hfsplus: use raw bio access for the volume headers

The hfsplus backup volume header is located two blocks from the end of
the device.  In case of device sizes that are not 4k aligned this means
we can't access it using buffer_heads when using the default 4k block
size.

Switch to using raw bios to read/write all buffer headers.  We were not
relying on any caching behaviour of the buffer heads anyway.  Additionally
always read in the backup volume header during mount to verify that we
can actually read it.

Signed-off-by: Christoph Hellwig <hch@tuxera.com>

1 files changed, 22 insertions, 26 deletions

diff --git a/fs/hfsplus/super.c b/fs/hfsplus/super.c
index 6a2349058618..fe8f7bffbea5 100644
--- a/fs/hfsplus/super.c
+++ b/fs/hfsplus/super.c
@@ -157,45 +157,40 @@ int hfsplus_sync_fs(struct super_block *sb, int wait)
 {
         struct hfsplus_sb_info *sbi = HFSPLUS_SB(sb);
         struct hfsplus_vh *vhdr = sbi->s_vhdr;
+        int write_backup = 0;
+        int error, error2;
 
         dprint(DBG_SUPER, "hfsplus_write_super\n");
 
-        mutex_lock(&sbi->vh_mutex);
-        mutex_lock(&sbi->alloc_mutex);
         sb->s_dirt = 0;
 
+        mutex_lock(&sbi->vh_mutex);
+        mutex_lock(&sbi->alloc_mutex);
         vhdr->free_blocks = cpu_to_be32(sbi->free_blocks);
         vhdr->next_cnid = cpu_to_be32(sbi->next_cnid);
         vhdr->folder_count = cpu_to_be32(sbi->folder_count);
         vhdr->file_count = cpu_to_be32(sbi->file_count);
 
-        mark_buffer_dirty(sbi->s_vhbh);
         if (test_and_clear_bit(HFSPLUS_SB_WRITEBACKUP, &sbi->flags)) {
-                if (sbi->sect_count) {
-                        struct buffer_head *bh;
-                        u32 block, offset;
-
-                        block = sbi->blockoffset;
-                        block += (sbi->sect_count - 2) >> (sb->s_blocksize_bits - 9);
-                        offset = ((sbi->sect_count - 2) << 9) & (sb->s_blocksize - 1);
-                        printk(KERN_DEBUG "hfs: backup: %u,%u,%u,%u\n",
-                                          sbi->blockoffset, sbi->sect_count,
-                                          block, offset);
-                        bh = sb_bread(sb, block);
-                        if (bh) {
-                                vhdr = (struct hfsplus_vh *)(bh->b_data + offset);
-                                if (be16_to_cpu(vhdr->signature) == HFSPLUS_VOLHEAD_SIG) {
-                                        memcpy(vhdr, sbi->s_vhdr, sizeof(*vhdr));
-                                        mark_buffer_dirty(bh);
-                                        brelse(bh);
-                                } else
-                                        printk(KERN_WARNING "hfs: backup not found!\n");
-                        }
-                }
+                memcpy(sbi->s_backup_vhdr, sbi->s_vhdr, sizeof(*sbi->s_vhdr));
+                write_backup = 1;
         }
+
+        error = hfsplus_submit_bio(sb->s_bdev,
+                                   sbi->part_start + HFSPLUS_VOLHEAD_SECTOR,
+                                   sbi->s_vhdr, WRITE_SYNC);
+        if (!write_backup)
+                goto out;
+
+        error2 = hfsplus_submit_bio(sb->s_bdev,
+                                  sbi->part_start + sbi->sect_count - 2,
+                                  sbi->s_backup_vhdr, WRITE_SYNC);
+        if (!error)
+                error2 = error;
+out:
         mutex_unlock(&sbi->alloc_mutex);
         mutex_unlock(&sbi->vh_mutex);
-        return 0;
+        return error;
 }
 
 static void hfsplus_write_super(struct super_block *sb)
@@ -229,7 +224,8 @@ static void hfsplus_put_super(struct super_block *sb)
         hfs_btree_close(sbi->ext_tree);
         iput(sbi->alloc_file);
         iput(sbi->hidden_dir);
-        brelse(sbi->s_vhbh);
+        kfree(sbi->s_vhdr);
+        kfree(sbi->s_backup_vhdr);
         unload_nls(sbi->nls);
         kfree(sb->s_fs_info);
         sb->s_fs_info = NULL;