From e2c7617ae36b27f97643bfa08aabe27e630c1a76 Mon Sep 17 00:00:00 2001 From: Andreas Rohner Date: Mon, 13 Oct 2014 15:53:20 -0700 Subject: nilfs2: add missing blkdev_issue_flush() to nilfs_sync_fs() 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 Signed-off-by: Ryusuke Konishi Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- fs/nilfs2/the_nilfs.h | 22 ++++++++++++++++++++++ 1 file changed, 22 insertions(+) (limited to 'fs/nilfs2/the_nilfs.h') diff --git a/fs/nilfs2/the_nilfs.h b/fs/nilfs2/the_nilfs.h index d01ead1bea9a..23778d385836 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 */ -- cgit v1.2.3