From f93793fd73a629f4c86b0d91fd84fe175705aff9 Mon Sep 17 00:00:00 2001 From: Russell King Date: Mon, 9 Dec 2019 11:09:04 +0000 Subject: fs/adfs: map: fix map scanning When scanning the map for a fragment id, we need to keep track of the free space links, so we don't inadvertently believe that the freespace link is a valid fragment id. Signed-off-by: Russell King Signed-off-by: Al Viro --- fs/adfs/map.c | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-) (limited to 'fs/adfs') diff --git a/fs/adfs/map.c b/fs/adfs/map.c index 82e1bf101fe6..a81de80c45c1 100644 --- a/fs/adfs/map.c +++ b/fs/adfs/map.c @@ -72,9 +72,12 @@ static int lookup_zone(const struct adfs_discmap *dm, const unsigned int idlen, const u32 idmask = (1 << idlen) - 1; unsigned char *map = dm->dm_bh->b_data; unsigned int start = dm->dm_startbit; - unsigned int fragend; + unsigned int freelink, fragend; u32 frag; + frag = GET_FRAG_ID(map, 8, idmask & 0x7fff); + freelink = frag ? 8 + frag : 0; + do { frag = GET_FRAG_ID(map, start, idmask); @@ -82,7 +85,9 @@ static int lookup_zone(const struct adfs_discmap *dm, const unsigned int idlen, if (fragend >= endbit) goto error; - if (frag == frag_id) { + if (start == freelink) { + freelink += frag & 0x7fff; + } else if (frag == frag_id) { unsigned int length = fragend + 1 - start; if (*offset < length) -- cgit v1.2.3