From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ryusuke Konishi Subject: Re: [PATCH v6 1/1] nilfs2: add missing blkdev_issue_flush() to nilfs_sync_fs() Date: Sun, 14 Sep 2014 02:06:09 +0900 (JST) Message-ID: <20140914.020609.1854857348878379764.konishi.ryusuke@lab.ntt.co.jp> References: <1410619073-26360-1-git-send-email-andreas.rohner@gmx.net> <1410619073-26360-2-git-send-email-andreas.rohner@gmx.net> Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Return-path: DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=sender:date:message-id:to:cc:subject:from:in-reply-to:references :mime-version:content-type:content-transfer-encoding; bh=D4Y0Ys339BWpj2KPRoI5pFQaDY5MfVcekbJQM/8pLOU=; b=NJb8Z97KgLAPYfP96tsUJD6sS85lWVfG78qPajTIl7WeAHPvl72nE71v48jKOp5EWo M/rJb4s9zQ6MWOBswFHEySth4vFywZxkGzqy0WbysV8hNG4V+aNaXc3SEmy2rddk54tB 9RagjQqqivT3mjLxewEiBbZTP9m1iOJtLxwVG7WupMwmueAZs0FBee0HTzE0v6wTtXsA 3maTt9cQfJj5nNXXst0Y+OsGclnIUu2cm/DtP/3UFP+B0bBeP4fKS5B2ChCJs1TvDRSZ RUNXH/3ToEUXDLxCgFEU0egWk3RBGZ8y0NJhV788ig0ruwzr7fAFeesZqY8xJSsRa7SS U5Rg== In-Reply-To: <1410619073-26360-2-git-send-email-andreas.rohner-hi6Y0CQ0nG0@public.gmane.org> Sender: linux-nilfs-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-ID: Content-Type: Text/Plain; charset="us-ascii" To: Andreas Rohner Cc: linux-nilfs-u79uwXL29TY76Z2rM5mHXA@public.gmane.org On Sat, 13 Sep 2014 16:37:53 +0200, Andreas Rohner wrote: > Under normal circumstances nilfs_sync_fs() writes out the super block, > which causes a flush of the underlying block device. But this depends on > the THE_NILFS_SB_DIRTY flag, which is only set if the pointer to the > last segment crosses a segment boundary. So if only a small amount of > data is written before the call to nilfs_sync_fs(), no flush of the > block device occurs. > > In the above case an additional call to blkdev_issue_flush() is needed. > To prevent unnecessary overhead, the new flag nilfs->ns_flushed_device > is introduced, which is cleared whenever new logs are written and set > whenever the block device is flushed. For convenience the function > nilfs_flush_device() is added, which contains the above logic. > > Signed-off-by: Andreas Rohner Applied, thank you! Ryusuke Konishi > --- > fs/nilfs2/file.c | 8 +++----- > fs/nilfs2/ioctl.c | 8 +++----- > fs/nilfs2/segment.c | 3 +++ > fs/nilfs2/super.c | 6 ++++++ > fs/nilfs2/the_nilfs.h | 22 ++++++++++++++++++++++ > 5 files changed, 37 insertions(+), 10 deletions(-) > > diff --git a/fs/nilfs2/file.c b/fs/nilfs2/file.c > index 2497815..e9e3325 100644 > --- a/fs/nilfs2/file.c > +++ b/fs/nilfs2/file.c > @@ -56,11 +56,9 @@ int nilfs_sync_file(struct file *file, loff_t start, loff_t end, int datasync) > mutex_unlock(&inode->i_mutex); > > nilfs = inode->i_sb->s_fs_info; > - if (!err && nilfs_test_opt(nilfs, BARRIER)) { > - err = blkdev_issue_flush(inode->i_sb->s_bdev, GFP_KERNEL, NULL); > - if (err != -EIO) > - err = 0; > - } > + if (!err) > + err = nilfs_flush_device(nilfs); > + > return err; > } > > diff --git a/fs/nilfs2/ioctl.c b/fs/nilfs2/ioctl.c > index 422fb54..9a20e51 100644 > --- a/fs/nilfs2/ioctl.c > +++ b/fs/nilfs2/ioctl.c > @@ -1022,11 +1022,9 @@ static int nilfs_ioctl_sync(struct inode *inode, struct file *filp, > return ret; > > nilfs = inode->i_sb->s_fs_info; > - if (nilfs_test_opt(nilfs, BARRIER)) { > - ret = blkdev_issue_flush(inode->i_sb->s_bdev, GFP_KERNEL, NULL); > - if (ret == -EIO) > - return ret; > - } > + ret = nilfs_flush_device(nilfs); > + if (ret < 0) > + return ret; > > if (argp != NULL) { > down_read(&nilfs->ns_segctor_sem); > diff --git a/fs/nilfs2/segment.c b/fs/nilfs2/segment.c > index a1a1916..0b7d2ca 100644 > --- a/fs/nilfs2/segment.c > +++ b/fs/nilfs2/segment.c > @@ -1833,6 +1833,7 @@ static void nilfs_segctor_complete_write(struct nilfs_sc_info *sci) > nilfs_set_next_segment(nilfs, segbuf); > > if (update_sr) { > + nilfs->ns_flushed_device = 0; > nilfs_set_last_segment(nilfs, segbuf->sb_pseg_start, > segbuf->sb_sum.seg_seq, nilfs->ns_cno++); > > @@ -2216,6 +2217,8 @@ int nilfs_construct_dsync_segment(struct super_block *sb, struct inode *inode, > sci->sc_dsync_end = end; > > err = nilfs_segctor_do_construct(sci, SC_LSEG_DSYNC); > + if (!err) > + nilfs->ns_flushed_device = 0; > > nilfs_transaction_unlock(sb); > return err; > diff --git a/fs/nilfs2/super.c b/fs/nilfs2/super.c > index 228f5bd..2e5b3ec 100644 > --- a/fs/nilfs2/super.c > +++ b/fs/nilfs2/super.c > @@ -310,6 +310,9 @@ int nilfs_commit_super(struct super_block *sb, int flag) > nilfs->ns_sbsize)); > } > clear_nilfs_sb_dirty(nilfs); > + nilfs->ns_flushed_device = 1; > + /* make sure store to ns_flushed_device cannot be reordered */ > + smp_wmb(); > return nilfs_sync_super(sb, flag); > } > > @@ -514,6 +517,9 @@ static int nilfs_sync_fs(struct super_block *sb, int wait) > } > up_write(&nilfs->ns_sem); > > + if (!err) > + err = nilfs_flush_device(nilfs); > + > return err; > } > > diff --git a/fs/nilfs2/the_nilfs.h b/fs/nilfs2/the_nilfs.h > index d01ead1..23778d3 100644 > --- a/fs/nilfs2/the_nilfs.h > +++ b/fs/nilfs2/the_nilfs.h > @@ -46,6 +46,7 @@ enum { > /** > * struct the_nilfs - struct to supervise multiple nilfs mount points > * @ns_flags: flags > + * @ns_flushed_device: flag indicating if all volatile data was flushed > * @ns_bdev: block device > * @ns_sem: semaphore for shared states > * @ns_snapshot_mount_mutex: mutex to protect snapshot mounts > @@ -103,6 +104,7 @@ enum { > */ > struct the_nilfs { > unsigned long ns_flags; > + int ns_flushed_device; > > struct block_device *ns_bdev; > struct rw_semaphore ns_sem; > @@ -371,4 +373,24 @@ static inline int nilfs_segment_is_active(struct the_nilfs *nilfs, __u64 n) > return n == nilfs->ns_segnum || n == nilfs->ns_nextnum; > } > > +static inline int nilfs_flush_device(struct the_nilfs *nilfs) > +{ > + int err; > + > + if (!nilfs_test_opt(nilfs, BARRIER) || nilfs->ns_flushed_device) > + return 0; > + > + nilfs->ns_flushed_device = 1; > + /* > + * the store to ns_flushed_device must not be reordered after > + * blkdev_issue_flush(). > + */ > + smp_wmb(); > + > + err = blkdev_issue_flush(nilfs->ns_bdev, GFP_KERNEL, NULL); > + if (err != -EIO) > + err = 0; > + return err; > +} > + > #endif /* _THE_NILFS_H */ > -- > 2.1.0 > > -- > To unsubscribe from this list: send the line "unsubscribe linux-nilfs" in > the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org > More majordomo info at http://vger.kernel.org/majordomo-info.html -- To unsubscribe from this list: send the line "unsubscribe linux-nilfs" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html