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https://github.com/Fishwaldo/Star64_linux.git
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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>
This commit is contained in:
Abhishek Kulkarni
Eric Van Hensbergen
parent
637d020a02
commit
60e78d2c99
12 changed files with 1009 additions and 42 deletions
196
fs/9p/v9fs.c
196
fs/9p/v9fs.c
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@ -34,21 +34,25 @@
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#include <net/9p/transport.h>
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#include "v9fs.h"
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#include "v9fs_vfs.h"
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#include "cache.h"
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static DEFINE_SPINLOCK(v9fs_sessionlist_lock);
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static LIST_HEAD(v9fs_sessionlist);
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/*
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* Option Parsing (code inspired by NFS code)
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* NOTE: each transport will parse its own options
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*/
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* Option Parsing (code inspired by NFS code)
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* NOTE: each transport will parse its own options
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*/
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enum {
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/* Options that take integer arguments */
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Opt_debug, Opt_dfltuid, Opt_dfltgid, Opt_afid,
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/* String options */
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Opt_uname, Opt_remotename, Opt_trans,
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Opt_uname, Opt_remotename, Opt_trans, Opt_cache, Opt_cachetag,
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/* Options that take no arguments */
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Opt_nodevmap,
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/* Cache options */
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Opt_cache_loose,
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Opt_cache_loose, Opt_fscache,
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/* Access options */
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Opt_access,
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/* Error token */
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@ -63,8 +67,10 @@ static const match_table_t tokens = {
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{Opt_uname, "uname=%s"},
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{Opt_remotename, "aname=%s"},
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{Opt_nodevmap, "nodevmap"},
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{Opt_cache_loose, "cache=loose"},
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{Opt_cache, "cache=%s"},
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{Opt_cache_loose, "loose"},
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{Opt_fscache, "fscache"},
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{Opt_cachetag, "cachetag=%s"},
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{Opt_access, "access=%s"},
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{Opt_err, NULL}
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};
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@ -89,16 +95,16 @@ static int v9fs_parse_options(struct v9fs_session_info *v9ses, char *opts)
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v9ses->afid = ~0;
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v9ses->debug = 0;
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v9ses->cache = 0;
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#ifdef CONFIG_9P_FSCACHE
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v9ses->cachetag = NULL;
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#endif
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if (!opts)
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return 0;
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options = kstrdup(opts, GFP_KERNEL);
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if (!options) {
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P9_DPRINTK(P9_DEBUG_ERROR,
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"failed to allocate copy of option string\n");
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return -ENOMEM;
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}
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if (!options)
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goto fail_option_alloc;
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while ((p = strsep(&options, ",")) != NULL) {
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int token;
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@ -143,16 +149,33 @@ static int v9fs_parse_options(struct v9fs_session_info *v9ses, char *opts)
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case Opt_cache_loose:
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v9ses->cache = CACHE_LOOSE;
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break;
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case Opt_fscache:
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v9ses->cache = CACHE_FSCACHE;
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break;
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case Opt_cachetag:
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#ifdef CONFIG_9P_FSCACHE
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v9ses->cachetag = match_strdup(&args[0]);
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#endif
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break;
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case Opt_cache:
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s = match_strdup(&args[0]);
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if (!s)
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goto fail_option_alloc;
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if (strcmp(s, "loose") == 0)
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v9ses->cache = CACHE_LOOSE;
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else if (strcmp(s, "fscache") == 0)
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v9ses->cache = CACHE_FSCACHE;
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else
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v9ses->cache = CACHE_NONE;
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kfree(s);
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break;
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case Opt_access:
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s = match_strdup(&args[0]);
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if (!s) {
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P9_DPRINTK(P9_DEBUG_ERROR,
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"failed to allocate copy"
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" of option argument\n");
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ret = -ENOMEM;
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break;
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}
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if (!s)
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goto fail_option_alloc;
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v9ses->flags &= ~V9FS_ACCESS_MASK;
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if (strcmp(s, "user") == 0)
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v9ses->flags |= V9FS_ACCESS_USER;
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@ -173,6 +196,11 @@ static int v9fs_parse_options(struct v9fs_session_info *v9ses, char *opts)
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}
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kfree(options);
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return ret;
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fail_option_alloc:
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P9_DPRINTK(P9_DEBUG_ERROR,
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"failed to allocate copy of option argument\n");
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return -ENOMEM;
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}
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/**
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@ -200,6 +228,10 @@ struct p9_fid *v9fs_session_init(struct v9fs_session_info *v9ses,
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return ERR_PTR(-ENOMEM);
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}
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spin_lock(&v9fs_sessionlist_lock);
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list_add(&v9ses->slist, &v9fs_sessionlist);
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spin_unlock(&v9fs_sessionlist_lock);
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v9ses->flags = V9FS_EXTENDED | V9FS_ACCESS_USER;
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strcpy(v9ses->uname, V9FS_DEFUSER);
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strcpy(v9ses->aname, V9FS_DEFANAME);
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@ -249,6 +281,11 @@ struct p9_fid *v9fs_session_init(struct v9fs_session_info *v9ses,
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else
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fid->uid = ~0;
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#ifdef CONFIG_9P_FSCACHE
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/* register the session for caching */
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v9fs_cache_session_get_cookie(v9ses);
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#endif
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return fid;
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error:
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@ -268,8 +305,18 @@ void v9fs_session_close(struct v9fs_session_info *v9ses)
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v9ses->clnt = NULL;
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}
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#ifdef CONFIG_9P_FSCACHE
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if (v9ses->fscache) {
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v9fs_cache_session_put_cookie(v9ses);
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kfree(v9ses->cachetag);
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}
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#endif
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__putname(v9ses->uname);
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__putname(v9ses->aname);
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spin_lock(&v9fs_sessionlist_lock);
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list_del(&v9ses->slist);
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spin_unlock(&v9fs_sessionlist_lock);
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}
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/**
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@ -286,25 +333,132 @@ void v9fs_session_cancel(struct v9fs_session_info *v9ses) {
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extern int v9fs_error_init(void);
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static struct kobject *v9fs_kobj;
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#ifdef CONFIG_9P_FSCACHE
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/**
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* v9fs_init - Initialize module
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* caches_show - list caches associated with a session
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*
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* Returns the size of buffer written.
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*/
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static ssize_t caches_show(struct kobject *kobj,
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struct kobj_attribute *attr,
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char *buf)
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{
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ssize_t n = 0, count = 0, limit = PAGE_SIZE;
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struct v9fs_session_info *v9ses;
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spin_lock(&v9fs_sessionlist_lock);
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list_for_each_entry(v9ses, &v9fs_sessionlist, slist) {
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if (v9ses->cachetag) {
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n = snprintf(buf, limit, "%s\n", v9ses->cachetag);
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if (n < 0) {
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count = n;
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break;
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}
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count += n;
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limit -= n;
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}
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}
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spin_unlock(&v9fs_sessionlist_lock);
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return count;
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}
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static struct kobj_attribute v9fs_attr_cache = __ATTR_RO(caches);
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#endif /* CONFIG_9P_FSCACHE */
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static struct attribute *v9fs_attrs[] = {
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#ifdef CONFIG_9P_FSCACHE
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&v9fs_attr_cache.attr,
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#endif
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NULL,
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};
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static struct attribute_group v9fs_attr_group = {
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.attrs = v9fs_attrs,
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};
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/**
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* v9fs_sysfs_init - Initialize the v9fs sysfs interface
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*
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*/
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static int v9fs_sysfs_init(void)
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{
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v9fs_kobj = kobject_create_and_add("9p", fs_kobj);
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if (!v9fs_kobj)
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return -ENOMEM;
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if (sysfs_create_group(v9fs_kobj, &v9fs_attr_group)) {
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kobject_put(v9fs_kobj);
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return -ENOMEM;
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}
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return 0;
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}
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/**
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* v9fs_sysfs_cleanup - Unregister the v9fs sysfs interface
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*
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*/
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static void v9fs_sysfs_cleanup(void)
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{
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sysfs_remove_group(v9fs_kobj, &v9fs_attr_group);
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kobject_put(v9fs_kobj);
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}
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/**
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* init_v9fs - Initialize module
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*
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*/
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static int __init init_v9fs(void)
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{
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int err;
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printk(KERN_INFO "Installing v9fs 9p2000 file system support\n");
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/* TODO: Setup list of registered trasnport modules */
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return register_filesystem(&v9fs_fs_type);
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err = register_filesystem(&v9fs_fs_type);
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if (err < 0) {
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printk(KERN_ERR "Failed to register filesystem\n");
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return err;
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}
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err = v9fs_cache_register();
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if (err < 0) {
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printk(KERN_ERR "Failed to register v9fs for caching\n");
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goto out_fs_unreg;
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}
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err = v9fs_sysfs_init();
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if (err < 0) {
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printk(KERN_ERR "Failed to register with sysfs\n");
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goto out_sysfs_cleanup;
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}
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return 0;
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out_sysfs_cleanup:
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v9fs_sysfs_cleanup();
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out_fs_unreg:
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unregister_filesystem(&v9fs_fs_type);
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return err;
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}
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/**
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* v9fs_init - shutdown module
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* exit_v9fs - shutdown module
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*
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*/
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static void __exit exit_v9fs(void)
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{
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v9fs_sysfs_cleanup();
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v9fs_cache_unregister();
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unregister_filesystem(&v9fs_fs_type);
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}
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