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authorLinus Torvalds <torvalds@linux-foundation.org>2014-06-21 14:20:38 -1000
committerLinus Torvalds <torvalds@linux-foundation.org>2014-06-21 14:20:38 -1000
commit147f1404db3ed0c3019002eef693c5d297b8f161 (patch)
tree7349fe8111e2ba8ee7a9aba69ec8893a69d8a573
parent401c58fcbbf570e7e4a8ee0e21ffd829deb4de0b (diff)
parentf41c5ad2ff2657978a9712b9ea80cd812a7da2b0 (diff)
downloadlinux-stericsson-147f1404db3ed0c3019002eef693c5d297b8f161.tar.gz
Merge branch 'for-3.16' of git://linux-nfs.org/~bfields/linux
Pull nfsd bugfixes from Bruce Fields: "Fixes for a new regression from the xdr encoding rewrite, and a delegation problem we've had for a while (made somewhat more annoying by the vfs delegation support added in 3.13)" * 'for-3.16' of git://linux-nfs.org/~bfields/linux: NFSD: fix bug for readdir of pseudofs NFSD: Don't hand out delegations for 30 seconds after recalling them.
-rw-r--r--fs/nfsd/nfs4state.c78
-rw-r--r--fs/nfsd/nfs4xdr.c1
2 files changed, 79 insertions, 0 deletions
diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
index c0d45cec9958..2204e1fe5725 100644
--- a/fs/nfsd/nfs4state.c
+++ b/fs/nfsd/nfs4state.c
@@ -41,6 +41,7 @@
#include <linux/ratelimit.h>
#include <linux/sunrpc/svcauth_gss.h>
#include <linux/sunrpc/addr.h>
+#include <linux/hash.h>
#include "xdr4.h"
#include "xdr4cb.h"
#include "vfs.h"
@@ -364,6 +365,79 @@ static struct nfs4_ol_stateid * nfs4_alloc_stateid(struct nfs4_client *clp)
return openlockstateid(nfs4_alloc_stid(clp, stateid_slab));
}
+/*
+ * When we recall a delegation, we should be careful not to hand it
+ * out again straight away.
+ * To ensure this we keep a pair of bloom filters ('new' and 'old')
+ * in which the filehandles of recalled delegations are "stored".
+ * If a filehandle appear in either filter, a delegation is blocked.
+ * When a delegation is recalled, the filehandle is stored in the "new"
+ * filter.
+ * Every 30 seconds we swap the filters and clear the "new" one,
+ * unless both are empty of course.
+ *
+ * Each filter is 256 bits. We hash the filehandle to 32bit and use the
+ * low 3 bytes as hash-table indices.
+ *
+ * 'state_lock', which is always held when block_delegations() is called,
+ * is used to manage concurrent access. Testing does not need the lock
+ * except when swapping the two filters.
+ */
+static struct bloom_pair {
+ int entries, old_entries;
+ time_t swap_time;
+ int new; /* index into 'set' */
+ DECLARE_BITMAP(set[2], 256);
+} blocked_delegations;
+
+static int delegation_blocked(struct knfsd_fh *fh)
+{
+ u32 hash;
+ struct bloom_pair *bd = &blocked_delegations;
+
+ if (bd->entries == 0)
+ return 0;
+ if (seconds_since_boot() - bd->swap_time > 30) {
+ spin_lock(&state_lock);
+ if (seconds_since_boot() - bd->swap_time > 30) {
+ bd->entries -= bd->old_entries;
+ bd->old_entries = bd->entries;
+ memset(bd->set[bd->new], 0,
+ sizeof(bd->set[0]));
+ bd->new = 1-bd->new;
+ bd->swap_time = seconds_since_boot();
+ }
+ spin_unlock(&state_lock);
+ }
+ hash = arch_fast_hash(&fh->fh_base, fh->fh_size, 0);
+ if (test_bit(hash&255, bd->set[0]) &&
+ test_bit((hash>>8)&255, bd->set[0]) &&
+ test_bit((hash>>16)&255, bd->set[0]))
+ return 1;
+
+ if (test_bit(hash&255, bd->set[1]) &&
+ test_bit((hash>>8)&255, bd->set[1]) &&
+ test_bit((hash>>16)&255, bd->set[1]))
+ return 1;
+
+ return 0;
+}
+
+static void block_delegations(struct knfsd_fh *fh)
+{
+ u32 hash;
+ struct bloom_pair *bd = &blocked_delegations;
+
+ hash = arch_fast_hash(&fh->fh_base, fh->fh_size, 0);
+
+ __set_bit(hash&255, bd->set[bd->new]);
+ __set_bit((hash>>8)&255, bd->set[bd->new]);
+ __set_bit((hash>>16)&255, bd->set[bd->new]);
+ if (bd->entries == 0)
+ bd->swap_time = seconds_since_boot();
+ bd->entries += 1;
+}
+
static struct nfs4_delegation *
alloc_init_deleg(struct nfs4_client *clp, struct nfs4_ol_stateid *stp, struct svc_fh *current_fh)
{
@@ -372,6 +446,8 @@ alloc_init_deleg(struct nfs4_client *clp, struct nfs4_ol_stateid *stp, struct sv
dprintk("NFSD alloc_init_deleg\n");
if (num_delegations > max_delegations)
return NULL;
+ if (delegation_blocked(&current_fh->fh_handle))
+ return NULL;
dp = delegstateid(nfs4_alloc_stid(clp, deleg_slab));
if (dp == NULL)
return dp;
@@ -2770,6 +2846,8 @@ static void nfsd_break_one_deleg(struct nfs4_delegation *dp)
/* Only place dl_time is set; protected by i_lock: */
dp->dl_time = get_seconds();
+ block_delegations(&dp->dl_fh);
+
nfsd4_cb_recall(dp);
}
diff --git a/fs/nfsd/nfs4xdr.c b/fs/nfsd/nfs4xdr.c
index 2d305a121f37..83baf2bfe9e9 100644
--- a/fs/nfsd/nfs4xdr.c
+++ b/fs/nfsd/nfs4xdr.c
@@ -2687,6 +2687,7 @@ nfsd4_encode_dirent(void *ccdv, const char *name, int namlen,
nfserr = nfserr_toosmall;
goto fail;
case nfserr_noent:
+ xdr_truncate_encode(xdr, start_offset);
goto skip_entry;
default:
/*