until after the ili_fsync_fields is cleared. > + */ > +static int > +xfs_fsync_flush_log( > + struct xfs_inode *ip, > + bool datasync, > + int *log_flushed) > +{ > + int error = 0; > + xfs_lsn_t lsn; > + > + xfs_ilock(ip, XFS_ILOCK_SHARED); > + lsn = xfs_fsync_lsn(ip, datasync); > + if (lsn) { > + error = xfs_log_force_lsn(ip->i_mount, lsn, XFS_LOG_SYNC, > + log_flushed); > + > + spin_lock(&ip->i_itemp->ili_lock); > + ip->i_itemp->ili_fsync_fields = 0; > + spin_unlock(&ip->i_itemp->ili_lock); > + } > + xfs_iunlock(ip, XFS_ILOCK_SHARED); > + return error; > +} > + > STATIC int > xfs_file_fsync( > struct file *file, > @@ -125,13 +173,10 @@ xfs_file_fsync( > loff_t end, > int datasync) > { > - struct inode *inode = file->f_mapping->host; > - struct xfs_inode *ip = XFS_I(inode); > - struct xfs_inode_log_item *iip = ip->i_itemp; > + struct xfs_inode *ip = XFS_I(file->f_mapping->host); > struct xfs_mount *mp = ip->i_mount; > int error = 0; > int log_flushed = 0; > - xfs_lsn_t lsn = 0; > > trace_xfs_file_fsync(ip); > > @@ -155,33 +200,7 @@ xfs_file_fsync( > else if (mp->m_logdev_targp != mp->m_ddev_targp) > xfs_blkdev_issue_flush(mp->m_ddev_targp); > > - /* > - * All metadata updates are logged, which means that we just have to > - * flush the log up to the latest LSN that touched the inode. If we have > - * concurrent fsync/fdatasync() calls, we need them to all block on the > - * log force before we clear the ili_fsync_fields field. This ensures > - * that we don't get a racing sync operation that does not wait for the > - * metadata to hit the journal before returning. If we race with > - * clearing the ili_fsync_fields, then all that will happen is the log > - * force will do nothing as the lsn will already be on disk. We can't > - * race with setting ili_fsync_fields because that is done under > - * XFS_ILOCK_EXCL, and that can't happen because we hold the lock shared > - * until after the ili_fsync_fields is cleared. > - */ > - xfs_ilock(ip, XFS_ILOCK_SHARED); > - if (xfs_ipincount(ip)) { > - if (!datasync || > - (iip->ili_fsync_fields & ~XFS_ILOG_TIMESTAMP)) > - lsn = iip->ili_last_lsn; > - } > - > - if (lsn) { > - error = xfs_log_force_lsn(mp, lsn, XFS_LOG_SYNC, &log_flushed); > - spin_lock(&iip->ili_lock); > - iip->ili_fsync_fields = 0; > - spin_unlock(&iip->ili_lock); > - } > - xfs_iunlock(ip, XFS_ILOCK_SHARED); > + error = xfs_fsync_flush_log(ip, datasync, &log_flushed); > > /* > * If we only have a single device, and the log force about was > -- > 2.29.2 > ^ permalink raw reply [flat|nested] 12+ messages in thread
* Re: [PATCH 1/2] xfs: refactor xfs_file_fsync 2021-01-12 15:33 ` Brian Foster @ 2021-01-12 17:12 ` Christoph Hellwig 0 siblings, 0 replies; 12+ messages in thread From: Christoph Hellwig @ 2021-01-12 17:12 UTC (permalink / raw) To: Brian Foster; +Cc: Christoph Hellwig, linux-xfs On Tue, Jan 12, 2021 at 10:33:47AM -0500, Brian Foster wrote: > Looks fine, though it might be nice to find some commonality with > xfs_log_force_inode(): The common logic is called xfs_log_force_lsn :) The fact that fsync checks and modifies ili_fsync_fields makes it rather impractival to share more code unfortunately. ^ permalink raw reply [flat|nested] 12+ messages in thread
end of thread, other threads:[~2021-01-28 8:03 UTC | newest] Thread overview: 12+ messages (download: mbox.gz / follow: Atom feed) -- links below jump to the message on this page -- 2021-01-22 16:46 avoid taking the iolock in fsync unless actually needed v2 Christoph Hellwig 2021-01-22 16:46 ` [PATCH 1/2] xfs: refactor xfs_file_fsync Christoph Hellwig 2021-01-22 21:08 ` Dave Chinner 2021-01-22 16:46 ` [PATCH 2/2] xfs: reduce ilock acquisitions in xfs_file_fsync Christoph Hellwig 2021-01-22 21:08 ` Dave Chinner 2021-01-23 6:41 ` Christoph Hellwig 2021-01-26 6:56 ` Christoph Hellwig 2021-01-25 13:16 ` Brian Foster 2021-01-28 8:00 ` Christoph Hellwig -- strict thread matches above, loose matches on Subject: below -- 2021-01-11 16:15 avoid taking the iolock in fsync unless actually needed Christoph Hellwig 2021-01-11 16:15 ` [PATCH 1/2] xfs: refactor xfs_file_fsync Christoph Hellwig 2021-01-12 15:33 ` Brian Foster 2021-01-12 17:12 ` Christoph Hellwig
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