diff options
| -rw-r--r-- | fs/btrfs/ctree.h | 6 | ||||
| -rw-r--r-- | fs/btrfs/ioctl.c | 22 | ||||
| -rw-r--r-- | fs/btrfs/send.c | 54 |
3 files changed, 79 insertions, 3 deletions
diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h index 3c9053a153b1..9318c7520f50 100644 --- a/fs/btrfs/ctree.h +++ b/fs/btrfs/ctree.h @@ -1814,6 +1814,12 @@ struct btrfs_root { struct list_head ordered_extents; struct list_head ordered_root; u64 nr_ordered_extents; + + /* + * Number of currently running SEND ioctls to prevent + * manipulation with the read-only status via SUBVOL_SETFLAGS + */ + int send_in_progress; }; struct btrfs_ioctl_defrag_range_args { diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c index 89c2f6169b92..c0dc05467ce8 100644 --- a/fs/btrfs/ioctl.c +++ b/fs/btrfs/ioctl.c @@ -1706,12 +1706,28 @@ static noinline int btrfs_ioctl_subvol_setflags(struct file *file, goto out_drop_sem; root_flags = btrfs_root_flags(&root->root_item); - if (flags & BTRFS_SUBVOL_RDONLY) + if (flags & BTRFS_SUBVOL_RDONLY) { btrfs_set_root_flags(&root->root_item, root_flags | BTRFS_ROOT_SUBVOL_RDONLY); - else - btrfs_set_root_flags(&root->root_item, + } else { + /* + * Block RO -> RW transition if this subvolume is involved in + * send + */ + spin_lock(&root->root_item_lock); + if (root->send_in_progress == 0) { + btrfs_set_root_flags(&root->root_item, root_flags & ~BTRFS_ROOT_SUBVOL_RDONLY); + spin_unlock(&root->root_item_lock); + } else { + spin_unlock(&root->root_item_lock); + btrfs_warn(root->fs_info, + "Attempt to set subvolume %llu read-write during send", + root->root_key.objectid); + ret = -EPERM; + goto out_drop_sem; + } + } trans = btrfs_start_transaction(root, 1); if (IS_ERR(trans)) { diff --git a/fs/btrfs/send.c b/fs/btrfs/send.c index e98c9bc003c8..572e8c758712 100644 --- a/fs/btrfs/send.c +++ b/fs/btrfs/send.c @@ -4769,6 +4769,7 @@ long btrfs_ioctl_send(struct file *mnt_file, void __user *arg_) struct send_ctx *sctx = NULL; u32 i; u64 *clone_sources_tmp = NULL; + int clone_sources_to_rollback = 0; if (!capable(CAP_SYS_ADMIN)) return -EPERM; @@ -4777,6 +4778,14 @@ long btrfs_ioctl_send(struct file *mnt_file, void __user *arg_) fs_info = send_root->fs_info; /* + * The subvolume must remain read-only during send, protect against + * making it RW. + */ + spin_lock(&send_root->root_item_lock); + send_root->send_in_progress++; + spin_unlock(&send_root->root_item_lock); + + /* * This is done when we lookup the root, it should already be complete * by the time we get here. */ @@ -4811,6 +4820,15 @@ long btrfs_ioctl_send(struct file *mnt_file, void __user *arg_) up_read(&send_root->fs_info->extent_commit_sem); } + /* + * Userspace tools do the checks and warn the user if it's + * not RO. + */ + if (!btrfs_root_readonly(send_root)) { + ret = -EPERM; + goto out; + } + arg = memdup_user(arg_, sizeof(*arg)); if (IS_ERR(arg)) { ret = PTR_ERR(arg); @@ -4897,6 +4915,15 @@ long btrfs_ioctl_send(struct file *mnt_file, void __user *arg_) ret = PTR_ERR(clone_root); goto out; } + clone_sources_to_rollback = i + 1; + spin_lock(&clone_root->root_item_lock); + clone_root->send_in_progress++; + if (!btrfs_root_readonly(clone_root)) { + spin_unlock(&clone_root->root_item_lock); + ret = -EPERM; + goto out; + } + spin_unlock(&clone_root->root_item_lock); sctx->clone_roots[i].root = clone_root; } vfree(clone_sources_tmp); @@ -4912,6 +4939,14 @@ long btrfs_ioctl_send(struct file *mnt_file, void __user *arg_) ret = PTR_ERR(sctx->parent_root); goto out; } + spin_lock(&sctx->parent_root->root_item_lock); + sctx->parent_root->send_in_progress++; + if (!btrfs_root_readonly(sctx->parent_root)) { + spin_unlock(&sctx->parent_root->root_item_lock); + ret = -EPERM; + goto out; + } + spin_unlock(&sctx->parent_root->root_item_lock); } /* @@ -4940,6 +4975,25 @@ long btrfs_ioctl_send(struct file *mnt_file, void __user *arg_) } out: + for (i = 0; sctx && i < clone_sources_to_rollback; i++) { + struct btrfs_root *r = sctx->clone_roots[i].root; + + spin_lock(&r->root_item_lock); + r->send_in_progress--; + spin_unlock(&r->root_item_lock); + } + if (sctx && !IS_ERR_OR_NULL(sctx->parent_root)) { + struct btrfs_root *r = sctx->parent_root; + + spin_lock(&r->root_item_lock); + r->send_in_progress--; + spin_unlock(&r->root_item_lock); + } + + spin_lock(&send_root->root_item_lock); + send_root->send_in_progress--; + spin_unlock(&send_root->root_item_lock); + kfree(arg); vfree(clone_sources_tmp); |