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>

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");

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 {

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;
 }

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);

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;

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;