Hello,
On (03/17/11 14:04), Andrew Morton wrote:
>[..]
> afaik this regression didn't get fixed. Jens put out a patch for
> George to test but there hasn't been any feedback on that yet. Could
> you guys please give it a spin?
>
Sorry for rather long reply. Seem to work fine for me.
Tested-by: Sergey Senozhatsky <sergey.senozhatsky@xxxxxxxxx>
Thanks,
Sergey
> From: Jens Axboe <axboe@xxxxxxxxx>
>
> When we move the potential dirty list entries to the
> default_backing_dev_info, reassign the sb->s_bdi as well.
> default_backing_dev_info will always be around. I hope this can fix it up
> for 2.6.38 and we can add the proper ref counting for .39.
>
> Cc: Anton Altaparmakov <aia21@xxxxxxxxx>
> Cc: George Spelvin <linux@xxxxxxxxxxx>
> Cc: Christoph Hellwig <hch@xxxxxx>
> Cc: Andreas Biemann <biessmann@xxxxxxxxxxxxx>
> Cc: Sergey Senozhatsky <sergey.senozhatsky@xxxxxxxxx>
> Tested-by: Torsten Hilbrich <torsten.hilbrich@xxxxxxxxxxx>
> Cc: <stable@xxxxxxxxxx> [2.6.38.x]
> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
> ---
>
> fs/super.c | 2 ++
> fs/sync.c | 4 ++--
> mm/backing-dev.c | 2 +-
> 3 files changed, 5 insertions(+), 3 deletions(-)
>
> diff -puN fs/super.c~vfs-fix-null-pointer-oops-in-sync_inodes_sb fs/super.c
> --- a/fs/super.c~vfs-fix-null-pointer-oops-in-sync_inodes_sb
> +++ a/fs/super.c
> @@ -72,6 +72,7 @@ static struct super_block *alloc_super(s
> #else
> INIT_LIST_HEAD(&s->s_files);
> #endif
> + s->s_bdi = &default_backing_dev_info;
> INIT_LIST_HEAD(&s->s_instances);
> INIT_HLIST_BL_HEAD(&s->s_anon);
> INIT_LIST_HEAD(&s->s_inodes);
> @@ -1006,6 +1007,7 @@ vfs_kern_mount(struct file_system_type *
> }
> BUG_ON(!mnt->mnt_sb);
> WARN_ON(!mnt->mnt_sb->s_bdi);
> + WARN_ON(mnt->mnt_sb->s_bdi == &default_backing_dev_info);
> mnt->mnt_sb->s_flags |= MS_BORN;
>
> error = security_sb_kern_mount(mnt->mnt_sb, flags, secdata);
> diff -puN fs/sync.c~vfs-fix-null-pointer-oops-in-sync_inodes_sb fs/sync.c
> --- a/fs/sync.c~vfs-fix-null-pointer-oops-in-sync_inodes_sb
> +++ a/fs/sync.c
> @@ -33,7 +33,7 @@ static int __sync_filesystem(struct supe
> * This should be safe, as we require bdi backing to actually
> * write out data in the first place
> */
> - if (!sb->s_bdi || sb->s_bdi == &noop_backing_dev_info)
> + if (sb->s_bdi == &noop_backing_dev_info)
> return 0;
>
> if (sb->s_qcop && sb->s_qcop->quota_sync)
> @@ -79,7 +79,7 @@ EXPORT_SYMBOL_GPL(sync_filesystem);
>
> static void sync_one_sb(struct super_block *sb, void *arg)
> {
> - if (!(sb->s_flags & MS_RDONLY) && sb->s_bdi)
> + if (!(sb->s_flags & MS_RDONLY))
> __sync_filesystem(sb, *(int *)arg);
> }
> /*
> diff -puN mm/backing-dev.c~vfs-fix-null-pointer-oops-in-sync_inodes_sb mm/backing-dev.c
> --- a/mm/backing-dev.c~vfs-fix-null-pointer-oops-in-sync_inodes_sb
> +++ a/mm/backing-dev.c
> @@ -598,7 +598,7 @@ static void bdi_prune_sb(struct backing_
> spin_lock(&sb_lock);
> list_for_each_entry(sb, &super_blocks, s_list) {
> if (sb->s_bdi == bdi)
> - sb->s_bdi = NULL;
> + sb->s_bdi = &default_backing_dev_info;
> }
> spin_unlock(&sb_lock);
> }
> _
>
>
> btw, Christoph: would this not have been be a less hacky hack?
>
> --- a/fs/fs-writeback.c~a
> +++ a/fs/fs-writeback.c
> @@ -73,7 +73,7 @@ static inline struct backing_dev_info *i
> {
> struct super_block *sb = inode->i_sb;
>
> - if (strcmp(sb->s_type->name, "bdev") == 0)
> + if (sb == blockdev_superblock)
> return inode->i_mapping->backing_dev_info;
>
> return sb->s_bdi;
> _
>
Attachment:
pgpWl_pT8odjh.pgp
Description: PGP signature
