diff options
Diffstat (limited to 'fs/ocfs2/refcounttree.c')
| -rw-r--r-- | fs/ocfs2/refcounttree.c | 166 |
1 files changed, 166 insertions, 0 deletions
diff --git a/fs/ocfs2/refcounttree.c b/fs/ocfs2/refcounttree.c index 7a8a384d8ad1..60287fc56bcb 100644 --- a/fs/ocfs2/refcounttree.c +++ b/fs/ocfs2/refcounttree.c @@ -42,6 +42,11 @@ #include <linux/writeback.h> #include <linux/pagevec.h> #include <linux/swap.h> +#include <linux/security.h> +#include <linux/fsnotify.h> +#include <linux/quotaops.h> +#include <linux/namei.h> +#include <linux/mount.h> struct ocfs2_cow_context { struct inode *inode; @@ -4145,3 +4150,164 @@ out: return error; } + +/* + * Below here are the bits used by OCFS2_IOC_REFLINK() to fake + * sys_reflink(). This will go away when vfs_reflink() exists in + * fs/namei.c. + */ + +/* copied from may_create in VFS. */ +static inline int ocfs2_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); +} + +/* copied from user_path_parent. */ +static int ocfs2_user_path_parent(const char __user *path, + struct nameidata *nd, char **name) +{ + char *s = getname(path); + int error; + + if (IS_ERR(s)) + return PTR_ERR(s); + + error = path_lookup(s, LOOKUP_PARENT, nd); + if (error) + putname(s); + else + *name = s; + + return error; +} + +/** + * ocfs2_vfs_reflink - Create a reference-counted link + * + * @old_dentry: source dentry + inode + * @dir: directory to create the target + * @new_dentry: target dentry + * @preserve: if true, preserve all file attributes + */ +int ocfs2_vfs_reflink(struct dentry *old_dentry, struct inode *dir, + struct dentry *new_dentry, bool preserve) +{ + struct inode *inode = old_dentry->d_inode; + int error; + + if (!inode) + return -ENOENT; + + error = ocfs2_may_create(dir, new_dentry); + if (error) + return error; + + if (dir->i_sb != inode->i_sb) + return -EXDEV; + + /* + * A reflink to an append-only or immutable file cannot be created. + */ + if (IS_APPEND(inode) || IS_IMMUTABLE(inode)) + return -EPERM; + + /* Only regular files can be reflinked. */ + if (!S_ISREG(inode->i_mode)) + return -EPERM; + + /* + * If the caller wants to preserve ownership, they require the + * rights to do so. + */ + if (preserve) { + if ((current_fsuid() != inode->i_uid) && !capable(CAP_CHOWN)) + return -EPERM; + if (!in_group_p(inode->i_gid) && !capable(CAP_CHOWN)) + return -EPERM; + } + + /* + * If the caller is modifying any aspect of the attributes, they + * are not creating a snapshot. They need read permission on the + * file. + */ + if (!preserve) { + error = inode_permission(inode, MAY_READ); + if (error) + return error; + } + + mutex_lock(&inode->i_mutex); + vfs_dq_init(dir); + error = ocfs2_reflink(old_dentry, dir, new_dentry, preserve); + mutex_unlock(&inode->i_mutex); + if (!error) + fsnotify_create(dir, new_dentry); + return error; +} +/* + * Most codes are copied from sys_linkat. + */ +int ocfs2_reflink_ioctl(struct inode *inode, + const char __user *oldname, + const char __user *newname, + bool preserve) +{ + struct dentry *new_dentry; + struct nameidata nd; + struct path old_path; + int error; + char *to = NULL; + + if (!ocfs2_refcount_tree(OCFS2_SB(inode->i_sb))) + return -EOPNOTSUPP; + + error = user_path_at(AT_FDCWD, oldname, 0, &old_path); + if (error) { + mlog_errno(error); + return error; + } + + error = ocfs2_user_path_parent(newname, &nd, &to); + if (error) { + mlog_errno(error); + goto out; + } + + error = -EXDEV; + if (old_path.mnt != nd.path.mnt) + goto out_release; + new_dentry = lookup_create(&nd, 0); + error = PTR_ERR(new_dentry); + if (IS_ERR(new_dentry)) { + mlog_errno(error); + goto out_unlock; + } + + error = mnt_want_write(nd.path.mnt); + if (error) { + mlog_errno(error); + goto out_dput; + } + + error = ocfs2_vfs_reflink(old_path.dentry, + nd.path.dentry->d_inode, + new_dentry, preserve); + mnt_drop_write(nd.path.mnt); +out_dput: + dput(new_dentry); +out_unlock: + mutex_unlock(&nd.path.dentry->d_inode->i_mutex); +out_release: + path_put(&nd.path); + putname(to); +out: + path_put(&old_path); + + return error; +} |