nilfs2: get rid of bd_mount_sem use from nilfs

This will remove every bd_mount_sem use in nilfs.

The intended exclusion control was replaced by the previous patch
("nilfs2: correct exclusion control in nilfs_remount function") for
nilfs_remount(), and this patch will replace remains with a new mutex
that this inserts in nilfs object.

Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Cc: Christoph Hellwig <hch@infradead.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

diff --git a/fs/nilfs2/cpfile.c b/fs/nilfs2/cpfile.c
index 300f1cd..cadd36b 100644 (file)
--- a/fs/nilfs2/cpfile.c
+++ b/fs/nilfs2/cpfile.c
@@ -864,11 +864,11 @@ int nilfs_cpfile_change_cpmode(struct inode *cpfile, __u64 cno, int mode)
        case NILFS_CHECKPOINT:
                /*
                 * Check for protecting existing snapshot mounts:
-                * bd_mount_sem is used to make this operation atomic and
+                * ns_mount_mutex is used to make this operation atomic and
                 * exclusive with a new mount job.  Though it doesn't cover
                 * umount, it's enough for the purpose.
                 */
-               down(&nilfs->ns_bdev->bd_mount_sem);
+               mutex_lock(&nilfs->ns_mount_mutex);
                if (nilfs_checkpoint_is_mounted(nilfs, cno, 1)) {
                        /* Current implementation does not have to protect
                           plain read-only mounts since they are exclusive
@@ -877,7 +877,7 @@ int nilfs_cpfile_change_cpmode(struct inode *cpfile, __u64 cno, int mode)
                        ret = -EBUSY;
                } else
                        ret = nilfs_cpfile_clear_snapshot(cpfile, cno);
-               up(&nilfs->ns_bdev->bd_mount_sem);
+               mutex_unlock(&nilfs->ns_mount_mutex);
                return ret;
        case NILFS_SNAPSHOT:
                return nilfs_cpfile_set_snapshot(cpfile, cno);

diff --git a/fs/nilfs2/super.c b/fs/nilfs2/super.c
index f02762f..1777a34 100644 (file)
--- a/fs/nilfs2/super.c
+++ b/fs/nilfs2/super.c
@@ -764,7 +764,7 @@ int nilfs_store_magic_and_option(struct super_block *sb,
  * @silent: silent mode flag
  * @nilfs: the_nilfs struct
  *
- * This function is called exclusively by bd_mount_mutex.
+ * This function is called exclusively by nilfs->ns_mount_mutex.
  * So, the recovery process is protected from other simultaneous mounts.
  */
 static int
@@ -1105,7 +1105,7 @@ nilfs_get_sb(struct file_system_type *fs_type, int flags,
                goto failed;
        }
 
-       down(&sd.bdev->bd_mount_sem);
+       mutex_lock(&nilfs->ns_mount_mutex);
 
        if (!sd.cno) {
                /*
@@ -1164,7 +1164,7 @@ nilfs_get_sb(struct file_system_type *fs_type, int flags,
                need_to_close = 0;
        }
 
-       up(&sd.bdev->bd_mount_sem);
+       mutex_unlock(&nilfs->ns_mount_mutex);
        put_nilfs(nilfs);
        if (need_to_close)
                close_bdev_exclusive(sd.bdev, flags);
@@ -1172,7 +1172,7 @@ nilfs_get_sb(struct file_system_type *fs_type, int flags,
        return 0;
 
  failed_unlock:
-       up(&sd.bdev->bd_mount_sem);
+       mutex_unlock(&nilfs->ns_mount_mutex);
        put_nilfs(nilfs);
  failed:
        close_bdev_exclusive(sd.bdev, flags);
@@ -1181,14 +1181,14 @@ nilfs_get_sb(struct file_system_type *fs_type, int flags,
 
  cancel_new:
        /* Abandoning the newly allocated superblock */
-       up(&sd.bdev->bd_mount_sem);
+       mutex_unlock(&nilfs->ns_mount_mutex);
        put_nilfs(nilfs);
        up_write(&s->s_umount);
        deactivate_super(s);
        /*
         * deactivate_super() invokes close_bdev_exclusive().
         * We must finish all post-cleaning before this call;
-        * put_nilfs() and unlocking bd_mount_sem need the block device.
+        * put_nilfs() needs the block device.
         */
        return err;
 }

diff --git a/fs/nilfs2/the_nilfs.c b/fs/nilfs2/the_nilfs.c
index 06e8dfd..e4e5c78 100644 (file)
--- a/fs/nilfs2/the_nilfs.c
+++ b/fs/nilfs2/the_nilfs.c
@@ -73,6 +73,7 @@ static struct the_nilfs *alloc_nilfs(struct block_device *bdev)
        atomic_set(&nilfs->ns_ndirtyblks, 0);
        init_rwsem(&nilfs->ns_sem);
        init_rwsem(&nilfs->ns_super_sem);
+       mutex_init(&nilfs->ns_mount_mutex);
        mutex_init(&nilfs->ns_writer_mutex);
        INIT_LIST_HEAD(&nilfs->ns_list);
        INIT_LIST_HEAD(&nilfs->ns_supers);

diff --git a/fs/nilfs2/the_nilfs.h b/fs/nilfs2/the_nilfs.h
index d0cf4fb..e8adbff 100644 (file)
--- a/fs/nilfs2/the_nilfs.h
+++ b/fs/nilfs2/the_nilfs.h
@@ -49,6 +49,7 @@ enum {
  * @ns_writer: back pointer to writable nilfs_sb_info
  * @ns_sem: semaphore for shared states
  * @ns_super_sem: semaphore for global operations across super block instances
+ * @ns_mount_mutex: mutex protecting mount process of nilfs
  * @ns_writer_mutex: mutex protecting ns_writer attach/detach
  * @ns_writer_refcount: number of referrers on ns_writer
  * @ns_current: back pointer to current mount
@@ -98,6 +99,7 @@ struct the_nilfs {
        struct nilfs_sb_info   *ns_writer;
        struct rw_semaphore     ns_sem;
        struct rw_semaphore     ns_super_sem;
+       struct mutex            ns_mount_mutex;
        struct mutex            ns_writer_mutex;
        atomic_t                ns_writer_refcount;