From: Fred Isaman <iisaman@xxxxxxxxxxxxxx> There is currently no good way for pnfs to communicate problems. For example - the linux read code first tries to do readahead through nfs_readpages. Failure there is ignored, and it will later call nfs_readpage. Failure there is also ignored, except that the lack of PG_uptodate is communicated back via -EIO. With pnfs, it would be useful to be able to communicate to nfs_readpage that direct disk IO failed on readahead, and that it should failover to using the MDS. Making the page flag PG_owner_priv_1 available as PG_pnfserr is one way to do so. (An alternative would be to embed this in the layout, but then pg_test can't easily access the info.) This may be better as generic pnfs code, in which case it should be put in pnfs.h, or even page-flags.h Signed-off-by: Fred Isaman <iisaman@xxxxxxxxxxxxxx> Signed-off-by: Benny Halevy <bhalevy@xxxxxxxxxxx> --- fs/nfs/blocklayout/blocklayout.h | 5 +++++ 1 files changed, 5 insertions(+), 0 deletions(-) diff --git a/fs/nfs/blocklayout/blocklayout.h b/fs/nfs/blocklayout/blocklayout.h index 8b06c93..493d4d3 100644 --- a/fs/nfs/blocklayout/blocklayout.h +++ b/fs/nfs/blocklayout/blocklayout.h @@ -37,6 +37,11 @@ #include <linux/nfs4_pnfs.h> #include <linux/dm-ioctl.h> /* Needed for struct dm_ioctl*/ +#define PG_pnfserr PG_owner_priv_1 +#define PagePnfsErr(page) test_bit(PG_pnfserr, &(page)->flags) +#define SetPagePnfsErr(page) set_bit(PG_pnfserr, &(page)->flags) +#define ClearPagePnfsErr(page) clear_bit(PG_pnfserr, &(page)->flags) + extern struct class shost_class; /* exported from drivers/scsi/hosts.c */ extern int dm_dev_create(struct dm_ioctl *param); /* from dm-ioctl.c */ extern int dm_dev_remove(struct dm_ioctl *param); /* from dm-ioctl.c */ -- 1.7.4.1 -- To unsubscribe from this list: send the line "unsubscribe linux-nfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
