ext2: merge xattr next entry check to ext2_xattr_entry_valid()

We have introduced ext2_xattr_entry_valid() for xattr
entry sanity check, so it's better to do relevant things
in one place.

Signed-off-by: Chengguang Xu <cgxu519@zoho.com.cn>
Signed-off-by: Jan Kara <jack@suse.cz>

diff --git a/fs/ext2/xattr.c b/fs/ext2/xattr.c
index d21dbf2..2850397 100644 (file)
--- a/fs/ext2/xattr.c
+++ b/fs/ext2/xattr.c
@@ -145,10 +145,16 @@ ext2_xattr_header_valid(struct ext2_xattr_header *header)
 }
 
 static bool
-ext2_xattr_entry_valid(struct ext2_xattr_entry *entry, size_t end_offs)
+ext2_xattr_entry_valid(struct ext2_xattr_entry *entry,
+                      char *end, size_t end_offs)
 {
+       struct ext2_xattr_entry *next;
        size_t size;
 
+       next = EXT2_XATTR_NEXT(entry);
+       if ((char *)next >= end)
+               return false;
+
        if (entry->e_value_block != 0)
                return false;
 
@@ -214,17 +220,14 @@ bad_block:
        /* find named attribute */
        entry = FIRST_ENTRY(bh);
        while (!IS_LAST_ENTRY(entry)) {
-               struct ext2_xattr_entry *next =
-                       EXT2_XATTR_NEXT(entry);
-               if ((char *)next >= end)
-                       goto bad_block;
-               if (!ext2_xattr_entry_valid(entry, inode->i_sb->s_blocksize))
+               if (!ext2_xattr_entry_valid(entry, end,
+                   inode->i_sb->s_blocksize))
                        goto bad_block;
                if (name_index == entry->e_name_index &&
                    name_len == entry->e_name_len &&
                    memcmp(name, entry->e_name, name_len) == 0)
                        goto found;
-               entry = next;
+               entry = EXT2_XATTR_NEXT(entry);
        }
        if (ext2_xattr_cache_insert(ea_block_cache, bh))
                ea_idebug(inode, "cache insert failed");
@@ -299,13 +302,10 @@ bad_block:
        /* check the on-disk data structure */
        entry = FIRST_ENTRY(bh);
        while (!IS_LAST_ENTRY(entry)) {
-               struct ext2_xattr_entry *next = EXT2_XATTR_NEXT(entry);
-
-               if ((char *)next >= end)
-                       goto bad_block;
-               if (!ext2_xattr_entry_valid(entry, inode->i_sb->s_blocksize))
+               if (!ext2_xattr_entry_valid(entry, end,
+                   inode->i_sb->s_blocksize))
                        goto bad_block;
-               entry = next;
+               entry = EXT2_XATTR_NEXT(entry);
        }
        if (ext2_xattr_cache_insert(ea_block_cache, bh))
                ea_idebug(inode, "cache insert failed");
@@ -390,7 +390,7 @@ ext2_xattr_set(struct inode *inode, int name_index, const char *name,
        struct super_block *sb = inode->i_sb;
        struct buffer_head *bh = NULL;
        struct ext2_xattr_header *header = NULL;
-       struct ext2_xattr_entry *here, *last;
+       struct ext2_xattr_entry *here = NULL, *last = NULL;
        size_t name_len, free, min_offs = sb->s_blocksize;
        int not_found = 1, error;
        char *end;
@@ -444,10 +444,7 @@ bad_block:
                 */
                last = FIRST_ENTRY(bh);
                while (!IS_LAST_ENTRY(last)) {
-                       struct ext2_xattr_entry *next = EXT2_XATTR_NEXT(last);
-                       if ((char *)next >= end)
-                               goto bad_block;
-                       if (!ext2_xattr_entry_valid(last, sb->s_blocksize))
+                       if (!ext2_xattr_entry_valid(last, end, sb->s_blocksize))
                                goto bad_block;
                        if (last->e_value_size) {
                                size_t offs = le16_to_cpu(last->e_value_offs);
@@ -465,7 +462,7 @@ bad_block:
                                if (not_found <= 0)
                                        here = last;
                        }
-                       last = next;
+                       last = EXT2_XATTR_NEXT(last);
                }
                if (not_found > 0)
                        here = last;
@@ -476,7 +473,6 @@ bad_block:
                /* We will use a new extended attribute block. */
                free = sb->s_blocksize -
                        sizeof(struct ext2_xattr_header) - sizeof(__u32);
-               here = last = NULL;  /* avoid gcc uninitialized warning. */
        }
 
        if (not_found) {