hfs: add error checking for hfs_find_init()

hfs_find_init() may fail with ENOMEM, but there are places, where the
returned value is not checked.  The consequences can be very unpleasant,
e.g.  kfree uninitialized pointer and inappropriate mutex unlocking.

The patch adds checks for errors in hfs_find_init().

Found by Linux Driver Verification project (linuxtesting.org).

Signed-off-by: Alexey Khoroshilov <khoroshilov@ispras.ru>
Reviewed-by: Vyacheslav Dubeyko <slava@dubeyko.com>
Cc: Hin-Tak Leung <htl10@users.sourceforge.net>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/fs/hfs/catalog.c b/fs/hfs/catalog.c
index 424b033..9569b39 100644
--- a/fs/hfs/catalog.c
+++ b/fs/hfs/catalog.c
@@ -92,7 +92,9 @@
 		return -ENOSPC;
 
 	sb = dir->i_sb;
-	hfs_find_init(HFS_SB(sb)->cat_tree, &fd);
+	err = hfs_find_init(HFS_SB(sb)->cat_tree, &fd);
+	if (err)
+		return err;
 
 	hfs_cat_build_key(sb, fd.search_key, cnid, NULL);
 	entry_size = hfs_cat_build_thread(sb, &entry, S_ISDIR(inode->i_mode) ?
@@ -214,7 +216,9 @@
 
 	dprint(DBG_CAT_MOD, "delete_cat: %s,%u\n", str ? str->name : NULL, cnid);
 	sb = dir->i_sb;
-	hfs_find_init(HFS_SB(sb)->cat_tree, &fd);
+	res = hfs_find_init(HFS_SB(sb)->cat_tree, &fd);
+	if (res)
+		return res;
 
 	hfs_cat_build_key(sb, fd.search_key, dir->i_ino, str);
 	res = hfs_brec_find(&fd);
@@ -281,7 +285,9 @@
 	dprint(DBG_CAT_MOD, "rename_cat: %u - %lu,%s - %lu,%s\n", cnid, src_dir->i_ino, src_name->name,
 		dst_dir->i_ino, dst_name->name);
 	sb = src_dir->i_sb;
-	hfs_find_init(HFS_SB(sb)->cat_tree, &src_fd);
+	err = hfs_find_init(HFS_SB(sb)->cat_tree, &src_fd);
+	if (err)
+		return err;
 	dst_fd = src_fd;
 
 	/* find the old dir entry and read the data */
diff --git a/fs/hfs/dir.c b/fs/hfs/dir.c
index 5f7f1ab..e1c8048 100644
--- a/fs/hfs/dir.c
+++ b/fs/hfs/dir.c
@@ -25,7 +25,9 @@
 	struct inode *inode = NULL;
 	int res;
 
-	hfs_find_init(HFS_SB(dir->i_sb)->cat_tree, &fd);
+	res = hfs_find_init(HFS_SB(dir->i_sb)->cat_tree, &fd);
+	if (res)
+		return ERR_PTR(res);
 	hfs_cat_build_key(dir->i_sb, fd.search_key, dir->i_ino, &dentry->d_name);
 	res = hfs_brec_read(&fd, &rec, sizeof(rec));
 	if (res) {
@@ -63,7 +65,9 @@
 	if (filp->f_pos >= inode->i_size)
 		return 0;
 
-	hfs_find_init(HFS_SB(sb)->cat_tree, &fd);
+	err = hfs_find_init(HFS_SB(sb)->cat_tree, &fd);
+	if (err)
+		return err;
 	hfs_cat_build_key(sb, fd.search_key, inode->i_ino, NULL);
 	err = hfs_brec_find(&fd);
 	if (err)
diff --git a/fs/hfs/extent.c b/fs/hfs/extent.c
index a67955a..813447b 100644
--- a/fs/hfs/extent.c
+++ b/fs/hfs/extent.c
@@ -107,7 +107,7 @@
 	return be16_to_cpu(ext->block) + be16_to_cpu(ext->count);
 }
 
-static void __hfs_ext_write_extent(struct inode *inode, struct hfs_find_data *fd)
+static int __hfs_ext_write_extent(struct inode *inode, struct hfs_find_data *fd)
 {
 	int res;
 
@@ -116,26 +116,31 @@
 	res = hfs_brec_find(fd);
 	if (HFS_I(inode)->flags & HFS_FLG_EXT_NEW) {
 		if (res != -ENOENT)
-			return;
+			return res;
 		hfs_brec_insert(fd, HFS_I(inode)->cached_extents, sizeof(hfs_extent_rec));
 		HFS_I(inode)->flags &= ~(HFS_FLG_EXT_DIRTY|HFS_FLG_EXT_NEW);
 	} else {
 		if (res)
-			return;
+			return res;
 		hfs_bnode_write(fd->bnode, HFS_I(inode)->cached_extents, fd->entryoffset, fd->entrylength);
 		HFS_I(inode)->flags &= ~HFS_FLG_EXT_DIRTY;
 	}
+	return 0;
 }
 
-void hfs_ext_write_extent(struct inode *inode)
+int hfs_ext_write_extent(struct inode *inode)
 {
 	struct hfs_find_data fd;
+	int res = 0;
 
 	if (HFS_I(inode)->flags & HFS_FLG_EXT_DIRTY) {
-		hfs_find_init(HFS_SB(inode->i_sb)->ext_tree, &fd);
-		__hfs_ext_write_extent(inode, &fd);
+		res = hfs_find_init(HFS_SB(inode->i_sb)->ext_tree, &fd);
+		if (res)
+			return res;
+		res = __hfs_ext_write_extent(inode, &fd);
 		hfs_find_exit(&fd);
 	}
+	return res;
 }
 
 static inline int __hfs_ext_read_extent(struct hfs_find_data *fd, struct hfs_extent *extent,
@@ -161,8 +166,11 @@
 {
 	int res;
 
-	if (HFS_I(inode)->flags & HFS_FLG_EXT_DIRTY)
-		__hfs_ext_write_extent(inode, fd);
+	if (HFS_I(inode)->flags & HFS_FLG_EXT_DIRTY) {
+		res = __hfs_ext_write_extent(inode, fd);
+		if (res)
+			return res;
+	}
 
 	res = __hfs_ext_read_extent(fd, HFS_I(inode)->cached_extents, inode->i_ino,
 				    block, HFS_IS_RSRC(inode) ? HFS_FK_RSRC : HFS_FK_DATA);
@@ -185,9 +193,11 @@
 	    block < HFS_I(inode)->cached_start + HFS_I(inode)->cached_blocks)
 		return 0;
 
-	hfs_find_init(HFS_SB(inode->i_sb)->ext_tree, &fd);
-	res = __hfs_ext_cache_extent(&fd, inode, block);
-	hfs_find_exit(&fd);
+	res = hfs_find_init(HFS_SB(inode->i_sb)->ext_tree, &fd);
+	if (!res) {
+		res = __hfs_ext_cache_extent(&fd, inode, block);
+		hfs_find_exit(&fd);
+	}
 	return res;
 }
 
@@ -298,7 +308,9 @@
 	if (total_blocks == blocks)
 		return 0;
 
-	hfs_find_init(HFS_SB(sb)->ext_tree, &fd);
+	res = hfs_find_init(HFS_SB(sb)->ext_tree, &fd);
+	if (res)
+		return res;
 	do {
 		res = __hfs_ext_read_extent(&fd, extent, cnid, total_blocks, type);
 		if (res)
@@ -438,7 +450,9 @@
 
 insert_extent:
 	dprint(DBG_EXTENT, "insert new extent\n");
-	hfs_ext_write_extent(inode);
+	res = hfs_ext_write_extent(inode);
+	if (res)
+		goto out;
 
 	memset(HFS_I(inode)->cached_extents, 0, sizeof(hfs_extent_rec));
 	HFS_I(inode)->cached_extents[0].block = cpu_to_be16(start);
@@ -466,7 +480,6 @@
 		struct address_space *mapping = inode->i_mapping;
 		void *fsdata;
 		struct page *page;
-		int res;
 
 		/* XXX: Can use generic_cont_expand? */
 		size = inode->i_size - 1;
@@ -488,7 +501,12 @@
 		goto out;
 
 	mutex_lock(&HFS_I(inode)->extents_lock);
-	hfs_find_init(HFS_SB(sb)->ext_tree, &fd);
+	res = hfs_find_init(HFS_SB(sb)->ext_tree, &fd);
+	if (res) {
+		mutex_unlock(&HFS_I(inode)->extents_lock);
+		/* XXX: We lack error handling of hfs_file_truncate() */
+		return;
+	}
 	while (1) {
 		if (alloc_cnt == HFS_I(inode)->first_blocks) {
 			hfs_free_extents(sb, HFS_I(inode)->first_extents,
diff --git a/fs/hfs/hfs_fs.h b/fs/hfs/hfs_fs.h
index 693df9f..67817af 100644
--- a/fs/hfs/hfs_fs.h
+++ b/fs/hfs/hfs_fs.h
@@ -174,7 +174,7 @@
 /* extent.c */
 extern int hfs_ext_keycmp(const btree_key *, const btree_key *);
 extern int hfs_free_fork(struct super_block *, struct hfs_cat_file *, int);
-extern void hfs_ext_write_extent(struct inode *);
+extern int hfs_ext_write_extent(struct inode *);
 extern int hfs_extend_file(struct inode *);
 extern void hfs_file_truncate(struct inode *);
 
diff --git a/fs/hfs/inode.c b/fs/hfs/inode.c
index 3031dfd..0847471 100644
--- a/fs/hfs/inode.c
+++ b/fs/hfs/inode.c
@@ -416,9 +416,12 @@
 	struct inode *main_inode = inode;
 	struct hfs_find_data fd;
 	hfs_cat_rec rec;
+	int res;
 
 	dprint(DBG_INODE, "hfs_write_inode: %lu\n", inode->i_ino);
-	hfs_ext_write_extent(inode);
+	res = hfs_ext_write_extent(inode);
+	if (res)
+		return res;
 
 	if (inode->i_ino < HFS_FIRSTUSER_CNID) {
 		switch (inode->i_ino) {
@@ -515,7 +518,11 @@
 	if (!inode)
 		return ERR_PTR(-ENOMEM);
 
-	hfs_find_init(HFS_SB(dir->i_sb)->cat_tree, &fd);
+	res = hfs_find_init(HFS_SB(dir->i_sb)->cat_tree, &fd);
+	if (res) {
+		iput(inode);
+		return ERR_PTR(res);
+	}
 	fd.search_key->cat = HFS_I(dir)->cat_key;
 	res = hfs_brec_read(&fd, &rec, sizeof(rec));
 	if (!res) {
diff --git a/fs/hfs/super.c b/fs/hfs/super.c
index bbaaa8a..719760b 100644
--- a/fs/hfs/super.c
+++ b/fs/hfs/super.c
@@ -418,7 +418,9 @@
 	}
 
 	/* try to get the root inode */
-	hfs_find_init(HFS_SB(sb)->cat_tree, &fd);
+	res = hfs_find_init(HFS_SB(sb)->cat_tree, &fd);
+	if (res)
+		goto bail_no_root;
 	res = hfs_cat_find_brec(sb, HFS_ROOT_CNID, &fd);
 	if (!res) {
 		if (fd.entrylength > sizeof(rec) || fd.entrylength < 0) {