diff options
Diffstat (limited to 'fs/btrfs/ioctl.c')
| -rw-r--r-- | fs/btrfs/ioctl.c | 102 |
1 files changed, 91 insertions, 11 deletions
diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c index 50c8a066d1f0..3d85f18bbba6 100644 --- a/fs/btrfs/ioctl.c +++ b/fs/btrfs/ioctl.c @@ -21,6 +21,7 @@ #include <linux/buffer_head.h> #include <linux/file.h> #include <linux/fs.h> +#include <linux/fsnotify.h> #include <linux/pagemap.h> #include <linux/highmem.h> #include <linux/time.h> @@ -28,12 +29,15 @@ #include <linux/string.h> #include <linux/smp_lock.h> #include <linux/backing-dev.h> +#include <linux/mount.h> #include <linux/mpage.h> +#include <linux/namei.h> #include <linux/swap.h> #include <linux/writeback.h> #include <linux/statfs.h> #include <linux/compat.h> #include <linux/bit_spinlock.h> +#include <linux/security.h> #include <linux/version.h> #include <linux/xattr.h> #include <linux/vmalloc.h> @@ -48,8 +52,9 @@ -static noinline int create_subvol(struct btrfs_root *root, char *name, - int namelen) +static noinline int create_subvol(struct btrfs_root *root, + struct dentry *dentry, + char *name, int namelen) { struct btrfs_trans_handle *trans; struct btrfs_key key; @@ -151,14 +156,11 @@ static noinline int create_subvol(struct btrfs_root *root, char *name, trans = btrfs_start_transaction(new_root, 1); BUG_ON(!trans); - ret = btrfs_create_subvol_root(new_root, trans, new_dirid, + ret = btrfs_create_subvol_root(new_root, dentry, trans, new_dirid, BTRFS_I(dir)->block_group); if (ret) goto fail; - /* Invalidate existing dcache entry for new subvolume. */ - btrfs_invalidate_dcache_root(root, name, namelen); - fail: nr = trans->blocks_used; err = btrfs_commit_transaction(trans, new_root); @@ -210,6 +212,79 @@ fail_unlock: return ret; } +/* copy of may_create in fs/namei.c() */ +static inline int btrfs_may_create(struct inode *dir, struct dentry *child) +{ + if (child->d_inode) + return -EEXIST; + if (IS_DEADDIR(dir)) + return -ENOENT; + return inode_permission(dir, MAY_WRITE | MAY_EXEC); +} + +/* + * Create a new subvolume below @parent. This is largely modeled after + * sys_mkdirat and vfs_mkdir, but we only do a single component lookup + * inside this filesystem so it's quite a bit simpler. + */ +static noinline int btrfs_mksubvol(struct path *parent, char *name, + int mode, int namelen) +{ + struct dentry *dentry; + int error; + + mutex_lock_nested(&parent->dentry->d_inode->i_mutex, I_MUTEX_PARENT); + + dentry = lookup_one_len(name, parent->dentry, namelen); + error = PTR_ERR(dentry); + if (IS_ERR(dentry)) + goto out_unlock; + + error = -EEXIST; + if (dentry->d_inode) + goto out_dput; + + if (!IS_POSIXACL(parent->dentry->d_inode)) + mode &= ~current->fs->umask; + error = mnt_want_write(parent->mnt); + if (error) + goto out_dput; + + error = btrfs_may_create(parent->dentry->d_inode, dentry); + if (error) + goto out_drop_write; + + mode &= (S_IRWXUGO|S_ISVTX); + error = security_inode_mkdir(parent->dentry->d_inode, dentry, mode); + if (error) + goto out_drop_write; + + /* + * Actually perform the low-level subvolume creation after all + * this VFS fuzz. + * + * Eventually we want to pass in an inode under which we create this + * subvolume, but for now all are under the filesystem root. + * + * Also we should pass on the mode eventually to allow creating new + * subvolume with specific mode bits. + */ + error = create_subvol(BTRFS_I(parent->dentry->d_inode)->root, dentry, + name, namelen); + if (error) + goto out_drop_write; + + fsnotify_mkdir(parent->dentry->d_inode, dentry); +out_drop_write: + mnt_drop_write(parent->mnt); +out_dput: + dput(dentry); +out_unlock: + mutex_unlock(&parent->dentry->d_inode->i_mutex); + return error; +} + + int btrfs_defrag_file(struct file *file) { struct inode *inode = fdentry(file)->d_inode; @@ -395,9 +470,10 @@ out: return ret; } -static noinline int btrfs_ioctl_snap_create(struct btrfs_root *root, +static noinline int btrfs_ioctl_snap_create(struct file *file, void __user *arg) { + struct btrfs_root *root = BTRFS_I(fdentry(file)->d_inode)->root; struct btrfs_ioctl_vol_args *vol_args; struct btrfs_dir_item *di; struct btrfs_path *path; @@ -444,10 +520,14 @@ static noinline int btrfs_ioctl_snap_create(struct btrfs_root *root, goto out; } - if (root == root->fs_info->tree_root) - ret = create_subvol(root, vol_args->name, namelen); - else + if (root == root->fs_info->tree_root) { + ret = btrfs_mksubvol(&file->f_path, vol_args->name, + file->f_path.dentry->d_inode->i_mode, + namelen); + } else { ret = create_snapshot(root, vol_args->name, namelen); + } + out: kfree(vol_args); return ret; @@ -761,7 +841,7 @@ long btrfs_ioctl(struct file *file, unsigned int switch (cmd) { case BTRFS_IOC_SNAP_CREATE: - return btrfs_ioctl_snap_create(root, (void __user *)arg); + return btrfs_ioctl_snap_create(file, (void __user *)arg); case BTRFS_IOC_DEFRAG: return btrfs_ioctl_defrag(file); case BTRFS_IOC_RESIZE: |