hfsplus: use atomic bitops for the superblock flags

The flags in the HFS+-specific superlock do get modified during runtime,
use atomic bitops to make the modifications SMP safe.

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

1 files changed, 4 insertions, 6 deletions

diff --git a/fs/hfsplus/super.c b/fs/hfsplus/super.c
index b766c170e4d..9a88d753610 100644
--- a/fs/hfsplus/super.c
+++ b/fs/hfsplus/super.c
@@ -119,7 +119,7 @@ static int hfsplus_system_write_inode(struct inode *inode)
         }
 
         if (fork->total_size != cpu_to_be64(inode->i_size)) {
-                sbi->flags |= HFSPLUS_SB_WRITEBACKUP;
+                set_bit(HFSPLUS_SB_WRITEBACKUP, &sbi->flags);
                 inode->i_sb->s_dirt = 1;
         }
         hfsplus_inode_write_fork(inode, fork);
@@ -170,7 +170,7 @@ int hfsplus_sync_fs(struct super_block *sb, int wait)
         vhdr->file_count = cpu_to_be32(sbi->file_count);
 
         mark_buffer_dirty(sbi->s_vhbh);
-        if (sbi->flags & HFSPLUS_SB_WRITEBACKUP) {
+        if (test_and_clear_bit(HFSPLUS_SB_WRITEBACKUP, &sbi->flags)) {
                 if (sbi->sect_count) {
                         struct buffer_head *bh;
                         u32 block, offset;
@@ -192,7 +192,6 @@ int hfsplus_sync_fs(struct super_block *sb, int wait)
                                         printk(KERN_WARNING "hfs: backup not found!\n");
                         }
                 }
-                sbi->flags &= ~HFSPLUS_SB_WRITEBACKUP;
         }
         mutex_unlock(&sbi->alloc_mutex);
         mutex_unlock(&sbi->vh_mutex);
@@ -276,7 +275,7 @@ static int hfsplus_remount(struct super_block *sb, int *flags, char *data)
                                "running fsck.hfsplus is recommended.  leaving read-only.\n");
                         sb->s_flags |= MS_RDONLY;
                         *flags |= MS_RDONLY;
-                } else if (sbi.flags & HFSPLUS_SB_FORCE) {
+                } else if (test_bit(HFSPLUS_SB_FORCE, &sbi.flags)) {
                         /* nothing */
                 } else if (vhdr->attributes & cpu_to_be32(HFSPLUS_VOL_SOFTLOCK)) {
                         printk(KERN_WARNING "hfs: filesystem is marked locked, leaving read-only.\n");
@@ -376,7 +375,7 @@ static int hfsplus_fill_super(struct super_block *sb, void *data, int silent)
                 printk(KERN_WARNING "hfs: Filesystem was not cleanly unmounted, "
                        "running fsck.hfsplus is recommended.  mounting read-only.\n");
                 sb->s_flags |= MS_RDONLY;
-        } else if (sbi->flags & HFSPLUS_SB_FORCE) {
+        } else if (test_and_clear_bit(HFSPLUS_SB_FORCE, &sbi->flags)) {
                 /* nothing */
         } else if (vhdr->attributes & cpu_to_be32(HFSPLUS_VOL_SOFTLOCK)) {
                 printk(KERN_WARNING "hfs: Filesystem is marked locked, mounting read-only.\n");
@@ -386,7 +385,6 @@ static int hfsplus_fill_super(struct super_block *sb, void *data, int silent)
                        "use the force option at your own risk, mounting read-only.\n");
                 sb->s_flags |= MS_RDONLY;
         }
-        sbi->flags &= ~HFSPLUS_SB_FORCE;
 
         /* Load metadata objects (B*Trees) */
         sbi->ext_tree = hfs_btree_open(sb, HFSPLUS_EXT_CNID);