1 files changed, 37 insertions, 8 deletions

diff --git a/fs/ext4/namei.c b/fs/ext4/namei.c
index 4909ced4e672..0cda080f3fd5 100644
--- a/fs/ext4/namei.c
+++ b/fs/ext4/namei.c
@@ -82,8 +82,18 @@ static struct buffer_head *ext4_append(handle_t *handle,
 static int ext4_dx_csum_verify(struct inode *inode,
 			       struct ext4_dir_entry *dirent);
 
+/*
+ * Hints to ext4_read_dirblock regarding whether we expect a directory
+ * block being read to be an index block, or a block containing
+ * directory entries (and if the latter, whether it was found via a
+ * logical block in an htree index block).  This is used to control
+ * what sort of sanity checkinig ext4_read_dirblock() will do on the
+ * directory block read from the storage device.  EITHER will means
+ * the caller doesn't know what kind of directory block will be read,
+ * so no specific verification will be done.
+ */
 typedef enum {
-	EITHER, INDEX, DIRENT
+	EITHER, INDEX, DIRENT, DIRENT_HTREE
 } dirblock_type_t;
 
 #define ext4_read_dirblock(inode, block, type) \
@@ -109,11 +119,14 @@ static struct buffer_head *__ext4_read_dirblock(struct inode *inode,
 
 		return bh;
 	}
-	if (!bh) {
+	if (!bh && (type == INDEX || type == DIRENT_HTREE)) {
 		ext4_error_inode(inode, func, line, block,
-				 "Directory hole found");
+				 "Directory hole found for htree %s block",
+				 (type == INDEX) ? "index" : "leaf");
 		return ERR_PTR(-EFSCORRUPTED);
 	}
+	if (!bh)
+		return NULL;
 	dirent = (struct ext4_dir_entry *) bh->b_data;
 	/* Determine whether or not we have an index block */
 	if (is_dx(inode)) {
@@ -980,7 +993,7 @@ static int htree_dirblock_to_tree(struct file *dir_file,
 
 	dxtrace(printk(KERN_INFO "In htree dirblock_to_tree: block %lu\n",
 							(unsigned long)block));
-	bh = ext4_read_dirblock(dir, block, DIRENT);
+	bh = ext4_read_dirblock(dir, block, DIRENT_HTREE);
 	if (IS_ERR(bh))
 		return PTR_ERR(bh);
 
@@ -1619,7 +1632,7 @@ static struct buffer_head * ext4_dx_find_entry(struct inode *dir,
 		return (struct buffer_head *) frame;
 	do {
 		block = dx_get_block(frame->at);
-		bh = ext4_read_dirblock(dir, block, DIRENT);
+		bh = ext4_read_dirblock(dir, block, DIRENT_HTREE);
 		if (IS_ERR(bh))
 			goto errout;
 
@@ -2203,6 +2216,11 @@ static int ext4_add_entry(handle_t *handle, struct dentry *dentry,
 	blocks = dir->i_size >> sb->s_blocksize_bits;
 	for (block = 0; block < blocks; block++) {
 		bh = ext4_read_dirblock(dir, block, DIRENT);
+		if (bh == NULL) {
+			bh = ext4_bread(handle, dir, block,
+					EXT4_GET_BLOCKS_CREATE);
+			goto add_to_new_block;
+		}
 		if (IS_ERR(bh)) {
 			retval = PTR_ERR(bh);
 			bh = NULL;
@@ -2223,6 +2241,7 @@ static int ext4_add_entry(handle_t *handle, struct dentry *dentry,
 		brelse(bh);
 	}
 	bh = ext4_append(handle, dir, &block);
+add_to_new_block:
 	if (IS_ERR(bh)) {
 		retval = PTR_ERR(bh);
 		bh = NULL;
@@ -2267,7 +2286,7 @@ again:
 		return PTR_ERR(frame);
 	entries = frame->entries;
 	at = frame->at;
-	bh = ext4_read_dirblock(dir, dx_get_block(frame->at), DIRENT);
+	bh = ext4_read_dirblock(dir, dx_get_block(frame->at), DIRENT_HTREE);
 	if (IS_ERR(bh)) {
 		err = PTR_ERR(bh);
 		bh = NULL;
@@ -2815,7 +2834,10 @@ bool ext4_empty_dir(struct inode *inode)
 		EXT4_ERROR_INODE(inode, "invalid size");
 		return true;
 	}
-	bh = ext4_read_dirblock(inode, 0, EITHER);
+	/* The first directory block must not be a hole,
+	 * so treat it as DIRENT_HTREE
+	 */
+	bh = ext4_read_dirblock(inode, 0, DIRENT_HTREE);
 	if (IS_ERR(bh))
 		return true;
 
@@ -2837,6 +2859,10 @@ bool ext4_empty_dir(struct inode *inode)
 			brelse(bh);
 			lblock = offset >> EXT4_BLOCK_SIZE_BITS(sb);
 			bh = ext4_read_dirblock(inode, lblock, EITHER);
+			if (bh == NULL) {
+				offset += sb->s_blocksize;
+				continue;
+			}
 			if (IS_ERR(bh))
 				return true;
 			de = (struct ext4_dir_entry_2 *) bh->b_data;
@@ -3402,7 +3428,10 @@ static struct buffer_head *ext4_get_first_dir_block(handle_t *handle,
 	struct buffer_head *bh;
 
 	if (!ext4_has_inline_data(inode)) {
-		bh = ext4_read_dirblock(inode, 0, EITHER);
+		/* The first directory block must not be a hole, so
+		 * treat it as DIRENT_HTREE
+		 */
+		bh = ext4_read_dirblock(inode, 0, DIRENT_HTREE);
 		if (IS_ERR(bh)) {
 			*retval = PTR_ERR(bh);
 			return NULL;