From fa0d2b9bd717340e0bc4850a80ac0eb344e9a7fb Mon Sep 17 00:00:00 2001 From: Li Zefan Date: Mon, 20 Dec 2010 15:53:28 +0800 Subject: Btrfs: Refactor btrfs_ioctl_snap_create() Split it into two functions for two different ioctls, since they share no common code. Signed-off-by: Li Zefan --- fs/btrfs/ioctl.c | 84 +++++++++++++++++++++++++++----------------------------- 1 file changed, 40 insertions(+), 44 deletions(-) (limited to 'fs') diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c index f87552a1d7ea..02554e19d974 100644 --- a/fs/btrfs/ioctl.c +++ b/fs/btrfs/ioctl.c @@ -946,58 +946,54 @@ out: } static noinline int btrfs_ioctl_snap_create(struct file *file, - void __user *arg, int subvol, - int v2) + void __user *arg, int subvol) { - struct btrfs_ioctl_vol_args *vol_args = NULL; - struct btrfs_ioctl_vol_args_v2 *vol_args_v2 = NULL; - char *name; - u64 fd; + struct btrfs_ioctl_vol_args *vol_args; int ret; - if (v2) { - u64 transid = 0; - u64 *ptr = NULL; + vol_args = memdup_user(arg, sizeof(*vol_args)); + if (IS_ERR(vol_args)) + return PTR_ERR(vol_args); + vol_args->name[BTRFS_PATH_NAME_MAX] = '\0'; - vol_args_v2 = memdup_user(arg, sizeof(*vol_args_v2)); - if (IS_ERR(vol_args_v2)) - return PTR_ERR(vol_args_v2); + ret = btrfs_ioctl_snap_create_transid(file, vol_args->name, + vol_args->fd, subvol, NULL); - if (vol_args_v2->flags & ~BTRFS_SUBVOL_CREATE_ASYNC) { - ret = -EINVAL; - goto out; - } - - name = vol_args_v2->name; - fd = vol_args_v2->fd; - vol_args_v2->name[BTRFS_SUBVOL_NAME_MAX] = '\0'; + kfree(vol_args); + return ret; +} - if (vol_args_v2->flags & BTRFS_SUBVOL_CREATE_ASYNC) - ptr = &transid; +static noinline int btrfs_ioctl_snap_create_v2(struct file *file, + void __user *arg, int subvol) +{ + struct btrfs_ioctl_vol_args_v2 *vol_args; + int ret; + u64 transid = 0; + u64 *ptr = NULL; - ret = btrfs_ioctl_snap_create_transid(file, name, fd, - subvol, ptr); + vol_args = memdup_user(arg, sizeof(*vol_args)); + if (IS_ERR(vol_args)) + return PTR_ERR(vol_args); + vol_args->name[BTRFS_SUBVOL_NAME_MAX] = '\0'; - if (ret == 0 && ptr && - copy_to_user(arg + - offsetof(struct btrfs_ioctl_vol_args_v2, - transid), ptr, sizeof(*ptr))) - ret = -EFAULT; - } else { - vol_args = memdup_user(arg, sizeof(*vol_args)); - if (IS_ERR(vol_args)) - return PTR_ERR(vol_args); - name = vol_args->name; - fd = vol_args->fd; - vol_args->name[BTRFS_PATH_NAME_MAX] = '\0'; - - ret = btrfs_ioctl_snap_create_transid(file, name, fd, - subvol, NULL); + if (vol_args->flags & ~BTRFS_SUBVOL_CREATE_ASYNC) { + ret = -EINVAL; + goto out; } + + if (vol_args->flags & BTRFS_SUBVOL_CREATE_ASYNC) + ptr = &transid; + + ret = btrfs_ioctl_snap_create_transid(file, vol_args->name, + vol_args->fd, subvol, ptr); + + if (ret == 0 && ptr && + copy_to_user(arg + + offsetof(struct btrfs_ioctl_vol_args_v2, + transid), ptr, sizeof(*ptr))) + ret = -EFAULT; out: kfree(vol_args); - kfree(vol_args_v2); - return ret; } @@ -2257,11 +2253,11 @@ long btrfs_ioctl(struct file *file, unsigned int case FS_IOC_GETVERSION: return btrfs_ioctl_getversion(file, argp); case BTRFS_IOC_SNAP_CREATE: - return btrfs_ioctl_snap_create(file, argp, 0, 0); + return btrfs_ioctl_snap_create(file, argp, 0); case BTRFS_IOC_SNAP_CREATE_V2: - return btrfs_ioctl_snap_create(file, argp, 0, 1); + return btrfs_ioctl_snap_create_v2(file, argp, 0); case BTRFS_IOC_SUBVOL_CREATE: - return btrfs_ioctl_snap_create(file, argp, 1, 0); + return btrfs_ioctl_snap_create(file, argp, 1); case BTRFS_IOC_SNAP_DESTROY: return btrfs_ioctl_snap_destroy(file, argp); case BTRFS_IOC_DEFAULT_SUBVOL: -- cgit v1.2.3 From b83cc9693f39689490970c19f6c5b866f6719a70 Mon Sep 17 00:00:00 2001 From: Li Zefan Date: Mon, 20 Dec 2010 16:04:08 +0800 Subject: Btrfs: Add readonly snapshots support Usage: Set BTRFS_SUBVOL_RDONLY of btrfs_ioctl_vol_arg_v2->flags, and call ioctl(BTRFS_I0CTL_SNAP_CREATE_V2). Implementation: - Set readonly bit of btrfs_root_item->flags. - Add readonly checks in btrfs_permission (inode_permission), btrfs_setattr, btrfs_set/remove_xattr and some ioctls. Changelog for v3: - Eliminate btrfs_root->readonly, but check btrfs_root->root_item.flags. - Rename BTRFS_ROOT_SNAP_RDONLY to BTRFS_ROOT_SUBVOL_RDONLY. Signed-off-by: Li Zefan --- fs/btrfs/ctree.h | 7 +++++++ fs/btrfs/inode.c | 8 ++++++++ fs/btrfs/ioctl.c | 42 ++++++++++++++++++++++++++++++++---------- fs/btrfs/ioctl.h | 1 + fs/btrfs/transaction.c | 8 ++++++++ fs/btrfs/transaction.h | 1 + fs/btrfs/xattr.c | 18 ++++++++++++++++++ 7 files changed, 75 insertions(+), 10 deletions(-) (limited to 'fs') diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h index af52f6d7a4d8..4403e5643d43 100644 --- a/fs/btrfs/ctree.h +++ b/fs/btrfs/ctree.h @@ -597,6 +597,8 @@ struct btrfs_dir_item { u8 type; } __attribute__ ((__packed__)); +#define BTRFS_ROOT_SUBVOL_RDONLY (1ULL << 0) + struct btrfs_root_item { struct btrfs_inode_item inode; __le64 generation; @@ -1893,6 +1895,11 @@ BTRFS_SETGET_STACK_FUNCS(root_limit, struct btrfs_root_item, byte_limit, 64); BTRFS_SETGET_STACK_FUNCS(root_last_snapshot, struct btrfs_root_item, last_snapshot, 64); +static inline bool btrfs_root_readonly(struct btrfs_root *root) +{ + return root->root_item.flags & BTRFS_ROOT_SUBVOL_RDONLY; +} + /* struct btrfs_super_block */ BTRFS_SETGET_STACK_FUNCS(super_bytenr, struct btrfs_super_block, bytenr, 64); diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c index 5f9194438f7c..956f1eb913b1 100644 --- a/fs/btrfs/inode.c +++ b/fs/btrfs/inode.c @@ -3671,8 +3671,12 @@ static int btrfs_setattr_size(struct inode *inode, struct iattr *attr) static int btrfs_setattr(struct dentry *dentry, struct iattr *attr) { struct inode *inode = dentry->d_inode; + struct btrfs_root *root = BTRFS_I(inode)->root; int err; + if (btrfs_root_readonly(root)) + return -EROFS; + err = inode_change_ok(inode, attr); if (err) return err; @@ -7206,6 +7210,10 @@ static int btrfs_set_page_dirty(struct page *page) static int btrfs_permission(struct inode *inode, int mask) { + struct btrfs_root *root = BTRFS_I(inode)->root; + + if (btrfs_root_readonly(root) && (mask & MAY_WRITE)) + return -EROFS; if ((BTRFS_I(inode)->flags & BTRFS_INODE_READONLY) && (mask & MAY_WRITE)) return -EACCES; return generic_permission(inode, mask, btrfs_check_acl); diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c index 02554e19d974..f066ccb5dddf 100644 --- a/fs/btrfs/ioctl.c +++ b/fs/btrfs/ioctl.c @@ -147,6 +147,9 @@ static int btrfs_ioctl_setflags(struct file *file, void __user *arg) unsigned int flags, oldflags; int ret; + if (btrfs_root_readonly(root)) + return -EROFS; + if (copy_from_user(&flags, arg, sizeof(flags))) return -EFAULT; @@ -360,7 +363,8 @@ fail: } static int create_snapshot(struct btrfs_root *root, struct dentry *dentry, - char *name, int namelen, u64 *async_transid) + char *name, int namelen, u64 *async_transid, + bool readonly) { struct inode *inode; struct dentry *parent; @@ -378,6 +382,7 @@ static int create_snapshot(struct btrfs_root *root, struct dentry *dentry, btrfs_init_block_rsv(&pending_snapshot->block_rsv); pending_snapshot->dentry = dentry; pending_snapshot->root = root; + pending_snapshot->readonly = readonly; trans = btrfs_start_transaction(root->fs_info->extent_root, 5); if (IS_ERR(trans)) { @@ -509,7 +514,7 @@ static inline int btrfs_may_create(struct inode *dir, struct dentry *child) static noinline int btrfs_mksubvol(struct path *parent, char *name, int namelen, struct btrfs_root *snap_src, - u64 *async_transid) + u64 *async_transid, bool readonly) { struct inode *dir = parent->dentry->d_inode; struct dentry *dentry; @@ -541,7 +546,7 @@ static noinline int btrfs_mksubvol(struct path *parent, if (snap_src) { error = create_snapshot(snap_src, dentry, - name, namelen, async_transid); + name, namelen, async_transid, readonly); } else { error = create_subvol(BTRFS_I(dir)->root, dentry, name, namelen, async_transid); @@ -901,7 +906,8 @@ static noinline int btrfs_ioctl_snap_create_transid(struct file *file, char *name, unsigned long fd, int subvol, - u64 *transid) + u64 *transid, + bool readonly) { struct btrfs_root *root = BTRFS_I(fdentry(file)->d_inode)->root; struct file *src_file; @@ -919,7 +925,7 @@ static noinline int btrfs_ioctl_snap_create_transid(struct file *file, if (subvol) { ret = btrfs_mksubvol(&file->f_path, name, namelen, - NULL, transid); + NULL, transid, readonly); } else { struct inode *src_inode; src_file = fget(fd); @@ -938,7 +944,7 @@ static noinline int btrfs_ioctl_snap_create_transid(struct file *file, } ret = btrfs_mksubvol(&file->f_path, name, namelen, BTRFS_I(src_inode)->root, - transid); + transid, readonly); fput(src_file); } out: @@ -957,7 +963,8 @@ static noinline int btrfs_ioctl_snap_create(struct file *file, vol_args->name[BTRFS_PATH_NAME_MAX] = '\0'; ret = btrfs_ioctl_snap_create_transid(file, vol_args->name, - vol_args->fd, subvol, NULL); + vol_args->fd, subvol, + NULL, false); kfree(vol_args); return ret; @@ -970,22 +977,27 @@ static noinline int btrfs_ioctl_snap_create_v2(struct file *file, int ret; u64 transid = 0; u64 *ptr = NULL; + bool readonly = false; vol_args = memdup_user(arg, sizeof(*vol_args)); if (IS_ERR(vol_args)) return PTR_ERR(vol_args); vol_args->name[BTRFS_SUBVOL_NAME_MAX] = '\0'; - if (vol_args->flags & ~BTRFS_SUBVOL_CREATE_ASYNC) { - ret = -EINVAL; + if (vol_args->flags & + ~(BTRFS_SUBVOL_CREATE_ASYNC | BTRFS_SUBVOL_RDONLY)) { + ret = -EOPNOTSUPP; goto out; } if (vol_args->flags & BTRFS_SUBVOL_CREATE_ASYNC) ptr = &transid; + if (vol_args->flags & BTRFS_SUBVOL_RDONLY) + readonly = true; ret = btrfs_ioctl_snap_create_transid(file, vol_args->name, - vol_args->fd, subvol, ptr); + vol_args->fd, subvol, + ptr, readonly); if (ret == 0 && ptr && copy_to_user(arg + @@ -1505,6 +1517,9 @@ static int btrfs_ioctl_defrag(struct file *file, void __user *argp) struct btrfs_ioctl_defrag_range_args *range; int ret; + if (btrfs_root_readonly(root)) + return -EROFS; + ret = mnt_want_write(file->f_path.mnt); if (ret) return ret; @@ -1633,6 +1648,9 @@ static noinline long btrfs_ioctl_clone(struct file *file, unsigned long srcfd, if (!(file->f_mode & FMODE_WRITE) || (file->f_flags & O_APPEND)) return -EINVAL; + if (btrfs_root_readonly(root)) + return -EROFS; + ret = mnt_want_write(file->f_path.mnt); if (ret) return ret; @@ -1954,6 +1972,10 @@ static long btrfs_ioctl_trans_start(struct file *file) if (file->private_data) goto out; + ret = -EROFS; + if (btrfs_root_readonly(root)) + goto out; + ret = mnt_want_write(file->f_path.mnt); if (ret) goto out; diff --git a/fs/btrfs/ioctl.h b/fs/btrfs/ioctl.h index c344d12c646b..52ae489974be 100644 --- a/fs/btrfs/ioctl.h +++ b/fs/btrfs/ioctl.h @@ -31,6 +31,7 @@ struct btrfs_ioctl_vol_args { }; #define BTRFS_SUBVOL_CREATE_ASYNC (1ULL << 0) +#define BTRFS_SUBVOL_RDONLY (1ULL << 1) #define BTRFS_SUBVOL_NAME_MAX 4039 struct btrfs_ioctl_vol_args_v2 { diff --git a/fs/btrfs/transaction.c b/fs/btrfs/transaction.c index f50e931fc217..29e30d832ec9 100644 --- a/fs/btrfs/transaction.c +++ b/fs/btrfs/transaction.c @@ -910,6 +910,7 @@ static noinline int create_pending_snapshot(struct btrfs_trans_handle *trans, u64 to_reserve = 0; u64 index = 0; u64 objectid; + u64 root_flags; new_root_item = kmalloc(sizeof(*new_root_item), GFP_NOFS); if (!new_root_item) { @@ -967,6 +968,13 @@ static noinline int create_pending_snapshot(struct btrfs_trans_handle *trans, btrfs_set_root_last_snapshot(&root->root_item, trans->transid); memcpy(new_root_item, &root->root_item, sizeof(*new_root_item)); + root_flags = btrfs_root_flags(new_root_item); + if (pending->readonly) + root_flags |= BTRFS_ROOT_SUBVOL_RDONLY; + else + root_flags &= ~BTRFS_ROOT_SUBVOL_RDONLY; + btrfs_set_root_flags(new_root_item, root_flags); + old = btrfs_lock_root_node(root); btrfs_cow_block(trans, root, old, NULL, 0, &old); btrfs_set_lock_blocking(old); diff --git a/fs/btrfs/transaction.h b/fs/btrfs/transaction.h index f104b57ad4ef..229a594cacd5 100644 --- a/fs/btrfs/transaction.h +++ b/fs/btrfs/transaction.h @@ -62,6 +62,7 @@ struct btrfs_pending_snapshot { struct btrfs_block_rsv block_rsv; /* extra metadata reseration for relocation */ int error; + bool readonly; struct list_head list; }; diff --git a/fs/btrfs/xattr.c b/fs/btrfs/xattr.c index 698fdd2c739c..a5776531dc2b 100644 --- a/fs/btrfs/xattr.c +++ b/fs/btrfs/xattr.c @@ -316,6 +316,15 @@ ssize_t btrfs_getxattr(struct dentry *dentry, const char *name, int btrfs_setxattr(struct dentry *dentry, const char *name, const void *value, size_t size, int flags) { + struct btrfs_root *root = BTRFS_I(dentry->d_inode)->root; + + /* + * The permission on security.* and system.* is not checked + * in permission(). + */ + if (btrfs_root_readonly(root)) + return -EROFS; + /* * If this is a request for a synthetic attribute in the system.* * namespace use the generic infrastructure to resolve a handler @@ -336,6 +345,15 @@ int btrfs_setxattr(struct dentry *dentry, const char *name, const void *value, int btrfs_removexattr(struct dentry *dentry, const char *name) { + struct btrfs_root *root = BTRFS_I(dentry->d_inode)->root; + + /* + * The permission on security.* and system.* is not checked + * in permission(). + */ + if (btrfs_root_readonly(root)) + return -EROFS; + /* * If this is a request for a synthetic attribute in the system.* * namespace use the generic infrastructure to resolve a handler -- cgit v1.2.3 From 0caa102da82799efaba88e234484786a9591c797 Mon Sep 17 00:00:00 2001 From: Li Zefan Date: Mon, 20 Dec 2010 16:30:25 +0800 Subject: Btrfs: Add BTRFS_IOC_SUBVOL_GETFLAGS/SETFLAGS ioctls This allows us to set a snapshot or a subvolume readonly or writable on the fly. Usage: Set BTRFS_SUBVOL_RDONLY of btrfs_ioctl_vol_arg_v2->flags, and then call ioctl(BTRFS_IOCTL_SUBVOL_SETFLAGS); Changelog for v3: - Change to pass __u64 as ioctl parameter. Changelog for v2: - Add _GETFLAGS ioctl. - Check if the passed fd is the root of a subvolume. - Change the name from _SNAP_SETFLAGS to _SUBVOL_SETFLAGS. Signed-off-by: Li Zefan --- fs/btrfs/ioctl.c | 83 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++ fs/btrfs/ioctl.h | 2 ++ 2 files changed, 85 insertions(+) (limited to 'fs') diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c index f066ccb5dddf..ad1983524f97 100644 --- a/fs/btrfs/ioctl.c +++ b/fs/btrfs/ioctl.c @@ -1009,6 +1009,85 @@ out: return ret; } +static noinline int btrfs_ioctl_subvol_getflags(struct file *file, + void __user *arg) +{ + struct inode *inode = fdentry(file)->d_inode; + struct btrfs_root *root = BTRFS_I(inode)->root; + int ret = 0; + u64 flags = 0; + + if (inode->i_ino != BTRFS_FIRST_FREE_OBJECTID) + return -EINVAL; + + down_read(&root->fs_info->subvol_sem); + if (btrfs_root_readonly(root)) + flags |= BTRFS_SUBVOL_RDONLY; + up_read(&root->fs_info->subvol_sem); + + if (copy_to_user(arg, &flags, sizeof(flags))) + ret = -EFAULT; + + return ret; +} + +static noinline int btrfs_ioctl_subvol_setflags(struct file *file, + void __user *arg) +{ + struct inode *inode = fdentry(file)->d_inode; + struct btrfs_root *root = BTRFS_I(inode)->root; + struct btrfs_trans_handle *trans; + u64 root_flags; + u64 flags; + int ret = 0; + + if (root->fs_info->sb->s_flags & MS_RDONLY) + return -EROFS; + + if (inode->i_ino != BTRFS_FIRST_FREE_OBJECTID) + return -EINVAL; + + if (copy_from_user(&flags, arg, sizeof(flags))) + return -EFAULT; + + if (flags & ~BTRFS_SUBVOL_CREATE_ASYNC) + return -EINVAL; + + if (flags & ~BTRFS_SUBVOL_RDONLY) + return -EOPNOTSUPP; + + down_write(&root->fs_info->subvol_sem); + + /* nothing to do */ + if (!!(flags & BTRFS_SUBVOL_RDONLY) == btrfs_root_readonly(root)) + goto out; + + root_flags = btrfs_root_flags(&root->root_item); + 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, + root_flags & ~BTRFS_ROOT_SUBVOL_RDONLY); + + trans = btrfs_start_transaction(root, 1); + if (IS_ERR(trans)) { + ret = PTR_ERR(trans); + goto out_reset; + } + + ret = btrfs_update_root(trans, root, + &root->root_key, &root->root_item); + + btrfs_commit_transaction(trans, root); +out_reset: + if (ret) + btrfs_set_root_flags(&root->root_item, root_flags); +out: + up_write(&root->fs_info->subvol_sem); + return ret; +} + /* * helper to check if the subvolume references other subvolumes */ @@ -2282,6 +2361,10 @@ long btrfs_ioctl(struct file *file, unsigned int return btrfs_ioctl_snap_create(file, argp, 1); case BTRFS_IOC_SNAP_DESTROY: return btrfs_ioctl_snap_destroy(file, argp); + case BTRFS_IOC_SUBVOL_GETFLAGS: + return btrfs_ioctl_subvol_getflags(file, argp); + case BTRFS_IOC_SUBVOL_SETFLAGS: + return btrfs_ioctl_subvol_setflags(file, argp); case BTRFS_IOC_DEFAULT_SUBVOL: return btrfs_ioctl_default_subvol(file, argp); case BTRFS_IOC_DEFRAG: diff --git a/fs/btrfs/ioctl.h b/fs/btrfs/ioctl.h index 52ae489974be..1223223351fa 100644 --- a/fs/btrfs/ioctl.h +++ b/fs/btrfs/ioctl.h @@ -194,4 +194,6 @@ struct btrfs_ioctl_space_args { #define BTRFS_IOC_WAIT_SYNC _IOW(BTRFS_IOCTL_MAGIC, 22, __u64) #define BTRFS_IOC_SNAP_CREATE_V2 _IOW(BTRFS_IOCTL_MAGIC, 23, \ struct btrfs_ioctl_vol_args_v2) +#define BTRFS_IOC_SUBVOL_GETFLAGS _IOW(BTRFS_IOCTL_MAGIC, 25, __u64) +#define BTRFS_IOC_SUBVOL_SETFLAGS _IOW(BTRFS_IOCTL_MAGIC, 26, __u64) #endif -- cgit v1.2.3