diff options
| -rw-r--r-- | fs/btrfs/ctree.h | 1 | ||||
| -rw-r--r-- | fs/btrfs/disk-io.c | 1 | ||||
| -rw-r--r-- | fs/btrfs/file.c | 2 | ||||
| -rw-r--r-- | fs/btrfs/inode.c | 10 |
4 files changed, 13 insertions, 1 deletions
diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h index cd75c906048..03e1c4ad341 100644 --- a/fs/btrfs/ctree.h +++ b/fs/btrfs/ctree.h @@ -333,6 +333,7 @@ struct btrfs_root { struct inode *inode; struct kobject root_kobj; struct completion kobj_unregister; + struct rw_semaphore snap_sem; u64 objectid; u64 last_trans; u32 blocksize; diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c index c25ef0a68f1..6c953a0e0aa 100644 --- a/fs/btrfs/disk-io.c +++ b/fs/btrfs/disk-io.c @@ -300,6 +300,7 @@ static int __setup_root(int blocksize, memset(&root->defrag_progress, 0, sizeof(root->defrag_progress)); memset(&root->root_kobj, 0, sizeof(root->root_kobj)); init_completion(&root->kobj_unregister); + init_rwsem(&root->snap_sem); root->defrag_running = 0; root->defrag_level = 0; root->root_key.objectid = objectid; diff --git a/fs/btrfs/file.c b/fs/btrfs/file.c index acef8cb7fb7..77f1950b0aa 100644 --- a/fs/btrfs/file.c +++ b/fs/btrfs/file.c @@ -160,6 +160,7 @@ static int dirty_and_release_pages(struct btrfs_trans_handle *trans, num_blocks = (write_bytes + pos - start_pos + root->blocksize - 1) >> inode->i_blkbits; + down_read(&BTRFS_I(inode)->root->snap_sem); end_of_last_block = start_pos + (num_blocks << inode->i_blkbits) - 1; lock_extent(em_tree, start_pos, end_of_last_block, GFP_NOFS); mutex_lock(&root->fs_info->fs_mutex); @@ -250,6 +251,7 @@ out_unlock: mutex_unlock(&root->fs_info->fs_mutex); unlock_extent(em_tree, start_pos, end_of_last_block, GFP_NOFS); free_extent_map(em); + up_read(&BTRFS_I(inode)->root->snap_sem); return err; } diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c index 6b3e4404dc6..1ace6d11e09 100644 --- a/fs/btrfs/inode.c +++ b/fs/btrfs/inode.c @@ -686,6 +686,7 @@ static int btrfs_truncate_page(struct address_space *mapping, loff_t from) if ((offset & (blocksize - 1)) == 0) goto out; + down_read(&BTRFS_I(inode)->root->snap_sem); ret = -ENOMEM; page = grab_cache_page(mapping, index); if (!page) @@ -704,6 +705,7 @@ static int btrfs_truncate_page(struct address_space *mapping, loff_t from) unlock_page(page); page_cache_release(page); + up_read(&BTRFS_I(inode)->root->snap_sem); out: return ret; } @@ -1668,6 +1670,7 @@ int btrfs_page_mkwrite(struct vm_area_struct *vma, struct page *page) int ret = -EINVAL; u64 page_start; + down_read(&BTRFS_I(inode)->root->snap_sem); lock_page(page); wait_on_page_writeback(page); size = i_size_read(inode); @@ -1688,6 +1691,7 @@ int btrfs_page_mkwrite(struct vm_area_struct *vma, struct page *page) ret = btrfs_cow_one_page(inode, page, end); out_unlock: + up_read(&BTRFS_I(inode)->root->snap_sem); unlock_page(page); return ret; } @@ -1851,6 +1855,10 @@ static int create_snapshot(struct btrfs_root *root, char *name, int namelen) if (!root->ref_cows) return -EINVAL; + down_write(&root->snap_sem); + freeze_bdev(root->fs_info->sb->s_bdev); + thaw_bdev(root->fs_info->sb->s_bdev, root->fs_info->sb); + mutex_lock(&root->fs_info->fs_mutex); trans = btrfs_start_transaction(root, 1); BUG_ON(!trans); @@ -1894,12 +1902,12 @@ static int create_snapshot(struct btrfs_root *root, char *name, int namelen) ret = btrfs_inc_root_ref(trans, root); if (ret) goto fail; - fail: err = btrfs_commit_transaction(trans, root); if (err && !ret) ret = err; mutex_unlock(&root->fs_info->fs_mutex); + up_write(&root->snap_sem); btrfs_btree_balance_dirty(root); return ret; } |