diff options
Diffstat (limited to 'fs/namei.c')
-rw-r--r-- | fs/namei.c | 332 |
1 files changed, 199 insertions, 133 deletions
diff --git a/fs/namei.c b/fs/namei.c index 645268f23eb6..3531deebad30 100644 --- a/fs/namei.c +++ b/fs/namei.c @@ -482,18 +482,6 @@ EXPORT_SYMBOL(path_put); * to restart the path walk from the beginning in ref-walk mode. */ -static inline void lock_rcu_walk(void) -{ - br_read_lock(&vfsmount_lock); - rcu_read_lock(); -} - -static inline void unlock_rcu_walk(void) -{ - rcu_read_unlock(); - br_read_unlock(&vfsmount_lock); -} - /** * unlazy_walk - try to switch to ref-walk mode. * @nd: nameidata pathwalk data @@ -512,26 +500,22 @@ static int unlazy_walk(struct nameidata *nd, struct dentry *dentry) BUG_ON(!(nd->flags & LOOKUP_RCU)); /* - * Get a reference to the parent first: we're - * going to make "path_put(nd->path)" valid in - * non-RCU context for "terminate_walk()". - * - * If this doesn't work, return immediately with - * RCU walking still active (and then we will do - * the RCU walk cleanup in terminate_walk()). + * After legitimizing the bastards, terminate_walk() + * will do the right thing for non-RCU mode, and all our + * subsequent exit cases should rcu_read_unlock() + * before returning. Do vfsmount first; if dentry + * can't be legitimized, just set nd->path.dentry to NULL + * and rely on dput(NULL) being a no-op. */ - if (!lockref_get_not_dead(&parent->d_lockref)) + if (!legitimize_mnt(nd->path.mnt, nd->m_seq)) return -ECHILD; - - /* - * After the mntget(), we terminate_walk() will do - * the right thing for non-RCU mode, and all our - * subsequent exit cases should unlock_rcu_walk() - * before returning. - */ - mntget(nd->path.mnt); nd->flags &= ~LOOKUP_RCU; + if (!lockref_get_not_dead(&parent->d_lockref)) { + nd->path.dentry = NULL; + goto out; + } + /* * For a negative lookup, the lookup sequence point is the parents * sequence point, and it only needs to revalidate the parent dentry. @@ -566,17 +550,17 @@ static int unlazy_walk(struct nameidata *nd, struct dentry *dentry) spin_unlock(&fs->lock); } - unlock_rcu_walk(); + rcu_read_unlock(); return 0; unlock_and_drop_dentry: spin_unlock(&fs->lock); drop_dentry: - unlock_rcu_walk(); + rcu_read_unlock(); dput(dentry); goto drop_root_mnt; out: - unlock_rcu_walk(); + rcu_read_unlock(); drop_root_mnt: if (!(nd->flags & LOOKUP_ROOT)) nd->root.mnt = NULL; @@ -608,17 +592,22 @@ static int complete_walk(struct nameidata *nd) if (!(nd->flags & LOOKUP_ROOT)) nd->root.mnt = NULL; + if (!legitimize_mnt(nd->path.mnt, nd->m_seq)) { + rcu_read_unlock(); + return -ECHILD; + } if (unlikely(!lockref_get_not_dead(&dentry->d_lockref))) { - unlock_rcu_walk(); + rcu_read_unlock(); + mntput(nd->path.mnt); return -ECHILD; } if (read_seqcount_retry(&dentry->d_seq, nd->seq)) { - unlock_rcu_walk(); + rcu_read_unlock(); dput(dentry); + mntput(nd->path.mnt); return -ECHILD; } - mntget(nd->path.mnt); - unlock_rcu_walk(); + rcu_read_unlock(); } if (likely(!(nd->flags & LOOKUP_JUMPED))) @@ -909,15 +898,15 @@ int follow_up(struct path *path) struct mount *parent; struct dentry *mountpoint; - br_read_lock(&vfsmount_lock); + read_seqlock_excl(&mount_lock); parent = mnt->mnt_parent; if (parent == mnt) { - br_read_unlock(&vfsmount_lock); + read_sequnlock_excl(&mount_lock); return 0; } mntget(&parent->mnt); mountpoint = dget(mnt->mnt_mountpoint); - br_read_unlock(&vfsmount_lock); + read_sequnlock_excl(&mount_lock); dput(path->dentry); path->dentry = mountpoint; mntput(path->mnt); @@ -1048,8 +1037,8 @@ static int follow_managed(struct path *path, unsigned flags) /* Something is mounted on this dentry in another * namespace and/or whatever was mounted there in this - * namespace got unmounted before we managed to get the - * vfsmount_lock */ + * namespace got unmounted before lookup_mnt() could + * get it */ } /* Handle an automount point */ @@ -1111,7 +1100,7 @@ static bool __follow_mount_rcu(struct nameidata *nd, struct path *path, if (!d_mountpoint(path->dentry)) break; - mounted = __lookup_mnt(path->mnt, path->dentry, 1); + mounted = __lookup_mnt(path->mnt, path->dentry); if (!mounted) break; path->mnt = &mounted->mnt; @@ -1132,7 +1121,7 @@ static void follow_mount_rcu(struct nameidata *nd) { while (d_mountpoint(nd->path.dentry)) { struct mount *mounted; - mounted = __lookup_mnt(nd->path.mnt, nd->path.dentry, 1); + mounted = __lookup_mnt(nd->path.mnt, nd->path.dentry); if (!mounted) break; nd->path.mnt = &mounted->mnt; @@ -1174,7 +1163,7 @@ failed: nd->flags &= ~LOOKUP_RCU; if (!(nd->flags & LOOKUP_ROOT)) nd->root.mnt = NULL; - unlock_rcu_walk(); + rcu_read_unlock(); return -ECHILD; } @@ -1308,8 +1297,8 @@ static struct dentry *lookup_dcache(struct qstr *name, struct dentry *dir, } /* - * Call i_op->lookup on the dentry. The dentry must be negative but may be - * hashed if it was pouplated with DCACHE_NEED_LOOKUP. + * Call i_op->lookup on the dentry. The dentry must be negative and + * unhashed. * * dir->d_inode->i_mutex must be held */ @@ -1501,7 +1490,7 @@ static void terminate_walk(struct nameidata *nd) nd->flags &= ~LOOKUP_RCU; if (!(nd->flags & LOOKUP_ROOT)) nd->root.mnt = NULL; - unlock_rcu_walk(); + rcu_read_unlock(); } } @@ -1511,18 +1500,9 @@ static void terminate_walk(struct nameidata *nd) * so we keep a cache of "no, this doesn't need follow_link" * for the common case. */ -static inline int should_follow_link(struct inode *inode, int follow) +static inline int should_follow_link(struct dentry *dentry, int follow) { - if (unlikely(!(inode->i_opflags & IOP_NOFOLLOW))) { - if (likely(inode->i_op->follow_link)) - return follow; - - /* This gets set once for the inode lifetime */ - spin_lock(&inode->i_lock); - inode->i_opflags |= IOP_NOFOLLOW; - spin_unlock(&inode->i_lock); - } - return 0; + return unlikely(d_is_symlink(dentry)) ? follow : 0; } static inline int walk_component(struct nameidata *nd, struct path *path, @@ -1552,7 +1532,7 @@ static inline int walk_component(struct nameidata *nd, struct path *path, if (!inode) goto out_path_put; - if (should_follow_link(inode, follow)) { + if (should_follow_link(path->dentry, follow)) { if (nd->flags & LOOKUP_RCU) { if (unlikely(unlazy_walk(nd, path->dentry))) { err = -ECHILD; @@ -1611,26 +1591,6 @@ static inline int nested_symlink(struct path *path, struct nameidata *nd) } /* - * We really don't want to look at inode->i_op->lookup - * when we don't have to. So we keep a cache bit in - * the inode ->i_opflags field that says "yes, we can - * do lookup on this inode". - */ -static inline int can_lookup(struct inode *inode) -{ - if (likely(inode->i_opflags & IOP_LOOKUP)) - return 1; - if (likely(!inode->i_op->lookup)) - return 0; - - /* We do this once for the lifetime of the inode */ - spin_lock(&inode->i_lock); - inode->i_opflags |= IOP_LOOKUP; - spin_unlock(&inode->i_lock); - return 1; -} - -/* * We can do the critical dentry name comparison and hashing * operations one word at a time, but we are limited to: * @@ -1638,11 +1598,6 @@ static inline int can_lookup(struct inode *inode) * do a "get_unaligned()" if this helps and is sufficiently * fast. * - * - Little-endian machines (so that we can generate the mask - * of low bytes efficiently). Again, we *could* do a byte - * swapping load on big-endian architectures if that is not - * expensive enough to make the optimization worthless. - * * - non-CONFIG_DEBUG_PAGEALLOC configurations (so that we * do not trap on the (extremely unlikely) case of a page * crossing operation. @@ -1686,7 +1641,7 @@ unsigned int full_name_hash(const unsigned char *name, unsigned int len) if (!len) goto done; } - mask = ~(~0ul << len*8); + mask = bytemask_from_count(len); hash += mask & a; done: return fold_hash(hash); @@ -1833,7 +1788,7 @@ static int link_path_walk(const char *name, struct nameidata *nd) if (err) return err; } - if (!can_lookup(nd->inode)) { + if (!d_is_directory(nd->path.dentry)) { err = -ENOTDIR; break; } @@ -1851,9 +1806,10 @@ static int path_init(int dfd, const char *name, unsigned int flags, nd->flags = flags | LOOKUP_JUMPED; nd->depth = 0; if (flags & LOOKUP_ROOT) { - struct inode *inode = nd->root.dentry->d_inode; + struct dentry *root = nd->root.dentry; + struct inode *inode = root->d_inode; if (*name) { - if (!can_lookup(inode)) + if (!d_is_directory(root)) return -ENOTDIR; retval = inode_permission(inode, MAY_EXEC); if (retval) @@ -1862,8 +1818,9 @@ static int path_init(int dfd, const char *name, unsigned int flags, nd->path = nd->root; nd->inode = inode; if (flags & LOOKUP_RCU) { - lock_rcu_walk(); + rcu_read_lock(); nd->seq = __read_seqcount_begin(&nd->path.dentry->d_seq); + nd->m_seq = read_seqbegin(&mount_lock); } else { path_get(&nd->path); } @@ -1872,9 +1829,10 @@ static int path_init(int dfd, const char *name, unsigned int flags, nd->root.mnt = NULL; + nd->m_seq = read_seqbegin(&mount_lock); if (*name=='/') { if (flags & LOOKUP_RCU) { - lock_rcu_walk(); + rcu_read_lock(); set_root_rcu(nd); } else { set_root(nd); @@ -1886,7 +1844,7 @@ static int path_init(int dfd, const char *name, unsigned int flags, struct fs_struct *fs = current->fs; unsigned seq; - lock_rcu_walk(); + rcu_read_lock(); do { seq = read_seqcount_begin(&fs->seq); @@ -1907,7 +1865,7 @@ static int path_init(int dfd, const char *name, unsigned int flags, dentry = f.file->f_path.dentry; if (*name) { - if (!can_lookup(dentry->d_inode)) { + if (!d_is_directory(dentry)) { fdput(f); return -ENOTDIR; } @@ -1918,7 +1876,7 @@ static int path_init(int dfd, const char *name, unsigned int flags, if (f.need_put) *fp = f.file; nd->seq = __read_seqcount_begin(&nd->path.dentry->d_seq); - lock_rcu_walk(); + rcu_read_lock(); } else { path_get(&nd->path); fdput(f); @@ -1989,7 +1947,7 @@ static int path_lookupat(int dfd, const char *name, err = complete_walk(nd); if (!err && nd->flags & LOOKUP_DIRECTORY) { - if (!can_lookup(nd->inode)) { + if (!d_is_directory(nd->path.dentry)) { path_put(&nd->path); err = -ENOTDIR; } @@ -2281,7 +2239,7 @@ done: } path->dentry = dentry; path->mnt = mntget(nd->path.mnt); - if (should_follow_link(dentry->d_inode, nd->flags & LOOKUP_FOLLOW)) + if (should_follow_link(dentry, nd->flags & LOOKUP_FOLLOW)) return 1; follow_mount(path); error = 0; @@ -2294,10 +2252,11 @@ out: * path_mountpoint - look up a path to be umounted * @dfd: directory file descriptor to start walk from * @name: full pathname to walk + * @path: pointer to container for result * @flags: lookup flags * * Look up the given name, but don't attempt to revalidate the last component. - * Returns 0 and "path" will be valid on success; Retuns error otherwise. + * Returns 0 and "path" will be valid on success; Returns error otherwise. */ static int path_mountpoint(int dfd, const char *name, struct path *path, unsigned int flags) @@ -2425,12 +2384,14 @@ static inline int check_sticky(struct inode *dir, struct inode *inode) * 10. We don't allow removal of NFS sillyrenamed files; it's handled by * nfs_async_unlink(). */ -static int may_delete(struct inode *dir,struct dentry *victim,int isdir) +static int may_delete(struct inode *dir, struct dentry *victim, bool isdir) { + struct inode *inode = victim->d_inode; int error; - if (!victim->d_inode) + if (d_is_negative(victim)) return -ENOENT; + BUG_ON(!inode); BUG_ON(victim->d_parent->d_inode != dir); audit_inode_child(dir, victim, AUDIT_TYPE_CHILD_DELETE); @@ -2440,15 +2401,16 @@ static int may_delete(struct inode *dir,struct dentry *victim,int isdir) return error; if (IS_APPEND(dir)) return -EPERM; - if (check_sticky(dir, victim->d_inode)||IS_APPEND(victim->d_inode)|| - IS_IMMUTABLE(victim->d_inode) || IS_SWAPFILE(victim->d_inode)) + + if (check_sticky(dir, inode) || IS_APPEND(inode) || + IS_IMMUTABLE(inode) || IS_SWAPFILE(inode)) return -EPERM; if (isdir) { - if (!S_ISDIR(victim->d_inode->i_mode)) + if (!d_is_directory(victim) && !d_is_autodir(victim)) return -ENOTDIR; if (IS_ROOT(victim)) return -EBUSY; - } else if (S_ISDIR(victim->d_inode->i_mode)) + } else if (d_is_directory(victim) || d_is_autodir(victim)) return -EISDIR; if (IS_DEADDIR(dir)) return -ENOENT; @@ -2467,6 +2429,7 @@ static int may_delete(struct inode *dir,struct dentry *victim,int isdir) */ static inline int may_create(struct inode *dir, struct dentry *child) { + audit_inode_child(dir, child, AUDIT_TYPE_CHILD_CREATE); if (child->d_inode) return -EEXIST; if (IS_DEADDIR(dir)) @@ -2982,7 +2945,7 @@ retry_lookup: /* * create/update audit record if it already exists. */ - if (path->dentry->d_inode) + if (d_is_positive(path->dentry)) audit_inode(name, path->dentry, 0); /* @@ -3011,12 +2974,12 @@ retry_lookup: finish_lookup: /* we _can_ be in RCU mode here */ error = -ENOENT; - if (!inode) { + if (d_is_negative(path->dentry)) { path_to_nameidata(path, nd); goto out; } - if (should_follow_link(inode, !symlink_ok)) { + if (should_follow_link(path->dentry, !symlink_ok)) { if (nd->flags & LOOKUP_RCU) { if (unlikely(unlazy_walk(nd, path->dentry))) { error = -ECHILD; @@ -3045,10 +3008,11 @@ finish_open: } audit_inode(name, nd->path.dentry, 0); error = -EISDIR; - if ((open_flag & O_CREAT) && S_ISDIR(nd->inode->i_mode)) + if ((open_flag & O_CREAT) && + (d_is_directory(nd->path.dentry) || d_is_autodir(nd->path.dentry))) goto out; error = -ENOTDIR; - if ((nd->flags & LOOKUP_DIRECTORY) && !can_lookup(nd->inode)) + if ((nd->flags & LOOKUP_DIRECTORY) && !d_is_directory(nd->path.dentry)) goto out; if (!S_ISREG(nd->inode->i_mode)) will_truncate = false; @@ -3274,7 +3238,7 @@ struct file *do_file_open_root(struct dentry *dentry, struct vfsmount *mnt, nd.root.mnt = mnt; nd.root.dentry = dentry; - if (dentry->d_inode->i_op->follow_link && op->intent & LOOKUP_OPEN) + if (d_is_symlink(dentry) && op->intent & LOOKUP_OPEN) return ERR_PTR(-ELOOP); file = path_openat(-1, &filename, &nd, op, flags | LOOKUP_RCU); @@ -3324,8 +3288,9 @@ struct dentry *kern_path_create(int dfd, const char *pathname, goto unlock; error = -EEXIST; - if (dentry->d_inode) + if (d_is_positive(dentry)) goto fail; + /* * Special case - lookup gave negative, but... we had foo/bar/ * From the vfs_mknod() POV we just have a negative dentry - @@ -3646,8 +3611,27 @@ SYSCALL_DEFINE1(rmdir, const char __user *, pathname) return do_rmdir(AT_FDCWD, pathname); } -int vfs_unlink(struct inode *dir, struct dentry *dentry) +/** + * vfs_unlink - unlink a filesystem object + * @dir: parent directory + * @dentry: victim + * @delegated_inode: returns victim inode, if the inode is delegated. + * + * The caller must hold dir->i_mutex. + * + * If vfs_unlink discovers a delegation, it will return -EWOULDBLOCK and + * return a reference to the inode in delegated_inode. The caller + * should then break the delegation on that inode and retry. Because + * breaking a delegation may take a long time, the caller should drop + * dir->i_mutex 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_unlink(struct inode *dir, struct dentry *dentry, struct inode **delegated_inode) { + struct inode *target = dentry->d_inode; int error = may_delete(dir, dentry, 0); if (error) @@ -3656,22 +3640,26 @@ int vfs_unlink(struct inode *dir, struct dentry *dentry) if (!dir->i_op->unlink) return -EPERM; - mutex_lock(&dentry->d_inode->i_mutex); + mutex_lock(&target->i_mutex); if (d_mountpoint(dentry)) error = -EBUSY; else { error = security_inode_unlink(dir, dentry); if (!error) { + error = try_break_deleg(target, delegated_inode); + if (error) + goto out; error = dir->i_op->unlink(dir, dentry); if (!error) dont_mount(dentry); } } - mutex_unlock(&dentry->d_inode->i_mutex); +out: + mutex_unlock(&target->i_mutex); /* We don't d_delete() NFS sillyrenamed files--they still exist. */ if (!error && !(dentry->d_flags & DCACHE_NFSFS_RENAMED)) { - fsnotify_link_count(dentry->d_inode); + fsnotify_link_count(target); d_delete(dentry); } @@ -3691,6 +3679,7 @@ static long do_unlinkat(int dfd, const char __user *pathname) struct dentry *dentry; struct nameidata nd; struct inode *inode = NULL; + struct inode *delegated_inode = NULL; unsigned int lookup_flags = 0; retry: name = user_path_parent(dfd, pathname, &nd, lookup_flags); @@ -3705,7 +3694,7 @@ retry: error = mnt_want_write(nd.path.mnt); if (error) goto exit1; - +retry_deleg: mutex_lock_nested(&nd.path.dentry->d_inode->i_mutex, I_MUTEX_PARENT); dentry = lookup_hash(&nd); error = PTR_ERR(dentry); @@ -3714,19 +3703,25 @@ retry: if (nd.last.name[nd.last.len]) goto slashes; inode = dentry->d_inode; - if (!inode) + if (d_is_negative(dentry)) goto slashes; ihold(inode); error = security_path_unlink(&nd.path, dentry); if (error) goto exit2; - error = vfs_unlink(nd.path.dentry->d_inode, dentry); + error = vfs_unlink(nd.path.dentry->d_inode, dentry, &delegated_inode); exit2: dput(dentry); } mutex_unlock(&nd.path.dentry->d_inode->i_mutex); if (inode) iput(inode); /* truncate the inode here */ + inode = NULL; + if (delegated_inode) { + error = break_deleg_wait(&delegated_inode); + if (!error) + goto retry_deleg; + } mnt_drop_write(nd.path.mnt); exit1: path_put(&nd.path); @@ -3739,8 +3734,12 @@ exit1: return error; slashes: - error = !dentry->d_inode ? -ENOENT : - S_ISDIR(dentry->d_inode->i_mode) ? -EISDIR : -ENOTDIR; + if (d_is_negative(dentry)) + error = -ENOENT; + else if (d_is_directory(dentry) || d_is_autodir(dentry)) + error = -EISDIR; + else + error = -ENOTDIR; goto exit2; } @@ -3816,7 +3815,26 @@ SYSCALL_DEFINE2(symlink, const char __user *, oldname, const char __user *, newn return sys_symlinkat(oldname, AT_FDCWD, newname); } -int vfs_link(struct dentry *old_dentry, struct inode *dir, struct dentry *new_dentry) +/** + * vfs_link - create a new link + * @old_dentry: object to be linked + * @dir: new parent + * @new_dentry: where to create the new link + * @delegated_inode: returns inode needing a delegation break + * + * The caller must hold dir->i_mutex + * + * If vfs_link discovers a delegation on the to-be-linked file in need + * of breaking, 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 the i_mutex 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_link(struct dentry *old_dentry, struct inode *dir, struct dentry *new_dentry, struct inode **delegated_inode) { struct inode *inode = old_dentry->d_inode; unsigned max_links = dir->i_sb->s_max_links; @@ -3852,8 +3870,11 @@ int vfs_link(struct dentry *old_dentry, struct inode *dir, struct dentry *new_de error = -ENOENT; else if (max_links && inode->i_nlink >= max_links) error = -EMLINK; - else - error = dir->i_op->link(old_dentry, dir, new_dentry); + else { + error = try_break_deleg(inode, delegated_inode); + if (!error) + error = dir->i_op->link(old_dentry, dir, new_dentry); + } if (!error && (inode->i_state & I_LINKABLE)) { spin_lock(&inode->i_lock); @@ -3880,6 +3901,7 @@ SYSCALL_DEFINE5(linkat, int, olddfd, const char __user *, oldname, { struct dentry *new_dentry; struct path old_path, new_path; + struct inode *delegated_inode = NULL; int how = 0; int error; @@ -3918,9 +3940,14 @@ retry: error = security_path_link(old_path.dentry, &new_path, new_dentry); if (error) goto out_dput; - error = vfs_link(old_path.dentry, new_path.dentry->d_inode, new_dentry); + error = vfs_link(old_path.dentry, new_path.dentry->d_inode, new_dentry, &delegated_inode); out_dput: done_path_create(&new_path, new_dentry); + if (delegated_inode) { + error = break_deleg_wait(&delegated_inode); + if (!error) + goto retry; + } if (retry_estale(error, how)) { how |= LOOKUP_REVAL; goto retry; @@ -3945,7 +3972,8 @@ SYSCALL_DEFINE2(link, const char __user *, oldname, const char __user *, newname * That's where 4.4 screws up. Current fix: serialization on * sb->s_vfs_rename_mutex. We might be more accurate, but that's another * story. - * c) we have to lock _three_ objects - parents and victim (if it exists). + * c) we have to lock _four_ objects - parents and victim (if it exists), + * and source (if it is not a directory). * And that - after we got ->i_mutex on parents (until then we don't know * whether the target exists). Solution: try to be smart with locking * order for inodes. We rely on the fact that tree topology may change @@ -4018,9 +4046,11 @@ out: } static int vfs_rename_other(struct inode *old_dir, struct dentry *old_dentry, - struct inode *new_dir, struct dentry *new_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); @@ -4028,13 +4058,20 @@ static int vfs_rename_other(struct inode *old_dir, struct dentry *old_dentry, return error; dget(new_dentry); - if (target) - mutex_lock(&target->i_mutex); + 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) { + 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 (error) goto out; @@ -4044,17 +4081,38 @@ static int vfs_rename_other(struct inode *old_dir, struct dentry *old_dentry, if (!(old_dir->i_sb->s_type->fs_flags & FS_RENAME_DOES_D_MOVE)) d_move(old_dentry, new_dentry); out: - if (target) - mutex_unlock(&target->i_mutex); + unlock_two_nondirectories(source, target); 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 *new_dir, struct dentry *new_dentry, + struct inode **delegated_inode) { int error; - int is_dir = S_ISDIR(old_dentry->d_inode->i_mode); + 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) @@ -4079,7 +4137,7 @@ int vfs_rename(struct inode *old_dir, struct dentry *old_dentry, 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); + error = vfs_rename_other(old_dir,old_dentry,new_dir,new_dentry,delegated_inode); if (!error) fsnotify_move(old_dir, new_dir, old_name, is_dir, new_dentry->d_inode, old_dentry); @@ -4095,6 +4153,7 @@ SYSCALL_DEFINE4(renameat, int, olddfd, const char __user *, oldname, struct dentry *old_dentry, *new_dentry; struct dentry *trap; struct nameidata oldnd, newnd; + struct inode *delegated_inode = NULL; struct filename *from; struct filename *to; unsigned int lookup_flags = 0; @@ -4134,6 +4193,7 @@ retry: newnd.flags &= ~LOOKUP_PARENT; newnd.flags |= LOOKUP_RENAME_TARGET; +retry_deleg: trap = lock_rename(new_dir, old_dir); old_dentry = lookup_hash(&oldnd); @@ -4142,10 +4202,10 @@ retry: goto exit3; /* source must exist */ error = -ENOENT; - if (!old_dentry->d_inode) + if (d_is_negative(old_dentry)) goto exit4; /* unless the source is a directory trailing slashes give -ENOTDIR */ - if (!S_ISDIR(old_dentry->d_inode->i_mode)) { + if (!d_is_directory(old_dentry) && !d_is_autodir(old_dentry)) { error = -ENOTDIR; if (oldnd.last.name[oldnd.last.len]) goto exit4; @@ -4170,13 +4230,19 @@ retry: if (error) goto exit5; error = vfs_rename(old_dir->d_inode, old_dentry, - new_dir->d_inode, new_dentry); + new_dir->d_inode, new_dentry, + &delegated_inode); exit5: dput(new_dentry); exit4: dput(old_dentry); exit3: unlock_rename(new_dir, old_dir); + if (delegated_inode) { + error = break_deleg_wait(&delegated_inode); + if (!error) + goto retry_deleg; + } mnt_drop_write(oldnd.path.mnt); exit2: if (retry_estale(error, lookup_flags)) |