diff options
| author | Russell King <rmk+kernel@armlinux.org.uk> | 2019-12-09 11:08:49 +0000 |
|---|---|---|
| committer | Al Viro <viro@zeniv.linux.org.uk> | 2020-01-20 20:12:40 -0500 |
| commit | 197ba3c519312a0bed91aeaf34095b2c09c6431a (patch) | |
| tree | be6067609c33ffdadfd27bacf3816094fcac7224 | |
| parent | 7b1952676256d2cdc03d0415a4c0e6bfb64e00ff (diff) | |
fs/adfs: map: incorporate map offsets into layout
lookup_zone() and scan_free_map() cope in different ways with the
location of the map data within a zone:
1. lookup_zone() adds a four byte offset to the map data pointer to
skip over the check and free link bytes.
2. scan_free_map() needs to use the free link pointer, which is an
offset from itself, so we end up adding a 32-bit offset to the
end pointer (aka mapsize) which is really confusing.
Rename mapsize to endbit as this is really what it is, and incorporate
the 32-bit offset into the map layout. This means that both dm_startbit
and dm_endbit are now bit offsets from the start of the buffer, rather
than four bytes in to the buffer.
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
| -rw-r--r-- | fs/adfs/map.c | 22 |
1 files changed, 11 insertions, 11 deletions
diff --git a/fs/adfs/map.c b/fs/adfs/map.c index 8ba8877110ff..55bd7c20158c 100644 --- a/fs/adfs/map.c +++ b/fs/adfs/map.c @@ -68,9 +68,9 @@ static DEFINE_RWLOCK(adfs_map_lock); static int lookup_zone(const struct adfs_discmap *dm, const unsigned int idlen, const u32 frag_id, unsigned int *offset) { - const unsigned int mapsize = dm->dm_endbit; + const unsigned int endbit = dm->dm_endbit; const u32 idmask = (1 << idlen) - 1; - unsigned char *map = dm->dm_bh->b_data + 4; + unsigned char *map = dm->dm_bh->b_data; unsigned int start = dm->dm_startbit; unsigned int mapptr; u32 frag; @@ -87,7 +87,7 @@ static int lookup_zone(const struct adfs_discmap *dm, const unsigned int idlen, u32 v = le32_to_cpu(_map[mapptr >> 5]) >> (mapptr & 31); while (v == 0) { mapptr = (mapptr & ~31) + 32; - if (mapptr >= mapsize) + if (mapptr >= endbit) goto error; v = le32_to_cpu(_map[mapptr >> 5]); } @@ -99,7 +99,7 @@ static int lookup_zone(const struct adfs_discmap *dm, const unsigned int idlen, goto found; again: start = mapptr; - } while (mapptr < mapsize); + } while (mapptr < endbit); return -1; error: @@ -127,7 +127,7 @@ found: static unsigned int scan_free_map(struct adfs_sb_info *asb, struct adfs_discmap *dm) { - const unsigned int mapsize = dm->dm_endbit + 32; + const unsigned int endbit = dm->dm_endbit; const unsigned int idlen = asb->s_idlen; const unsigned int frag_idlen = idlen <= 15 ? idlen : 15; const u32 idmask = (1 << frag_idlen) - 1; @@ -165,7 +165,7 @@ scan_free_map(struct adfs_sb_info *asb, struct adfs_discmap *dm) u32 v = le32_to_cpu(_map[mapptr >> 5]) >> (mapptr & 31); while (v == 0) { mapptr = (mapptr & ~31) + 32; - if (mapptr >= mapsize) + if (mapptr >= endbit) goto error; v = le32_to_cpu(_map[mapptr >> 5]); } @@ -345,19 +345,19 @@ static void adfs_map_layout(struct adfs_discmap *dm, unsigned int nzones, dm[0].dm_bh = NULL; dm[0].dm_startblk = 0; - dm[0].dm_startbit = ADFS_DR_SIZE_BITS; - dm[0].dm_endbit = zone_size; + dm[0].dm_startbit = 32 + ADFS_DR_SIZE_BITS; + dm[0].dm_endbit = 32 + zone_size; for (zone = 1; zone < nzones; zone++) { dm[zone].dm_bh = NULL; dm[zone].dm_startblk = zone * zone_size - ADFS_DR_SIZE_BITS; - dm[zone].dm_startbit = 0; - dm[zone].dm_endbit = zone_size; + dm[zone].dm_startbit = 32; + dm[zone].dm_endbit = 32 + zone_size; } size = adfs_disc_size(dr) >> dr->log2bpmb; size -= (nzones - 1) * zone_size - ADFS_DR_SIZE_BITS; - dm[nzones - 1].dm_endbit = size; + dm[nzones - 1].dm_endbit = 32 + size; } static int adfs_map_read(struct adfs_discmap *dm, struct super_block *sb, |