Merge tag 'ovl-fixes-5.2-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/vfs

Pull overlayfs fixes from Miklos Szeredi:
 "Fix two regressions in this cycle, and a couple of older bugs"

* tag 'ovl-fixes-5.2-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/vfs:
  ovl: make i_ino consistent with st_ino in more cases
  ovl: fix typo in MODULE_PARM_DESC
  ovl: fix bogus -Wmaybe-unitialized warning
  ovl: don't fail with disconnected lower NFS
  ovl: fix wrong flags check in FS_IOC_FS[SG]ETXATTR ioctls

5 files changed, 90 insertions, 59 deletions

diff --git a/fs/overlayfs/copy_up.c b/fs/overlayfs/copy_up.c
index 56feaa739979..7ec3acd90d0b 100644
--- a/fs/overlayfs/copy_up.c
+++ b/fs/overlayfs/copy_up.c
@@ -37,7 +37,7 @@ static int ovl_ccup_get(char *buf, const struct kernel_param *param)
 }
 
 module_param_call(check_copy_up, ovl_ccup_set, ovl_ccup_get, NULL, 0644);
-MODULE_PARM_DESC(ovl_check_copy_up, "Obsolete; does nothing");
+MODULE_PARM_DESC(check_copy_up, "Obsolete; does nothing");
 
 int ovl_copy_xattr(struct dentry *old, struct dentry *new)
 {
diff --git a/fs/overlayfs/dir.c b/fs/overlayfs/dir.c
index 93872bb50230..2f39046ebfa4 100644
--- a/fs/overlayfs/dir.c
+++ b/fs/overlayfs/dir.c
@@ -21,7 +21,7 @@
 
 static unsigned short ovl_redirect_max = 256;
 module_param_named(redirect_max, ovl_redirect_max, ushort, 0644);
-MODULE_PARM_DESC(ovl_redirect_max,
+MODULE_PARM_DESC(redirect_max,
 		 "Maximum length of absolute redirect xattr value");
 
 static int ovl_set_redirect(struct dentry *dentry, bool samedir);
diff --git a/fs/overlayfs/file.c b/fs/overlayfs/file.c
index 340a6ad45914..75d8d00fa087 100644
--- a/fs/overlayfs/file.c
+++ b/fs/overlayfs/file.c
@@ -409,37 +409,16 @@ static long ovl_real_ioctl(struct file *file, unsigned int cmd,
 	return ret;
 }
 
-static unsigned int ovl_get_inode_flags(struct inode *inode)
-{
-	unsigned int flags = READ_ONCE(inode->i_flags);
-	unsigned int ovl_iflags = 0;
-
-	if (flags & S_SYNC)
-		ovl_iflags |= FS_SYNC_FL;
-	if (flags & S_APPEND)
-		ovl_iflags |= FS_APPEND_FL;
-	if (flags & S_IMMUTABLE)
-		ovl_iflags |= FS_IMMUTABLE_FL;
-	if (flags & S_NOATIME)
-		ovl_iflags |= FS_NOATIME_FL;
-
-	return ovl_iflags;
-}
-
 static long ovl_ioctl_set_flags(struct file *file, unsigned int cmd,
-				unsigned long arg)
+				unsigned long arg, unsigned int iflags)
 {
 	long ret;
 	struct inode *inode = file_inode(file);
-	unsigned int flags;
-	unsigned int old_flags;
+	unsigned int old_iflags;
 
 	if (!inode_owner_or_capable(inode))
 		return -EACCES;
 
-	if (get_user(flags, (int __user *) arg))
-		return -EFAULT;
-
 	ret = mnt_want_write_file(file);
 	if (ret)
 		return ret;
@@ -448,8 +427,8 @@ static long ovl_ioctl_set_flags(struct file *file, unsigned int cmd,
 
 	/* Check the capability before cred override */
 	ret = -EPERM;
-	old_flags = ovl_get_inode_flags(inode);
-	if (((flags ^ old_flags) & (FS_APPEND_FL | FS_IMMUTABLE_FL)) &&
+	old_iflags = READ_ONCE(inode->i_flags);
+	if (((iflags ^ old_iflags) & (S_APPEND | S_IMMUTABLE)) &&
 	    !capable(CAP_LINUX_IMMUTABLE))
 		goto unlock;
 
@@ -469,6 +448,63 @@ unlock:
 
 }
 
+static unsigned int ovl_fsflags_to_iflags(unsigned int flags)
+{
+	unsigned int iflags = 0;
+
+	if (flags & FS_SYNC_FL)
+		iflags |= S_SYNC;
+	if (flags & FS_APPEND_FL)
+		iflags |= S_APPEND;
+	if (flags & FS_IMMUTABLE_FL)
+		iflags |= S_IMMUTABLE;
+	if (flags & FS_NOATIME_FL)
+		iflags |= S_NOATIME;
+
+	return iflags;
+}
+
+static long ovl_ioctl_set_fsflags(struct file *file, unsigned int cmd,
+				  unsigned long arg)
+{
+	unsigned int flags;
+
+	if (get_user(flags, (int __user *) arg))
+		return -EFAULT;
+
+	return ovl_ioctl_set_flags(file, cmd, arg,
+				   ovl_fsflags_to_iflags(flags));
+}
+
+static unsigned int ovl_fsxflags_to_iflags(unsigned int xflags)
+{
+	unsigned int iflags = 0;
+
+	if (xflags & FS_XFLAG_SYNC)
+		iflags |= S_SYNC;
+	if (xflags & FS_XFLAG_APPEND)
+		iflags |= S_APPEND;
+	if (xflags & FS_XFLAG_IMMUTABLE)
+		iflags |= S_IMMUTABLE;
+	if (xflags & FS_XFLAG_NOATIME)
+		iflags |= S_NOATIME;
+
+	return iflags;
+}
+
+static long ovl_ioctl_set_fsxflags(struct file *file, unsigned int cmd,
+				   unsigned long arg)
+{
+	struct fsxattr fa;
+
+	memset(&fa, 0, sizeof(fa));
+	if (copy_from_user(&fa, (void __user *) arg, sizeof(fa)))
+		return -EFAULT;
+
+	return ovl_ioctl_set_flags(file, cmd, arg,
+				   ovl_fsxflags_to_iflags(fa.fsx_xflags));
+}
+
 static long ovl_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 {
 	long ret;
@@ -480,8 +516,11 @@ static long ovl_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 		break;
 
 	case FS_IOC_SETFLAGS:
+		ret = ovl_ioctl_set_fsflags(file, cmd, arg);
+		break;
+
 	case FS_IOC_FSSETXATTR:
-		ret = ovl_ioctl_set_flags(file, cmd, arg);
+		ret = ovl_ioctl_set_fsxflags(file, cmd, arg);
 		break;
 
 	default:
diff --git a/fs/overlayfs/inode.c b/fs/overlayfs/inode.c
index f7eba21effa5..f0389849fd80 100644
--- a/fs/overlayfs/inode.c
+++ b/fs/overlayfs/inode.c
@@ -553,15 +553,15 @@ static void ovl_fill_inode(struct inode *inode, umode_t mode, dev_t rdev,
 	int xinobits = ovl_xino_bits(inode->i_sb);
 
 	/*
-	 * When NFS export is enabled and d_ino is consistent with st_ino
-	 * (samefs or i_ino has enough bits to encode layer), set the same
-	 * value used for d_ino to i_ino, because nfsd readdirplus compares
-	 * d_ino values to i_ino values of child entries. When called from
+	 * When d_ino is consistent with st_ino (samefs or i_ino has enough
+	 * bits to encode layer), set the same value used for st_ino to i_ino,
+	 * so inode number exposed via /proc/locks and a like will be
+	 * consistent with d_ino and st_ino values. An i_ino value inconsistent
+	 * with d_ino also causes nfsd readdirplus to fail.  When called from
 	 * ovl_new_inode(), ino arg is 0, so i_ino will be updated to real
 	 * upper inode i_ino on ovl_inode_init() or ovl_inode_update().
 	 */
-	if (inode->i_sb->s_export_op &&
-	    (ovl_same_sb(inode->i_sb) || xinobits)) {
+	if (ovl_same_sb(inode->i_sb) || xinobits) {
 		inode->i_ino = ino;
 		if (xinobits && fsid && !(ino >> (64 - xinobits)))
 			inode->i_ino |= (unsigned long)fsid << (64 - xinobits);
diff --git a/fs/overlayfs/super.c b/fs/overlayfs/super.c
index 746ea36f3171..e300c1371b7b 100644
--- a/fs/overlayfs/super.c
+++ b/fs/overlayfs/super.c
@@ -31,29 +31,29 @@ struct ovl_dir_cache;
 
 static bool ovl_redirect_dir_def = IS_ENABLED(CONFIG_OVERLAY_FS_REDIRECT_DIR);
 module_param_named(redirect_dir, ovl_redirect_dir_def, bool, 0644);
-MODULE_PARM_DESC(ovl_redirect_dir_def,
+MODULE_PARM_DESC(redirect_dir,
 		 "Default to on or off for the redirect_dir feature");
 
 static bool ovl_redirect_always_follow =
 	IS_ENABLED(CONFIG_OVERLAY_FS_REDIRECT_ALWAYS_FOLLOW);
 module_param_named(redirect_always_follow, ovl_redirect_always_follow,
 		   bool, 0644);
-MODULE_PARM_DESC(ovl_redirect_always_follow,
+MODULE_PARM_DESC(redirect_always_follow,
 		 "Follow redirects even if redirect_dir feature is turned off");
 
 static bool ovl_index_def = IS_ENABLED(CONFIG_OVERLAY_FS_INDEX);
 module_param_named(index, ovl_index_def, bool, 0644);
-MODULE_PARM_DESC(ovl_index_def,
+MODULE_PARM_DESC(index,
 		 "Default to on or off for the inodes index feature");
 
 static bool ovl_nfs_export_def = IS_ENABLED(CONFIG_OVERLAY_FS_NFS_EXPORT);
 module_param_named(nfs_export, ovl_nfs_export_def, bool, 0644);
-MODULE_PARM_DESC(ovl_nfs_export_def,
+MODULE_PARM_DESC(nfs_export,
 		 "Default to on or off for the NFS export feature");
 
 static bool ovl_xino_auto_def = IS_ENABLED(CONFIG_OVERLAY_FS_XINO_AUTO);
 module_param_named(xino_auto, ovl_xino_auto_def, bool, 0644);
-MODULE_PARM_DESC(ovl_xino_auto_def,
+MODULE_PARM_DESC(xino_auto,
 		 "Auto enable xino feature");
 
 static void ovl_entry_stack_free(struct ovl_entry *oe)
@@ -66,7 +66,7 @@ static void ovl_entry_stack_free(struct ovl_entry *oe)
 
 static bool ovl_metacopy_def = IS_ENABLED(CONFIG_OVERLAY_FS_METACOPY);
 module_param_named(metacopy, ovl_metacopy_def, bool, 0644);
-MODULE_PARM_DESC(ovl_metacopy_def,
+MODULE_PARM_DESC(metacopy,
 		 "Default to on or off for the metadata only copy up feature");
 
 static void ovl_dentry_release(struct dentry *dentry)
@@ -995,8 +995,8 @@ static int ovl_setup_trap(struct super_block *sb, struct dentry *dir,
 	int err;
 
 	trap = ovl_get_trap_inode(sb, dir);
-	err = PTR_ERR(trap);
-	if (IS_ERR(trap)) {
+	err = PTR_ERR_OR_ZERO(trap);
+	if (err) {
 		if (err == -ELOOP)
 			pr_err("overlayfs: conflicting %s path\n", name);
 		return err;
@@ -1471,23 +1471,20 @@ out_err:
  * Check if this layer root is a descendant of:
  * - another layer of this overlayfs instance
  * - upper/work dir of any overlayfs instance
- * - a disconnected dentry (detached root)
  */
 static int ovl_check_layer(struct super_block *sb, struct dentry *dentry,
 			   const char *name)
 {
-	struct dentry *next, *parent;
-	bool is_root = false;
+	struct dentry *next = dentry, *parent;
 	int err = 0;
 
-	if (!dentry || dentry == dentry->d_sb->s_root)
+	if (!dentry)
 		return 0;
 
-	next = dget(dentry);
-	/* Walk back ancestors to fs root (inclusive) looking for traps */
-	do {
-		parent = dget_parent(next);
-		is_root = (parent == next);
+	parent = dget_parent(next);
+
+	/* Walk back ancestors to root (inclusive) looking for traps */
+	while (!err && parent != next) {
 		if (ovl_is_inuse(parent)) {
 			err = -EBUSY;
 			pr_err("overlayfs: %s path overlapping in-use upperdir/workdir\n",
@@ -1496,17 +1493,12 @@ static int ovl_check_layer(struct super_block *sb, struct dentry *dentry,
 			err = -ELOOP;
 			pr_err("overlayfs: overlapping %s path\n", name);
 		}
-		dput(next);
 		next = parent;
-	} while (!err && !is_root);
-
-	/* Did we really walk to fs root or found a detached root? */
-	if (!err && next != dentry->d_sb->s_root) {
-		err = -ESTALE;
-		pr_err("overlayfs: disconnected %s path\n", name);
+		parent = dget_parent(next);
+		dput(next);
 	}
 
-	dput(next);
+	dput(parent);
 
 	return err;
 }