ext2: a zero block number is actually legit

It may not happen in normal operation, but a zero block value is legit
and means an all-zero block.  For anything which uses the cache, we
have dealt with that by always keeping a zero block in the cache.

Signed-off-by: H. Peter Anvin <hpa@zytor.com>

1 files changed, 5 insertions, 4 deletions

diff --git a/core/fs/ext2/ext2.c b/core/fs/ext2/ext2.c
index bc758249..52543407 100644
--- a/core/fs/ext2/ext2.c
+++ b/core/fs/ext2/ext2.c
@@ -184,8 +184,7 @@ ext2_find_entry(struct fs_info *fs, struct inode *inode, const char *dname)
     size_t dname_len = strlen(dname);
 
     while (i < inode->size) {
-	if (!(block = ext2_bmap(inode, index++)))
-	    return NULL;
+	block = ext2_bmap(inode, index++);
 	data = get_cache(fs->fs_dev, block);
 	offset = 0;
 	maxoffset =  min(BLOCK_SIZE(fs), i-inode->size);
@@ -323,8 +322,10 @@ static struct dirent * ext2_readdir(struct file *file)
     block_t index = file->offset >> fs->block_shift;
     block_t block;
 
-    if (!(block = ext2_bmap(inode, index)))
-	return NULL;
+    if (file->offset >= inode->size)
+	return NULL;		/* End of file */
+
+    block = ext2_bmap(inode, index);
 
     data = get_cache(fs->fs_dev, block);
     de = (const struct ext2_dir_entry *)