hfsplus: introduce alloc_mutex

Use a new per-sb alloc_mutex instead of abusing i_mutex of the alloc_file
to protect block allocations.  This gets rid of lockdep nesting warnings
and prepares for extending the scope of alloc_mutex.

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

3 files changed, 8 insertions, 4 deletions

diff --git a/fs/hfsplus/bitmap.c b/fs/hfsplus/bitmap.c
index ea30afc2a03c..8a781769a901 100644
--- a/fs/hfsplus/bitmap.c
+++ b/fs/hfsplus/bitmap.c
@@ -29,7 +29,7 @@ int hfsplus_block_allocate(struct super_block *sb, u32 size, u32 offset, u32 *ma
                 return size;
 
         dprint(DBG_BITMAP, "block_allocate: %u,%u,%u\n", size, offset, len);
-        mutex_lock(&HFSPLUS_SB(sb).alloc_file->i_mutex);
+        mutex_lock(&HFSPLUS_SB(sb).alloc_mutex);
         mapping = HFSPLUS_SB(sb).alloc_file->i_mapping;
         page = read_mapping_page(mapping, offset / PAGE_CACHE_BITS, NULL);
         if (IS_ERR(page)) {
@@ -154,7 +154,7 @@ done:
         sb->s_dirt = 1;
         dprint(DBG_BITMAP, "-> %u,%u\n", start, *max);
 out:
-        mutex_unlock(&HFSPLUS_SB(sb).alloc_file->i_mutex);
+        mutex_unlock(&HFSPLUS_SB(sb).alloc_mutex);
         return start;
 }
 
@@ -175,7 +175,7 @@ int hfsplus_block_free(struct super_block *sb, u32 offset, u32 count)
         if ((offset + count) > HFSPLUS_SB(sb).total_blocks)
                 return -2;
 
-        mutex_lock(&HFSPLUS_SB(sb).alloc_file->i_mutex);
+        mutex_lock(&HFSPLUS_SB(sb).alloc_mutex);
         mapping = HFSPLUS_SB(sb).alloc_file->i_mapping;
         pnr = offset / PAGE_CACHE_BITS;
         page = read_mapping_page(mapping, pnr, NULL);
@@ -226,7 +226,7 @@ out:
         kunmap(page);
         HFSPLUS_SB(sb).free_blocks += len;
         sb->s_dirt = 1;
-        mutex_unlock(&HFSPLUS_SB(sb).alloc_file->i_mutex);
+        mutex_unlock(&HFSPLUS_SB(sb).alloc_mutex);
 
         return 0;
 }
diff --git a/fs/hfsplus/hfsplus_fs.h b/fs/hfsplus/hfsplus_fs.h
index dc856be3c2b0..df0a6312f0f0 100644
--- a/fs/hfsplus/hfsplus_fs.h
+++ b/fs/hfsplus/hfsplus_fs.h
@@ -116,6 +116,9 @@ struct hfsplus_sb_info {
         struct inode *hidden_dir;
         struct nls_table *nls;
 
+        /* synchronize block allocations */
+        struct mutex alloc_mutex;
+
         /* Runtime variables */
         u32 blockoffset;
         u32 sect_count;
diff --git a/fs/hfsplus/super.c b/fs/hfsplus/super.c
index 3b55c050c742..3dc62aa58728 100644
--- a/fs/hfsplus/super.c
+++ b/fs/hfsplus/super.c
@@ -321,6 +321,7 @@ static int hfsplus_fill_super(struct super_block *sb, void *data, int silent)
 
         sb->s_fs_info = sbi;
         INIT_HLIST_HEAD(&sbi->rsrc_inodes);
+        mutex_init(&sbi->alloc_mutex);
         hfsplus_fill_defaults(sbi);
         if (!hfsplus_parse_options(data, sbi)) {
                 printk(KERN_ERR "hfs: unable to parse mount options\n");