diff options
| -rw-r--r-- | fs/nilfs2/super.c | 92 | ||||
| -rw-r--r-- | fs/nilfs2/the_nilfs.h | 3 |
2 files changed, 35 insertions, 60 deletions
diff --git a/fs/nilfs2/super.c b/fs/nilfs2/super.c index 3c9833e3e74a..5a8c5e4731b3 100644 --- a/fs/nilfs2/super.c +++ b/fs/nilfs2/super.c @@ -67,8 +67,6 @@ MODULE_LICENSE("GPL"); static void nilfs_write_super(struct super_block *sb); static int nilfs_remount(struct super_block *sb, int *flags, char *data); -static int test_exclusive_mount(struct file_system_type *fs_type, - struct block_device *bdev, int flags); /** * nilfs_error() - report failure condition on a filesystem @@ -329,6 +327,10 @@ static void nilfs_put_super(struct super_block *sb) nilfs_commit_super(sbi, 1); up_write(&nilfs->ns_sem); } + down_write(&nilfs->ns_sem); + if (nilfs->ns_current == sbi) + nilfs->ns_current = NULL; + up_write(&nilfs->ns_sem); nilfs_detach_checkpoint(sbi); put_nilfs(sbi->s_nilfs); @@ -880,6 +882,11 @@ nilfs_fill_super(struct super_block *sb, void *data, int silent, goto failed_root; } + down_write(&nilfs->ns_sem); + if (!nilfs_test_opt(sbi, SNAPSHOT)) + nilfs->ns_current = sbi; + up_write(&nilfs->ns_sem); + return 0; failed_root: @@ -958,14 +965,16 @@ static int nilfs_remount(struct super_block *sb, int *flags, char *data) * by fsck since we originally mounted the partition.) */ down(&sb->s_bdev->bd_mount_sem); - /* Check existing RW-mount */ - if (test_exclusive_mount(sb->s_type, sb->s_bdev, 0)) { + down_read(&nilfs->ns_sem); + if (nilfs->ns_current && nilfs->ns_current != sbi) { printk(KERN_WARNING "NILFS (device %s): couldn't " - "remount because a RW-mount exists.\n", + "remount because an RW-mount exists.\n", sb->s_id); + up_read(&nilfs->ns_sem); err = -EBUSY; goto rw_remount_failed; } + up_read(&nilfs->ns_sem); if (sbi->s_snapshot_cno != nilfs_last_cno(nilfs)) { printk(KERN_WARNING "NILFS (device %s): couldn't " "remount because the current RO-mount is not " @@ -984,6 +993,7 @@ static int nilfs_remount(struct super_block *sb, int *flags, char *data) down_write(&nilfs->ns_sem); nilfs_setup_super(sbi); + nilfs->ns_current = sbi; up_write(&nilfs->ns_sem); up(&sb->s_bdev->bd_mount_sem); @@ -1118,10 +1128,23 @@ nilfs_get_sb(struct file_system_type *fs_type, int flags, } down(&sd.bdev->bd_mount_sem); - if (!sd.cno && - (err = test_exclusive_mount(fs_type, sd.bdev, flags ^ MS_RDONLY))) { - err = (err < 0) ? : -EBUSY; - goto failed_unlock; + + if (!sd.cno) { + /* + * Check if an exclusive mount exists or not. + * Snapshot mounts coexist with a current mount + * (i.e. rw-mount or ro-mount), whereas rw-mount and + * ro-mount are mutually exclusive. + */ + down_read(&nilfs->ns_sem); + if (nilfs->ns_current && + ((nilfs->ns_current->s_super->s_flags ^ flags) + & MS_RDONLY)) { + up_read(&nilfs->ns_sem); + err = -EBUSY; + goto failed_unlock; + } + up_read(&nilfs->ns_sem); } /* @@ -1182,57 +1205,6 @@ nilfs_get_sb(struct file_system_type *fs_type, int flags, return err; } -static int nilfs_test_bdev_super3(struct super_block *s, void *data) -{ - struct nilfs_super_data *sd = data; - int ret; - - if (s->s_bdev != sd->bdev) - return 0; - if (down_read_trylock(&s->s_umount)) { - ret = (s->s_flags & MS_RDONLY) && s->s_root && - nilfs_test_opt(NILFS_SB(s), SNAPSHOT); - up_read(&s->s_umount); - if (ret) - return 0; /* ignore snapshot mounts */ - } - return !((sd->flags ^ s->s_flags) & MS_RDONLY); -} - -static int __false_bdev_super(struct super_block *s, void *data) -{ -#if 0 /* XXX: workaround for lock debug. This is not good idea */ - up_write(&s->s_umount); -#endif - return -EFAULT; -} - -/** - * test_exclusive_mount - check whether an exclusive RW/RO mount exists or not. - * fs_type: filesystem type - * bdev: block device - * flag: 0 (check rw-mount) or MS_RDONLY (check ro-mount) - * res: pointer to an integer to store result - * - * This function must be called within a section protected by bd_mount_mutex. - */ -static int test_exclusive_mount(struct file_system_type *fs_type, - struct block_device *bdev, int flags) -{ - struct super_block *s; - struct nilfs_super_data sd = { .flags = flags, .bdev = bdev }; - - s = sget(fs_type, nilfs_test_bdev_super3, __false_bdev_super, &sd); - if (IS_ERR(s)) { - if (PTR_ERR(s) != -EFAULT) - return PTR_ERR(s); - return 0; /* Not found */ - } - up_write(&s->s_umount); - deactivate_super(s); - return 1; /* Found */ -} - struct file_system_type nilfs_fs_type = { .owner = THIS_MODULE, .name = "nilfs2", diff --git a/fs/nilfs2/the_nilfs.h b/fs/nilfs2/the_nilfs.h index 116caf96e7f3..99f7e29a5335 100644 --- a/fs/nilfs2/the_nilfs.h +++ b/fs/nilfs2/the_nilfs.h @@ -50,6 +50,7 @@ enum { * @ns_sem: semaphore for shared states * @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 * @ns_sbh: buffer heads of on-disk super blocks * @ns_sbp: pointers to super block data * @ns_sbwtime: previous write time of super blocks @@ -98,6 +99,8 @@ struct the_nilfs { struct mutex ns_writer_mutex; atomic_t ns_writer_refcount; + struct nilfs_sb_info *ns_current; + /* * used for * - loading the latest checkpoint exclusively. |