1 files changed, 186 insertions, 61 deletions

diff --git a/fs/adfs/map.c b/fs/adfs/map.c
index f44d12cef5be..a81de80c45c1 100644
--- a/fs/adfs/map.c
+++ b/fs/adfs/map.c
@@ -4,6 +4,8 @@
  *
  *  Copyright (C) 1997-2002 Russell King
  */
+#include <linux/slab.h>
+#include <linux/statfs.h>
 #include <asm/unaligned.h>
 #include "adfs.h"
 
@@ -66,54 +68,41 @@ 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;
+	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);
-		mapptr = start + idlen;
-
-		/*
-		 * find end of fragment
-		 */
-		{
-			__le32 *_map = (__le32 *)map;
-			u32 v = le32_to_cpu(_map[mapptr >> 5]) >> (mapptr & 31);
-			while (v == 0) {
-				mapptr = (mapptr & ~31) + 32;
-				if (mapptr >= mapsize)
-					goto error;
-				v = le32_to_cpu(_map[mapptr >> 5]);
-			}
-
-			mapptr += 1 + ffz(~v);
+
+		fragend = find_next_bit_le(map, endbit, start + idlen);
+		if (fragend >= endbit)
+			goto error;
+
+		if (start == freelink) {
+			freelink += frag & 0x7fff;
+		} else if (frag == frag_id) {
+			unsigned int length = fragend + 1 - start;
+
+			if (*offset < length)
+				return start + *offset;
+			*offset -= length;
 		}
 
-		if (frag == frag_id)
-			goto found;
-again:
-		start = mapptr;
-	} while (mapptr < mapsize);
+		start = fragend + 1;
+	} while (start < endbit);
 	return -1;
 
 error:
 	printk(KERN_ERR "adfs: oversized fragment 0x%x at 0x%x-0x%x\n",
-		frag, start, mapptr);
+		frag, start, fragend);
 	return -1;
-
-found:
-	{
-		int length = mapptr - start;
-		if (*offset >= length) {
-			*offset -= length;
-			goto again;
-		}
-	}
-	return start + *offset;
 }
 
 /*
@@ -125,12 +114,12 @@ 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;
 	unsigned char *map = dm->dm_bh->b_data;
-	unsigned int start = 8, mapptr;
+	unsigned int start = 8, fragend;
 	u32 frag;
 	unsigned long total = 0;
 
@@ -149,29 +138,13 @@ scan_free_map(struct adfs_sb_info *asb, struct adfs_discmap *dm)
 	do {
 		start += frag;
 
-		/*
-		 * get fragment id
-		 */
 		frag = GET_FRAG_ID(map, start, idmask);
-		mapptr = start + idlen;
-
-		/*
-		 * find end of fragment
-		 */
-		{
-			__le32 *_map = (__le32 *)map;
-			u32 v = le32_to_cpu(_map[mapptr >> 5]) >> (mapptr & 31);
-			while (v == 0) {
-				mapptr = (mapptr & ~31) + 32;
-				if (mapptr >= mapsize)
-					goto error;
-				v = le32_to_cpu(_map[mapptr >> 5]);
-			}
-
-			mapptr += 1 + ffz(~v);
-		}
 
-		total += mapptr - start;
+		fragend = find_next_bit_le(map, endbit, start + idlen);
+		if (fragend >= endbit)
+			goto error;
+
+		total += fragend + 1 - start;
 	} while (frag >= idlen + 1);
 
 	if (frag != 0)
@@ -220,10 +193,10 @@ found:
  *  total_free = E(free_in_zone_n)
  *              nzones
  */
-unsigned int
-adfs_map_free(struct super_block *sb)
+void adfs_map_statfs(struct super_block *sb, struct kstatfs *buf)
 {
 	struct adfs_sb_info *asb = ADFS_SB(sb);
+	struct adfs_discrecord *dr = adfs_map_discrecord(asb->s_map);
 	struct adfs_discmap *dm;
 	unsigned int total = 0;
 	unsigned int zone;
@@ -235,7 +208,10 @@ adfs_map_free(struct super_block *sb)
 		total += scan_free_map(asb, dm++);
 	} while (--zone > 0);
 
-	return signed_asl(total, asb->s_map2blk);
+	buf->f_blocks  = adfs_disc_size(dr) >> sb->s_blocksize_bits;
+	buf->f_files   = asb->s_ids_per_zone * asb->s_map_size;
+	buf->f_bavail  =
+	buf->f_bfree   = signed_asl(total, asb->s_map2blk);
 }
 
 int adfs_map_lookup(struct super_block *sb, u32 frag_id, unsigned int offset)
@@ -280,3 +256,152 @@ bad_fragment:
 		   frag_id, zone, asb->s_map_size);
 	return 0;
 }
+
+static unsigned char adfs_calczonecheck(struct super_block *sb, unsigned char *map)
+{
+	unsigned int v0, v1, v2, v3;
+	int i;
+
+	v0 = v1 = v2 = v3 = 0;
+	for (i = sb->s_blocksize - 4; i; i -= 4) {
+		v0 += map[i]     + (v3 >> 8);
+		v3 &= 0xff;
+		v1 += map[i + 1] + (v0 >> 8);
+		v0 &= 0xff;
+		v2 += map[i + 2] + (v1 >> 8);
+		v1 &= 0xff;
+		v3 += map[i + 3] + (v2 >> 8);
+		v2 &= 0xff;
+	}
+	v0 +=           v3 >> 8;
+	v1 += map[1] + (v0 >> 8);
+	v2 += map[2] + (v1 >> 8);
+	v3 += map[3] + (v2 >> 8);
+
+	return v0 ^ v1 ^ v2 ^ v3;
+}
+
+static int adfs_checkmap(struct super_block *sb, struct adfs_discmap *dm)
+{
+	unsigned char crosscheck = 0, zonecheck = 1;
+	int i;
+
+	for (i = 0; i < ADFS_SB(sb)->s_map_size; i++) {
+		unsigned char *map;
+
+		map = dm[i].dm_bh->b_data;
+
+		if (adfs_calczonecheck(sb, map) != map[0]) {
+			adfs_error(sb, "zone %d fails zonecheck", i);
+			zonecheck = 0;
+		}
+		crosscheck ^= map[3];
+	}
+	if (crosscheck != 0xff)
+		adfs_error(sb, "crosscheck != 0xff");
+	return crosscheck == 0xff && zonecheck;
+}
+
+/*
+ * Layout the map - the first zone contains a copy of the disc record,
+ * and the last zone must be limited to the size of the filesystem.
+ */
+static void adfs_map_layout(struct adfs_discmap *dm, unsigned int nzones,
+			    struct adfs_discrecord *dr)
+{
+	unsigned int zone, zone_size;
+	u64 size;
+
+	zone_size = (8 << dr->log2secsize) - le16_to_cpu(dr->zone_spare);
+
+	dm[0].dm_bh       = NULL;
+	dm[0].dm_startblk = 0;
+	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 = 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 = 32 + size;
+}
+
+static int adfs_map_read(struct adfs_discmap *dm, struct super_block *sb,
+			 unsigned int map_addr, unsigned int nzones)
+{
+	unsigned int zone;
+
+	for (zone = 0; zone < nzones; zone++) {
+		dm[zone].dm_bh = sb_bread(sb, map_addr + zone);
+		if (!dm[zone].dm_bh)
+			return -EIO;
+	}
+
+	return 0;
+}
+
+static void adfs_map_relse(struct adfs_discmap *dm, unsigned int nzones)
+{
+	unsigned int zone;
+
+	for (zone = 0; zone < nzones; zone++)
+		brelse(dm[zone].dm_bh);
+}
+
+struct adfs_discmap *adfs_read_map(struct super_block *sb, struct adfs_discrecord *dr)
+{
+	struct adfs_sb_info *asb = ADFS_SB(sb);
+	struct adfs_discmap *dm;
+	unsigned int map_addr, zone_size, nzones;
+	int ret;
+
+	nzones    = dr->nzones | dr->nzones_high << 8;
+	zone_size = (8 << dr->log2secsize) - le16_to_cpu(dr->zone_spare);
+
+	asb->s_idlen = dr->idlen;
+	asb->s_map_size = nzones;
+	asb->s_map2blk = dr->log2bpmb - dr->log2secsize;
+	asb->s_log2sharesize = dr->log2sharesize;
+	asb->s_ids_per_zone = zone_size / (asb->s_idlen + 1);
+
+	map_addr = (nzones >> 1) * zone_size -
+		     ((nzones > 1) ? ADFS_DR_SIZE_BITS : 0);
+	map_addr = signed_asl(map_addr, asb->s_map2blk);
+
+	dm = kmalloc_array(nzones, sizeof(*dm), GFP_KERNEL);
+	if (dm == NULL) {
+		adfs_error(sb, "not enough memory");
+		return ERR_PTR(-ENOMEM);
+	}
+
+	adfs_map_layout(dm, nzones, dr);
+
+	ret = adfs_map_read(dm, sb, map_addr, nzones);
+	if (ret) {
+		adfs_error(sb, "unable to read map");
+		goto error_free;
+	}
+
+	if (adfs_checkmap(sb, dm))
+		return dm;
+
+	adfs_error(sb, "map corrupted");
+
+error_free:
+	adfs_map_relse(dm, nzones);
+	kfree(dm);
+	return ERR_PTR(-EIO);
+}
+
+void adfs_free_map(struct super_block *sb)
+{
+	struct adfs_sb_info *asb = ADFS_SB(sb);
+
+	adfs_map_relse(asb->s_map, asb->s_map_size);
+	kfree(asb->s_map);
+}