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authorAndreas Rohner <andreas.rohner@gmx.net>2014-10-13 15:53:20 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2014-10-14 02:18:20 +0200
commite2c7617ae36b27f97643bfa08aabe27e630c1a76 (patch)
tree306dc0642ffbd8c4f837b7fbae960a49116053e6 /fs/nilfs2/the_nilfs.h
parent0f2a84f41aff6cefd1bc768738159d0cacea2f2d (diff)
downloadop-kernel-dev-e2c7617ae36b27f97643bfa08aabe27e630c1a76.zip
op-kernel-dev-e2c7617ae36b27f97643bfa08aabe27e630c1a76.tar.gz
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 <andreas.rohner@gmx.net> Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'fs/nilfs2/the_nilfs.h')
-rw-r--r--fs/nilfs2/the_nilfs.h22
1 files changed, 22 insertions, 0 deletions
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 */
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