diff options
| -rw-r--r-- | fs/block_dev.c | 74 | ||||
| -rw-r--r-- | fs/ioctl.c | 15 | ||||
| -rw-r--r-- | fs/super.c | 90 | ||||
| -rw-r--r-- | include/linux/fs.h | 2 |
4 files changed, 110 insertions, 71 deletions
diff --git a/fs/block_dev.c b/fs/block_dev.c index 39cb6591d37d..1aba036dcabf 100644 --- a/fs/block_dev.c +++ b/fs/block_dev.c @@ -245,38 +245,14 @@ struct super_block *freeze_bdev(struct block_device *bdev) sb = get_active_super(bdev); if (!sb) goto out; - down_write(&sb->s_umount); - if (sb->s_flags & MS_RDONLY) { - sb->s_frozen = SB_FREEZE_TRANS; - up_write(&sb->s_umount); + error = freeze_super(sb); + if (error) { + deactivate_super(sb); + bdev->bd_fsfreeze_count--; mutex_unlock(&bdev->bd_fsfreeze_mutex); - return sb; - } - - sb->s_frozen = SB_FREEZE_WRITE; - smp_wmb(); - - sync_filesystem(sb); - - sb->s_frozen = SB_FREEZE_TRANS; - smp_wmb(); - - sync_blockdev(sb->s_bdev); - - if (sb->s_op->freeze_fs) { - error = sb->s_op->freeze_fs(sb); - if (error) { - printk(KERN_ERR - "VFS:Filesystem freeze failed\n"); - sb->s_frozen = SB_UNFROZEN; - deactivate_locked_super(sb); - bdev->bd_fsfreeze_count--; - mutex_unlock(&bdev->bd_fsfreeze_mutex); - return ERR_PTR(error); - } + return ERR_PTR(error); } - up_write(&sb->s_umount); - + deactivate_super(sb); out: sync_blockdev(bdev); mutex_unlock(&bdev->bd_fsfreeze_mutex); @@ -297,40 +273,22 @@ int thaw_bdev(struct block_device *bdev, struct super_block *sb) mutex_lock(&bdev->bd_fsfreeze_mutex); if (!bdev->bd_fsfreeze_count) - goto out_unlock; + goto out; error = 0; if (--bdev->bd_fsfreeze_count > 0) - goto out_unlock; + goto out; if (!sb) - goto out_unlock; - - BUG_ON(sb->s_bdev != bdev); - down_write(&sb->s_umount); - if (sb->s_flags & MS_RDONLY) - goto out_unfrozen; - - if (sb->s_op->unfreeze_fs) { - error = sb->s_op->unfreeze_fs(sb); - if (error) { - printk(KERN_ERR - "VFS:Filesystem thaw failed\n"); - sb->s_frozen = SB_FREEZE_TRANS; - bdev->bd_fsfreeze_count++; - mutex_unlock(&bdev->bd_fsfreeze_mutex); - return error; - } - } - -out_unfrozen: - sb->s_frozen = SB_UNFROZEN; - smp_wmb(); - wake_up(&sb->s_wait_unfrozen); + goto out; - if (sb) - deactivate_locked_super(sb); -out_unlock: + error = thaw_super(sb); + if (error) { + bdev->bd_fsfreeze_count++; + mutex_unlock(&bdev->bd_fsfreeze_mutex); + return error; + } +out: mutex_unlock(&bdev->bd_fsfreeze_mutex); return 0; } diff --git a/fs/ioctl.c b/fs/ioctl.c index 7faefb4da939..2d140a713861 100644 --- a/fs/ioctl.c +++ b/fs/ioctl.c @@ -525,15 +525,8 @@ static int ioctl_fsfreeze(struct file *filp) if (sb->s_op->freeze_fs == NULL) return -EOPNOTSUPP; - /* If a blockdevice-backed filesystem isn't specified, return. */ - if (sb->s_bdev == NULL) - return -EINVAL; - /* Freeze */ - sb = freeze_bdev(sb->s_bdev); - if (IS_ERR(sb)) - return PTR_ERR(sb); - return 0; + return freeze_super(sb); } static int ioctl_fsthaw(struct file *filp) @@ -543,12 +536,8 @@ static int ioctl_fsthaw(struct file *filp) if (!capable(CAP_SYS_ADMIN)) return -EPERM; - /* If a blockdevice-backed filesystem isn't specified, return EINVAL. */ - if (sb->s_bdev == NULL) - return -EINVAL; - /* Thaw */ - return thaw_bdev(sb->s_bdev, sb); + return thaw_super(sb); } /* diff --git a/fs/super.c b/fs/super.c index c248ac6a1a21..89afca5055ab 100644 --- a/fs/super.c +++ b/fs/super.c @@ -944,6 +944,96 @@ out: EXPORT_SYMBOL_GPL(vfs_kern_mount); +/** + * freeze_super -- lock the filesystem and force it into a consistent state + * @super: the super to lock + * + * Syncs the super to make sure the filesystem is consistent and calls the fs's + * freeze_fs. Subsequent calls to this without first thawing the fs will return + * -EBUSY. + */ +int freeze_super(struct super_block *sb) +{ + int ret; + + atomic_inc(&sb->s_active); + down_write(&sb->s_umount); + if (sb->s_frozen) { + deactivate_locked_super(sb); + return -EBUSY; + } + + if (sb->s_flags & MS_RDONLY) { + sb->s_frozen = SB_FREEZE_TRANS; + smp_wmb(); + up_write(&sb->s_umount); + return 0; + } + + sb->s_frozen = SB_FREEZE_WRITE; + smp_wmb(); + + sync_filesystem(sb); + + sb->s_frozen = SB_FREEZE_TRANS; + smp_wmb(); + + sync_blockdev(sb->s_bdev); + if (sb->s_op->freeze_fs) { + ret = sb->s_op->freeze_fs(sb); + if (ret) { + printk(KERN_ERR + "VFS:Filesystem freeze failed\n"); + sb->s_frozen = SB_UNFROZEN; + deactivate_locked_super(sb); + return ret; + } + } + up_write(&sb->s_umount); + return 0; +} +EXPORT_SYMBOL(freeze_super); + +/** + * thaw_super -- unlock filesystem + * @sb: the super to thaw + * + * Unlocks the filesystem and marks it writeable again after freeze_super(). + */ +int thaw_super(struct super_block *sb) +{ + int error; + + down_write(&sb->s_umount); + if (sb->s_frozen == SB_UNFROZEN) { + up_write(&sb->s_umount); + return -EINVAL; + } + + if (sb->s_flags & MS_RDONLY) + goto out; + + if (sb->s_op->unfreeze_fs) { + error = sb->s_op->unfreeze_fs(sb); + if (error) { + printk(KERN_ERR + "VFS:Filesystem thaw failed\n"); + sb->s_frozen = SB_FREEZE_TRANS; + up_write(&sb->s_umount); + return error; + } + } + +out: + sb->s_frozen = SB_UNFROZEN; + smp_wmb(); + wake_up(&sb->s_wait_unfrozen); + deactivate_locked_super(sb); + + return 0; +} +EXPORT_SYMBOL(thaw_super); + static struct vfsmount *fs_set_subtype(struct vfsmount *mnt, const char *fstype) { int err; diff --git a/include/linux/fs.h b/include/linux/fs.h index eeb04ba17b63..d51256bc6328 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -1797,6 +1797,8 @@ extern void drop_collected_mounts(struct vfsmount *); extern int iterate_mounts(int (*)(struct vfsmount *, void *), void *, struct vfsmount *); extern int vfs_statfs(struct dentry *, struct kstatfs *); +extern int freeze_super(struct super_block *super); +extern int thaw_super(struct super_block *super); extern int current_umask(void); |