[PATCH 2/7] Assign bdi in super_block

Jens Axboe
2009-09-14T09:37:39Z

We do this automatically in get_sb_bdev() from the set_bdev_super()
callback. Filesystems that have their own private backing_dev_info
must assign that in ->fill_super().

Note that ->s_bdi assignment is required for proper writeback!

Acked-by: Christoph Hellwig <hch@infradead.org>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
---
fs/btrfs/disk-io.c | 1 +
fs/fuse/inode.c | 2 ++
fs/super.c | 6 ++++++
fs/sync.c | 9 ++++++++-
fs/ubifs/super.c | 1 +
include/linux/fs.h | 1 +
6 files changed, 19 insertions(+), 1 deletions(-)

diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index 15831d5..8b81927 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -1600,6 +1600,7 @@ struct btrfs_root *open_ctree(struct super_block *sb,

sb->s_blocksize = 4096;
sb->s_blocksize_bits = blksize_bits(4096);
+ sb->s_bdi = &fs_info->bdi;

/*
* we set the i_size on the btree inode to the max possible int.
diff --git a/fs/fuse/inode.c b/fs/fuse/inode.c
index 4567db6..e5dbecd 100644
--- a/fs/fuse/inode.c
+++ b/fs/fuse/inode.c
@@ -894,6 +894,8 @@ static int fuse_fill_super(struct super_block *sb, void *data, int silent)
if (err)
goto err_put_conn;

+ sb->s_bdi = &fc->bdi;
+
/* Handle umasking inside the fuse code */
if (sb->s_flags & MS_POSIXACL)
fc->dont_mask = 1;
diff --git a/fs/super.c b/fs/super.c
index 9cda337..b03fea8 100644
--- a/fs/super.c
+++ b/fs/super.c
@@ -707,6 +707,12 @@ static int set_bdev_super(struct super_block *s, void *data)
{
s->s_bdev = data;
s->s_dev = s->s_bdev->bd_dev;
+
+ /*
+ * We set the bdi here to the queue backing, file systems can
+ * overwrite this in ->fill_super()
+ */
+ s->s_bdi = &bdev_get_queue(s->s_bdev)->backing_dev_info;
return 0;
}

diff --git a/fs/sync.c b/fs/sync.c
index 103cc7f..8582c34 100644
--- a/fs/sync.c
+++ b/fs/sync.c
@@ -27,6 +27,13 @@
*/
static int __sync_filesystem(struct super_block *sb, int wait)
{
+ /*
+ * This should be safe, as we require bdi backing to actually
+ * write out data in the first place
+ */
+ if (!sb->s_bdi)
+ return 0;
+
/* Avoid doing twice syncing and cache pruning for quota sync */
if (!wait) {
writeout_quota_sb(sb, -1);
@@ -101,7 +108,7 @@ restart:
spin_unlock(&sb_lock);

down_read(&sb->s_umount);
- if (!(sb->s_flags & MS_RDONLY) && sb->s_root)
+ if (!(sb->s_flags & MS_RDONLY) && sb->s_root && sb->s_bdi)
__sync_filesystem(sb, wait);
up_read(&sb->s_umount);

diff --git a/fs/ubifs/super.c b/fs/ubifs/super.c
index 51763aa..c4af069 100644
--- a/fs/ubifs/super.c
+++ b/fs/ubifs/super.c
@@ -1980,6 +1980,7 @@ static int ubifs_fill_super(struct super_block *sb, void *data, int silent)
if (err)
goto out_bdi;

+ sb->s_bdi = &c->bdi;
sb->s_fs_info = c;
sb->s_magic = UBIFS_SUPER_MAGIC;
sb->s_blocksize = UBIFS_BLOCK_SIZE;
diff --git a/include/linux/fs.h b/include/linux/fs.h
index a79f483..f998adc 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -1343,6 +1343,7 @@ struct super_block {
int s_nr_dentry_unused; /* # of dentry on lru */

struct block_device *s_bdev;
+ struct backing_dev_info *s_bdi;
struct mtd_info *s_mtd;
struct list_head s_instances;
struct quota_info s_dquot; /* Diskquota specific options */
--
1.6.4.1.207.g68ea