* [Qemu-devel] [PATCH V2 1/2] block/nfs: refuse readahead if cache.direct is on
2016-05-19 12:48 [Qemu-devel] [PATCH V2 0/2] block/nfs: add support for libnfs pagecache Peter Lieven
@ 2016-05-19 12:48 ` Peter Lieven
2016-05-19 12:48 ` [Qemu-devel] [PATCH V2 2/2] block/nfs: add support for libnfs pagecache Peter Lieven
` (2 subsequent siblings)
3 siblings, 0 replies; 5+ messages in thread
From: Peter Lieven @ 2016-05-19 12:48 UTC (permalink / raw)
To: qemu-block
Cc: qemu-devel, jcody, ronniesahlberg, famz, Peter Lieven,
qemu-stable
if we open a NFS export with disabled cache we should refuse
the readahead feature as it will cache data inside libnfs.
If a export was opened with readahead enabled it should
futher not be allowed to disable the cache while running.
Cc: qemu-stable@nongnu.org
Signed-off-by: Peter Lieven <pl@kamp.de>
---
block/nfs.c | 20 ++++++++++++++++----
1 file changed, 16 insertions(+), 4 deletions(-)
diff --git a/block/nfs.c b/block/nfs.c
index 9f51cc3..60be45e 100644
--- a/block/nfs.c
+++ b/block/nfs.c
@@ -1,7 +1,7 @@
/*
* QEMU Block driver for native access to files on NFS shares
*
- * Copyright (c) 2014 Peter Lieven <pl@kamp.de>
+ * Copyright (c) 2014-2016 Peter Lieven <pl@kamp.de>
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
@@ -47,6 +47,7 @@ typedef struct NFSClient {
bool has_zero_init;
AioContext *aio_context;
blkcnt_t st_blocks;
+ bool cache_used;
} NFSClient;
typedef struct NFSRPC {
@@ -278,7 +279,7 @@ static void nfs_file_close(BlockDriverState *bs)
}
static int64_t nfs_client_open(NFSClient *client, const char *filename,
- int flags, Error **errp)
+ int flags, Error **errp, int open_flags)
{
int ret = -EINVAL, i;
struct stat st;
@@ -330,12 +331,18 @@ static int64_t nfs_client_open(NFSClient *client, const char *filename,
nfs_set_tcp_syncnt(client->context, val);
#ifdef LIBNFS_FEATURE_READAHEAD
} else if (!strcmp(qp->p[i].name, "readahead")) {
+ if (open_flags & BDRV_O_NOCACHE) {
+ error_setg(errp, "Cannot enable NFS readahead "
+ "if cache.direct = on");
+ goto fail;
+ }
if (val > QEMU_NFS_MAX_READAHEAD_SIZE) {
error_report("NFS Warning: Truncating NFS readahead"
" size to %d", QEMU_NFS_MAX_READAHEAD_SIZE);
val = QEMU_NFS_MAX_READAHEAD_SIZE;
}
nfs_set_readahead(client->context, val);
+ client->cache_used = true;
#endif
#ifdef LIBNFS_FEATURE_DEBUG
} else if (!strcmp(qp->p[i].name, "debug")) {
@@ -418,7 +425,7 @@ static int nfs_file_open(BlockDriverState *bs, QDict *options, int flags,
}
ret = nfs_client_open(client, qemu_opt_get(opts, "filename"),
(flags & BDRV_O_RDWR) ? O_RDWR : O_RDONLY,
- errp);
+ errp, bs->open_flags);
if (ret < 0) {
goto out;
}
@@ -454,7 +461,7 @@ static int nfs_file_create(const char *url, QemuOpts *opts, Error **errp)
total_size = ROUND_UP(qemu_opt_get_size_del(opts, BLOCK_OPT_SIZE, 0),
BDRV_SECTOR_SIZE);
- ret = nfs_client_open(client, url, O_CREAT, errp);
+ ret = nfs_client_open(client, url, O_CREAT, errp, 0);
if (ret < 0) {
goto out;
}
@@ -516,6 +523,11 @@ static int nfs_reopen_prepare(BDRVReopenState *state,
return -EACCES;
}
+ if ((state->flags & BDRV_O_NOCACHE) && client->cache_used) {
+ error_setg(errp, "Cannot disable cache if libnfs readahead is enabled");
+ return -EINVAL;
+ }
+
/* Update cache for read-only reopens */
if (!(state->flags & BDRV_O_RDWR)) {
ret = nfs_fstat(client->context, client->fh, &st);
--
1.9.1
^ permalink raw reply related [flat|nested] 5+ messages in thread* [Qemu-devel] [PATCH V2 2/2] block/nfs: add support for libnfs pagecache
2016-05-19 12:48 [Qemu-devel] [PATCH V2 0/2] block/nfs: add support for libnfs pagecache Peter Lieven
2016-05-19 12:48 ` [Qemu-devel] [PATCH V2 1/2] block/nfs: refuse readahead if cache.direct is on Peter Lieven
@ 2016-05-19 12:48 ` Peter Lieven
2016-05-19 21:03 ` [Qemu-devel] [PATCH V2 0/2] " Jeff Cody
2016-05-19 21:05 ` Jeff Cody
3 siblings, 0 replies; 5+ messages in thread
From: Peter Lieven @ 2016-05-19 12:48 UTC (permalink / raw)
To: qemu-block; +Cc: qemu-devel, jcody, ronniesahlberg, famz, Peter Lieven
upcoming libnfs will have support for a read cache that can
significantly help to speed up requests since libnfs by design
circumvents the kernel cache.
Example:
qemu -cdrom nfs://127.0.0.1/iso/my.iso?pagecache=1024
The pagecache parameters takes the maximum amount of pages to
cache. A page in libnfs is always the NFS_BLKSIZE which is
4KB.
Signed-off-by: Peter Lieven <pl@kamp.de>
---
block/nfs.c | 37 ++++++++++++++++++++++++++++++++++++-
1 file changed, 36 insertions(+), 1 deletion(-)
diff --git a/block/nfs.c b/block/nfs.c
index 60be45e..15d6832 100644
--- a/block/nfs.c
+++ b/block/nfs.c
@@ -38,6 +38,7 @@
#include <nfsc/libnfs.h>
#define QEMU_NFS_MAX_READAHEAD_SIZE 1048576
+#define QEMU_NFS_MAX_PAGECACHE_SIZE (8388608 / NFS_BLKSIZE)
#define QEMU_NFS_MAX_DEBUG_LEVEL 2
typedef struct NFSClient {
@@ -342,6 +343,26 @@ static int64_t nfs_client_open(NFSClient *client, const char *filename,
val = QEMU_NFS_MAX_READAHEAD_SIZE;
}
nfs_set_readahead(client->context, val);
+#ifdef LIBNFS_FEATURE_PAGECACHE
+ nfs_set_pagecache_ttl(client->context, 0);
+#endif
+ client->cache_used = true;
+#endif
+#ifdef LIBNFS_FEATURE_PAGECACHE
+ nfs_set_pagecache_ttl(client->context, 0);
+ } else if (!strcmp(qp->p[i].name, "pagecache")) {
+ if (open_flags & BDRV_O_NOCACHE) {
+ error_setg(errp, "Cannot enable NFS pagecache "
+ "if cache.direct = on");
+ goto fail;
+ }
+ if (val > QEMU_NFS_MAX_PAGECACHE_SIZE) {
+ error_report("NFS Warning: Truncating NFS pagecache"
+ " size to %d pages", QEMU_NFS_MAX_PAGECACHE_SIZE);
+ val = QEMU_NFS_MAX_PAGECACHE_SIZE;
+ }
+ nfs_set_pagecache(client->context, val);
+ nfs_set_pagecache_ttl(client->context, 0);
client->cache_used = true;
#endif
#ifdef LIBNFS_FEATURE_DEBUG
@@ -524,7 +545,8 @@ static int nfs_reopen_prepare(BDRVReopenState *state,
}
if ((state->flags & BDRV_O_NOCACHE) && client->cache_used) {
- error_setg(errp, "Cannot disable cache if libnfs readahead is enabled");
+ error_setg(errp, "Cannot disable cache if libnfs readahead or"
+ " pagecache is enabled");
return -EINVAL;
}
@@ -542,6 +564,15 @@ static int nfs_reopen_prepare(BDRVReopenState *state,
return 0;
}
+#ifdef LIBNFS_FEATURE_PAGECACHE
+static void nfs_invalidate_cache(BlockDriverState *bs,
+ Error **errp)
+{
+ NFSClient *client = bs->opaque;
+ nfs_pagecache_invalidate(client->context, client->fh);
+}
+#endif
+
static BlockDriver bdrv_nfs = {
.format_name = "nfs",
.protocol_name = "nfs",
@@ -565,6 +596,10 @@ static BlockDriver bdrv_nfs = {
.bdrv_detach_aio_context = nfs_detach_aio_context,
.bdrv_attach_aio_context = nfs_attach_aio_context,
+
+#ifdef LIBNFS_FEATURE_PAGECACHE
+ .bdrv_invalidate_cache = nfs_invalidate_cache,
+#endif
};
static void nfs_block_init(void)
--
1.9.1
^ permalink raw reply related [flat|nested] 5+ messages in thread