Re: [PATCH -next] ext4: Fix remount with 'abort' option isn't effective

[yebin]

On 2021/12/21 22:43, Lukas Czerner wrote:
> Hi,
>
> nice catch. This is a bug indeed. However I am currently in a process of
> changing the ctx_set/clear/test_ helpers because currently it generates
> functions that are unused.
>
> While I am at it I can just create a custom ctx_set_mount_flags()
> helper that would behave as expected so that we won't have to specify
> "1 < EXT4_MF_FS_ABORTED" which is not really obvious and hence error
> prone.
Actually, I fixed the first version as follows:

diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index b72d989b77fb..199920ffc7d3 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -2049,8 +2049,8 @@ struct ext4_fs_context {
 	unsigned int	mask_s_mount_opt;
 	unsigned int	vals_s_mount_opt2;
 	unsigned int	mask_s_mount_opt2;
-	unsigned int	vals_s_mount_flags;
-	unsigned int	mask_s_mount_flags;
+	unsigned long	vals_s_mount_flags;
+	unsigned long	mask_s_mount_flags;
 	unsigned int	opt_flags;	/* MOPT flags */
 	unsigned int	spec;
 	u32		s_max_batch_time;
@@ -2166,7 +2166,12 @@ static inline bool ctx_test_##name(struct ext4_fs_context *ctx, int flag)\
 EXT4_SET_CTX(flags);
 EXT4_SET_CTX(mount_opt);
 EXT4_SET_CTX(mount_opt2);
-EXT4_SET_CTX(mount_flags);
+
+static inline void ctx_set_mount_flags(struct ext4_fs_context *ctx, int bit)
+{
+	set_bit(bit, &ctx->mask_s_mount_flags);
+	set_bit(bit, &ctx->vals_s_mount_flags);
+}


I think 'mask_s_mount_flags' is useless now.
> My plan is to send my patch set including this one tomorrow, will that
> be fine with you ?
>
> -Lukas
>
> On Tue, Dec 21, 2021 at 08:32:14PM +0800, Ye Bin wrote:
> > We test remount with 'abort' option as follows:
> > [root@localhost home]# mount  /dev/sda test
> > [root@localhost home]# mount | grep test
> > /dev/sda on /home/test type ext4 (rw,relatime)
> > [root@localhost home]# mount -o remount,abort test
> > [root@localhost home]# mount | grep test
> > /dev/sda on /home/test type ext4 (rw,relatime)
> >
> > Obviously, remount 'abort' option isn't effective.
> > After 6e47a3cc68fc commit we process abort option with 'ctx_set_mount_flags':
> > static inline void ctx_set_mount_flags(struct ext4_fs_context *ctx, int flag)
> > {
> > 	ctx->mask_s_mount_flags |= flag;
> > 	ctx->vals_s_mount_flags |= flag;
> > }
> >
> > But we test 'abort' option with 'ext4_test_mount_flag':
> > static inline int ext4_test_mount_flag(struct super_block *sb, int bit)
> > {
> >          return test_bit(bit, &EXT4_SB(sb)->s_mount_flags);
> > }
> >
> > To solve this issue, pass (1 <<  EXT4_MF_FS_ABORTED) to 'ctx_set_mount_flags'.
> >
> > Fixes:6e47a3cc68fc("ext4: get rid of super block and sbi from handle_mount_ops()")
> > Signed-off-by: Ye Bin <yebin10@xxxxxxxxxx>
> > ---
> >   fs/ext4/super.c | 2 +-
> >   1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/fs/ext4/super.c b/fs/ext4/super.c
> > index b72d989b77fb..071b7b3c5678 100644
> > --- a/fs/ext4/super.c
> > +++ b/fs/ext4/super.c
> > @@ -2236,7 +2236,7 @@ static int ext4_parse_param(struct fs_context *fc, struct fs_parameter *param)
> >   			 param->key);
> >   		return 0;
> >   	case Opt_abort:
> > -		ctx_set_mount_flags(ctx, EXT4_MF_FS_ABORTED);
> > +		ctx_set_mount_flags(ctx, 1 << EXT4_MF_FS_ABORTED);
> >   		return 0;
> >   	case Opt_i_version:
> >   		ctx_set_flags(ctx, SB_I_VERSION);
> > --
> > 2.31.1
> .