vfs-6.16-rc3.fixes

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Merge tag 'vfs-6.16-rc3.fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs

Pull vfs fixes from Christian Brauner:

 - Fix a regression in overlayfs caused by reworking the lookup_one*()
   set of helpers

 - Make sure that the name of the dentry is printed in overlayfs'
   mkdir() helper

 - Add missing iocb values to TRACE_IOCB_STRINGS define

 - Unlock the superblock during iterate_supers_type(). This was an
   accidental internal api change

 - Drop a misleading assert in file_seek_cur_needs_f_lock() helper

 - Never refuse to return PIDFD_GET_INGO when parent pid is zero

   That can trivially happen in container scenarios where the parent
   process might be located in an ancestor pid namespace

 - Don't revalidate in try_lookup_noperm() as that causes regression for
   filesystems such as cifs

 - Fix simple_xattr_list() and reset the err variable after
   security_inode_listsecurity() got called so as not to confuse
   userspace about the length of the xattr

* tag 'vfs-6.16-rc3.fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs:
  fs: drop assert in file_seek_cur_needs_f_lock
  fs: unlock the superblock during iterate_supers_type
  ovl: fix debug print in case of mkdir error
  VFS: change try_lookup_noperm() to skip revalidation
  fs: add missing values to TRACE_IOCB_STRINGS
  fs/xattr.c: fix simple_xattr_list()
  ovl: fix regression caused by lookup helpers API changes
  pidfs: never refuse ppid == 0 in PIDFD_GET_INFO

fs/file.c

@@ -1198,8 +1198,12 @@ bool file_seek_cur_needs_f_lock(struct file *file)
 	if (!(file->f_mode & FMODE_ATOMIC_POS) && !file->f_op->iterate_shared)
 		return false;
 
-	VFS_WARN_ON_ONCE((file_count(file) > 1) &&
-			 !mutex_is_locked(&file->f_pos_lock));
+	/*
+	 * Note that we are not guaranteed to be called after fdget_pos() on
+	 * this file obj, in which case the caller is expected to provide the
+	 * appropriate locking.
+	 */
+
 	return true;
 }
 

fs/namei.c

@@ -2917,7 +2917,8 @@ static int lookup_one_common(struct mnt_idmap *idmap,
  * @base:	base directory to lookup from
  *
  * Look up a dentry by name in the dcache, returning NULL if it does not
- * currently exist.  The function does not try to create a dentry.
+ * currently exist.  The function does not try to create a dentry and if one
+ * is found it doesn't try to revalidate it.
  *
  * Note that this routine is purely a helper for filesystem usage and should
  * not be called by generic code.  It does no permission checking.
@@ -2933,7 +2934,7 @@ struct dentry *try_lookup_noperm(struct qstr *name, struct dentry *base)
 	if (err)
 		return ERR_PTR(err);
 
-	return lookup_dcache(name, base, 0);
+	return d_lookup(base, name);
 }
 EXPORT_SYMBOL(try_lookup_noperm);
 
@@ -3057,14 +3058,22 @@ EXPORT_SYMBOL(lookup_one_positive_unlocked);
  * Note that this routine is purely a helper for filesystem usage and should
  * not be called by generic code. It does no permission checking.
  *
- * Unlike lookup_noperm, it should be called without the parent
+ * Unlike lookup_noperm(), it should be called without the parent
  * i_rwsem held, and will take the i_rwsem itself if necessary.
+ *
+ * Unlike try_lookup_noperm() it *does* revalidate the dentry if it already
+ * existed.
  */
 struct dentry *lookup_noperm_unlocked(struct qstr *name, struct dentry *base)
 {
 	struct dentry *ret;
+	int err;
 
-	ret = try_lookup_noperm(name, base);
+	err = lookup_noperm_common(name, base);
+	if (err)
+		return ERR_PTR(err);
+
+	ret = lookup_dcache(name, base, 0);
 	if (!ret)
 		ret = lookup_slow(name, base, 0);
 	return ret;

fs/overlayfs/namei.c

@@ -1393,7 +1393,7 @@ out:
 bool ovl_lower_positive(struct dentry *dentry)
 {
 	struct ovl_entry *poe = OVL_E(dentry->d_parent);
-	struct qstr *name = &dentry->d_name;
+	const struct qstr *name = &dentry->d_name;
 	const struct cred *old_cred;
 	unsigned int i;
 	bool positive = false;
@@ -1416,9 +1416,15 @@ bool ovl_lower_positive(struct dentry *dentry)
 		struct dentry *this;
 		struct ovl_path *parentpath = &ovl_lowerstack(poe)[i];
 
+		/*
+		 * We need to make a non-const copy of dentry->d_name,
+		 * because lookup_one_positive_unlocked() will hash name
+		 * with parentpath base, which is on another (lower fs).
+		 */
 		this = lookup_one_positive_unlocked(
 				mnt_idmap(parentpath->layer->mnt),
-				name, parentpath->dentry);
+				&QSTR_LEN(name->name, name->len),
+				parentpath->dentry);
 		if (IS_ERR(this)) {
 			switch (PTR_ERR(this)) {
 			case -ENOENT:

fs/overlayfs/overlayfs.h

@@ -246,9 +246,11 @@ static inline struct dentry *ovl_do_mkdir(struct ovl_fs *ofs,
 					  struct dentry *dentry,
 					  umode_t mode)
 {
-	dentry = vfs_mkdir(ovl_upper_mnt_idmap(ofs), dir, dentry, mode);
-	pr_debug("mkdir(%pd2, 0%o) = %i\n", dentry, mode, PTR_ERR_OR_ZERO(dentry));
-	return dentry;
+	struct dentry *ret;
+
+	ret = vfs_mkdir(ovl_upper_mnt_idmap(ofs), dir, dentry, mode);
+	pr_debug("mkdir(%pd2, 0%o) = %i\n", dentry, mode, PTR_ERR_OR_ZERO(ret));
+	return ret;
 }
 
 static inline int ovl_do_mknod(struct ovl_fs *ofs,

fs/pidfs.c

@@ -366,7 +366,7 @@ static long pidfd_info(struct file *file, unsigned int cmd, unsigned long arg)
 	kinfo.pid = task_pid_vnr(task);
 	kinfo.mask |= PIDFD_INFO_PID;
 
-	if (kinfo.pid == 0 || kinfo.tgid == 0 || (kinfo.ppid == 0 && kinfo.pid != 1))
+	if (kinfo.pid == 0 || kinfo.tgid == 0)
 		return -ESRCH;
 
 copy_out:

fs/super.c

@@ -964,8 +964,10 @@ void iterate_supers_type(struct file_system_type *type,
 		spin_unlock(&sb_lock);
 
 		locked = super_lock_shared(sb);
-		if (locked)
+		if (locked) {
 			f(sb, arg);
+			super_unlock_shared(sb);
+		}
 
 		spin_lock(&sb_lock);
 		if (p)

fs/xattr.c

@@ -1479,6 +1479,7 @@ ssize_t simple_xattr_list(struct inode *inode, struct simple_xattrs *xattrs,
 		buffer += err;
 	}
 	remaining_size -= err;
+	err = 0;
 
 	read_lock(&xattrs->lock);
 	for (rbp = rb_first(&xattrs->rb_root); rbp; rbp = rb_next(rbp)) {

include/linux/fs.h

@@ -399,7 +399,9 @@ struct readahead_control;
 	{ IOCB_WAITQ,		"WAITQ" }, \
 	{ IOCB_NOIO,		"NOIO" }, \
 	{ IOCB_ALLOC_CACHE,	"ALLOC_CACHE" }, \
-	{ IOCB_DIO_CALLER_COMP,	"CALLER_COMP" }
+	{ IOCB_DIO_CALLER_COMP,	"CALLER_COMP" }, \
+	{ IOCB_AIO_RW,		"AIO_RW" }, \
+	{ IOCB_HAS_METADATA,	"AIO_HAS_METADATA" }
 
 struct kiocb {
 	struct file		*ki_filp;