9p: Add fscache support to 9p
This patch adds a persistent, read-only caching facility for
9p clients using the FS-Cache caching backend.
When the fscache facility is enabled, each inode is associated
with a corresponding vcookie which is an index into the FS-Cache
indexing tree. The FS-Cache indexing tree is indexed at 3 levels:
- session object associated with each mount.
- inode/vcookie
- actual data (pages)
A cache tag is chosen randomly for each session. These tags can
be read off /sys/fs/9p/caches and can be passed as a mount-time
parameter to re-attach to the specified caching session.
Signed-off-by: Abhishek Kulkarni <adkulkar@umail.iu.edu>
Signed-off-by: Eric Van Hensbergen <ericvh@gmail.com>
diff --git a/fs/9p/Kconfig b/fs/9p/Kconfig
index 74e0723..7952337 100644
--- a/fs/9p/Kconfig
+++ b/fs/9p/Kconfig
@@ -8,3 +8,12 @@
See <http://v9fs.sf.net> for more information.
If unsure, say N.
+
+config 9P_FSCACHE
+ bool "Enable 9P client caching support (EXPERIMENTAL)"
+ depends on EXPERIMENTAL
+ depends on 9P_FS=m && FSCACHE || 9P_FS=y && FSCACHE=y
+ help
+ Choose Y here to enable persistent, read-only local
+ caching support for 9p clients using FS-Cache
+
diff --git a/fs/9p/Makefile b/fs/9p/Makefile
index bc7f0d1..1a940ec 100644
--- a/fs/9p/Makefile
+++ b/fs/9p/Makefile
@@ -8,5 +8,6 @@
vfs_dir.o \
vfs_dentry.o \
v9fs.o \
- fid.o \
+ fid.o
+9p-$(CONFIG_9P_FSCACHE) += cache.o
diff --git a/fs/9p/cache.c b/fs/9p/cache.c
new file mode 100644
index 0000000..51c94e2
--- /dev/null
+++ b/fs/9p/cache.c
@@ -0,0 +1,474 @@
+/*
+ * V9FS cache definitions.
+ *
+ * Copyright (C) 2009 by Abhishek Kulkarni <adkulkar@umail.iu.edu>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2
+ * as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to:
+ * Free Software Foundation
+ * 51 Franklin Street, Fifth Floor
+ * Boston, MA 02111-1301 USA
+ *
+ */
+
+#include <linux/jiffies.h>
+#include <linux/file.h>
+#include <linux/stat.h>
+#include <linux/sched.h>
+#include <linux/fs.h>
+#include <net/9p/9p.h>
+
+#include "v9fs.h"
+#include "cache.h"
+
+#define CACHETAG_LEN 11
+
+struct kmem_cache *vcookie_cache;
+
+struct fscache_netfs v9fs_cache_netfs = {
+ .name = "9p",
+ .version = 0,
+};
+
+static void init_once(void *foo)
+{
+ struct v9fs_cookie *vcookie = (struct v9fs_cookie *) foo;
+ vcookie->fscache = NULL;
+ vcookie->qid = NULL;
+ inode_init_once(&vcookie->inode);
+}
+
+/**
+ * v9fs_init_vcookiecache - initialize a cache for vcookies to maintain
+ * vcookie to inode mapping
+ *
+ * Returns 0 on success.
+ */
+
+static int v9fs_init_vcookiecache(void)
+{
+ vcookie_cache = kmem_cache_create("vcookie_cache",
+ sizeof(struct v9fs_cookie),
+ 0, (SLAB_RECLAIM_ACCOUNT|
+ SLAB_MEM_SPREAD),
+ init_once);
+ if (!vcookie_cache)
+ return -ENOMEM;
+
+ return 0;
+}
+
+/**
+ * v9fs_destroy_vcookiecache - destroy the cache of vcookies
+ *
+ */
+
+static void v9fs_destroy_vcookiecache(void)
+{
+ kmem_cache_destroy(vcookie_cache);
+}
+
+int __v9fs_cache_register(void)
+{
+ int ret;
+ ret = v9fs_init_vcookiecache();
+ if (ret < 0)
+ return ret;
+
+ return fscache_register_netfs(&v9fs_cache_netfs);
+}
+
+void __v9fs_cache_unregister(void)
+{
+ v9fs_destroy_vcookiecache();
+ fscache_unregister_netfs(&v9fs_cache_netfs);
+}
+
+/**
+ * v9fs_random_cachetag - Generate a random tag to be associated
+ * with a new cache session.
+ *
+ * The value of jiffies is used for a fairly randomly cache tag.
+ */
+
+static
+int v9fs_random_cachetag(struct v9fs_session_info *v9ses)
+{
+ v9ses->cachetag = kmalloc(CACHETAG_LEN, GFP_KERNEL);
+ if (!v9ses->cachetag)
+ return -ENOMEM;
+
+ return scnprintf(v9ses->cachetag, CACHETAG_LEN, "%lu", jiffies);
+}
+
+static uint16_t v9fs_cache_session_get_key(const void *cookie_netfs_data,
+ void *buffer, uint16_t bufmax)
+{
+ struct v9fs_session_info *v9ses;
+ uint16_t klen = 0;
+
+ v9ses = (struct v9fs_session_info *)cookie_netfs_data;
+ P9_DPRINTK(P9_DEBUG_FSC, "session %p buf %p size %u", v9ses,
+ buffer, bufmax);
+
+ if (v9ses->cachetag)
+ klen = strlen(v9ses->cachetag);
+
+ if (klen > bufmax)
+ return 0;
+
+ memcpy(buffer, v9ses->cachetag, klen);
+ P9_DPRINTK(P9_DEBUG_FSC, "cache session tag %s", v9ses->cachetag);
+ return klen;
+}
+
+const struct fscache_cookie_def v9fs_cache_session_index_def = {
+ .name = "9P.session",
+ .type = FSCACHE_COOKIE_TYPE_INDEX,
+ .get_key = v9fs_cache_session_get_key,
+};
+
+void v9fs_cache_session_get_cookie(struct v9fs_session_info *v9ses)
+{
+ /* If no cache session tag was specified, we generate a random one. */
+ if (!v9ses->cachetag)
+ v9fs_random_cachetag(v9ses);
+
+ v9ses->fscache = fscache_acquire_cookie(v9fs_cache_netfs.primary_index,
+ &v9fs_cache_session_index_def,
+ v9ses);
+ P9_DPRINTK(P9_DEBUG_FSC, "session %p get cookie %p", v9ses,
+ v9ses->fscache);
+}
+
+void v9fs_cache_session_put_cookie(struct v9fs_session_info *v9ses)
+{
+ P9_DPRINTK(P9_DEBUG_FSC, "session %p put cookie %p", v9ses,
+ v9ses->fscache);
+ fscache_relinquish_cookie(v9ses->fscache, 0);
+ v9ses->fscache = NULL;
+}
+
+
+static uint16_t v9fs_cache_inode_get_key(const void *cookie_netfs_data,
+ void *buffer, uint16_t bufmax)
+{
+ const struct v9fs_cookie *vcookie = cookie_netfs_data;
+ memcpy(buffer, &vcookie->qid->path, sizeof(vcookie->qid->path));
+
+ P9_DPRINTK(P9_DEBUG_FSC, "inode %p get key %llu", &vcookie->inode,
+ vcookie->qid->path);
+ return sizeof(vcookie->qid->path);
+}
+
+static void v9fs_cache_inode_get_attr(const void *cookie_netfs_data,
+ uint64_t *size)
+{
+ const struct v9fs_cookie *vcookie = cookie_netfs_data;
+ *size = i_size_read(&vcookie->inode);
+
+ P9_DPRINTK(P9_DEBUG_FSC, "inode %p get attr %llu", &vcookie->inode,
+ *size);
+}
+
+static uint16_t v9fs_cache_inode_get_aux(const void *cookie_netfs_data,
+ void *buffer, uint16_t buflen)
+{
+ const struct v9fs_cookie *vcookie = cookie_netfs_data;
+ memcpy(buffer, &vcookie->qid->version, sizeof(vcookie->qid->version));
+
+ P9_DPRINTK(P9_DEBUG_FSC, "inode %p get aux %u", &vcookie->inode,
+ vcookie->qid->version);
+ return sizeof(vcookie->qid->version);
+}
+
+static enum
+fscache_checkaux v9fs_cache_inode_check_aux(void *cookie_netfs_data,
+ const void *buffer,
+ uint16_t buflen)
+{
+ const struct v9fs_cookie *vcookie = cookie_netfs_data;
+
+ if (buflen != sizeof(vcookie->qid->version))
+ return FSCACHE_CHECKAUX_OBSOLETE;
+
+ if (memcmp(buffer, &vcookie->qid->version,
+ sizeof(vcookie->qid->version)))
+ return FSCACHE_CHECKAUX_OBSOLETE;
+
+ return FSCACHE_CHECKAUX_OKAY;
+}
+
+static void v9fs_cache_inode_now_uncached(void *cookie_netfs_data)
+{
+ struct v9fs_cookie *vcookie = cookie_netfs_data;
+ struct pagevec pvec;
+ pgoff_t first;
+ int loop, nr_pages;
+
+ pagevec_init(&pvec, 0);
+ first = 0;
+
+ for (;;) {
+ nr_pages = pagevec_lookup(&pvec, vcookie->inode.i_mapping,
+ first,
+ PAGEVEC_SIZE - pagevec_count(&pvec));
+ if (!nr_pages)
+ break;
+
+ for (loop = 0; loop < nr_pages; loop++)
+ ClearPageFsCache(pvec.pages[loop]);
+
+ first = pvec.pages[nr_pages - 1]->index + 1;
+
+ pvec.nr = nr_pages;
+ pagevec_release(&pvec);
+ cond_resched();
+ }
+}
+
+const struct fscache_cookie_def v9fs_cache_inode_index_def = {
+ .name = "9p.inode",
+ .type = FSCACHE_COOKIE_TYPE_DATAFILE,
+ .get_key = v9fs_cache_inode_get_key,
+ .get_attr = v9fs_cache_inode_get_attr,
+ .get_aux = v9fs_cache_inode_get_aux,
+ .check_aux = v9fs_cache_inode_check_aux,
+ .now_uncached = v9fs_cache_inode_now_uncached,
+};
+
+void v9fs_cache_inode_get_cookie(struct inode *inode)
+{
+ struct v9fs_cookie *vcookie;
+ struct v9fs_session_info *v9ses;
+
+ if (!S_ISREG(inode->i_mode))
+ return;
+
+ vcookie = v9fs_inode2cookie(inode);
+ if (vcookie->fscache)
+ return;
+
+ v9ses = v9fs_inode2v9ses(inode);
+ vcookie->fscache = fscache_acquire_cookie(v9ses->fscache,
+ &v9fs_cache_inode_index_def,
+ vcookie);
+
+ P9_DPRINTK(P9_DEBUG_FSC, "inode %p get cookie %p", inode,
+ vcookie->fscache);
+}
+
+void v9fs_cache_inode_put_cookie(struct inode *inode)
+{
+ struct v9fs_cookie *vcookie = v9fs_inode2cookie(inode);
+
+ if (!vcookie->fscache)
+ return;
+ P9_DPRINTK(P9_DEBUG_FSC, "inode %p put cookie %p", inode,
+ vcookie->fscache);
+
+ fscache_relinquish_cookie(vcookie->fscache, 0);
+ vcookie->fscache = NULL;
+}
+
+void v9fs_cache_inode_flush_cookie(struct inode *inode)
+{
+ struct v9fs_cookie *vcookie = v9fs_inode2cookie(inode);
+
+ if (!vcookie->fscache)
+ return;
+ P9_DPRINTK(P9_DEBUG_FSC, "inode %p flush cookie %p", inode,
+ vcookie->fscache);
+
+ fscache_relinquish_cookie(vcookie->fscache, 1);
+ vcookie->fscache = NULL;
+}
+
+void v9fs_cache_inode_set_cookie(struct inode *inode, struct file *filp)
+{
+ struct v9fs_cookie *vcookie = v9fs_inode2cookie(inode);
+ struct p9_fid *fid;
+
+ if (!vcookie->fscache)
+ return;
+
+ spin_lock(&vcookie->lock);
+ fid = filp->private_data;
+ if ((filp->f_flags & O_ACCMODE) != O_RDONLY)
+ v9fs_cache_inode_flush_cookie(inode);
+ else
+ v9fs_cache_inode_get_cookie(inode);
+
+ spin_unlock(&vcookie->lock);
+}
+
+void v9fs_cache_inode_reset_cookie(struct inode *inode)
+{
+ struct v9fs_cookie *vcookie = v9fs_inode2cookie(inode);
+ struct v9fs_session_info *v9ses;
+ struct fscache_cookie *old;
+
+ if (!vcookie->fscache)
+ return;
+
+ old = vcookie->fscache;
+
+ spin_lock(&vcookie->lock);
+ fscache_relinquish_cookie(vcookie->fscache, 1);
+
+ v9ses = v9fs_inode2v9ses(inode);
+ vcookie->fscache = fscache_acquire_cookie(v9ses->fscache,
+ &v9fs_cache_inode_index_def,
+ vcookie);
+
+ P9_DPRINTK(P9_DEBUG_FSC, "inode %p revalidating cookie old %p new %p",
+ inode, old, vcookie->fscache);
+
+ spin_unlock(&vcookie->lock);
+}
+
+int __v9fs_fscache_release_page(struct page *page, gfp_t gfp)
+{
+ struct inode *inode = page->mapping->host;
+ struct v9fs_cookie *vcookie = v9fs_inode2cookie(inode);
+
+ BUG_ON(!vcookie->fscache);
+
+ if (PageFsCache(page)) {
+ if (fscache_check_page_write(vcookie->fscache, page)) {
+ if (!(gfp & __GFP_WAIT))
+ return 0;
+ fscache_wait_on_page_write(vcookie->fscache, page);
+ }
+
+ fscache_uncache_page(vcookie->fscache, page);
+ ClearPageFsCache(page);
+ }
+
+ return 1;
+}
+
+void __v9fs_fscache_invalidate_page(struct page *page)
+{
+ struct inode *inode = page->mapping->host;
+ struct v9fs_cookie *vcookie = v9fs_inode2cookie(inode);
+
+ BUG_ON(!vcookie->fscache);
+
+ if (PageFsCache(page)) {
+ fscache_wait_on_page_write(vcookie->fscache, page);
+ BUG_ON(!PageLocked(page));
+ fscache_uncache_page(vcookie->fscache, page);
+ ClearPageFsCache(page);
+ }
+}
+
+static void v9fs_vfs_readpage_complete(struct page *page, void *data,
+ int error)
+{
+ if (!error)
+ SetPageUptodate(page);
+
+ unlock_page(page);
+}
+
+/**
+ * __v9fs_readpage_from_fscache - read a page from cache
+ *
+ * Returns 0 if the pages are in cache and a BIO is submitted,
+ * 1 if the pages are not in cache and -error otherwise.
+ */
+
+int __v9fs_readpage_from_fscache(struct inode *inode, struct page *page)
+{
+ int ret;
+ const struct v9fs_cookie *vcookie = v9fs_inode2cookie(inode);
+
+ P9_DPRINTK(P9_DEBUG_FSC, "inode %p page %p", inode, page);
+ if (!vcookie->fscache)
+ return -ENOBUFS;
+
+ ret = fscache_read_or_alloc_page(vcookie->fscache,
+ page,
+ v9fs_vfs_readpage_complete,
+ NULL,
+ GFP_KERNEL);
+ switch (ret) {
+ case -ENOBUFS:
+ case -ENODATA:
+ P9_DPRINTK(P9_DEBUG_FSC, "page/inode not in cache %d", ret);
+ return 1;
+ case 0:
+ P9_DPRINTK(P9_DEBUG_FSC, "BIO submitted");
+ return ret;
+ default:
+ P9_DPRINTK(P9_DEBUG_FSC, "ret %d", ret);
+ return ret;
+ }
+}
+
+/**
+ * __v9fs_readpages_from_fscache - read multiple pages from cache
+ *
+ * Returns 0 if the pages are in cache and a BIO is submitted,
+ * 1 if the pages are not in cache and -error otherwise.
+ */
+
+int __v9fs_readpages_from_fscache(struct inode *inode,
+ struct address_space *mapping,
+ struct list_head *pages,
+ unsigned *nr_pages)
+{
+ int ret;
+ const struct v9fs_cookie *vcookie = v9fs_inode2cookie(inode);
+
+ P9_DPRINTK(P9_DEBUG_FSC, "inode %p pages %u", inode, *nr_pages);
+ if (!vcookie->fscache)
+ return -ENOBUFS;
+
+ ret = fscache_read_or_alloc_pages(vcookie->fscache,
+ mapping, pages, nr_pages,
+ v9fs_vfs_readpage_complete,
+ NULL,
+ mapping_gfp_mask(mapping));
+ switch (ret) {
+ case -ENOBUFS:
+ case -ENODATA:
+ P9_DPRINTK(P9_DEBUG_FSC, "pages/inodes not in cache %d", ret);
+ return 1;
+ case 0:
+ BUG_ON(!list_empty(pages));
+ BUG_ON(*nr_pages != 0);
+ P9_DPRINTK(P9_DEBUG_FSC, "BIO submitted");
+ return ret;
+ default:
+ P9_DPRINTK(P9_DEBUG_FSC, "ret %d", ret);
+ return ret;
+ }
+}
+
+/**
+ * __v9fs_readpage_to_fscache - write a page to the cache
+ *
+ */
+
+void __v9fs_readpage_to_fscache(struct inode *inode, struct page *page)
+{
+ int ret;
+ const struct v9fs_cookie *vcookie = v9fs_inode2cookie(inode);
+
+ P9_DPRINTK(P9_DEBUG_FSC, "inode %p page %p", inode, page);
+ ret = fscache_write_page(vcookie->fscache, page, GFP_KERNEL);
+ P9_DPRINTK(P9_DEBUG_FSC, "ret = %d", ret);
+ if (ret != 0)
+ v9fs_uncache_page(inode, page);
+}
diff --git a/fs/9p/cache.h b/fs/9p/cache.h
new file mode 100644
index 0000000..a94192b
--- /dev/null
+++ b/fs/9p/cache.h
@@ -0,0 +1,176 @@
+/*
+ * V9FS cache definitions.
+ *
+ * Copyright (C) 2009 by Abhishek Kulkarni <adkulkar@umail.iu.edu>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2
+ * as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to:
+ * Free Software Foundation
+ * 51 Franklin Street, Fifth Floor
+ * Boston, MA 02111-1301 USA
+ *
+ */
+
+#ifndef _9P_CACHE_H
+#ifdef CONFIG_9P_FSCACHE
+#include <linux/fscache.h>
+#include <linux/spinlock.h>
+
+extern struct kmem_cache *vcookie_cache;
+
+struct v9fs_cookie {
+ spinlock_t lock;
+ struct inode inode;
+ struct fscache_cookie *fscache;
+ struct p9_qid *qid;
+};
+
+static inline struct v9fs_cookie *v9fs_inode2cookie(const struct inode *inode)
+{
+ return container_of(inode, struct v9fs_cookie, inode);
+}
+
+extern struct fscache_netfs v9fs_cache_netfs;
+extern const struct fscache_cookie_def v9fs_cache_session_index_def;
+extern const struct fscache_cookie_def v9fs_cache_inode_index_def;
+
+extern void v9fs_cache_session_get_cookie(struct v9fs_session_info *v9ses);
+extern void v9fs_cache_session_put_cookie(struct v9fs_session_info *v9ses);
+
+extern void v9fs_cache_inode_get_cookie(struct inode *inode);
+extern void v9fs_cache_inode_put_cookie(struct inode *inode);
+extern void v9fs_cache_inode_flush_cookie(struct inode *inode);
+extern void v9fs_cache_inode_set_cookie(struct inode *inode, struct file *filp);
+extern void v9fs_cache_inode_reset_cookie(struct inode *inode);
+
+extern int __v9fs_cache_register(void);
+extern void __v9fs_cache_unregister(void);
+
+extern int __v9fs_fscache_release_page(struct page *page, gfp_t gfp);
+extern void __v9fs_fscache_invalidate_page(struct page *page);
+extern int __v9fs_readpage_from_fscache(struct inode *inode,
+ struct page *page);
+extern int __v9fs_readpages_from_fscache(struct inode *inode,
+ struct address_space *mapping,
+ struct list_head *pages,
+ unsigned *nr_pages);
+extern void __v9fs_readpage_to_fscache(struct inode *inode, struct page *page);
+
+
+/**
+ * v9fs_cache_register - Register v9fs file system with the cache
+ */
+static inline int v9fs_cache_register(void)
+{
+ return __v9fs_cache_register();
+}
+
+/**
+ * v9fs_cache_unregister - Unregister v9fs from the cache
+ */
+static inline void v9fs_cache_unregister(void)
+{
+ __v9fs_cache_unregister();
+}
+
+static inline int v9fs_fscache_release_page(struct page *page,
+ gfp_t gfp)
+{
+ return __v9fs_fscache_release_page(page, gfp);
+}
+
+static inline void v9fs_fscache_invalidate_page(struct page *page)
+{
+ __v9fs_fscache_invalidate_page(page);
+}
+
+static inline int v9fs_readpage_from_fscache(struct inode *inode,
+ struct page *page)
+{
+ return __v9fs_readpage_from_fscache(inode, page);
+}
+
+static inline int v9fs_readpages_from_fscache(struct inode *inode,
+ struct address_space *mapping,
+ struct list_head *pages,
+ unsigned *nr_pages)
+{
+ return __v9fs_readpages_from_fscache(inode, mapping, pages,
+ nr_pages);
+}
+
+static inline void v9fs_readpage_to_fscache(struct inode *inode,
+ struct page *page)
+{
+ if (PageFsCache(page))
+ __v9fs_readpage_to_fscache(inode, page);
+}
+
+static inline void v9fs_uncache_page(struct inode *inode, struct page *page)
+{
+ struct v9fs_cookie *vcookie = v9fs_inode2cookie(inode);
+ fscache_uncache_page(vcookie->fscache, page);
+ BUG_ON(PageFsCache(page));
+}
+
+static inline void v9fs_vcookie_set_qid(struct inode *inode,
+ struct p9_qid *qid)
+{
+ struct v9fs_cookie *vcookie = v9fs_inode2cookie(inode);
+ spin_lock(&vcookie->lock);
+ vcookie->qid = qid;
+ spin_unlock(&vcookie->lock);
+}
+
+#else /* CONFIG_9P_FSCACHE */
+
+static inline int v9fs_cache_register(void)
+{
+ return 1;
+}
+
+static inline void v9fs_cache_unregister(void) {}
+
+static inline int v9fs_fscache_release_page(struct page *page,
+ gfp_t gfp) {
+ return 1;
+}
+
+static inline void v9fs_fscache_invalidate_page(struct page *page) {}
+
+static inline int v9fs_readpage_from_fscache(struct inode *inode,
+ struct page *page)
+{
+ return -ENOBUFS;
+}
+
+static inline int v9fs_readpages_from_fscache(struct inode *inode,
+ struct address_space *mapping,
+ struct list_head *pages,
+ unsigned *nr_pages)
+{
+ return -ENOBUFS;
+}
+
+static inline void v9fs_readpage_to_fscache(struct inode *inode,
+ struct page *page)
+{}
+
+static inline void v9fs_uncache_page(struct inode *inode, struct page *page)
+{}
+
+static inline void v9fs_vcookie_set_qid(struct inode *inode,
+ struct p9_qid *qid)
+{}
+
+#endif /* CONFIG_9P_FSCACHE */
+#endif /* _9P_CACHE_H */
diff --git a/fs/9p/v9fs.c b/fs/9p/v9fs.c
index f7003cf..cf62b05 100644
--- a/fs/9p/v9fs.c
+++ b/fs/9p/v9fs.c
@@ -34,21 +34,25 @@
#include <net/9p/transport.h>
#include "v9fs.h"
#include "v9fs_vfs.h"
+#include "cache.h"
+
+static DEFINE_SPINLOCK(v9fs_sessionlist_lock);
+static LIST_HEAD(v9fs_sessionlist);
/*
- * Option Parsing (code inspired by NFS code)
- * NOTE: each transport will parse its own options
- */
+ * Option Parsing (code inspired by NFS code)
+ * NOTE: each transport will parse its own options
+ */
enum {
/* Options that take integer arguments */
Opt_debug, Opt_dfltuid, Opt_dfltgid, Opt_afid,
/* String options */
- Opt_uname, Opt_remotename, Opt_trans,
+ Opt_uname, Opt_remotename, Opt_trans, Opt_cache, Opt_cachetag,
/* Options that take no arguments */
Opt_nodevmap,
/* Cache options */
- Opt_cache_loose,
+ Opt_cache_loose, Opt_fscache,
/* Access options */
Opt_access,
/* Error token */
@@ -63,8 +67,10 @@
{Opt_uname, "uname=%s"},
{Opt_remotename, "aname=%s"},
{Opt_nodevmap, "nodevmap"},
- {Opt_cache_loose, "cache=loose"},
+ {Opt_cache, "cache=%s"},
{Opt_cache_loose, "loose"},
+ {Opt_fscache, "fscache"},
+ {Opt_cachetag, "cachetag=%s"},
{Opt_access, "access=%s"},
{Opt_err, NULL}
};
@@ -89,16 +95,16 @@
v9ses->afid = ~0;
v9ses->debug = 0;
v9ses->cache = 0;
+#ifdef CONFIG_9P_FSCACHE
+ v9ses->cachetag = NULL;
+#endif
if (!opts)
return 0;
options = kstrdup(opts, GFP_KERNEL);
- if (!options) {
- P9_DPRINTK(P9_DEBUG_ERROR,
- "failed to allocate copy of option string\n");
- return -ENOMEM;
- }
+ if (!options)
+ goto fail_option_alloc;
while ((p = strsep(&options, ",")) != NULL) {
int token;
@@ -143,16 +149,33 @@
case Opt_cache_loose:
v9ses->cache = CACHE_LOOSE;
break;
+ case Opt_fscache:
+ v9ses->cache = CACHE_FSCACHE;
+ break;
+ case Opt_cachetag:
+#ifdef CONFIG_9P_FSCACHE
+ v9ses->cachetag = match_strdup(&args[0]);
+#endif
+ break;
+ case Opt_cache:
+ s = match_strdup(&args[0]);
+ if (!s)
+ goto fail_option_alloc;
+
+ if (strcmp(s, "loose") == 0)
+ v9ses->cache = CACHE_LOOSE;
+ else if (strcmp(s, "fscache") == 0)
+ v9ses->cache = CACHE_FSCACHE;
+ else
+ v9ses->cache = CACHE_NONE;
+ kfree(s);
+ break;
case Opt_access:
s = match_strdup(&args[0]);
- if (!s) {
- P9_DPRINTK(P9_DEBUG_ERROR,
- "failed to allocate copy"
- " of option argument\n");
- ret = -ENOMEM;
- break;
- }
+ if (!s)
+ goto fail_option_alloc;
+
v9ses->flags &= ~V9FS_ACCESS_MASK;
if (strcmp(s, "user") == 0)
v9ses->flags |= V9FS_ACCESS_USER;
@@ -173,6 +196,11 @@
}
kfree(options);
return ret;
+
+fail_option_alloc:
+ P9_DPRINTK(P9_DEBUG_ERROR,
+ "failed to allocate copy of option argument\n");
+ return -ENOMEM;
}
/**
@@ -200,6 +228,10 @@
return ERR_PTR(-ENOMEM);
}
+ spin_lock(&v9fs_sessionlist_lock);
+ list_add(&v9ses->slist, &v9fs_sessionlist);
+ spin_unlock(&v9fs_sessionlist_lock);
+
v9ses->flags = V9FS_EXTENDED | V9FS_ACCESS_USER;
strcpy(v9ses->uname, V9FS_DEFUSER);
strcpy(v9ses->aname, V9FS_DEFANAME);
@@ -249,6 +281,11 @@
else
fid->uid = ~0;
+#ifdef CONFIG_9P_FSCACHE
+ /* register the session for caching */
+ v9fs_cache_session_get_cookie(v9ses);
+#endif
+
return fid;
error:
@@ -268,8 +305,18 @@
v9ses->clnt = NULL;
}
+#ifdef CONFIG_9P_FSCACHE
+ if (v9ses->fscache) {
+ v9fs_cache_session_put_cookie(v9ses);
+ kfree(v9ses->cachetag);
+ }
+#endif
__putname(v9ses->uname);
__putname(v9ses->aname);
+
+ spin_lock(&v9fs_sessionlist_lock);
+ list_del(&v9ses->slist);
+ spin_unlock(&v9fs_sessionlist_lock);
}
/**
@@ -286,25 +333,132 @@
extern int v9fs_error_init(void);
+static struct kobject *v9fs_kobj;
+
+#ifdef CONFIG_9P_FSCACHE
/**
- * v9fs_init - Initialize module
+ * caches_show - list caches associated with a session
+ *
+ * Returns the size of buffer written.
+ */
+
+static ssize_t caches_show(struct kobject *kobj,
+ struct kobj_attribute *attr,
+ char *buf)
+{
+ ssize_t n = 0, count = 0, limit = PAGE_SIZE;
+ struct v9fs_session_info *v9ses;
+
+ spin_lock(&v9fs_sessionlist_lock);
+ list_for_each_entry(v9ses, &v9fs_sessionlist, slist) {
+ if (v9ses->cachetag) {
+ n = snprintf(buf, limit, "%s\n", v9ses->cachetag);
+ if (n < 0) {
+ count = n;
+ break;
+ }
+
+ count += n;
+ limit -= n;
+ }
+ }
+
+ spin_unlock(&v9fs_sessionlist_lock);
+ return count;
+}
+
+static struct kobj_attribute v9fs_attr_cache = __ATTR_RO(caches);
+#endif /* CONFIG_9P_FSCACHE */
+
+static struct attribute *v9fs_attrs[] = {
+#ifdef CONFIG_9P_FSCACHE
+ &v9fs_attr_cache.attr,
+#endif
+ NULL,
+};
+
+static struct attribute_group v9fs_attr_group = {
+ .attrs = v9fs_attrs,
+};
+
+/**
+ * v9fs_sysfs_init - Initialize the v9fs sysfs interface
+ *
+ */
+
+static int v9fs_sysfs_init(void)
+{
+ v9fs_kobj = kobject_create_and_add("9p", fs_kobj);
+ if (!v9fs_kobj)
+ return -ENOMEM;
+
+ if (sysfs_create_group(v9fs_kobj, &v9fs_attr_group)) {
+ kobject_put(v9fs_kobj);
+ return -ENOMEM;
+ }
+
+ return 0;
+}
+
+/**
+ * v9fs_sysfs_cleanup - Unregister the v9fs sysfs interface
+ *
+ */
+
+static void v9fs_sysfs_cleanup(void)
+{
+ sysfs_remove_group(v9fs_kobj, &v9fs_attr_group);
+ kobject_put(v9fs_kobj);
+}
+
+/**
+ * init_v9fs - Initialize module
*
*/
static int __init init_v9fs(void)
{
+ int err;
printk(KERN_INFO "Installing v9fs 9p2000 file system support\n");
/* TODO: Setup list of registered trasnport modules */
- return register_filesystem(&v9fs_fs_type);
+ err = register_filesystem(&v9fs_fs_type);
+ if (err < 0) {
+ printk(KERN_ERR "Failed to register filesystem\n");
+ return err;
+ }
+
+ err = v9fs_cache_register();
+ if (err < 0) {
+ printk(KERN_ERR "Failed to register v9fs for caching\n");
+ goto out_fs_unreg;
+ }
+
+ err = v9fs_sysfs_init();
+ if (err < 0) {
+ printk(KERN_ERR "Failed to register with sysfs\n");
+ goto out_sysfs_cleanup;
+ }
+
+ return 0;
+
+out_sysfs_cleanup:
+ v9fs_sysfs_cleanup();
+
+out_fs_unreg:
+ unregister_filesystem(&v9fs_fs_type);
+
+ return err;
}
/**
- * v9fs_init - shutdown module
+ * exit_v9fs - shutdown module
*
*/
static void __exit exit_v9fs(void)
{
+ v9fs_sysfs_cleanup();
+ v9fs_cache_unregister();
unregister_filesystem(&v9fs_fs_type);
}
diff --git a/fs/9p/v9fs.h b/fs/9p/v9fs.h
index 38762bf..019f4cc 100644
--- a/fs/9p/v9fs.h
+++ b/fs/9p/v9fs.h
@@ -51,6 +51,7 @@
enum p9_cache_modes {
CACHE_NONE,
CACHE_LOOSE,
+ CACHE_FSCACHE,
};
/**
@@ -60,6 +61,8 @@
* @debug: debug level
* @afid: authentication handle
* @cache: cache mode of type &p9_cache_modes
+ * @cachetag: the tag of the cache associated with this session
+ * @fscache: session cookie associated with FS-Cache
* @options: copy of options string given by user
* @uname: string user name to mount hierarchy as
* @aname: mount specifier for remote hierarchy
@@ -68,7 +71,7 @@
* @dfltgid: default numeric groupid to mount hierarchy as
* @uid: if %V9FS_ACCESS_SINGLE, the numeric uid which mounted the hierarchy
* @clnt: reference to 9P network client instantiated for this session
- * @debugfs_dir: reference to debugfs_dir which can be used for add'l debug
+ * @slist: reference to list of registered 9p sessions
*
* This structure holds state for each session instance established during
* a sys_mount() .
@@ -84,6 +87,10 @@
unsigned short debug;
unsigned int afid;
unsigned int cache;
+#ifdef CONFIG_9P_FSCACHE
+ char *cachetag;
+ struct fscache_cookie *fscache;
+#endif
char *uname; /* user name to mount as */
char *aname; /* name of remote hierarchy being mounted */
@@ -92,11 +99,9 @@
unsigned int dfltgid; /* default gid for legacy support */
u32 uid; /* if ACCESS_SINGLE, the uid that has access */
struct p9_client *clnt; /* 9p client */
- struct dentry *debugfs_dir;
+ struct list_head slist; /* list of sessions registered with v9fs */
};
-extern struct dentry *v9fs_debugfs_root;
-
struct p9_fid *v9fs_session_init(struct v9fs_session_info *, const char *,
char *);
void v9fs_session_close(struct v9fs_session_info *v9ses);
diff --git a/fs/9p/v9fs_vfs.h b/fs/9p/v9fs_vfs.h
index f0c7de7..3a7560e 100644
--- a/fs/9p/v9fs_vfs.h
+++ b/fs/9p/v9fs_vfs.h
@@ -44,7 +44,13 @@
extern const struct dentry_operations v9fs_dentry_operations;
extern const struct dentry_operations v9fs_cached_dentry_operations;
+#ifdef CONFIG_9P_FSCACHE
+struct inode *v9fs_alloc_inode(struct super_block *sb);
+void v9fs_destroy_inode(struct inode *inode);
+#endif
+
struct inode *v9fs_get_inode(struct super_block *sb, int mode);
+void v9fs_clear_inode(struct inode *inode);
ino_t v9fs_qid2ino(struct p9_qid *qid);
void v9fs_stat2inode(struct p9_wstat *, struct inode *, struct super_block *);
int v9fs_dir_release(struct inode *inode, struct file *filp);
diff --git a/fs/9p/vfs_addr.c b/fs/9p/vfs_addr.c
index 9282828..90e3844 100644
--- a/fs/9p/vfs_addr.c
+++ b/fs/9p/vfs_addr.c
@@ -38,6 +38,7 @@
#include "v9fs.h"
#include "v9fs_vfs.h"
+#include "cache.h"
/**
* v9fs_vfs_readpage - read an entire page in from 9P
@@ -52,18 +53,31 @@
int retval;
loff_t offset;
char *buffer;
+ struct inode *inode;
+ inode = page->mapping->host;
P9_DPRINTK(P9_DEBUG_VFS, "\n");
+
+ BUG_ON(!PageLocked(page));
+
+ retval = v9fs_readpage_from_fscache(inode, page);
+ if (retval == 0)
+ return retval;
+
buffer = kmap(page);
offset = page_offset(page);
retval = v9fs_file_readn(filp, buffer, NULL, PAGE_CACHE_SIZE, offset);
- if (retval < 0)
+ if (retval < 0) {
+ v9fs_uncache_page(inode, page);
goto done;
+ }
memset(buffer + retval, 0, PAGE_CACHE_SIZE - retval);
flush_dcache_page(page);
SetPageUptodate(page);
+
+ v9fs_readpage_to_fscache(inode, page);
retval = 0;
done:
@@ -72,6 +86,78 @@
return retval;
}
+/**
+ * v9fs_vfs_readpages - read a set of pages from 9P
+ *
+ * @filp: file being read
+ * @mapping: the address space
+ * @pages: list of pages to read
+ * @nr_pages: count of pages to read
+ *
+ */
+
+static int v9fs_vfs_readpages(struct file *filp, struct address_space *mapping,
+ struct list_head *pages, unsigned nr_pages)
+{
+ int ret = 0;
+ struct inode *inode;
+
+ inode = mapping->host;
+ P9_DPRINTK(P9_DEBUG_VFS, "inode: %p file: %p\n", inode, filp);
+
+ ret = v9fs_readpages_from_fscache(inode, mapping, pages, &nr_pages);
+ if (ret == 0)
+ return ret;
+
+ ret = read_cache_pages(mapping, pages, (void *)v9fs_vfs_readpage, filp);
+ P9_DPRINTK(P9_DEBUG_VFS, " = %d\n", ret);
+ return ret;
+}
+
+/**
+ * v9fs_release_page - release the private state associated with a page
+ *
+ * Returns 1 if the page can be released, false otherwise.
+ */
+
+static int v9fs_release_page(struct page *page, gfp_t gfp)
+{
+ if (PagePrivate(page))
+ return 0;
+
+ return v9fs_fscache_release_page(page, gfp);
+}
+
+/**
+ * v9fs_invalidate_page - Invalidate a page completely or partially
+ *
+ * @page: structure to page
+ * @offset: offset in the page
+ */
+
+static void v9fs_invalidate_page(struct page *page, unsigned long offset)
+{
+ if (offset == 0)
+ v9fs_fscache_invalidate_page(page);
+}
+
+/**
+ * v9fs_launder_page - Writeback a dirty page
+ * Since the writes go directly to the server, we simply return a 0
+ * here to indicate success.
+ *
+ * Returns 0 on success.
+ */
+
+static int v9fs_launder_page(struct page *page)
+{
+ return 0;
+}
+
const struct address_space_operations v9fs_addr_operations = {
.readpage = v9fs_vfs_readpage,
+ .readpages = v9fs_vfs_readpages,
+ .releasepage = v9fs_release_page,
+ .invalidatepage = v9fs_invalidate_page,
+ .launder_page = v9fs_launder_page,
};
diff --git a/fs/9p/vfs_file.c b/fs/9p/vfs_file.c
index cafaa46..3902bf4 100644
--- a/fs/9p/vfs_file.c
+++ b/fs/9p/vfs_file.c
@@ -41,6 +41,7 @@
#include "v9fs.h"
#include "v9fs_vfs.h"
#include "fid.h"
+#include "cache.h"
static const struct file_operations v9fs_cached_file_operations;
@@ -86,6 +87,10 @@
/* enable cached file options */
if(file->f_op == &v9fs_file_operations)
file->f_op = &v9fs_cached_file_operations;
+
+#ifdef CONFIG_9P_FSCACHE
+ v9fs_cache_inode_set_cookie(inode, file);
+#endif
}
return 0;
@@ -238,8 +243,9 @@
if (total > 0) {
pg_start = origin >> PAGE_CACHE_SHIFT;
pg_end = (origin + total - 1) >> PAGE_CACHE_SHIFT;
- invalidate_inode_pages2_range(inode->i_mapping, pg_start,
- pg_end);
+ if (inode->i_mapping && inode->i_mapping->nrpages)
+ invalidate_inode_pages2_range(inode->i_mapping,
+ pg_start, pg_end);
*offset += total;
i_size_write(inode, i_size_read(inode) + total);
inode->i_blocks = (i_size_read(inode) + 512 - 1) >> 9;
diff --git a/fs/9p/vfs_inode.c b/fs/9p/vfs_inode.c
index f3bfa87..5947628a 100644
--- a/fs/9p/vfs_inode.c
+++ b/fs/9p/vfs_inode.c
@@ -40,6 +40,7 @@
#include "v9fs.h"
#include "v9fs_vfs.h"
#include "fid.h"
+#include "cache.h"
static const struct inode_operations v9fs_dir_inode_operations;
static const struct inode_operations v9fs_dir_inode_operations_ext;
@@ -197,6 +198,39 @@
wstat->extension = NULL;
}
+#ifdef CONFIG_9P_FSCACHE
+/**
+ * v9fs_alloc_inode - helper function to allocate an inode
+ * This callback is executed before setting up the inode so that we
+ * can associate a vcookie with each inode.
+ *
+ */
+
+struct inode *v9fs_alloc_inode(struct super_block *sb)
+{
+ struct v9fs_cookie *vcookie;
+ vcookie = (struct v9fs_cookie *)kmem_cache_alloc(vcookie_cache,
+ GFP_KERNEL);
+ if (!vcookie)
+ return NULL;
+
+ vcookie->fscache = NULL;
+ vcookie->qid = NULL;
+ spin_lock_init(&vcookie->lock);
+ return &vcookie->inode;
+}
+
+/**
+ * v9fs_destroy_inode - destroy an inode
+ *
+ */
+
+void v9fs_destroy_inode(struct inode *inode)
+{
+ kmem_cache_free(vcookie_cache, v9fs_inode2cookie(inode));
+}
+#endif
+
/**
* v9fs_get_inode - helper function to setup an inode
* @sb: superblock
@@ -326,6 +360,21 @@
}
*/
+
+/**
+ * v9fs_clear_inode - release an inode
+ * @inode: inode to release
+ *
+ */
+void v9fs_clear_inode(struct inode *inode)
+{
+ filemap_fdatawrite(inode->i_mapping);
+
+#ifdef CONFIG_9P_FSCACHE
+ v9fs_cache_inode_put_cookie(inode);
+#endif
+}
+
/**
* v9fs_inode_from_fid - populate an inode by issuing a attribute request
* @v9ses: session information
@@ -356,8 +405,14 @@
v9fs_stat2inode(st, ret, sb);
ret->i_ino = v9fs_qid2ino(&st->qid);
+
+#ifdef CONFIG_9P_FSCACHE
+ v9fs_vcookie_set_qid(ret, &st->qid);
+ v9fs_cache_inode_get_cookie(ret);
+#endif
p9stat_free(st);
kfree(st);
+
return ret;
error:
@@ -751,7 +806,7 @@
P9_DPRINTK(P9_DEBUG_VFS, "dentry: %p\n", dentry);
err = -EPERM;
v9ses = v9fs_inode2v9ses(dentry->d_inode);
- if (v9ses->cache == CACHE_LOOSE)
+ if (v9ses->cache == CACHE_LOOSE || v9ses->cache == CACHE_FSCACHE)
return simple_getattr(mnt, dentry, stat);
fid = v9fs_fid_lookup(dentry);
diff --git a/fs/9p/vfs_super.c b/fs/9p/vfs_super.c
index 8961f1a..14a86448 100644
--- a/fs/9p/vfs_super.c
+++ b/fs/9p/vfs_super.c
@@ -44,21 +44,9 @@
#include "v9fs_vfs.h"
#include "fid.h"
-static void v9fs_clear_inode(struct inode *);
static const struct super_operations v9fs_super_ops;
/**
- * v9fs_clear_inode - release an inode
- * @inode: inode to release
- *
- */
-
-static void v9fs_clear_inode(struct inode *inode)
-{
- filemap_fdatawrite(inode->i_mapping);
-}
-
-/**
* v9fs_set_super - set the superblock
* @s: super block
* @data: file system specific data
@@ -220,6 +208,10 @@
}
static const struct super_operations v9fs_super_ops = {
+#ifdef CONFIG_9P_FSCACHE
+ .alloc_inode = v9fs_alloc_inode,
+ .destroy_inode = v9fs_destroy_inode,
+#endif
.statfs = simple_statfs,
.clear_inode = v9fs_clear_inode,
.show_options = generic_show_options,
diff --git a/include/net/9p/9p.h b/include/net/9p/9p.h
index b77c147..a7fb548 100644
--- a/include/net/9p/9p.h
+++ b/include/net/9p/9p.h
@@ -38,6 +38,8 @@
* @P9_DEBUG_SLABS: memory management tracing
* @P9_DEBUG_FCALL: verbose dump of protocol messages
* @P9_DEBUG_FID: fid allocation/deallocation tracking
+ * @P9_DEBUG_PKT: packet marshalling/unmarshalling
+ * @P9_DEBUG_FSC: FS-cache tracing
*
* These flags are passed at mount time to turn on various levels of
* verbosity and tracing which will be output to the system logs.
@@ -54,6 +56,7 @@
P9_DEBUG_FCALL = (1<<8),
P9_DEBUG_FID = (1<<9),
P9_DEBUG_PKT = (1<<10),
+ P9_DEBUG_FSC = (1<<11),
};
#ifdef CONFIG_NET_9P_DEBUG
