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-rw-r--r--xlators/performance/symlink-cache/src/symlink-cache.c399
1 files changed, 399 insertions, 0 deletions
diff --git a/xlators/performance/symlink-cache/src/symlink-cache.c b/xlators/performance/symlink-cache/src/symlink-cache.c
new file mode 100644
index 00000000000..fc207a6272e
--- /dev/null
+++ b/xlators/performance/symlink-cache/src/symlink-cache.c
@@ -0,0 +1,399 @@
+/*
+ Copyright (c) 2008 Z RESEARCH, Inc. <http://www.zresearch.com>
+ This file is part of GlusterFS.
+
+ GlusterFS is free software; you can redistribute it and/or modify
+ it under the terms of the GNU General Public License as published
+ by the Free Software Foundation; either version 3 of the License,
+ or (at your option) any later version.
+
+ GlusterFS 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, see
+ <http://www.gnu.org/licenses/>.
+*/
+
+
+#ifndef _CONFIG_H
+#define _CONFIG_H
+#include "config.h"
+#endif
+
+#include "glusterfs.h"
+#include "logging.h"
+#include "dict.h"
+#include "xlator.h"
+#include "list.h"
+#include "compat.h"
+#include "compat-errno.h"
+#include "common-utils.h"
+
+struct symlink_cache {
+ time_t ctime;
+ char *readlink;
+};
+
+
+static int
+symlink_inode_ctx_get (inode_t *inode, xlator_t *this, void **ctx)
+{
+ int ret = 0;
+ uint64_t tmp_ctx = 0;
+ ret = inode_ctx_get (inode, this, &tmp_ctx);
+ if (-1 == ret)
+ gf_log (this->name, GF_LOG_ERROR, "dict get failed");
+ else
+ *ctx = (void *)(long)tmp_ctx;
+
+ return 0;
+}
+
+
+static int
+symlink_inode_ctx_set (inode_t *inode, xlator_t *this, void *ctx)
+{
+ int ret = 0;
+ ret = inode_ctx_put (inode, this, (uint64_t)(long) ctx);
+ if (-1 == ret)
+ gf_log (this->name, GF_LOG_ERROR, "dict set failed");
+
+ return 0;
+}
+
+
+int
+sc_cache_update (xlator_t *this, inode_t *inode, const char *link)
+{
+ struct symlink_cache *sc = NULL;
+
+ symlink_inode_ctx_get (inode, this, VOID(&sc));
+ if (!sc)
+ return 0;
+
+ if (!sc->readlink) {
+ gf_log (this->name, GF_LOG_DEBUG,
+ "updating cache: %s", link);
+
+ sc->readlink = strdup (link);
+ } else {
+ gf_log (this->name, GF_LOG_DEBUG,
+ "not updating existing cache: %s with %s",
+ sc->readlink, link);
+ }
+
+ return 0;
+}
+
+
+int
+sc_cache_set (xlator_t *this, inode_t *inode, struct stat *buf,
+ const char *link)
+{
+ struct symlink_cache *sc = NULL;
+ int ret = -1;
+ int need_set = 0;
+
+
+ symlink_inode_ctx_get (inode, this, VOID(&sc));
+ if (!sc) {
+ need_set = 1;
+ sc = CALLOC (1, sizeof (*sc));
+ if (!sc) {
+ gf_log (this->name, GF_LOG_ERROR,
+ "out of memory :(");
+ goto err;
+ }
+ }
+
+ if (sc->readlink) {
+ gf_log (this->name, GF_LOG_DEBUG,
+ "replacing old cache: %s with new cache: %s",
+ sc->readlink, link);
+ FREE (sc->readlink);
+ sc->readlink = NULL;
+ }
+
+ if (link) {
+ sc->readlink = strdup (link);
+ if (!sc->readlink) {
+ gf_log (this->name, GF_LOG_ERROR,
+ "out of memory :(");
+ goto err;
+ }
+ }
+
+ sc->ctime = buf->st_ctime;
+
+ gf_log (this->name, GF_LOG_DEBUG,
+ "setting symlink cache: %s", link);
+
+ if (need_set) {
+ ret = symlink_inode_ctx_set (inode, this, sc);
+
+ if (ret < 0) {
+ gf_log (this->name, GF_LOG_ERROR,
+ "could not set inode context (%s)",
+ strerror (-ret));
+ goto err;
+ }
+ }
+
+ return 0;
+err:
+
+ if (sc) {
+ if (sc->readlink)
+ FREE (sc->readlink);
+ sc->readlink = NULL;
+ FREE (sc);
+ }
+
+ return -1;
+}
+
+
+int
+sc_cache_flush (xlator_t *this, inode_t *inode)
+{
+ struct symlink_cache *sc = NULL;
+
+ symlink_inode_ctx_get (inode, this, VOID(&sc));
+ if (!sc)
+ return 0;
+
+ if (sc->readlink) {
+ gf_log (this->name, GF_LOG_DEBUG,
+ "flushing cache: %s", sc->readlink);
+
+ FREE (sc->readlink);
+ sc->readlink = NULL;
+ }
+
+ FREE (sc);
+
+ return 0;
+}
+
+
+int
+sc_cache_validate (xlator_t *this, inode_t *inode, struct stat *buf)
+{
+ struct symlink_cache *sc = NULL;
+ uint64_t tmp_sc = 0;
+
+ if (!S_ISLNK (buf->st_mode)) {
+ sc_cache_flush (this, inode);
+ return 0;
+ }
+
+ symlink_inode_ctx_get (inode, this, VOID(&sc));
+
+ if (!sc) {
+ sc_cache_set (this, inode, buf, NULL);
+ inode_ctx_get (inode, this, &tmp_sc);
+
+ if (!sc) {
+ gf_log (this->name, GF_LOG_ERROR,
+ "out of memory :(");
+ return 0;
+ }
+ sc = (struct symlink_cache *)(long)tmp_sc;
+ }
+
+ if (sc->ctime == buf->st_ctime)
+ return 0;
+
+ /* STALE */
+ if (sc->readlink) {
+ gf_log (this->name, GF_LOG_DEBUG,
+ "flushing cache: %s", sc->readlink);
+
+ FREE (sc->readlink);
+ sc->readlink = NULL;
+ }
+
+ sc->ctime = buf->st_ctime;
+
+ return 0;
+}
+
+
+
+int
+sc_cache_get (xlator_t *this, inode_t *inode, char **link)
+{
+ struct symlink_cache *sc = NULL;
+
+ symlink_inode_ctx_get (inode, this, VOID(&sc));
+
+ if (!sc)
+ return 0;
+
+ if (link && sc->readlink)
+ *link = strdup (sc->readlink);
+ return 0;
+}
+
+
+int
+sc_readlink_cbk (call_frame_t *frame, void *cookie,
+ xlator_t *this, int op_ret, int op_errno,
+ const char *link)
+{
+ if (op_ret > 0)
+ sc_cache_update (this, frame->local, link);
+
+ inode_unref (frame->local);
+ frame->local = NULL;
+
+ STACK_UNWIND (frame, op_ret, op_errno, link);
+ return 0;
+}
+
+
+int
+sc_readlink (call_frame_t *frame, xlator_t *this,
+ loc_t *loc, size_t size)
+{
+ char *link = NULL;
+
+ sc_cache_get (this, loc->inode, &link);
+
+ if (link) {
+ /* cache hit */
+ gf_log (this->name, GF_LOG_DEBUG,
+ "cache hit %s -> %s",
+ loc->path, link);
+ STACK_UNWIND (frame, strlen (link) + 1, 0, link);
+ FREE (link);
+ return 0;
+ }
+
+ frame->local = inode_ref (loc->inode);
+
+ STACK_WIND (frame, sc_readlink_cbk,
+ FIRST_CHILD(this),
+ FIRST_CHILD(this)->fops->readlink,
+ loc, size);
+
+ return 0;
+}
+
+
+int
+sc_symlink_cbk (call_frame_t *frame, void *cookie,
+ xlator_t *this, int op_ret, int op_errno,
+ inode_t *inode, struct stat *buf)
+{
+ if (op_ret == 0) {
+ if (frame->local) {
+ sc_cache_set (this, inode, buf, frame->local);
+ }
+ }
+
+ STACK_UNWIND (frame, op_ret, op_errno, inode, buf);
+ return 0;
+}
+
+
+int
+sc_symlink (call_frame_t *frame, xlator_t *this,
+ const char *dst, loc_t *src)
+{
+ frame->local = strdup (dst);
+
+ STACK_WIND (frame, sc_symlink_cbk,
+ FIRST_CHILD(this),
+ FIRST_CHILD(this)->fops->symlink,
+ dst, src);
+
+ return 0;
+}
+
+
+int
+sc_lookup_cbk (call_frame_t *frame, void *cookie,
+ xlator_t *this, int op_ret, int op_errno,
+ inode_t *inode, struct stat *buf, dict_t *xattr)
+{
+ if (op_ret == 0)
+ sc_cache_validate (this, inode, buf);
+ else
+ sc_cache_flush (this, inode);
+
+ STACK_UNWIND (frame, op_ret, op_errno, inode, buf, xattr);
+ return 0;
+}
+
+
+int
+sc_lookup (call_frame_t *frame, xlator_t *this,
+ loc_t *loc, dict_t *xattr_req)
+{
+ STACK_WIND (frame, sc_lookup_cbk,
+ FIRST_CHILD(this),
+ FIRST_CHILD(this)->fops->lookup,
+ loc, xattr_req);
+
+ return 0;
+}
+
+
+int
+sc_forget (xlator_t *this,
+ inode_t *inode)
+{
+ sc_cache_flush (this, inode);
+
+ return 0;
+}
+
+
+int32_t
+init (xlator_t *this)
+{
+
+ if (!this->children || this->children->next)
+ {
+ gf_log (this->name, GF_LOG_ERROR,
+ "FATAL: volume (%s) not configured with exactly one "
+ "child", this->name);
+ return -1;
+ }
+
+ if (!this->parents) {
+ gf_log (this->name, GF_LOG_WARNING,
+ "dangling volume. check volfile ");
+ }
+
+ return 0;
+}
+
+
+void
+fini (xlator_t *this)
+{
+ return;
+}
+
+
+struct xlator_fops fops = {
+ .lookup = sc_lookup,
+ .symlink = sc_symlink,
+ .readlink = sc_readlink,
+};
+
+struct xlator_mops mops = {
+};
+
+struct xlator_cbks cbks = {
+ .forget = sc_forget,
+};
+
+struct volume_options options[] = {
+ { .key = {NULL} },
+};
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