Commit 197ba3c5 authored by Russell King's avatar Russell King Committed by Al Viro
Browse files

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: default avatarRussell King <rmk+kernel@armlinux.org.uk>
Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
parent 7b195267

fs/adfs/map.c

+11 −11
Original line number Diff line number Diff line
@@ -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,

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