Push lock_super() into the ->remount_fs() of filesystems that care about it
Al Viro [Wed, 6 May 2009 14:43:07 +0000 (10:43 -0400)]
Note that since we can't run into contention between remount_fs and write_super
(due to exclusion on s_umount), we have to care only about filesystems that
touch lock_super() on their own.  Out of those ext3, ext4, hpfs, sysv and ufs
do need it; fat doesn't since its ->remount_fs() only accesses assign-once
data (basically, it's "we have no atime on directories and only have atime on
files for vfat; force nodiratime and possibly noatime into *flags").

[folded a build fix from hch]

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

fs/ext3/super.c
fs/ext4/super.c
fs/hpfs/super.c
fs/super.c
fs/sysv/inode.c
fs/ufs/super.c

index 546b8d7..e213a26 100644 (file)
@@ -2491,6 +2491,7 @@ static int ext3_remount (struct super_block * sb, int * flags, char * data)
 #endif
 
        /* Store the original options */
+       lock_super(sb);
        old_sb_flags = sb->s_flags;
        old_opts.s_mount_opt = sbi->s_mount_opt;
        old_opts.s_resuid = sbi->s_resuid;
@@ -2598,6 +2599,7 @@ static int ext3_remount (struct super_block * sb, int * flags, char * data)
                    old_opts.s_qf_names[i] != sbi->s_qf_names[i])
                        kfree(old_opts.s_qf_names[i]);
 #endif
+       unlock_super(sb);
        return 0;
 restore_opts:
        sb->s_flags = old_sb_flags;
@@ -2614,6 +2616,7 @@ restore_opts:
                sbi->s_qf_names[i] = old_opts.s_qf_names[i];
        }
 #endif
+       unlock_super(sb);
        return err;
 }
 
index 1d4180b..a9c6834 100644 (file)
@@ -3421,6 +3421,7 @@ static int ext4_remount(struct super_block *sb, int *flags, char *data)
 #endif
 
        /* Store the original options */
+       lock_super(sb);
        old_sb_flags = sb->s_flags;
        old_opts.s_mount_opt = sbi->s_mount_opt;
        old_opts.s_resuid = sbi->s_resuid;
@@ -3554,6 +3555,7 @@ static int ext4_remount(struct super_block *sb, int *flags, char *data)
                    old_opts.s_qf_names[i] != sbi->s_qf_names[i])
                        kfree(old_opts.s_qf_names[i]);
 #endif
+       unlock_super(sb);
        return 0;
 
 restore_opts:
@@ -3573,6 +3575,7 @@ restore_opts:
                sbi->s_qf_names[i] = old_opts.s_qf_names[i];
        }
 #endif
+       unlock_super(sb);
        return err;
 }
 
index 437a32e..f68193c 100644 (file)
@@ -398,6 +398,7 @@ static int hpfs_remount_fs(struct super_block *s, int *flags, char *data)
        
        *flags |= MS_NOATIME;
        
+       lock_super(s);
        uid = sbi->sb_uid; gid = sbi->sb_gid;
        umask = 0777 & ~sbi->sb_mode;
        lowercase = sbi->sb_lowercase; conv = sbi->sb_conv;
@@ -430,9 +431,11 @@ static int hpfs_remount_fs(struct super_block *s, int *flags, char *data)
 
        replace_mount_options(s, new_opts);
 
+       unlock_super(s);
        return 0;
 
 out_err:
+       unlock_super(s);
        kfree(new_opts);
        return -EINVAL;
 }
index bdd7158..2a49fed 100644 (file)
@@ -556,9 +556,7 @@ int do_remount_sb(struct super_block *sb, int flags, void *data, int force)
        remount_rw = !(flags & MS_RDONLY) && (sb->s_flags & MS_RDONLY);
 
        if (sb->s_op->remount_fs) {
-               lock_super(sb);
                retval = sb->s_op->remount_fs(sb, &flags, data);
-               unlock_super(sb);
                if (retval)
                        return retval;
        }
index a818986..e0a39f1 100644 (file)
@@ -61,10 +61,12 @@ clean:
 static int sysv_remount(struct super_block *sb, int *flags, char *data)
 {
        struct sysv_sb_info *sbi = SYSV_SB(sb);
+       lock_super(sb);
        if (sbi->s_forced_ro)
                *flags |= MS_RDONLY;
        if (!(*flags & MS_RDONLY))
                sb->s_dirt = 1;
+       unlock_super(sb);
        return 0;
 }
 
index 2b4d2b6..a5ecabf 100644 (file)
@@ -1181,6 +1181,7 @@ static int ufs_remount (struct super_block *sb, int *mount_flags, char *data)
        unsigned new_mount_opt, ufstype;
        unsigned flags;
        
+       lock_super(sb);
        uspi = UFS_SB(sb)->s_uspi;
        flags = UFS_SB(sb)->s_flags;
        usb1 = ubh_get_usb_first(uspi);
@@ -1193,17 +1194,21 @@ static int ufs_remount (struct super_block *sb, int *mount_flags, char *data)
        ufstype = UFS_SB(sb)->s_mount_opt & UFS_MOUNT_UFSTYPE;
        new_mount_opt = 0;
        ufs_set_opt (new_mount_opt, ONERROR_LOCK);
-       if (!ufs_parse_options (data, &new_mount_opt))
+       if (!ufs_parse_options (data, &new_mount_opt)) {
+               unlock_super(sb);
                return -EINVAL;
+       }
        if (!(new_mount_opt & UFS_MOUNT_UFSTYPE)) {
                new_mount_opt |= ufstype;
        } else if ((new_mount_opt & UFS_MOUNT_UFSTYPE) != ufstype) {
                printk("ufstype can't be changed during remount\n");
+               unlock_super(sb);
                return -EINVAL;
        }
 
        if ((*mount_flags & MS_RDONLY) == (sb->s_flags & MS_RDONLY)) {
                UFS_SB(sb)->s_mount_opt = new_mount_opt;
+               unlock_super(sb);
                return 0;
        }
        
@@ -1228,6 +1233,7 @@ static int ufs_remount (struct super_block *sb, int *mount_flags, char *data)
 #ifndef CONFIG_UFS_FS_WRITE
                printk("ufs was compiled with read-only support, "
                "can't be mounted as read-write\n");
+               unlock_super(sb);
                return -EINVAL;
 #else
                if (ufstype != UFS_MOUNT_UFSTYPE_SUN && 
@@ -1236,16 +1242,19 @@ static int ufs_remount (struct super_block *sb, int *mount_flags, char *data)
                    ufstype != UFS_MOUNT_UFSTYPE_SUNx86 &&
                    ufstype != UFS_MOUNT_UFSTYPE_UFS2) {
                        printk("this ufstype is read-only supported\n");
+                       unlock_super(sb);
                        return -EINVAL;
                }
                if (!ufs_read_cylinder_structures(sb)) {
                        printk("failed during remounting\n");
+                       unlock_super(sb);
                        return -EPERM;
                }
                sb->s_flags &= ~MS_RDONLY;
 #endif
        }
        UFS_SB(sb)->s_mount_opt = new_mount_opt;
+       unlock_super(sb);
        return 0;
 }