Merge tag 'ovl-fixes-5.6-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/vfs

Pull overlayfs fixes from Miklos Szeredi:
 "Fix three bugs introduced in this cycle"

* tag 'ovl-fixes-5.6-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/vfs:
  ovl: fix lockdep warning for async write
  ovl: fix some xino configurations
  ovl: fix lock in ovl_llseek()

5 files changed, 23 insertions, 4 deletions

diff --git a/fs/overlayfs/Kconfig b/fs/overlayfs/Kconfig
index 444e2da4f60e..714c14c47ca5 100644
--- a/fs/overlayfs/Kconfig
+++ b/fs/overlayfs/Kconfig
@@ -93,6 +93,7 @@ config OVERLAY_FS_XINO_AUTO
 	bool "Overlayfs: auto enable inode number mapping"
 	default n
 	depends on OVERLAY_FS
+	depends on 64BIT
 	help
 	  If this config option is enabled then overlay filesystems will use
 	  unused high bits in undelying filesystem inode numbers to map all
diff --git a/fs/overlayfs/file.c b/fs/overlayfs/file.c
index a5317216de73..87c362f65448 100644
--- a/fs/overlayfs/file.c
+++ b/fs/overlayfs/file.c
@@ -244,6 +244,9 @@ static void ovl_aio_cleanup_handler(struct ovl_aio_req *aio_req)
 	if (iocb->ki_flags & IOCB_WRITE) {
 		struct inode *inode = file_inode(orig_iocb->ki_filp);
 
+		/* Actually acquired in ovl_write_iter() */
+		__sb_writers_acquired(file_inode(iocb->ki_filp)->i_sb,
+				      SB_FREEZE_WRITE);
 		file_end_write(iocb->ki_filp);
 		ovl_copyattr(ovl_inode_real(inode), inode);
 	}
@@ -346,6 +349,9 @@ static ssize_t ovl_write_iter(struct kiocb *iocb, struct iov_iter *iter)
 			goto out;
 
 		file_start_write(real.file);
+		/* Pacify lockdep, same trick as done in aio_write() */
+		__sb_writers_release(file_inode(real.file)->i_sb,
+				     SB_FREEZE_WRITE);
 		aio_req->fd = real;
 		real.flags = 0;
 		aio_req->orig_iocb = iocb;
diff --git a/fs/overlayfs/overlayfs.h b/fs/overlayfs/overlayfs.h
index 3623d28aa4fa..3d3f2b8bdae5 100644
--- a/fs/overlayfs/overlayfs.h
+++ b/fs/overlayfs/overlayfs.h
@@ -318,7 +318,12 @@ static inline unsigned int ovl_xino_bits(struct super_block *sb)
 	return ovl_same_dev(sb) ? OVL_FS(sb)->xino_mode : 0;
 }
 
-static inline int ovl_inode_lock(struct inode *inode)
+static inline void ovl_inode_lock(struct inode *inode)
+{
+	mutex_lock(&OVL_I(inode)->lock);
+}
+
+static inline int ovl_inode_lock_interruptible(struct inode *inode)
 {
 	return mutex_lock_interruptible(&OVL_I(inode)->lock);
 }
diff --git a/fs/overlayfs/super.c b/fs/overlayfs/super.c
index 319fe0d355b0..ac967f1cb6e5 100644
--- a/fs/overlayfs/super.c
+++ b/fs/overlayfs/super.c
@@ -1411,6 +1411,8 @@ static int ovl_get_layers(struct super_block *sb, struct ovl_fs *ofs,
 		if (ofs->config.xino == OVL_XINO_ON)
 			pr_info("\"xino=on\" is useless with all layers on same fs, ignore.\n");
 		ofs->xino_mode = 0;
+	} else if (ofs->config.xino == OVL_XINO_OFF) {
+		ofs->xino_mode = -1;
 	} else if (ofs->config.xino == OVL_XINO_ON && ofs->xino_mode < 0) {
 		/*
 		 * This is a roundup of number of bits needed for encoding
@@ -1623,8 +1625,13 @@ static int ovl_fill_super(struct super_block *sb, void *data, int silent)
 	sb->s_stack_depth = 0;
 	sb->s_maxbytes = MAX_LFS_FILESIZE;
 	/* Assume underlaying fs uses 32bit inodes unless proven otherwise */
-	if (ofs->config.xino != OVL_XINO_OFF)
+	if (ofs->config.xino != OVL_XINO_OFF) {
 		ofs->xino_mode = BITS_PER_LONG - 32;
+		if (!ofs->xino_mode) {
+			pr_warn("xino not supported on 32bit kernel, falling back to xino=off.\n");
+			ofs->config.xino = OVL_XINO_OFF;
+		}
+	}
 
 	/* alloc/destroy_inode needed for setting up traps in inode cache */
 	sb->s_op = &ovl_super_operations;
diff --git a/fs/overlayfs/util.c b/fs/overlayfs/util.c
index ea005085803f..042f7eb4f7f4 100644
--- a/fs/overlayfs/util.c
+++ b/fs/overlayfs/util.c
@@ -509,7 +509,7 @@ int ovl_copy_up_start(struct dentry *dentry, int flags)
 	struct inode *inode = d_inode(dentry);
 	int err;
 
-	err = ovl_inode_lock(inode);
+	err = ovl_inode_lock_interruptible(inode);
 	if (!err && ovl_already_copied_up_locked(dentry, flags)) {
 		err = 1; /* Already copied up */
 		ovl_inode_unlock(inode);
@@ -764,7 +764,7 @@ int ovl_nlink_start(struct dentry *dentry)
 			return err;
 	}
 
-	err = ovl_inode_lock(inode);
+	err = ovl_inode_lock_interruptible(inode);
 	if (err)
 		return err;