switch fat to ->s_d_op, close exportfs races there

don't bother with lock_super() in fat_fill_super() callers, while we are at it - there won't be any concurrency anyway. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

switch fat to ->s_d_op, close exportfs races there
don't bother with lock_super() in fat_fill_super() callers, while we are at it - there won't be any concurrency anyway. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Al Viro
1 parent 6cc9c1d2c1
Showing 4 changed files with 25 additions and 45 deletions Side-by-side Diff
fs/fat/fat.h
fs/fat/inode.c
fs/fat/namei_msdos.c
fs/fat/namei_vfat.c
@@ -319,7 +319,8 @@
 			struct msdos_dir_entry *de, loff_t i_pos);
 extern int fat_sync_inode(struct inode *inode);
 extern int fat_fill_super(struct super_block *sb, void *data, int silent,
-			const struct inode_operations *fs_dir_inode_ops, int isvfat);
+			const struct inode_operations *fs_dir_inode_ops,
+			int isvfat, void (*setup)(struct super_block *));
  
 extern int fat_flush_inodes(struct super_block *sb, struct inode *i1,
 		            struct inode *i2);
@@ -703,7 +703,6 @@
 		struct fid *fid, int fh_len, int fh_type)
 {
 	struct inode *inode = NULL;
-	struct dentry *result;
 	u32 *fh = fid->raw;
  
 	if (fh_len < 5 || fh_type != 3)
@@ -748,10 +747,7 @@
 	 * the fat_iget lookup again.  If that fails, then we are totally out
 	 * of luck.  But all that is for another day
 	 */
-	result = d_obtain_alias(inode);
-	if (!IS_ERR(result))
-		d_set_d_op(result, sb->s_root->d_op);
-	return result;
+	return d_obtain_alias(inode);
 }
  
 static int
@@ -799,8 +795,6 @@
 	brelse(bh);
  
 	parent = d_obtain_alias(inode);
-	if (!IS_ERR(parent))
-		d_set_d_op(parent, sb->s_root->d_op);
 out:
 	unlock_super(sb);
  
@@ -1244,7 +1238,8 @@
  * Read the super block of an MS-DOS FS.
  */
 int fat_fill_super(struct super_block *sb, void *data, int silent,
-		   const struct inode_operations *fs_dir_inode_ops, int isvfat)
+		   const struct inode_operations *fs_dir_inode_ops, int isvfat,
+		   void (*setup)(struct super_block *))
 {
 	struct inode *root_inode = NULL, *fat_inode = NULL;
 	struct buffer_head *bh;
@@ -1279,6 +1274,8 @@
 	error = parse_options(data, isvfat, silent, &debug, &sbi->options);
 	if (error)
 		goto out_fail;
+
+	setup(sb); /* flavour-specific stuff that needs options */
  
 	error = -EIO;
 	sb_min_blocksize(sb, 512);
@@ -227,11 +227,7 @@
 	}
 out:
 	unlock_super(sb);
-	d_set_d_op(dentry, &msdos_dentry_operations);
-	dentry = d_splice_alias(inode, dentry);
-	if (dentry)
-		d_set_d_op(dentry, &msdos_dentry_operations);
-	return dentry;
+	return d_splice_alias(inode, dentry);
  
 error:
 	unlock_super(sb);
  
  
@@ -661,21 +657,16 @@
 	.getattr	= fat_getattr,
 };
  
-static int msdos_fill_super(struct super_block *sb, void *data, int silent)
+static void setup(struct super_block *sb)
 {
-	int res;
-
-	lock_super(sb);
-	res = fat_fill_super(sb, data, silent, &msdos_dir_inode_operations, 0);
-	if (res) {
-		unlock_super(sb);
-		return res;
-	}
-
+	sb->s_d_op = &msdos_dentry_operations;
 	sb->s_flags |= MS_NOATIME;
-	d_set_d_op(sb->s_root, &msdos_dentry_operations);
-	unlock_super(sb);
-	return 0;
+}
+
+static int msdos_fill_super(struct super_block *sb, void *data, int silent)
+{
+	return fat_fill_super(sb, data, silent, &msdos_dir_inode_operations,
+			     0, setup);
 }
  
 static struct dentry *msdos_mount(struct file_system_type *fs_type,
@@ -772,13 +772,10 @@
  
 out:
 	unlock_super(sb);
-	d_set_d_op(dentry, sb->s_root->d_op);
 	dentry->d_time = dentry->d_parent->d_inode->i_version;
 	dentry = d_splice_alias(inode, dentry);
-	if (dentry) {
-		d_set_d_op(dentry, sb->s_root->d_op);
+	if (dentry)
 		dentry->d_time = dentry->d_parent->d_inode->i_version;
-	}
 	return dentry;
  
 error:
  
  
  
  
@@ -1066,24 +1063,18 @@
 	.getattr	= fat_getattr,
 };
  
-static int vfat_fill_super(struct super_block *sb, void *data, int silent)
+static void setup(struct super_block *sb)
 {
-	int res;
-
-	lock_super(sb);
-	res = fat_fill_super(sb, data, silent, &vfat_dir_inode_operations, 1);
-	if (res) {
-		unlock_super(sb);
-		return res;
-	}
-
 	if (MSDOS_SB(sb)->options.name_check != 's')
-		d_set_d_op(sb->s_root, &vfat_ci_dentry_ops);
+		sb->s_d_op = &vfat_ci_dentry_ops;
 	else
-		d_set_d_op(sb->s_root, &vfat_dentry_ops);
+		sb->s_d_op = &vfat_dentry_ops;
+}
  
-	unlock_super(sb);
-	return 0;
+static int vfat_fill_super(struct super_block *sb, void *data, int silent)
+{
+	return fat_fill_super(sb, data, silent, &vfat_dir_inode_operations,
+			     1, setup);
 }
  
 static struct dentry *vfat_mount(struct file_system_type *fs_type,
...	...	@@ -319,7 +319,8 @@
319	319	struct msdos_dir_entry *de, loff_t i_pos);
320	320	extern int fat_sync_inode(struct inode *inode);
321	321	extern int fat_fill_super(struct super_block sb, void data, int silent,
322		- const struct inode_operations *fs_dir_inode_ops, int isvfat);
	322	+ const struct inode_operations *fs_dir_inode_ops,
	323	+ int isvfat, void (setup)(struct super_block ));
323	324
324	325	extern int fat_flush_inodes(struct super_block sb, struct inode i1,
325	326	struct inode *i2);
...	...	@@ -703,7 +703,6 @@
703	703	struct fid *fid, int fh_len, int fh_type)
704	704	{
705	705	struct inode *inode = NULL;
706		- struct dentry *result;
707	706	u32 *fh = fid->raw;
708	707
709	708	if (fh_len < 5 \|\| fh_type != 3)
...	...	@@ -748,10 +747,7 @@
748	747	* the fat_iget lookup again. If that fails, then we are totally out
749	748	* of luck. But all that is for another day
750	749	*/
751		- result = d_obtain_alias(inode);
752		- if (!IS_ERR(result))
753		- d_set_d_op(result, sb->s_root->d_op);
754		- return result;
	750	+ return d_obtain_alias(inode);
755	751	}
756	752
757	753	static int
...	...	@@ -799,8 +795,6 @@
799	795	brelse(bh);
800	796
801	797	parent = d_obtain_alias(inode);
802		- if (!IS_ERR(parent))
803		- d_set_d_op(parent, sb->s_root->d_op);
804	798	out:
805	799	unlock_super(sb);
806	800
...	...	@@ -1244,7 +1238,8 @@
1244	1238	* Read the super block of an MS-DOS FS.
1245	1239	*/
1246	1240	int fat_fill_super(struct super_block sb, void data, int silent,
1247		- const struct inode_operations *fs_dir_inode_ops, int isvfat)
	1241	+ const struct inode_operations *fs_dir_inode_ops, int isvfat,
	1242	+ void (setup)(struct super_block ))
1248	1243	{
1249	1244	struct inode root_inode = NULL, fat_inode = NULL;
1250	1245	struct buffer_head *bh;
...	...	@@ -1279,6 +1274,8 @@
1279	1274	error = parse_options(data, isvfat, silent, &debug, &sbi->options);
1280	1275	if (error)
1281	1276	goto out_fail;
	1277	+
	1278	+ setup(sb); /* flavour-specific stuff that needs options */
1282	1279
1283	1280	error = -EIO;
1284	1281	sb_min_blocksize(sb, 512);
...	...	@@ -227,11 +227,7 @@
227	227	}
228	228	out:
229	229	unlock_super(sb);
230		- d_set_d_op(dentry, &msdos_dentry_operations);
231		- dentry = d_splice_alias(inode, dentry);
232		- if (dentry)
233		- d_set_d_op(dentry, &msdos_dentry_operations);
234		- return dentry;
	230	+ return d_splice_alias(inode, dentry);
235	231
236	232	error:
237	233	unlock_super(sb);
238	234
239	235
...	...	@@ -661,21 +657,16 @@
661	657	.getattr = fat_getattr,
662	658	};
663	659
664		-static int msdos_fill_super(struct super_block sb, void data, int silent)
	660	+static void setup(struct super_block *sb)
665	661	{
666		- int res;
667		-
668		- lock_super(sb);
669		- res = fat_fill_super(sb, data, silent, &msdos_dir_inode_operations, 0);
670		- if (res) {
671		- unlock_super(sb);
672		- return res;
673		- }
674		-
	662	+ sb->s_d_op = &msdos_dentry_operations;
675	663	sb->s_flags \|= MS_NOATIME;
676		- d_set_d_op(sb->s_root, &msdos_dentry_operations);
677		- unlock_super(sb);
678		- return 0;
	664	+}
	665	+
	666	+static int msdos_fill_super(struct super_block sb, void data, int silent)
	667	+{
	668	+ return fat_fill_super(sb, data, silent, &msdos_dir_inode_operations,
	669	+ 0, setup);
679	670	}
680	671
681	672	static struct dentry msdos_mount(struct file_system_type fs_type,
...	...	@@ -772,13 +772,10 @@
772	772
773	773	out:
774	774	unlock_super(sb);
775		- d_set_d_op(dentry, sb->s_root->d_op);
776	775	dentry->d_time = dentry->d_parent->d_inode->i_version;
777	776	dentry = d_splice_alias(inode, dentry);
778		- if (dentry) {
779		- d_set_d_op(dentry, sb->s_root->d_op);
	777	+ if (dentry)
780	778	dentry->d_time = dentry->d_parent->d_inode->i_version;
781		- }
782	779	return dentry;
783	780
784	781	error:
785	782
786	783
787	784
788	785
...	...	@@ -1066,24 +1063,18 @@
1066	1063	.getattr = fat_getattr,
1067	1064	};
1068	1065
1069		-static int vfat_fill_super(struct super_block sb, void data, int silent)
	1066	+static void setup(struct super_block *sb)
1070	1067	{
1071		- int res;
1072		-
1073		- lock_super(sb);
1074		- res = fat_fill_super(sb, data, silent, &vfat_dir_inode_operations, 1);
1075		- if (res) {
1076		- unlock_super(sb);
1077		- return res;
1078		- }
1079		-
1080	1068	if (MSDOS_SB(sb)->options.name_check != 's')
1081		- d_set_d_op(sb->s_root, &vfat_ci_dentry_ops);
	1069	+ sb->s_d_op = &vfat_ci_dentry_ops;
1082	1070	else
1083		- d_set_d_op(sb->s_root, &vfat_dentry_ops);
	1071	+ sb->s_d_op = &vfat_dentry_ops;
	1072	+}
1084	1073
1085		- unlock_super(sb);
1086		- return 0;
	1074	+static int vfat_fill_super(struct super_block sb, void data, int silent)
	1075	+{
	1076	+ return fat_fill_super(sb, data, silent, &vfat_dir_inode_operations,
	1077	+ 1, setup);
1087	1078	}
1088	1079
1089	1080	static struct dentry vfat_mount(struct file_system_type fs_type,