diff options
author | Linus Torvalds <torvalds@linux-foundation.org> | 2014-04-04 14:03:05 -0700 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2014-04-04 14:03:05 -0700 |
commit | 7df934526c0b3775613502dcd19ab6d2da8cce1e (patch) | |
tree | 01e6a4ea20c676228f4acefc6ae776d2e52072db /fs/namei.c | |
parent | 3c83e61e67256e0bb08c46cc2db43b58fd617251 (diff) | |
parent | bd42998a6bcb9b1708dac9ca9876e3d304c16f3d (diff) | |
download | linux-7df934526c0b3775613502dcd19ab6d2da8cce1e.tar.bz2 |
Merge branch 'cross-rename' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/vfs
Pull renameat2 system call from Miklos Szeredi:
"This adds a new syscall, renameat2(), which is the same as renameat()
but with a flags argument.
The purpose of extending rename is to add cross-rename, a symmetric
variant of rename, which exchanges the two files. This allows
interesting things, which were not possible before, for example
atomically replacing a directory tree with a symlink, etc... This
also allows overlayfs and friends to operate on whiteouts atomically.
Andy Lutomirski also suggested a "noreplace" flag, which disables the
overwriting behavior of rename.
These two flags, RENAME_EXCHANGE and RENAME_NOREPLACE are only
implemented for ext4 as an example and for testing"
* 'cross-rename' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/vfs:
ext4: add cross rename support
ext4: rename: split out helper functions
ext4: rename: move EMLINK check up
ext4: rename: create ext4_renament structure for local vars
vfs: add cross-rename
vfs: lock_two_nondirectories: allow directory args
security: add flags to rename hooks
vfs: add RENAME_NOREPLACE flag
vfs: add renameat2 syscall
vfs: rename: use common code for dir and non-dir
vfs: rename: move d_move() up
vfs: add d_is_dir()
Diffstat (limited to 'fs/namei.c')
-rw-r--r-- | fs/namei.c | 315 |
1 files changed, 171 insertions, 144 deletions
diff --git a/fs/namei.c b/fs/namei.c index 4b491b431990..c1178880f23c 100644 --- a/fs/namei.c +++ b/fs/namei.c @@ -1796,7 +1796,7 @@ static int link_path_walk(const char *name, struct nameidata *nd) if (err) return err; } - if (!d_is_directory(nd->path.dentry)) { + if (!d_can_lookup(nd->path.dentry)) { err = -ENOTDIR; break; } @@ -1817,7 +1817,7 @@ static int path_init(int dfd, const char *name, unsigned int flags, struct dentry *root = nd->root.dentry; struct inode *inode = root->d_inode; if (*name) { - if (!d_is_directory(root)) + if (!d_can_lookup(root)) return -ENOTDIR; retval = inode_permission(inode, MAY_EXEC); if (retval) @@ -1873,7 +1873,7 @@ static int path_init(int dfd, const char *name, unsigned int flags, dentry = f.file->f_path.dentry; if (*name) { - if (!d_is_directory(dentry)) { + if (!d_can_lookup(dentry)) { fdput(f); return -ENOTDIR; } @@ -1955,7 +1955,7 @@ static int path_lookupat(int dfd, const char *name, err = complete_walk(nd); if (!err && nd->flags & LOOKUP_DIRECTORY) { - if (!d_is_directory(nd->path.dentry)) { + if (!d_can_lookup(nd->path.dentry)) { path_put(&nd->path); err = -ENOTDIR; } @@ -2414,11 +2414,11 @@ static int may_delete(struct inode *dir, struct dentry *victim, bool isdir) IS_IMMUTABLE(inode) || IS_SWAPFILE(inode)) return -EPERM; if (isdir) { - if (!d_is_directory(victim) && !d_is_autodir(victim)) + if (!d_is_dir(victim)) return -ENOTDIR; if (IS_ROOT(victim)) return -EBUSY; - } else if (d_is_directory(victim) || d_is_autodir(victim)) + } else if (d_is_dir(victim)) return -EISDIR; if (IS_DEADDIR(dir)) return -ENOENT; @@ -3016,11 +3016,10 @@ finish_open: } audit_inode(name, nd->path.dentry, 0); error = -EISDIR; - if ((open_flag & O_CREAT) && - (d_is_directory(nd->path.dentry) || d_is_autodir(nd->path.dentry))) + if ((open_flag & O_CREAT) && d_is_dir(nd->path.dentry)) goto out; error = -ENOTDIR; - if ((nd->flags & LOOKUP_DIRECTORY) && !d_is_directory(nd->path.dentry)) + if ((nd->flags & LOOKUP_DIRECTORY) && !d_can_lookup(nd->path.dentry)) goto out; if (!S_ISREG(nd->inode->i_mode)) will_truncate = false; @@ -3744,7 +3743,7 @@ exit1: slashes: if (d_is_negative(dentry)) error = -ENOENT; - else if (d_is_directory(dentry) || d_is_autodir(dentry)) + else if (d_is_dir(dentry)) error = -EISDIR; else error = -ENOTDIR; @@ -3974,7 +3973,28 @@ SYSCALL_DEFINE2(link, const char __user *, oldname, const char __user *, newname return sys_linkat(AT_FDCWD, oldname, AT_FDCWD, newname, 0); } -/* +/** + * vfs_rename - rename a filesystem object + * @old_dir: parent of source + * @old_dentry: source + * @new_dir: parent of destination + * @new_dentry: destination + * @delegated_inode: returns an inode needing a delegation break + * @flags: rename flags + * + * The caller must hold multiple mutexes--see lock_rename()). + * + * If vfs_rename discovers a delegation in need of breaking at either + * the source or destination, it will return -EWOULDBLOCK and return a + * reference to the inode in delegated_inode. The caller should then + * break the delegation and retry. Because breaking a delegation may + * take a long time, the caller should drop all locks before doing + * so. + * + * Alternatively, a caller may pass NULL for delegated_inode. This may + * be appropriate for callers that expect the underlying filesystem not + * to be NFS exported. + * * The worst of all namespace operations - renaming directory. "Perverted" * doesn't even start to describe it. Somebody in UCB had a heck of a trip... * Problems: @@ -4002,163 +4022,139 @@ SYSCALL_DEFINE2(link, const char __user *, oldname, const char __user *, newname * ->i_mutex on parents, which works but leads to some truly excessive * locking]. */ -static int vfs_rename_dir(struct inode *old_dir, struct dentry *old_dentry, - struct inode *new_dir, struct dentry *new_dentry) +int vfs_rename(struct inode *old_dir, struct dentry *old_dentry, + struct inode *new_dir, struct dentry *new_dentry, + struct inode **delegated_inode, unsigned int flags) { - int error = 0; + int error; + bool is_dir = d_is_dir(old_dentry); + const unsigned char *old_name; + struct inode *source = old_dentry->d_inode; struct inode *target = new_dentry->d_inode; + bool new_is_dir = false; unsigned max_links = new_dir->i_sb->s_max_links; + if (source == target) + return 0; + + error = may_delete(old_dir, old_dentry, is_dir); + if (error) + return error; + + if (!target) { + error = may_create(new_dir, new_dentry); + } else { + new_is_dir = d_is_dir(new_dentry); + + if (!(flags & RENAME_EXCHANGE)) + error = may_delete(new_dir, new_dentry, is_dir); + else + error = may_delete(new_dir, new_dentry, new_is_dir); + } + if (error) + return error; + + if (!old_dir->i_op->rename) + return -EPERM; + + if (flags && !old_dir->i_op->rename2) + return -EINVAL; + /* * If we are going to change the parent - check write permissions, * we'll need to flip '..'. */ if (new_dir != old_dir) { - error = inode_permission(old_dentry->d_inode, MAY_WRITE); - if (error) - return error; + if (is_dir) { + error = inode_permission(source, MAY_WRITE); + if (error) + return error; + } + if ((flags & RENAME_EXCHANGE) && new_is_dir) { + error = inode_permission(target, MAY_WRITE); + if (error) + return error; + } } - error = security_inode_rename(old_dir, old_dentry, new_dir, new_dentry); + error = security_inode_rename(old_dir, old_dentry, new_dir, new_dentry, + flags); if (error) return error; + old_name = fsnotify_oldname_init(old_dentry->d_name.name); dget(new_dentry); - if (target) + if (!is_dir || (flags & RENAME_EXCHANGE)) + lock_two_nondirectories(source, target); + else if (target) mutex_lock(&target->i_mutex); error = -EBUSY; if (d_mountpoint(old_dentry) || d_mountpoint(new_dentry)) goto out; - error = -EMLINK; - if (max_links && !target && new_dir != old_dir && - new_dir->i_nlink >= max_links) - goto out; - - if (target) + if (max_links && new_dir != old_dir) { + error = -EMLINK; + if (is_dir && !new_is_dir && new_dir->i_nlink >= max_links) + goto out; + if ((flags & RENAME_EXCHANGE) && !is_dir && new_is_dir && + old_dir->i_nlink >= max_links) + goto out; + } + if (is_dir && !(flags & RENAME_EXCHANGE) && target) shrink_dcache_parent(new_dentry); - error = old_dir->i_op->rename(old_dir, old_dentry, new_dir, new_dentry); - if (error) - goto out; - - if (target) { - target->i_flags |= S_DEAD; - dont_mount(new_dentry); + if (!is_dir) { + error = try_break_deleg(source, delegated_inode); + if (error) + goto out; } -out: - if (target) - mutex_unlock(&target->i_mutex); - dput(new_dentry); - if (!error) - if (!(old_dir->i_sb->s_type->fs_flags & FS_RENAME_DOES_D_MOVE)) - d_move(old_dentry,new_dentry); - return error; -} - -static int vfs_rename_other(struct inode *old_dir, struct dentry *old_dentry, - struct inode *new_dir, struct dentry *new_dentry, - struct inode **delegated_inode) -{ - struct inode *target = new_dentry->d_inode; - struct inode *source = old_dentry->d_inode; - int error; - - error = security_inode_rename(old_dir, old_dentry, new_dir, new_dentry); - if (error) - return error; - - dget(new_dentry); - lock_two_nondirectories(source, target); - - error = -EBUSY; - if (d_mountpoint(old_dentry)||d_mountpoint(new_dentry)) - goto out; - - error = try_break_deleg(source, delegated_inode); - if (error) - goto out; - if (target) { + if (target && !new_is_dir) { error = try_break_deleg(target, delegated_inode); if (error) goto out; } - error = old_dir->i_op->rename(old_dir, old_dentry, new_dir, new_dentry); + if (!flags) { + error = old_dir->i_op->rename(old_dir, old_dentry, + new_dir, new_dentry); + } else { + error = old_dir->i_op->rename2(old_dir, old_dentry, + new_dir, new_dentry, flags); + } if (error) goto out; - if (target) + if (!(flags & RENAME_EXCHANGE) && target) { + if (is_dir) + target->i_flags |= S_DEAD; dont_mount(new_dentry); - if (!(old_dir->i_sb->s_type->fs_flags & FS_RENAME_DOES_D_MOVE)) - d_move(old_dentry, new_dentry); + } + if (!(old_dir->i_sb->s_type->fs_flags & FS_RENAME_DOES_D_MOVE)) { + if (!(flags & RENAME_EXCHANGE)) + d_move(old_dentry, new_dentry); + else + d_exchange(old_dentry, new_dentry); + } out: - unlock_two_nondirectories(source, target); + if (!is_dir || (flags & RENAME_EXCHANGE)) + unlock_two_nondirectories(source, target); + else if (target) + mutex_unlock(&target->i_mutex); dput(new_dentry); - return error; -} - -/** - * vfs_rename - rename a filesystem object - * @old_dir: parent of source - * @old_dentry: source - * @new_dir: parent of destination - * @new_dentry: destination - * @delegated_inode: returns an inode needing a delegation break - * - * The caller must hold multiple mutexes--see lock_rename()). - * - * If vfs_rename discovers a delegation in need of breaking at either - * the source or destination, it will return -EWOULDBLOCK and return a - * reference to the inode in delegated_inode. The caller should then - * break the delegation and retry. Because breaking a delegation may - * take a long time, the caller should drop all locks before doing - * so. - * - * Alternatively, a caller may pass NULL for delegated_inode. This may - * be appropriate for callers that expect the underlying filesystem not - * to be NFS exported. - */ -int vfs_rename(struct inode *old_dir, struct dentry *old_dentry, - struct inode *new_dir, struct dentry *new_dentry, - struct inode **delegated_inode) -{ - int error; - int is_dir = d_is_directory(old_dentry) || d_is_autodir(old_dentry); - const unsigned char *old_name; - - if (old_dentry->d_inode == new_dentry->d_inode) - return 0; - - error = may_delete(old_dir, old_dentry, is_dir); - if (error) - return error; - - if (!new_dentry->d_inode) - error = may_create(new_dir, new_dentry); - else - error = may_delete(new_dir, new_dentry, is_dir); - if (error) - return error; - - if (!old_dir->i_op->rename) - return -EPERM; - - old_name = fsnotify_oldname_init(old_dentry->d_name.name); - - if (is_dir) - error = vfs_rename_dir(old_dir,old_dentry,new_dir,new_dentry); - else - error = vfs_rename_other(old_dir,old_dentry,new_dir,new_dentry,delegated_inode); - if (!error) + if (!error) { fsnotify_move(old_dir, new_dir, old_name, is_dir, - new_dentry->d_inode, old_dentry); + !(flags & RENAME_EXCHANGE) ? target : NULL, old_dentry); + if (flags & RENAME_EXCHANGE) { + fsnotify_move(new_dir, old_dir, old_dentry->d_name.name, + new_is_dir, NULL, new_dentry); + } + } fsnotify_oldname_free(old_name); return error; } -SYSCALL_DEFINE4(renameat, int, olddfd, const char __user *, oldname, - int, newdfd, const char __user *, newname) +SYSCALL_DEFINE5(renameat2, int, olddfd, const char __user *, oldname, + int, newdfd, const char __user *, newname, unsigned int, flags) { struct dentry *old_dir, *new_dir; struct dentry *old_dentry, *new_dentry; @@ -4170,6 +4166,13 @@ SYSCALL_DEFINE4(renameat, int, olddfd, const char __user *, oldname, unsigned int lookup_flags = 0; bool should_retry = false; int error; + + if (flags & ~(RENAME_NOREPLACE | RENAME_EXCHANGE)) + return -EINVAL; + + if ((flags & RENAME_NOREPLACE) && (flags & RENAME_EXCHANGE)) + return -EINVAL; + retry: from = user_path_parent(olddfd, oldname, &oldnd, lookup_flags); if (IS_ERR(from)) { @@ -4193,6 +4196,8 @@ retry: goto exit2; new_dir = newnd.path.dentry; + if (flags & RENAME_NOREPLACE) + error = -EEXIST; if (newnd.last_type != LAST_NORM) goto exit2; @@ -4202,7 +4207,8 @@ retry: oldnd.flags &= ~LOOKUP_PARENT; newnd.flags &= ~LOOKUP_PARENT; - newnd.flags |= LOOKUP_RENAME_TARGET; + if (!(flags & RENAME_EXCHANGE)) + newnd.flags |= LOOKUP_RENAME_TARGET; retry_deleg: trap = lock_rename(new_dir, old_dir); @@ -4215,34 +4221,49 @@ retry_deleg: error = -ENOENT; if (d_is_negative(old_dentry)) goto exit4; + new_dentry = lookup_hash(&newnd); + error = PTR_ERR(new_dentry); + if (IS_ERR(new_dentry)) + goto exit4; + error = -EEXIST; + if ((flags & RENAME_NOREPLACE) && d_is_positive(new_dentry)) + goto exit5; + if (flags & RENAME_EXCHANGE) { + error = -ENOENT; + if (d_is_negative(new_dentry)) + goto exit5; + + if (!d_is_dir(new_dentry)) { + error = -ENOTDIR; + if (newnd.last.name[newnd.last.len]) + goto exit5; + } + } /* unless the source is a directory trailing slashes give -ENOTDIR */ - if (!d_is_directory(old_dentry) && !d_is_autodir(old_dentry)) { + if (!d_is_dir(old_dentry)) { error = -ENOTDIR; if (oldnd.last.name[oldnd.last.len]) - goto exit4; - if (newnd.last.name[newnd.last.len]) - goto exit4; + goto exit5; + if (!(flags & RENAME_EXCHANGE) && newnd.last.name[newnd.last.len]) + goto exit5; } /* source should not be ancestor of target */ error = -EINVAL; if (old_dentry == trap) - goto exit4; - new_dentry = lookup_hash(&newnd); - error = PTR_ERR(new_dentry); - if (IS_ERR(new_dentry)) - goto exit4; + goto exit5; /* target should not be an ancestor of source */ - error = -ENOTEMPTY; + if (!(flags & RENAME_EXCHANGE)) + error = -ENOTEMPTY; if (new_dentry == trap) goto exit5; error = security_path_rename(&oldnd.path, old_dentry, - &newnd.path, new_dentry); + &newnd.path, new_dentry, flags); if (error) goto exit5; error = vfs_rename(old_dir->d_inode, old_dentry, - new_dir->d_inode, new_dentry, - &delegated_inode); + new_dir->d_inode, new_dentry, + &delegated_inode, flags); exit5: dput(new_dentry); exit4: @@ -4272,9 +4293,15 @@ exit: return error; } +SYSCALL_DEFINE4(renameat, int, olddfd, const char __user *, oldname, + int, newdfd, const char __user *, newname) +{ + return sys_renameat2(olddfd, oldname, newdfd, newname, 0); +} + SYSCALL_DEFINE2(rename, const char __user *, oldname, const char __user *, newname) { - return sys_renameat(AT_FDCWD, oldname, AT_FDCWD, newname); + return sys_renameat2(AT_FDCWD, oldname, AT_FDCWD, newname, 0); } int vfs_readlink(struct dentry *dentry, char __user *buffer, int buflen, const char *link) |