fs: move mark_files_ro into file_table.c

[firefly-linux-kernel-4.4.55.git] / fs / super.c

diff --git a/fs/super.c b/fs/super.c
index 786fe7d72790ac5646197224fc2af88222dade0a..c170551c23fe0a2af1e24f8a9b206c3b0f96d7ce 100644 (file)
--- a/fs/super.c
+++ b/fs/super.c
@@ -207,6 +207,34 @@ void deactivate_super(struct super_block *s)
 
 EXPORT_SYMBOL(deactivate_super);
 
+/**
+ *     deactivate_locked_super -       drop an active reference to superblock
+ *     @s: superblock to deactivate
+ *
+ *     Equivalent of up_write(&s->s_umount); deactivate_super(s);, except that
+ *     it does not unlock it until it's all over.  As the result, it's safe to
+ *     use to dispose of new superblock on ->get_sb() failure exits - nobody
+ *     will see the sucker until it's all over.  Equivalent using up_write +
+ *     deactivate_super is safe for that purpose only if superblock is either
+ *     safe to use or has NULL ->s_root when we unlock.
+ */
+void deactivate_locked_super(struct super_block *s)
+{
+       struct file_system_type *fs = s->s_type;
+       if (atomic_dec_and_lock(&s->s_active, &sb_lock)) {
+               s->s_count -= S_BIAS-1;
+               spin_unlock(&sb_lock);
+               vfs_dq_off(s, 0);
+               fs->kill_sb(s);
+               put_filesystem(fs);
+               put_super(s);
+       } else {
+               up_write(&s->s_umount);
+       }
+}
+
+EXPORT_SYMBOL(deactivate_locked_super);
+
 /**
  *     grab_super - acquire an active reference
  *     @s: reference we are trying to make active
@@ -587,45 +615,6 @@ out:
        return err;
 }
 
-/**
- *     mark_files_ro - mark all files read-only
- *     @sb: superblock in question
- *
- *     All files are marked read-only.  We don't care about pending
- *     delete files so this should be used in 'force' mode only.
- */
-
-static void mark_files_ro(struct super_block *sb)
-{
-       struct file *f;
-
-retry:
-       file_list_lock();
-       list_for_each_entry(f, &sb->s_files, f_u.fu_list) {
-               struct vfsmount *mnt;
-               if (!S_ISREG(f->f_path.dentry->d_inode->i_mode))
-                      continue;
-               if (!file_count(f))
-                       continue;
-               if (!(f->f_mode & FMODE_WRITE))
-                       continue;
-               f->f_mode &= ~FMODE_WRITE;
-               if (file_check_writeable(f) != 0)
-                       continue;
-               file_release_write(f);
-               mnt = mntget(f->f_path.mnt);
-               file_list_unlock();
-               /*
-                * This can sleep, so we can't hold
-                * the file_list_lock() spinlock.
-                */
-               mnt_drop_write(mnt);
-               mntput(mnt);
-               goto retry;
-       }
-       file_list_unlock();
-}
-
 /**
  *     do_remount_sb - asks filesystem to change mount options.
  *     @sb:    superblock in question
@@ -797,8 +786,7 @@ int get_sb_ns(struct file_system_type *fs_type, int flags, void *data,
                sb->s_flags = flags;
                err = fill_super(sb, data, flags & MS_SILENT ? 1 : 0);
                if (err) {
-                       up_write(&sb->s_umount);
-                       deactivate_super(sb);
+                       deactivate_locked_super(sb);
                        return err;
                }
 
@@ -854,8 +842,7 @@ int get_sb_bdev(struct file_system_type *fs_type,
 
        if (s->s_root) {
                if ((flags ^ s->s_flags) & MS_RDONLY) {
-                       up_write(&s->s_umount);
-                       deactivate_super(s);
+                       deactivate_locked_super(s);
                        error = -EBUSY;
                        goto error_bdev;
                }
@@ -870,8 +857,7 @@ int get_sb_bdev(struct file_system_type *fs_type,
                sb_set_blocksize(s, block_size(bdev));
                error = fill_super(s, data, flags & MS_SILENT ? 1 : 0);
                if (error) {
-                       up_write(&s->s_umount);
-                       deactivate_super(s);
+                       deactivate_locked_super(s);
                        goto error;
                }
 
@@ -897,7 +883,7 @@ void kill_block_super(struct super_block *sb)
        struct block_device *bdev = sb->s_bdev;
        fmode_t mode = sb->s_mode;
 
-       bdev->bd_super = 0;
+       bdev->bd_super = NULL;
        generic_shutdown_super(sb);
        sync_blockdev(bdev);
        close_bdev_exclusive(bdev, mode);
@@ -921,8 +907,7 @@ int get_sb_nodev(struct file_system_type *fs_type,
 
        error = fill_super(s, data, flags & MS_SILENT ? 1 : 0);
        if (error) {
-               up_write(&s->s_umount);
-               deactivate_super(s);
+               deactivate_locked_super(s);
                return error;
        }
        s->s_flags |= MS_ACTIVE;
@@ -952,8 +937,7 @@ int get_sb_single(struct file_system_type *fs_type,
                s->s_flags = flags;
                error = fill_super(s, data, flags & MS_SILENT ? 1 : 0);
                if (error) {
-                       up_write(&s->s_umount);
-                       deactivate_super(s);
+                       deactivate_locked_super(s);
                        return error;
                }
                s->s_flags |= MS_ACTIVE;
@@ -1006,8 +990,7 @@ vfs_kern_mount(struct file_system_type *type, int flags, const char *name, void
        return mnt;
 out_sb:
        dput(mnt->mnt_root);
-       up_write(&mnt->mnt_sb->s_umount);
-       deactivate_super(mnt->mnt_sb);
+       deactivate_locked_super(mnt->mnt_sb);
 out_free_secdata:
        free_secdata(secdata);
 out_mnt: