From mboxrd@z Thu Jan 1 00:00:00 1970 From: Andreas Rohner Subject: [PATCH v5 1/1] nilfs2: add missing blkdev_issue_flush() to nilfs_sync_fs() Date: Sat, 13 Sep 2014 15:55:56 +0200 Message-ID: <1410616556-25943-2-git-send-email-andreas.rohner@gmx.net> References: <1410616556-25943-1-git-send-email-andreas.rohner@gmx.net> Return-path: In-Reply-To: <1410616556-25943-1-git-send-email-andreas.rohner-hi6Y0CQ0nG0@public.gmane.org> Sender: linux-nilfs-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-ID: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: linux-nilfs-u79uwXL29TY76Z2rM5mHXA@public.gmane.org Cc: Andreas Rohner 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 --- 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..5a530f3 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 == -EIO) + 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