diff options
Diffstat (limited to 'fs/btrfs/ioctl.c')
| -rw-r--r-- | fs/btrfs/ioctl.c | 35 |
1 files changed, 30 insertions, 5 deletions
diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c index 1ae45bd9d27d..57bc9f33fa3c 100644 --- a/fs/btrfs/ioctl.c +++ b/fs/btrfs/ioctl.c @@ -611,6 +611,23 @@ fail: return ret; } +static void btrfs_wait_nocow_write(struct btrfs_root *root) +{ + s64 writers; + DEFINE_WAIT(wait); + + do { + prepare_to_wait(&root->subv_writers->wait, &wait, + TASK_UNINTERRUPTIBLE); + + writers = percpu_counter_sum(&root->subv_writers->counter); + if (writers) + schedule(); + + finish_wait(&root->subv_writers->wait, &wait); + } while (writers); +} + static int create_snapshot(struct btrfs_root *root, struct inode *dir, struct dentry *dentry, char *name, int namelen, u64 *async_transid, bool readonly, @@ -624,15 +641,21 @@ static int create_snapshot(struct btrfs_root *root, struct inode *dir, if (!root->ref_cows) return -EINVAL; + atomic_inc(&root->will_be_snapshoted); + smp_mb__after_atomic_inc(); + btrfs_wait_nocow_write(root); + ret = btrfs_start_delalloc_inodes(root, 0); if (ret) - return ret; + goto out; btrfs_wait_ordered_extents(root, -1); pending_snapshot = kzalloc(sizeof(*pending_snapshot), GFP_NOFS); - if (!pending_snapshot) - return -ENOMEM; + if (!pending_snapshot) { + ret = -ENOMEM; + goto out; + } btrfs_init_block_rsv(&pending_snapshot->block_rsv, BTRFS_BLOCK_RSV_TEMP); @@ -649,7 +672,7 @@ static int create_snapshot(struct btrfs_root *root, struct inode *dir, &pending_snapshot->qgroup_reserved, false); if (ret) - goto out; + goto free; pending_snapshot->dentry = dentry; pending_snapshot->root = root; @@ -700,8 +723,10 @@ fail: btrfs_subvolume_release_metadata(BTRFS_I(dir)->root, &pending_snapshot->block_rsv, pending_snapshot->qgroup_reserved); -out: +free: kfree(pending_snapshot); +out: + atomic_dec(&root->will_be_snapshoted); return ret; } |