pNFS: Add tracking to limit the number of pNFS retries
When the client is reading or writing using pNFS, and hits an error
on the DS, then it typically sends a LAYOUTERROR and/or LAYOUTRETURN
to the MDS, before redirtying the failed pages, and going for a new
round of reads/writebacks. The problem is that if the server has no
way to fix the DS, then we may need a way to interrupt this loop
after a set number of attempts have been made.
This patch adds an optional module parameter that allows the admin
to specify how many times to retry the read/writeback process before
failing with a fatal error.
The default behaviour is to retry forever.
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
diff --git a/include/linux/nfs_page.h b/include/linux/nfs_page.h
index b7d0f15..8b36800 100644
--- a/include/linux/nfs_page.h
+++ b/include/linux/nfs_page.h
@@ -53,6 +53,7 @@
struct nfs_write_verifier wb_verf; /* Commit cookie */
struct nfs_page *wb_this_page; /* list of reqs for this page */
struct nfs_page *wb_head; /* head pointer for req list */
+ unsigned short wb_nio; /* Number of I/O attempts */
};
struct nfs_pageio_descriptor;
@@ -87,7 +88,6 @@
};
struct nfs_pageio_descriptor {
- unsigned char pg_moreio : 1;
struct inode *pg_inode;
const struct nfs_pageio_ops *pg_ops;
const struct nfs_rw_ops *pg_rw_ops;
@@ -105,6 +105,8 @@
struct nfs_pgio_mirror pg_mirrors_static[1];
struct nfs_pgio_mirror *pg_mirrors_dynamic;
u32 pg_mirror_idx; /* current mirror */
+ unsigned short pg_maxretrans;
+ unsigned char pg_moreio : 1;
};
/* arbitrarily selected limit to number of mirrors */