9p: add bdi backing to mount session

This ensures that dirty data gets flushed properly.

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>

3 files changed, 13 insertions, 0 deletions

diff --git a/fs/9p/v9fs.c b/fs/9p/v9fs.c
index 5c5bc8480070..f8b86e92cd66 100644
--- a/fs/9p/v9fs.c
+++ b/fs/9p/v9fs.c
@@ -238,6 +238,13 @@ struct p9_fid *v9fs_session_init(struct v9fs_session_info *v9ses,
                 return ERR_PTR(-ENOMEM);
         }
 
+        rc = bdi_setup_and_register(&v9ses->bdi, "9p", BDI_CAP_MAP_COPY);
+        if (rc) {
+                __putname(v9ses->aname);
+                __putname(v9ses->uname);
+                return ERR_PTR(rc);
+        }
+
         spin_lock(&v9fs_sessionlist_lock);
         list_add(&v9ses->slist, &v9fs_sessionlist);
         spin_unlock(&v9fs_sessionlist_lock);
@@ -301,6 +308,7 @@ struct p9_fid *v9fs_session_init(struct v9fs_session_info *v9ses,
         return fid;
 
 error:
+        bdi_destroy(&v9ses->bdi);
         return ERR_PTR(retval);
 }
 
@@ -326,6 +334,8 @@ void v9fs_session_close(struct v9fs_session_info *v9ses)
         __putname(v9ses->uname);
         __putname(v9ses->aname);
 
+        bdi_destroy(&v9ses->bdi);
+
         spin_lock(&v9fs_sessionlist_lock);
         list_del(&v9ses->slist);
         spin_unlock(&v9fs_sessionlist_lock);
diff --git a/fs/9p/v9fs.h b/fs/9p/v9fs.h
index a0a8d3dd1361..bec4d0bcb458 100644
--- a/fs/9p/v9fs.h
+++ b/fs/9p/v9fs.h
@@ -20,6 +20,7 @@
  *  Boston, MA  02111-1301  USA
  *
  */
+#include <linux/backing-dev.h>
 
 /**
  * enum p9_session_flags - option flags for each 9P session
@@ -102,6 +103,7 @@ struct v9fs_session_info {
         u32 uid;                /* if ACCESS_SINGLE, the uid that has access */
         struct p9_client *clnt; /* 9p client */
         struct list_head slist; /* list of sessions registered with v9fs */
+        struct backing_dev_info bdi;
 };
 
 struct p9_fid *v9fs_session_init(struct v9fs_session_info *, const char *,
diff --git a/fs/9p/vfs_super.c b/fs/9p/vfs_super.c
index 491108bd6e0d..806da5d3b3a0 100644
--- a/fs/9p/vfs_super.c
+++ b/fs/9p/vfs_super.c
@@ -77,6 +77,7 @@ v9fs_fill_super(struct super_block *sb, struct v9fs_session_info *v9ses,
         sb->s_blocksize = 1 << sb->s_blocksize_bits;
         sb->s_magic = V9FS_MAGIC;
         sb->s_op = &v9fs_super_ops;
+        sb->s_bdi = &v9ses->bdi;
 
         sb->s_flags = flags | MS_ACTIVE | MS_SYNCHRONOUS | MS_DIRSYNC |
             MS_NOATIME;