Re: [PATCH]add supporting second super block of nilfs2

[Jiro SEKIBA]

Oops

I forgot to supply ChangeLog entry.
I'll resend the patch.  Sorry for the careless-miss.

At Sun, 23 May 2010 20:59:15 +0900,
Jiro SEKIBA wrote:
> 
> [1  <text/plain; ISO-8859-7 (quoted-printable)>]
> Hi,
> 
> Thank you for the comments.
> 
> At Tue, 18 May 2010 18:21:18 +0200,
> Vladimir 'φ-coder/phcoder' Serbinenko wrote:
> > 
> > Jiro SEKIBA wrote:
> > > Hi,
> > >
> > > This is a patch to support second super block of nilfs2.
> > > It will use the second super block when first one is accidentally
> > > collapsed or not synced properly.
> > >
> > >   
> > Is it limited to only 2 blocks?
> 
> Yes, nilfs2 has super blocks at the beginning and the end of the partition.
> 
> > > NILFS has redundant super blocks.  Those are identical if unmounted 
> > > cleanly.
> > > However when one of these is collapsed or old, correct one or newer one
> > > should be used to find latest log correctly.
> > >
> > > Test on both PPC and x86.
> > >
> > >   
> > 
> > +  grub_disk_read (disk, 1 * 2, 0, sizeof (struct grub_nilfs2_super_block),
> > +             &data->sblock);
> > Please macroify
> > 
> > +  grub_disk_read (disk, (disk->total_sectors - 8), 0,
> > +             sizeof (struct grub_nilfs2_super_block), &sb2);
> > total_sectors is a size of disk, not partition. Use grub_disk_get_size to 
> > automatically get the size of underlying object (disk or partition).
> > Some disks have unknown size. CDROM is an example of it. Even worse trying 
> > to read from a sector past the boundary will hang the system for few 
> > minutes.
> > Disks on OFW suffer the same problem. Perhaps we should add 
> > GRUB_DISK_SIZE_UNKNOWN 0xffffffffffffffffULL for this case
> 
> Thank you the correction.
> I fixed to use grub_disk_get_size() to obtain the size.
> Also, I added the macro in grub/disk.h for the case that size
> of partition is unknown.
> 
> >  as an indicator and avoid querying back labels of such disks
> > +  /* Swap if first super block is invalid or oloder than second one. */
> > 
> > Typo
> > 
> > Could you supply the ChangeLog entry?
> > 
> > -- 
> > Regards
> > Vladimir 'φ-coder/phcoder' Serbinenko
> > 
> > 
> 
> -- 
> Jiro SEKIBA <address@hidden>
> 
> [2 nilfs2-support-2nd-sbv2.patch <text/plain; US-ASCII (quoted-printable)>]
> === modified file 'fs/nilfs2.c'
> --- fs/nilfs2.c       2010-04-24 20:09:08 +0000
> +++ fs/nilfs2.c       2010-05-23 19:50:16 +0000
> @@ -49,6 +49,13 @@
>  #define NILFS_BTREE_LEVEL_NODE_MIN      (NILFS_BTREE_LEVEL_DATA + 1)
>  #define NILFS_BTREE_LEVEL_MAX           14
>  
> +/* nilfs 1st super block posission from beginning of the partition
> +   in 512 block size */
> +#define NILFS_1ST_SUPER_BLOCK        2
> +/* nilfs 2nd super block posission from end of the partition
> +   in 512 block size */
> +#define NILFS_2ND_SUPER_BLOCK        8
> +
>  struct grub_nilfs2_inode
>  {
>    grub_uint64_t i_blocks;
> @@ -703,6 +710,52 @@
>    return 1;
>  }
>  
> +static grub_err_t
> +grub_nilfs2_load_sb (struct grub_nilfs2_data *data)
> +{
> +  grub_disk_t disk = data->disk;
> +  struct grub_nilfs2_super_block sb2;
> +  grub_uint64_t partition_size;
> +  int valid[2];
> +  int swp = 0;
> +
> +  /* Read first super block. */
> +  grub_disk_read (disk, NILFS_1ST_SUPER_BLOCK, 0,
> +               sizeof (struct grub_nilfs2_super_block), &data->sblock);
> +  /* Make sure if 1st super block is valid.  */
> +  valid[0] = grub_nilfs2_valid_sb (&data->sblock);
> +
> +  partition_size = grub_disk_get_size (disk);
> +  if (partition_size != GRUB_DISK_SIZE_UNKNOWN)
> +    {
> +      /* Read second super block. */
> +      grub_disk_read (disk, partition_size - NILFS_2ND_SUPER_BLOCK, 0,
> +                   sizeof (struct grub_nilfs2_super_block), &sb2);
> +      /* Make sure if 2nd super block is valid.  */
> +      valid[1] = grub_nilfs2_valid_sb (&sb2);
> +    }
> +  else
> +    /* 2nd super block may not exist, so it's invalid. */
> +    valid[1] = 0;
> +
> +
> +
> +  if (!valid[0] && !valid[1])
> +    return grub_error (GRUB_ERR_BAD_FS, "not a nilfs2 filesystem");
> +
> +  swp = valid[1] && (!valid[0] ||
> +                  grub_le_to_cpu64 (data->sblock.s_last_cno) <
> +                  grub_le_to_cpu64 (sb2.s_last_cno));
> +
> +  /* swap if first super block is invalid or older than second one. */
> +  if (swp)
> +    grub_memcpy (&data->sblock, &sb2,
> +              sizeof (struct grub_nilfs2_super_block));
> +
> +  grub_errno = GRUB_ERR_NONE;
> +  return grub_errno;
> +}
> +
>  static struct grub_nilfs2_data *
>  grub_nilfs2_mount (grub_disk_t disk)
>  {
> @@ -717,19 +770,13 @@
>    if (!data)
>      return 0;
>  
> +  data->disk = disk;
> +
>    /* Read the superblock.  */
> -  grub_disk_read (disk, 1 * 2, 0, sizeof (struct grub_nilfs2_super_block),
> -               &data->sblock);
> +  grub_nilfs2_load_sb (data);
>    if (grub_errno)
>      goto fail;
>  
> -  /* Make sure this is an nilfs2 filesystem.  */
> -  if (!grub_nilfs2_valid_sb (&data->sblock))
> -    {
> -      grub_error (GRUB_ERR_BAD_FS, "not a nilfs2 filesystem");
> -      goto fail;
> -    }
> -
>    nilfs2_block_count = (1 << LOG2_NILFS2_BLOCK_SIZE (data));
>  
>    /* Read the last segment summary. */
> @@ -748,8 +795,6 @@
>    if (grub_errno)
>      goto fail;
>  
> -  data->disk = disk;
> -
>    grub_nilfs2_read_last_checkpoint (data, &last_checkpoint);
>  
>    if (grub_errno)
> 
> === modified file 'include/grub/disk.h'
> --- include/grub/disk.h       2010-01-07 00:58:54 +0000
> +++ include/grub/disk.h       2010-05-23 18:53:34 +0000
> @@ -138,6 +138,9 @@
>  #define GRUB_DISK_CACHE_SIZE 8
>  #define GRUB_DISK_CACHE_BITS 3
>  
> +/* Return value of grub_disk_get_size() in case disk size is unknown. */
> +#define GRUB_DISK_SIZE_UNKNOWN        0xffffffffffffffffULL
> +
>  /* This is called from the memory manager.  */
>  void grub_disk_cache_invalidate_all (void);
>  
> 
> [3  <text/plain; ISO-8859-1 (quoted-printable)>]
> 
> [4  <text/plain; us-ascii (7bit)>]
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-- 
Jiro SEKIBA <address@hidden>