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 THE_NILFS_FLUSHED is
introduced, which is cleared whenever new logs are written and set
whenever the block device is flushed.
Signed-off-by: Andreas Rohner <andreas.rohner@xxxxxxx>
---
fs/nilfs2/file.c | 3 ++-
fs/nilfs2/ioctl.c | 3 ++-
fs/nilfs2/segment.c | 2 ++
fs/nilfs2/super.c | 8 ++++++++
fs/nilfs2/the_nilfs.h | 6 ++++++
5 files changed, 20 insertions(+), 2 deletions(-)
diff --git a/fs/nilfs2/file.c b/fs/nilfs2/file.c
index 2497815..7857460 100644
--- a/fs/nilfs2/file.c
+++ b/fs/nilfs2/file.c
@@ -56,7 +56,8 @@ 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)) {
+ if (!err && nilfs_test_opt(nilfs, BARRIER) &&
+ !test_and_set_nilfs_flushed(nilfs)) {
err = blkdev_issue_flush(inode->i_sb->s_bdev, GFP_KERNEL, NULL);
if (err != -EIO)
err = 0;
diff --git a/fs/nilfs2/ioctl.c b/fs/nilfs2/ioctl.c
index 422fb54..dc5d101 100644
--- a/fs/nilfs2/ioctl.c
+++ b/fs/nilfs2/ioctl.c
@@ -1022,7 +1022,8 @@ 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)) {
+ if (nilfs_test_opt(nilfs, BARRIER) &&
+ !test_and_set_nilfs_flushed(nilfs)) {
ret = blkdev_issue_flush(inode->i_sb->s_bdev, GFP_KERNEL, NULL);
if (ret == -EIO)
return ret;
diff --git a/fs/nilfs2/segment.c b/fs/nilfs2/segment.c
index a1a1916..54a6be1 100644
--- a/fs/nilfs2/segment.c
+++ b/fs/nilfs2/segment.c
@@ -1842,6 +1842,8 @@ static void nilfs_segctor_complete_write(struct nilfs_sc_info *sci)
nilfs_segctor_clear_metadata_dirty(sci);
} else
clear_bit(NILFS_SC_SUPER_ROOT, &sci->sc_flags);
+
+ clear_nilfs_flushed(nilfs);
}
static int nilfs_segctor_wait(struct nilfs_sc_info *sci)
diff --git a/fs/nilfs2/super.c b/fs/nilfs2/super.c
index 228f5bd..332fdf0 100644
--- a/fs/nilfs2/super.c
+++ b/fs/nilfs2/super.c
@@ -310,6 +310,7 @@ int nilfs_commit_super(struct super_block *sb, int flag)
nilfs->ns_sbsize));
}
clear_nilfs_sb_dirty(nilfs);
+ set_nilfs_flushed(nilfs);
return nilfs_sync_super(sb, flag);
}
@@ -514,6 +515,13 @@ static int nilfs_sync_fs(struct super_block *sb, int wait)
}
up_write(&nilfs->ns_sem);
+ if (wait && !err && nilfs_test_opt(nilfs, BARRIER) &&
+ !test_and_set_nilfs_flushed(nilfs)) {
+ err = blkdev_issue_flush(sb->s_bdev, GFP_KERNEL, NULL);
+ if (err != -EIO)
+ err = 0;
+ }
+
return err;
}
diff --git a/fs/nilfs2/the_nilfs.h b/fs/nilfs2/the_nilfs.h
index d01ead1..d12a8ce 100644
--- a/fs/nilfs2/the_nilfs.h
+++ b/fs/nilfs2/the_nilfs.h
@@ -41,6 +41,7 @@ enum {
THE_NILFS_DISCONTINUED, /* 'next' pointer chain has broken */
THE_NILFS_GC_RUNNING, /* gc process is running */
THE_NILFS_SB_DIRTY, /* super block is dirty */
+ THE_NILFS_FLUSHED, /* volatile data was flushed to disk */
};
/**
@@ -202,6 +203,10 @@ struct the_nilfs {
};
#define THE_NILFS_FNS(bit, name) \
+static inline int test_and_set_nilfs_##name(struct the_nilfs *nilfs) \
+{ \
+ return test_and_set_bit(THE_NILFS_##bit, &(nilfs)->ns_flags); \
+} \
static inline void set_nilfs_##name(struct the_nilfs *nilfs) \
{ \
set_bit(THE_NILFS_##bit, &(nilfs)->ns_flags); \
@@ -219,6 +224,7 @@ THE_NILFS_FNS(INIT, init)
THE_NILFS_FNS(DISCONTINUED, discontinued)
THE_NILFS_FNS(GC_RUNNING, gc_running)
THE_NILFS_FNS(SB_DIRTY, sb_dirty)
+THE_NILFS_FNS(FLUSHED, flushed)
/*
* Mount option operations
--
2.1.0
--
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