Merge branch 'work.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs

Pull misc vfs updates from Al Viro:
 "Assorted stuff all over the place"

* 'work.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  useful constants: struct qstr for ".."
  hostfs_open(): don't open-code file_dentry()
  whack-a-mole: kill strlen_user() (again)
  autofs: should_expire() argument is guaranteed to be positive
  apparmor:match_mn() - constify devpath argument
  buffer: a small optimization in grow_buffers
  get rid of autofs_getpath()
  constify dentry argument of dentry_path()/dentry_path_raw()

arch/csky/include/asm/uaccess.h

@@ -397,8 +397,6 @@ long __strncpy_from_user(char *dst, const char *src, long count);
  */
 long strnlen_user(const char *src, long n);
 
-#define strlen_user(str) strnlen_user(str, 32767)
-
 struct exception_table_entry {
 	unsigned long insn;
 	unsigned long nextinsn;

arch/csky/lib/usercopy.c

@@ -116,7 +116,7 @@ long strncpy_from_user(char *dst, const char *src, long count)
 EXPORT_SYMBOL(strncpy_from_user);
 
 /*
- * strlen_user: - Get the size of a string in user space.
+ * strnlen_user: - Get the size of a string in user space.
  * @str: The string to measure.
  * @n:   The maximum valid length
  *

arch/nds32/include/asm/uaccess.h

@@ -260,7 +260,6 @@ do {									\
 
 extern unsigned long __arch_clear_user(void __user * addr, unsigned long n);
 extern long strncpy_from_user(char *dest, const char __user * src, long count);
-extern __must_check long strlen_user(const char __user * str);
 extern __must_check long strnlen_user(const char __user * str, long n);
 extern unsigned long __arch_copy_from_user(void *to, const void __user * from,
                                            unsigned long n);

arch/nios2/include/asm/uaccess.h

@@ -83,7 +83,6 @@ raw_copy_to_user(void __user *to, const void *from, unsigned long n);
 
 extern long strncpy_from_user(char *__to, const char __user *__from,
 			      long __len);
-extern __must_check long strlen_user(const char __user *str);
 extern __must_check long strnlen_user(const char __user *s, long n);
 
 /* Optimized macros */

arch/riscv/include/asm/uaccess.h

@@ -375,7 +375,6 @@ raw_copy_to_user(void __user *to, const void *from, unsigned long n)
 
 extern long strncpy_from_user(char *dest, const char __user *src, long count);
 
-extern long __must_check strlen_user(const char __user *str);
 extern long __must_check strnlen_user(const char __user *str, long n);
 
 extern

fs/autofs/autofs_i.h

@@ -87,6 +87,7 @@ struct autofs_wait_queue {
 	autofs_wqt_t wait_queue_token;
 	/* We use the following to see what we are waiting for */
 	struct qstr name;
+	u32 offset;
 	u32 dev;
 	u64 ino;
 	kuid_t uid;

fs/autofs/expire.c

@@ -355,7 +355,7 @@ static struct dentry *should_expire(struct dentry *dentry,
 		return NULL;
 	}
 
-	if (d_really_is_positive(dentry) && d_is_symlink(dentry)) {
+	if (d_is_symlink(dentry)) {
 		pr_debug("checking symlink %p %pd\n", dentry, dentry);
 
 		/* Forced expire, user space handles busy mounts */

fs/autofs/waitq.c

@@ -30,7 +30,7 @@ void autofs_catatonic_mode(struct autofs_sb_info *sbi)
 	while (wq) {
 		nwq = wq->next;
 		wq->status = -ENOENT; /* Magic is gone - report failure */
-		kfree(wq->name.name);
+		kfree(wq->name.name - wq->offset);
 		wq->name.name = NULL;
 		wq->wait_ctr--;
 		wake_up_interruptible(&wq->queue);
@@ -175,51 +175,6 @@ static void autofs_notify_daemon(struct autofs_sb_info *sbi,
 	fput(pipe);
 }
 
-static int autofs_getpath(struct autofs_sb_info *sbi,
-			  struct dentry *dentry, char *name)
-{
-	struct dentry *root = sbi->sb->s_root;
-	struct dentry *tmp;
-	char *buf;
-	char *p;
-	int len;
-	unsigned seq;
-
-rename_retry:
-	buf = name;
-	len = 0;
-
-	seq = read_seqbegin(&rename_lock);
-	rcu_read_lock();
-	spin_lock(&sbi->fs_lock);
-	for (tmp = dentry ; tmp != root ; tmp = tmp->d_parent)
-		len += tmp->d_name.len + 1;
-
-	if (!len || --len > NAME_MAX) {
-		spin_unlock(&sbi->fs_lock);
-		rcu_read_unlock();
-		if (read_seqretry(&rename_lock, seq))
-			goto rename_retry;
-		return 0;
-	}
-
-	*(buf + len) = '\0';
-	p = buf + len - dentry->d_name.len;
-	strncpy(p, dentry->d_name.name, dentry->d_name.len);
-
-	for (tmp = dentry->d_parent; tmp != root ; tmp = tmp->d_parent) {
-		*(--p) = '/';
-		p -= tmp->d_name.len;
-		strncpy(p, tmp->d_name.name, tmp->d_name.len);
-	}
-	spin_unlock(&sbi->fs_lock);
-	rcu_read_unlock();
-	if (read_seqretry(&rename_lock, seq))
-		goto rename_retry;
-
-	return len;
-}
-
 static struct autofs_wait_queue *
 autofs_find_wait(struct autofs_sb_info *sbi, const struct qstr *qstr)
 {
@@ -352,6 +307,7 @@ int autofs_wait(struct autofs_sb_info *sbi,
 	struct qstr qstr;
 	char *name;
 	int status, ret, type;
+	unsigned int offset = 0;
 	pid_t pid;
 	pid_t tgid;
 
@@ -389,20 +345,23 @@ int autofs_wait(struct autofs_sb_info *sbi,
 		return -ENOMEM;
 
 	/* If this is a direct mount request create a dummy name */
-	if (IS_ROOT(dentry) && autofs_type_trigger(sbi->type))
+	if (IS_ROOT(dentry) && autofs_type_trigger(sbi->type)) {
+		qstr.name = name;
 		qstr.len = sprintf(name, "%p", dentry);
-	else {
-		qstr.len = autofs_getpath(sbi, dentry, name);
-		if (!qstr.len) {
+	} else {
+		char *p = dentry_path_raw(dentry, name, NAME_MAX);
+		if (IS_ERR(p)) {
 			kfree(name);
 			return -ENOENT;
 		}
+		qstr.name = ++p; // skip the leading slash
+		qstr.len = strlen(p);
+		offset = p - name;
 	}
-	qstr.name = name;
 	qstr.hash = full_name_hash(dentry, name, qstr.len);
 
 	if (mutex_lock_interruptible(&sbi->wq_mutex)) {
-		kfree(qstr.name);
+		kfree(name);
 		return -EINTR;
 	}
 
@@ -410,7 +369,7 @@ int autofs_wait(struct autofs_sb_info *sbi,
 	if (ret <= 0) {
 		if (ret != -EINTR)
 			mutex_unlock(&sbi->wq_mutex);
-		kfree(qstr.name);
+		kfree(name);
 		return ret;
 	}
 
@@ -418,7 +377,7 @@ int autofs_wait(struct autofs_sb_info *sbi,
 		/* Create a new wait queue */
 		wq = kmalloc(sizeof(struct autofs_wait_queue), GFP_KERNEL);
 		if (!wq) {
-			kfree(qstr.name);
+			kfree(name);
 			mutex_unlock(&sbi->wq_mutex);
 			return -ENOMEM;
 		}
@@ -430,6 +389,7 @@ int autofs_wait(struct autofs_sb_info *sbi,
 		sbi->queues = wq;
 		init_waitqueue_head(&wq->queue);
 		memcpy(&wq->name, &qstr, sizeof(struct qstr));
+		wq->offset = offset;
 		wq->dev = autofs_get_dev(sbi);
 		wq->ino = autofs_get_ino(sbi);
 		wq->uid = current_uid();
@@ -469,7 +429,7 @@ int autofs_wait(struct autofs_sb_info *sbi,
 			 (unsigned long) wq->wait_queue_token, wq->name.len,
 			 wq->name.name, notify);
 		mutex_unlock(&sbi->wq_mutex);
-		kfree(qstr.name);
+		kfree(name);
 	}
 
 	/*
@@ -540,7 +500,7 @@ int autofs_wait_release(struct autofs_sb_info *sbi,
 	}
 
 	*wql = wq->next;	/* Unlink from chain */
-	kfree(wq->name.name);
+	kfree(wq->name.name - wq->offset);
 	wq->name.name = NULL;	/* Do not wait on this queue */
 	wq->status = status;
 	wake_up(&wq->queue);

fs/buffer.c

@@ -1020,11 +1020,7 @@ grow_buffers(struct block_device *bdev, sector_t block, int size, gfp_t gfp)
 	pgoff_t index;
 	int sizebits;
 
-	sizebits = -1;
-	do {
-		sizebits++;
-	} while ((size << sizebits) < PAGE_SIZE);
-
+	sizebits = PAGE_SHIFT - __ffs(size);
 	index = block >> sizebits;
 
 	/*

fs/d_path.c

@@ -326,9 +326,9 @@ char *simple_dname(struct dentry *dentry, char *buffer, int buflen)
 /*
  * Write full pathname from the root of the filesystem into the buffer.
  */
-static char *__dentry_path(struct dentry *d, char *buf, int buflen)
+static char *__dentry_path(const struct dentry *d, char *buf, int buflen)
 {
-	struct dentry *dentry;
+	const struct dentry *dentry;
 	char *end, *retval;
 	int len, seq = 0;
 	int error = 0;
@@ -347,7 +347,7 @@ restart:
 	*retval = '/';
 	read_seqbegin_or_lock(&rename_lock, &seq);
 	while (!IS_ROOT(dentry)) {
-		struct dentry *parent = dentry->d_parent;
+		const struct dentry *parent = dentry->d_parent;
 
 		prefetch(parent);
 		error = prepend_name(&end, &len, &dentry->d_name);
@@ -371,13 +371,13 @@ Elong:
 	return ERR_PTR(-ENAMETOOLONG);
 }
 
-char *dentry_path_raw(struct dentry *dentry, char *buf, int buflen)
+char *dentry_path_raw(const struct dentry *dentry, char *buf, int buflen)
 {
 	return __dentry_path(dentry, buf, buflen);
 }
 EXPORT_SYMBOL(dentry_path_raw);
 
-char *dentry_path(struct dentry *dentry, char *buf, int buflen)
+char *dentry_path(const struct dentry *dentry, char *buf, int buflen)
 {
 	char *p = NULL;
 	char *retval;

fs/dcache.c

@@ -84,6 +84,8 @@ const struct qstr empty_name = QSTR_INIT("", 0);
 EXPORT_SYMBOL(empty_name);
 const struct qstr slash_name = QSTR_INIT("/", 1);
 EXPORT_SYMBOL(slash_name);
+const struct qstr dotdot_name = QSTR_INIT("..", 2);
+EXPORT_SYMBOL(dotdot_name);
 
 /*
  * This is the single most critical data structure when it comes

fs/ext2/namei.c

@@ -81,11 +81,10 @@ static struct dentry *ext2_lookup(struct inode * dir, struct dentry *dentry, uns
 
 struct dentry *ext2_get_parent(struct dentry *child)
 {
-	struct qstr dotdot = QSTR_INIT("..", 2);
 	ino_t ino;
 	int res;
 
-	res = ext2_inode_by_name(d_inode(child), &dotdot, &ino);
+	res = ext2_inode_by_name(d_inode(child), &dotdot_name, &ino);
 	if (res)
 		return ERR_PTR(res);
 

fs/ext4/namei.c

@@ -1814,11 +1814,10 @@ static struct dentry *ext4_lookup(struct inode *dir, struct dentry *dentry, unsi
 struct dentry *ext4_get_parent(struct dentry *child)
 {
 	__u32 ino;
-	static const struct qstr dotdot = QSTR_INIT("..", 2);
 	struct ext4_dir_entry_2 * de;
 	struct buffer_head *bh;
 
-	bh = ext4_find_entry(d_inode(child), &dotdot, &de, NULL);
+	bh = ext4_find_entry(d_inode(child), &dotdot_name, &de, NULL);
 	if (IS_ERR(bh))
 		return ERR_CAST(bh);
 	if (!bh)

fs/f2fs/dir.c

@@ -449,9 +449,7 @@ struct f2fs_dir_entry *f2fs_find_entry(struct inode *dir,
 
 struct f2fs_dir_entry *f2fs_parent_dir(struct inode *dir, struct page **p)
 {
-	struct qstr dotdot = QSTR_INIT("..", 2);
-
-	return f2fs_find_entry(dir, &dotdot, p);
+	return f2fs_find_entry(dir, &dotdot_name, p);
 }
 
 ino_t f2fs_inode_by_name(struct inode *dir, const struct qstr *qstr,

fs/f2fs/namei.c

@@ -416,9 +416,8 @@ out:
 
 struct dentry *f2fs_get_parent(struct dentry *child)
 {
-	struct qstr dotdot = QSTR_INIT("..", 2);
 	struct page *page;
-	unsigned long ino = f2fs_inode_by_name(d_inode(child), &dotdot, &page);
+	unsigned long ino = f2fs_inode_by_name(d_inode(child), &dotdot_name, &page);
 	if (!ino) {
 		if (IS_ERR(page))
 			return ERR_CAST(page);

fs/fuse/inode.c

@@ -873,14 +873,13 @@ static struct dentry *fuse_get_parent(struct dentry *child)
 	struct inode *inode;
 	struct dentry *parent;
 	struct fuse_entry_out outarg;
-	const struct qstr name = QSTR_INIT("..", 2);
 	int err;
 
 	if (!fc->export_support)
 		return ERR_PTR(-ESTALE);
 
 	err = fuse_lookup_name(child_inode->i_sb, get_node_id(child_inode),
-			       &name, &outarg, &inode);
+			       &dotdot_name, &outarg, &inode);
 	if (err) {
 		if (err == -ENOENT)
 			return ERR_PTR(-ESTALE);

fs/hostfs/hostfs_kern.c

@@ -316,7 +316,7 @@ retry:
 	if (mode & FMODE_WRITE)
 		r = w = 1;
 
-	name = dentry_name(d_real(file->f_path.dentry, file->f_inode));
+	name = dentry_name(file_dentry(file));
 	if (name == NULL)
 		return -ENOMEM;
 

fs/nilfs2/namei.c

@@ -440,10 +440,9 @@ static struct dentry *nilfs_get_parent(struct dentry *child)
 {
 	unsigned long ino;
 	struct inode *inode;
-	struct qstr dotdot = QSTR_INIT("..", 2);
 	struct nilfs_root *root;
 
-	ino = nilfs_inode_by_name(d_inode(child), &dotdot);
+	ino = nilfs_inode_by_name(d_inode(child), &dotdot_name);
 	if (!ino)
 		return ERR_PTR(-ENOENT);
 

fs/udf/namei.c

@@ -1215,11 +1215,10 @@ static struct dentry *udf_get_parent(struct dentry *child)
 {
 	struct kernel_lb_addr tloc;
 	struct inode *inode = NULL;
-	struct qstr dotdot = QSTR_INIT("..", 2);
 	struct fileIdentDesc cfi;
 	struct udf_fileident_bh fibh;
 
-	if (!udf_find_entry(d_inode(child), &dotdot, &fibh, &cfi))
+	if (!udf_find_entry(d_inode(child), &dotdot_name, &fibh, &cfi))
 		return ERR_PTR(-EACCES);
 
 	if (fibh.sbh != fibh.ebh)

fs/ufs/super.c

@@ -128,10 +128,9 @@ static struct dentry *ufs_fh_to_parent(struct super_block *sb, struct fid *fid,
 
 static struct dentry *ufs_get_parent(struct dentry *child)
 {
-	struct qstr dot_dot = QSTR_INIT("..", 2);
 	ino_t ino;
 
-	ino = ufs_inode_by_name(d_inode(child), &dot_dot);
+	ino = ufs_inode_by_name(d_inode(child), &dotdot_name);
 	if (!ino)
 		return ERR_PTR(-ENOENT);
 	return d_obtain_alias(ufs_iget(child->d_sb, ino));

include/linux/dcache.h

@@ -59,6 +59,7 @@ struct qstr {
 
 extern const struct qstr empty_name;
 extern const struct qstr slash_name;
+extern const struct qstr dotdot_name;
 
 struct dentry_stat_t {
 	long nr_dentry;
@@ -300,8 +301,8 @@ char *dynamic_dname(struct dentry *, char *, int, const char *, ...);
 extern char *__d_path(const struct path *, const struct path *, char *, int);
 extern char *d_absolute_path(const struct path *, char *, int);
 extern char *d_path(const struct path *, char *, int);
-extern char *dentry_path_raw(struct dentry *, char *, int);
-extern char *dentry_path(struct dentry *, char *, int);
+extern char *dentry_path_raw(const struct dentry *, char *, int);
+extern char *dentry_path(const struct dentry *, char *, int);
 
 /* Allocation counts.. */
 

security/apparmor/mount.c

@@ -370,7 +370,7 @@ audit:
  * Returns: 0 on success else error
  */
 static int match_mnt(struct aa_profile *profile, const struct path *path,
-		     char *buffer, struct path *devpath, char *devbuffer,
+		     char *buffer, const struct path *devpath, char *devbuffer,
 		     const char *type, unsigned long flags, void *data,
 		     bool binary)
 {
@@ -579,7 +579,7 @@ out:
 	return error;
 }
 
-static int profile_umount(struct aa_profile *profile, struct path *path,
+static int profile_umount(struct aa_profile *profile, const struct path *path,
 			  char *buffer)
 {
 	struct aa_perms perms = { };