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>

6 files changed, 30 insertions, 28 deletions

diff --git a/fs/hfsplus/btree.c b/fs/hfsplus/btree.c
index f75cf222b8b4..27504f57a485 100644
--- a/fs/hfsplus/btree.c
+++ b/fs/hfsplus/btree.c
@@ -61,12 +61,12 @@ struct hfs_btree *hfs_btree_open(struct super_block *sb, u32 id)
         if (id == HFSPLUS_EXT_CNID) {
                 tree->keycmp = hfsplus_ext_cmp_key;
         } else if (id == HFSPLUS_CAT_CNID) {
-                if ((HFSPLUS_SB(sb)->flags & HFSPLUS_SB_HFSX) &&
+                if (test_bit(HFSPLUS_SB_HFSX, &HFSPLUS_SB(sb)->flags) &&
                     (head->key_type == HFSPLUS_KEY_BINARY))
                         tree->keycmp = hfsplus_cat_bin_cmp_key;
                 else {
                         tree->keycmp = hfsplus_cat_case_cmp_key;
-                        HFSPLUS_SB(sb)->flags |= HFSPLUS_SB_CASEFOLD;
+                        set_bit(HFSPLUS_SB_CASEFOLD, &HFSPLUS_SB(sb)->flags);
                 }
         } else {
                 printk(KERN_ERR "hfs: unknown B*Tree requested\n");
diff --git a/fs/hfsplus/hfsplus_fs.h b/fs/hfsplus/hfsplus_fs.h
index 08865ed70f00..c521d44f0747 100644
--- a/fs/hfsplus/hfsplus_fs.h
+++ b/fs/hfsplus/hfsplus_fs.h
@@ -150,11 +150,11 @@ struct hfsplus_sb_info {
         unsigned long flags;
 };
 
-#define HFSPLUS_SB_WRITEBACKUP  0x0001
-#define HFSPLUS_SB_NODECOMPOSE  0x0002
-#define HFSPLUS_SB_FORCE        0x0004
-#define HFSPLUS_SB_HFSX         0x0008
-#define HFSPLUS_SB_CASEFOLD     0x0010
+#define HFSPLUS_SB_WRITEBACKUP  0
+#define HFSPLUS_SB_NODECOMPOSE  1
+#define HFSPLUS_SB_FORCE        2
+#define HFSPLUS_SB_HFSX         3
+#define HFSPLUS_SB_CASEFOLD     4
 
 
 struct hfsplus_inode_info {
diff --git a/fs/hfsplus/options.c b/fs/hfsplus/options.c
index f2598aef206e..f9ab276a4d8d 100644
--- a/fs/hfsplus/options.c
+++ b/fs/hfsplus/options.c
@@ -143,13 +143,13 @@ int hfsplus_parse_options(char *input, struct hfsplus_sb_info *sbi)
                         kfree(p);
                         break;
                 case opt_decompose:
-                        sbi->flags &= ~HFSPLUS_SB_NODECOMPOSE;
+                        clear_bit(HFSPLUS_SB_NODECOMPOSE, &sbi->flags);
                         break;
                 case opt_nodecompose:
-                        sbi->flags |= HFSPLUS_SB_NODECOMPOSE;
+                        set_bit(HFSPLUS_SB_NODECOMPOSE, &sbi->flags);
                         break;
                 case opt_force:
-                        sbi->flags |= HFSPLUS_SB_FORCE;
+                        set_bit(HFSPLUS_SB_FORCE, &sbi->flags);
                         break;
                 default:
                         return 0;
@@ -184,7 +184,7 @@ int hfsplus_show_options(struct seq_file *seq, struct vfsmount *mnt)
                 seq_printf(seq, ",session=%u", sbi->session);
         if (sbi->nls)
                 seq_printf(seq, ",nls=%s", sbi->nls->charset);
-        if (sbi->flags & HFSPLUS_SB_NODECOMPOSE)
+        if (test_bit(HFSPLUS_SB_NODECOMPOSE, &sbi->flags))
                 seq_printf(seq, ",nodecompose");
         return 0;
 }
diff --git a/fs/hfsplus/super.c b/fs/hfsplus/super.c
index b766c170e4d8..9a88d7536103 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);
diff --git a/fs/hfsplus/unicode.c b/fs/hfsplus/unicode.c
index a15fcffce74f..b66d67de882c 100644
--- a/fs/hfsplus/unicode.c
+++ b/fs/hfsplus/unicode.c
@@ -132,7 +132,7 @@ int hfsplus_uni2asc(struct super_block *sb, const struct hfsplus_unistr *ustr, c
         ustrlen = be16_to_cpu(ustr->length);
         len = *len_p;
         ce1 = NULL;
-        compose = !(HFSPLUS_SB(sb)->flags & HFSPLUS_SB_NODECOMPOSE);
+        compose = !test_bit(HFSPLUS_SB_NODECOMPOSE, &HFSPLUS_SB(sb)->flags);
 
         while (ustrlen > 0) {
                 c0 = be16_to_cpu(*ip++);
@@ -293,7 +293,7 @@ int hfsplus_asc2uni(struct super_block *sb, struct hfsplus_unistr *ustr,
         u16 *dstr, outlen = 0;
         wchar_t c;
 
-        decompose = !(HFSPLUS_SB(sb)->flags & HFSPLUS_SB_NODECOMPOSE);
+        decompose = !test_bit(HFSPLUS_SB_NODECOMPOSE, &HFSPLUS_SB(sb)->flags);
         while (outlen < HFSPLUS_MAX_STRLEN && len > 0) {
                 size = asc2unichar(sb, astr, len, &c);
 
@@ -330,8 +330,8 @@ int hfsplus_hash_dentry(struct dentry *dentry, struct qstr *str)
         wchar_t c;
         u16 c2;
 
-        casefold = (HFSPLUS_SB(sb)->flags & HFSPLUS_SB_CASEFOLD);
-        decompose = !(HFSPLUS_SB(sb)->flags & HFSPLUS_SB_NODECOMPOSE);
+        casefold = test_bit(HFSPLUS_SB_CASEFOLD, &HFSPLUS_SB(sb)->flags);
+        decompose = !test_bit(HFSPLUS_SB_NODECOMPOSE, &HFSPLUS_SB(sb)->flags);
         hash = init_name_hash();
         astr = str->name;
         len = str->len;
@@ -373,8 +373,8 @@ int hfsplus_compare_dentry(struct dentry *dentry, struct qstr *s1, struct qstr *
         u16 c1, c2;
         wchar_t c;
 
-        casefold = (HFSPLUS_SB(sb)->flags & HFSPLUS_SB_CASEFOLD);
-        decompose = !(HFSPLUS_SB(sb)->flags & HFSPLUS_SB_NODECOMPOSE);
+        casefold = test_bit(HFSPLUS_SB_CASEFOLD, &HFSPLUS_SB(sb)->flags);
+        decompose = !test_bit(HFSPLUS_SB_NODECOMPOSE, &HFSPLUS_SB(sb)->flags);
         astr1 = s1->name;
         len1 = s1->len;
         astr2 = s2->name;
diff --git a/fs/hfsplus/wrapper.c b/fs/hfsplus/wrapper.c
index c89e198e8a2a..8972c20b3216 100644
--- a/fs/hfsplus/wrapper.c
+++ b/fs/hfsplus/wrapper.c
@@ -123,7 +123,7 @@ int hfsplus_read_wrapper(struct super_block *sb)
                 if (vhdr->signature == cpu_to_be16(HFSPLUS_VOLHEAD_SIG))
                         break;
                 if (vhdr->signature == cpu_to_be16(HFSPLUS_VOLHEAD_SIGX)) {
-                        sbi->flags |= HFSPLUS_SB_HFSX;
+                        set_bit(HFSPLUS_SB_HFSX, &sbi->flags);
                         break;
                 }
                 brelse(bh);
@@ -169,10 +169,14 @@ int hfsplus_read_wrapper(struct super_block *sb)
                 return -EIO;
 
         /* should still be the same... */
-        if (vhdr->signature != (sbi->flags & HFSPLUS_SB_HFSX ?
-                                cpu_to_be16(HFSPLUS_VOLHEAD_SIGX) :
-                                cpu_to_be16(HFSPLUS_VOLHEAD_SIG)))
-                goto error;
+        if (test_bit(HFSPLUS_SB_HFSX, &sbi->flags)) {
+                if (vhdr->signature != cpu_to_be16(HFSPLUS_VOLHEAD_SIGX))
+                        goto error;
+        } else {
+                if (vhdr->signature != cpu_to_be16(HFSPLUS_VOLHEAD_SIG))
+                        goto error;
+        }
+
         sbi->s_vhbh = bh;
         sbi->s_vhdr = vhdr;