hfsplus: add per-superblock lock for volume header updates

Lock updates to the mutal fields in the volume header, and document the
locing in the hfsplus_sb_info structure.

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

1 files changed, 7 insertions, 0 deletions

diff --git a/fs/hfsplus/super.c b/fs/hfsplus/super.c
index 923f385b32ca..b766c170e4d8 100644
--- a/fs/hfsplus/super.c
+++ b/fs/hfsplus/super.c
@@ -160,6 +160,7 @@ int hfsplus_sync_fs(struct super_block *sb, int wait)
 
         dprint(DBG_SUPER, "hfsplus_write_super\n");
 
+        mutex_lock(&sbi->vh_mutex);
         mutex_lock(&sbi->alloc_mutex);
         sb->s_dirt = 0;
 
@@ -194,6 +195,7 @@ int hfsplus_sync_fs(struct super_block *sb, int wait)
                 sbi->flags &= ~HFSPLUS_SB_WRITEBACKUP;
         }
         mutex_unlock(&sbi->alloc_mutex);
+        mutex_unlock(&sbi->vh_mutex);
         return 0;
 }
 
@@ -319,6 +321,7 @@ static int hfsplus_fill_super(struct super_block *sb, void *data, int silent)
 
         sb->s_fs_info = sbi;
         mutex_init(&sbi->alloc_mutex);
+        mutex_init(&sbi->vh_mutex);
         hfsplus_fill_defaults(sbi);
         if (!hfsplus_parse_options(data, sbi)) {
                 printk(KERN_ERR "hfs: unable to parse mount options\n");
@@ -453,9 +456,13 @@ static int hfsplus_fill_super(struct super_block *sb, void *data, int silent)
 
         if (!sbi->hidden_dir) {
                 printk(KERN_DEBUG "hfs: create hidden dir...\n");
+
+                mutex_lock(&sbi->vh_mutex);
                 sbi->hidden_dir = hfsplus_new_inode(sb, S_IFDIR);
                 hfsplus_create_cat(sbi->hidden_dir->i_ino, sb->s_root->d_inode,
                                    &str, sbi->hidden_dir);
+                mutex_unlock(&sbi->vh_mutex);
+
                 mark_inode_dirty(sbi->hidden_dir);
         }
 out: