Hi. Sorry, it took really long to catch all the things around, but it is better than never.
History says that commit which introduced per-bdi writeback broke pohmelfs, since it does not have backing store device and did not fill appropriate superblock entry, which lead to crash on umoount. Jens provided a patch below, which I tested to fix the problem. There is a problem though, when all writes happend before umount, but did net yet written back to storage, get lost. I can not say whether this happens because of per-bdi writeback (it should not I think), but that's what happens. Albeit being a bug, it will not be fixed :) The reason is simple, new backing storage for POHMELFS (a distributed hash table called elliptics network) is essentially ready and I start working on porting POHMELFS to it, which means all its bugs will be fixed there^W^Werased and written from scratch. Jens, thanks a lot for you patch, Greg please pull it up. If you did not find it or can not extract from the reply, I will resend. Thanks everyone! On Wed, Dec 30, 2009 at 10:14:34AM +0100, Jens Axboe ([email protected]) wrote: > Since pohmelfs isn't tied to a single block device, it needs to setup a > backing dev like nfs/btrfs/etc do. Here's a completely untested patch. > > diff --git a/drivers/staging/pohmelfs/inode.c > b/drivers/staging/pohmelfs/inode.c > index f69b778..cd25811 100644 > --- a/drivers/staging/pohmelfs/inode.c > +++ b/drivers/staging/pohmelfs/inode.c > @@ -36,6 +36,7 @@ > #define POHMELFS_MAGIC_NUM 0x504f482e > > static struct kmem_cache *pohmelfs_inode_cache; > +static atomic_t psb_bdi_num = ATOMIC_INIT(0); > > /* > * Removes inode from all trees, drops local name cache and removes all > queued > @@ -1331,6 +1332,8 @@ static void pohmelfs_put_super(struct super_block *sb) > pohmelfs_crypto_exit(psb); > pohmelfs_state_exit(psb); > > + bdi_destroy(&psb->bdi); > + > kfree(psb); > sb->s_fs_info = NULL; > } > @@ -1815,11 +1818,22 @@ static int pohmelfs_fill_super(struct super_block > *sb, void *data, int silent) > if (!psb) > goto err_out_exit; > > + err = bdi_init(&psb->bdi); > + if (err) > + goto err_out_free_sb; > + > + err = bdi_register(&psb->bdi, NULL, "pfs-%d", > atomic_inc_return(&psb_bdi_num)); > + if (err) { > + bdi_destroy(&psb->bdi); > + goto err_out_free_sb; > + } > + > sb->s_fs_info = psb; > sb->s_op = &pohmelfs_sb_ops; > sb->s_magic = POHMELFS_MAGIC_NUM; > sb->s_maxbytes = MAX_LFS_FILESIZE; > sb->s_blocksize = PAGE_SIZE; > + sb->s_bdi = &psb->bdi; > > psb->sb = sb; > > @@ -1863,11 +1877,11 @@ static int pohmelfs_fill_super(struct super_block > *sb, void *data, int silent) > > err = pohmelfs_parse_options((char *) data, psb, 0); > if (err) > - goto err_out_free_sb; > + goto err_out_free_bdi; > > err = pohmelfs_copy_crypto(psb); > if (err) > - goto err_out_free_sb; > + goto err_out_free_bdi; > > err = pohmelfs_state_init(psb); > if (err) > @@ -1916,6 +1930,8 @@ err_out_state_exit: > err_out_free_strings: > kfree(psb->cipher_string); > kfree(psb->hash_string); > +err_out_free_bdi: > + bdi_destroy(&psb->bdi); > err_out_free_sb: > kfree(psb); > err_out_exit: > diff --git a/drivers/staging/pohmelfs/netfs.h > b/drivers/staging/pohmelfs/netfs.h > index 623a07d..01cba00 100644 > --- a/drivers/staging/pohmelfs/netfs.h > +++ b/drivers/staging/pohmelfs/netfs.h > @@ -18,6 +18,7 @@ > > #include <linux/types.h> > #include <linux/connector.h> > +#include <linux/backing-dev.h> > > #define POHMELFS_CN_IDX 5 > #define POHMELFS_CN_VAL 0 > @@ -624,6 +625,8 @@ struct pohmelfs_sb { > > struct super_block *sb; > > + struct backing_dev_info bdi; > + > /* > * Algorithm strings. > */ > > -- > Jens Axboe -- Evgeniy Polyakov -- To unsubscribe from this list: send the line "unsubscribe kernel-testers" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
