nfsd: more robust allocation failure handling in nfsd_reply_cache_init

Currently, we try to allocate the cache as a single, large chunk, which
can fail if no big chunks of memory are available. We _do_ try to size
it according to the amount of memory in the box, but if the server is
started well after boot time, then the allocation can fail due to memory
fragmentation.

Fall back to doing a vzalloc if the kcalloc fails, and switch the
shutdown code to do a kvfree to handle freeing correctly.

Reported-by: Olaf Hering <olaf@aepfle.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

diff --git a/fs/nfsd/nfscache.c b/fs/nfsd/nfscache.c
index 54cde9a5864e18f12ed198474c4f48c0dc8b1f16..d6b97b424ad1729ee8e542abbead3040c2e98ecb 100644 (file)
--- a/fs/nfsd/nfscache.c
+++ b/fs/nfsd/nfscache.c
@@ -9,6 +9,7 @@
  */
 
 #include <linux/slab.h>
+#include <linux/vmalloc.h>
 #include <linux/sunrpc/addr.h>
 #include <linux/highmem.h>
 #include <linux/log2.h>
@@ -174,8 +175,12 @@ int nfsd_reply_cache_init(void)
                goto out_nomem;
 
        drc_hashtbl = kcalloc(hashsize, sizeof(*drc_hashtbl), GFP_KERNEL);
-       if (!drc_hashtbl)
-               goto out_nomem;
+       if (!drc_hashtbl) {
+               drc_hashtbl = vzalloc(hashsize * sizeof(*drc_hashtbl));
+               if (!drc_hashtbl)
+                       goto out_nomem;
+       }
+
        for (i = 0; i < hashsize; i++) {
                INIT_LIST_HEAD(&drc_hashtbl[i].lru_head);
                spin_lock_init(&drc_hashtbl[i].cache_lock);
@@ -204,7 +209,7 @@ void nfsd_reply_cache_shutdown(void)
                }
        }
 
-       kfree (drc_hashtbl);
+       kvfree(drc_hashtbl);
        drc_hashtbl = NULL;
        drc_hashsize = 0;