Re: 2.4.14 still not making fs dirty when it should

Andrew Morton
2001-11-30T08:00:53Z

Andreas Dilger wrote:
>
> On Nov 29, 2001 12:22 -0800, Andrew Morton wrote:
> > This actually happens. On a stock RH7.1 setup, you can
> > hit reset as soon as you get the first login prompt. fsck
> > will not be run on reboot. If you run it by hand, fsck
> > finds errors.
> >
> > Andreas, my one-liner was, umm, hasty. I think you had
> > a decent fix for this?
>
> Yes, I thought I did as well. It may have gotten lost during the
> -ac -> Linus merge, as I thought it was in there (some other ext2
> fixes that were definitely in -ac are not in 2.4.16). Luckily,
> I was just generating patches of all my local changes last night,
> so I have a brand-new patch to fix this.
>
> It _should_ do the right thing, but please give it a once-over, as
> I wrote it a long time ago. The theory is - changing the dirty
> flag is synchronously written to disk, but other superblock changes
> are async as they always have been (sync_super vs. commit_super).
>

Your patch isn't working quite as intended, because of this
code in ext2_remount:

/*
* Mounting a RDONLY partition read-write, so reread and
* store the current valid flag. (It may have been changed
* by e2fsck since we originally mounted the partition.)
*/
sb->u.ext2_sb.s_mount_state = le16_to_cpu(es->s_state);
if (!ext2_setup_super (sb, es, 0))
sb->s_flags &= ~MS_RDONLY;

see, when we call ext2_setup_super(), MS_RDONLY is set, so
ext2_setup_super() doesn't write the superblock. That's
trivially fixed.

The below patch passes all the mount/remount tests I could think
of.

--- linux-2.4.17-pre1/fs/ext2/super.c Thu Nov 22 23:02:58 2001
+++ linux-akpm/fs/ext2/super.c Thu Nov 29 23:54:53 2001
@@ -28,6 +28,8 @@
#include <asm/uaccess.h>

+static void ext2_sync_super(struct super_block *sb,
+ struct ext2_super_block *es);

static char error_buf[1024];

@@ -35,13 +37,13 @@ void ext2_error (struct super_block * sb
const char * fmt, ...)
{
va_list args;
+ struct ext2_super_block *es = EXT2_SB(sb)->s_es;

if (!(sb->s_flags & MS_RDONLY)) {
sb->u.ext2_sb.s_mount_state |= EXT2_ERROR_FS;
- sb->u.ext2_sb.s_es->s_state =
- cpu_to_le16(le16_to_cpu(sb->u.ext2_sb.s_es->s_state) | EXT2_ERROR_FS);
- mark_buffer_dirty(sb->u.ext2_sb.s_sbh);
- sb->s_dirt = 1;
+ es->s_state =
+ cpu_to_le16(le16_to_cpu(es->s_state) | EXT2_ERROR_FS);
+ ext2_sync_super(sb, es);
}
va_start (args, fmt);
vsprintf (error_buf, fmt, args);
@@ -124,8 +126,10 @@ void ext2_put_super (struct super_block
int i;

if (!(sb->s_flags & MS_RDONLY)) {
- sb->u.ext2_sb.s_es->s_state = le16_to_cpu(sb->u.ext2_sb.s_mount_state);
- mark_buffer_dirty(sb->u.ext2_sb.s_sbh);
+ struct ext2_super_block *es = EXT2_SB(sb)->s_es;
+
+ es->s_state = le16_to_cpu(EXT2_SB(sb)->s_mount_state);
+ ext2_sync_super(sb, es);
}
db_count = EXT2_SB(sb)->s_gdb_count;
for (i = 0; i < db_count; i++)
@@ -305,13 +309,10 @@ static int ext2_setup_super (struct supe
(le32_to_cpu(es->s_lastcheck) + le32_to_cpu(es->s_checkinterval) <= CURRENT_TIME))
printk ("EXT2-fs warning: checktime reached, "
"running e2fsck is recommended\n");
- es->s_state = cpu_to_le16(le16_to_cpu(es->s_state) & ~EXT2_VALID_FS);
if (!(__s16) le16_to_cpu(es->s_max_mnt_count))
es->s_max_mnt_count = (__s16) cpu_to_le16(EXT2_DFL_MAX_MNT_COUNT);
es->s_mnt_count=cpu_to_le16(le16_to_cpu(es->s_mnt_count) + 1);
- es->s_mtime = cpu_to_le32(CURRENT_TIME);
- mark_buffer_dirty(sb->u.ext2_sb.s_sbh);
- sb->s_dirt = 1;
+ ext2_write_super(sb);
if (test_opt (sb, DEBUG))
printk ("[EXT II FS %s, %s, bs=%lu, fs=%lu, gc=%lu, "
"bpg=%lu, ipg=%lu, mo=%04lx]\n",
@@ -664,6 +665,15 @@ static void ext2_commit_super (struct su
sb->s_dirt = 0;
}

+static void ext2_sync_super(struct super_block *sb, struct ext2_super_block *es)
+{
+ es->s_wtime = cpu_to_le32(CURRENT_TIME);
+ mark_buffer_dirty(EXT2_SB(sb)->s_sbh);
+ ll_rw_block(WRITE, 1, &EXT2_SB(sb)->s_sbh);
+ wait_on_buffer(EXT2_SB(sb)->s_sbh);
+ sb->s_dirt = 0;
+}
+
/*
* In the second extended file system, it is not necessary to
* write the super block since we use a mapping of the
@@ -682,13 +692,14 @@ void ext2_write_super (struct super_bloc
if (!(sb->s_flags & MS_RDONLY)) {
es = sb->u.ext2_sb.s_es;

- ext2_debug ("setting valid to 0\n");
-
if (le16_to_cpu(es->s_state) & EXT2_VALID_FS) {
- es->s_state = cpu_to_le16(le16_to_cpu(es->s_state) & ~EXT2_VALID_FS);
+ ext2_debug ("setting valid to 0\n");
+ es->s_state = cpu_to_le16(le16_to_cpu(es->s_state) &
+ ~EXT2_VALID_FS);
es->s_mtime = cpu_to_le32(CURRENT_TIME);
- }
- ext2_commit_super (sb, es);
+ ext2_sync_super(sb, es);
+ } else
+ ext2_commit_super (sb, es);
}
sb->s_dirt = 0;
}
@@ -725,11 +736,7 @@ int ext2_remount (struct super_block * s
*/
es->s_state = cpu_to_le16(sb->u.ext2_sb.s_mount_state);
es->s_mtime = cpu_to_le32(CURRENT_TIME);
- mark_buffer_dirty(sb->u.ext2_sb.s_sbh);
- sb->s_dirt = 1;
- ext2_commit_super (sb, es);
- }
- else {
+ } else {
int ret;
if ((ret = EXT2_HAS_RO_COMPAT_FEATURE(sb,
~EXT2_FEATURE_RO_COMPAT_SUPP))) {
@@ -747,6 +754,7 @@ int ext2_remount (struct super_block * s
if (!ext2_setup_super (sb, es, 0))
sb->s_flags &= ~MS_RDONLY;
}
+ ext2_sync_super(sb, es);
return 0;
}