5 files changed, 76 insertions, 20 deletions

diff --git a/fs/hpfs/buffer.c b/fs/hpfs/buffer.c
index 8057fe4e6574..f626114449e4 100644
--- a/fs/hpfs/buffer.c
+++ b/fs/hpfs/buffer.c
@@ -10,6 +10,30 @@
 #include <linux/blkdev.h>
 #include "hpfs_fn.h"
 
+secno hpfs_search_hotfix_map(struct super_block *s, secno sec)
+{
+	unsigned i;
+	struct hpfs_sb_info *sbi = hpfs_sb(s);
+	for (i = 0; unlikely(i < sbi->n_hotfixes); i++) {
+		if (sbi->hotfix_from[i] == sec) {
+			return sbi->hotfix_to[i];
+		}
+	}
+	return sec;
+}
+
+unsigned hpfs_search_hotfix_map_for_range(struct super_block *s, secno sec, unsigned n)
+{
+	unsigned i;
+	struct hpfs_sb_info *sbi = hpfs_sb(s);
+	for (i = 0; unlikely(i < sbi->n_hotfixes); i++) {
+		if (sbi->hotfix_from[i] >= sec && sbi->hotfix_from[i] < sec + n) {
+			n = sbi->hotfix_from[i] - sec;
+		}
+	}
+	return n;
+}
+
 void hpfs_prefetch_sectors(struct super_block *s, unsigned secno, int n)
 {
 	struct buffer_head *bh;
@@ -18,6 +42,9 @@ void hpfs_prefetch_sectors(struct super_block *s, unsigned secno, int n)
 	if (n <= 0 || unlikely(secno >= hpfs_sb(s)->sb_fs_size))
 		return;
 
+	if (unlikely(hpfs_search_hotfix_map_for_range(s, secno, n) != n))
+		return;
+
 	bh = sb_find_get_block(s, secno);
 	if (bh) {
 		if (buffer_uptodate(bh)) {
@@ -51,7 +78,7 @@ void *hpfs_map_sector(struct super_block *s, unsigned secno, struct buffer_head
 
 	cond_resched();
 
-	*bhp = bh = sb_bread(s, secno);
+	*bhp = bh = sb_bread(s, hpfs_search_hotfix_map(s, secno));
 	if (bh != NULL)
 		return bh->b_data;
 	else {
@@ -71,7 +98,7 @@ void *hpfs_get_sector(struct super_block *s, unsigned secno, struct buffer_head
 
 	cond_resched();
 
-	if ((*bhp = bh = sb_getblk(s, secno)) != NULL) {
+	if ((*bhp = bh = sb_getblk(s, hpfs_search_hotfix_map(s, secno))) != NULL) {
 		if (!buffer_uptodate(bh)) wait_on_buffer(bh);
 		set_buffer_uptodate(bh);
 		return bh->b_data;
@@ -99,10 +126,10 @@ void *hpfs_map_4sectors(struct super_block *s, unsigned secno, struct quad_buffe
 
 	hpfs_prefetch_sectors(s, secno, 4 + ahead);
 
-	if (!(qbh->bh[0] = sb_bread(s, secno + 0))) goto bail0;
-	if (!(qbh->bh[1] = sb_bread(s, secno + 1))) goto bail1;
-	if (!(qbh->bh[2] = sb_bread(s, secno + 2))) goto bail2;
-	if (!(qbh->bh[3] = sb_bread(s, secno + 3))) goto bail3;
+	if (!hpfs_map_sector(s, secno + 0, &qbh->bh[0], 0)) goto bail0;
+	if (!hpfs_map_sector(s, secno + 1, &qbh->bh[1], 0)) goto bail1;
+	if (!hpfs_map_sector(s, secno + 2, &qbh->bh[2], 0)) goto bail2;
+	if (!hpfs_map_sector(s, secno + 3, &qbh->bh[3], 0)) goto bail3;
 
 	if (likely(qbh->bh[1]->b_data == qbh->bh[0]->b_data + 1 * 512) &&
 	    likely(qbh->bh[2]->b_data == qbh->bh[0]->b_data + 2 * 512) &&
diff --git a/fs/hpfs/file.c b/fs/hpfs/file.c
index 7ca28d604bf7..d3bcdd975700 100644
--- a/fs/hpfs/file.c
+++ b/fs/hpfs/file.c
@@ -83,6 +83,11 @@ static int hpfs_get_block(struct inode *inode, sector_t iblock, struct buffer_he
 	if (s) {
 		if (bh_result->b_size >> 9 < n_secs)
 			n_secs = bh_result->b_size >> 9;
+		n_secs = hpfs_search_hotfix_map_for_range(inode->i_sb, s, n_secs);
+		if (unlikely(!n_secs)) {
+			s = hpfs_search_hotfix_map(inode->i_sb, s);
+			n_secs = 1;
+		}
 		map_bh(bh_result, inode->i_sb, s);
 		bh_result->b_size = n_secs << 9;
 		goto ret_0;
@@ -101,7 +106,7 @@ static int hpfs_get_block(struct inode *inode, sector_t iblock, struct buffer_he
 	inode->i_blocks++;
 	hpfs_i(inode)->mmu_private += 512;
 	set_buffer_new(bh_result);
-	map_bh(bh_result, inode->i_sb, s);
+	map_bh(bh_result, inode->i_sb, hpfs_search_hotfix_map(inode->i_sb, s));
 	ret_0:
 	r = 0;
 	ret_r:
@@ -181,7 +186,7 @@ static int hpfs_write_end(struct file *file, struct address_space *mapping,
 
 static sector_t _hpfs_bmap(struct address_space *mapping, sector_t block)
 {
-	return generic_block_bmap(mapping,block,hpfs_get_block);
+	return generic_block_bmap(mapping, block, hpfs_get_block);
 }
 
 const struct address_space_operations hpfs_aops = {
diff --git a/fs/hpfs/hpfs_fn.h b/fs/hpfs/hpfs_fn.h
index c4867b5116dd..975654a63c13 100644
--- a/fs/hpfs/hpfs_fn.h
+++ b/fs/hpfs/hpfs_fn.h
@@ -88,6 +88,10 @@ struct hpfs_sb_info {
 	unsigned sb_max_fwd_alloc;	/* max forwad allocation */
 	int sb_timeshift;
 	struct rcu_head rcu;
+
+	unsigned n_hotfixes;
+	secno hotfix_from[256];
+	secno hotfix_to[256];
 };
 
 /* Four 512-byte buffers and the 2k block obtained by concatenating them */
@@ -217,6 +221,8 @@ void hpfs_remove_fnode(struct super_block *, fnode_secno fno);
 
 /* buffer.c */
 
+secno hpfs_search_hotfix_map(struct super_block *s, secno sec);
+unsigned hpfs_search_hotfix_map_for_range(struct super_block *s, secno sec, unsigned n);
 void hpfs_prefetch_sectors(struct super_block *, unsigned, int);
 void *hpfs_map_sector(struct super_block *, unsigned, struct buffer_head **, int);
 void *hpfs_get_sector(struct super_block *, unsigned, struct buffer_head **);
@@ -285,6 +291,7 @@ __le32 *hpfs_map_bitmap(struct super_block *, unsigned, struct quad_buffer_head
 void hpfs_prefetch_bitmap(struct super_block *, unsigned);
 unsigned char *hpfs_load_code_page(struct super_block *, secno);
 __le32 *hpfs_load_bitmap_directory(struct super_block *, secno bmp);
+void hpfs_load_hotfix_map(struct super_block *s, struct hpfs_spare_block *spareblock);
 struct fnode *hpfs_map_fnode(struct super_block *s, ino_t, struct buffer_head **);
 struct anode *hpfs_map_anode(struct super_block *s, anode_secno, struct buffer_head **);
 struct dnode *hpfs_map_dnode(struct super_block *s, dnode_secno, struct quad_buffer_head *);
diff --git a/fs/hpfs/map.c b/fs/hpfs/map.c
index 442770edcdc7..a69bbc1e87f8 100644
--- a/fs/hpfs/map.c
+++ b/fs/hpfs/map.c
@@ -130,6 +130,32 @@ __le32 *hpfs_load_bitmap_directory(struct super_block *s, secno bmp)
 	return b;
 }
 
+void hpfs_load_hotfix_map(struct super_block *s, struct hpfs_spare_block *spareblock)
+{
+	struct quad_buffer_head qbh;
+	u32 *directory;
+	u32 n_hotfixes, n_used_hotfixes;
+	unsigned i;
+
+	n_hotfixes = le32_to_cpu(spareblock->n_spares);
+	n_used_hotfixes = le32_to_cpu(spareblock->n_spares_used);
+
+	if (n_hotfixes > 256 || n_used_hotfixes > n_hotfixes) {
+		hpfs_error(s, "invalid number of hotfixes: %u, used: %u", n_hotfixes, n_used_hotfixes);
+		return;
+	}
+	if (!(directory = hpfs_map_4sectors(s, le32_to_cpu(spareblock->hotfix_map), &qbh, 0))) {
+		hpfs_error(s, "can't load hotfix map");
+		return;
+	}
+	for (i = 0; i < n_used_hotfixes; i++) {
+		hpfs_sb(s)->hotfix_from[i] = le32_to_cpu(directory[i]);
+		hpfs_sb(s)->hotfix_to[i] = le32_to_cpu(directory[n_hotfixes + i]);
+	}
+	hpfs_sb(s)->n_hotfixes = n_used_hotfixes;
+	hpfs_brelse4(&qbh);
+}
+
 /*
  * Load fnode to memory
  */
diff --git a/fs/hpfs/super.c b/fs/hpfs/super.c
index 68a9bed05628..a561591896bd 100644
--- a/fs/hpfs/super.c
+++ b/fs/hpfs/super.c
@@ -628,6 +628,9 @@ static int hpfs_fill_super(struct super_block *s, void *options, int silent)
 		goto bail4;
 	}
 
+	if (spareblock->n_spares_used)
+		hpfs_load_hotfix_map(s, spareblock);
+
 	/* Load bitmap directory */
 	if (!(sbi->sb_bmp_dir = hpfs_load_bitmap_directory(s, le32_to_cpu(superblock->bitmaps))))
 		goto bail4;
@@ -647,18 +650,6 @@ static int hpfs_fill_super(struct super_block *s, void *options, int silent)
 		mark_buffer_dirty(bh2);
 	}
 
-	if (spareblock->hotfixes_used || spareblock->n_spares_used) {
-		if (errs >= 2) {
-			pr_err("Hotfixes not supported here, try chkdsk\n");
-			mark_dirty(s, 0);
-			goto bail4;
-		}
-		hpfs_error(s, "hotfixes not supported here, try chkdsk");
-		if (errs == 0)
-			pr_err("Proceeding, but your filesystem will be probably corrupted by this driver...\n");
-		else
-			pr_err("This driver may read bad files or crash when operating on disk with hotfixes.\n");
-	}
 	if (le32_to_cpu(spareblock->n_dnode_spares) != le32_to_cpu(spareblock->n_dnode_spares_free)) {
 		if (errs >= 2) {
 			pr_err("Spare dnodes used, try chkdsk\n");