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-rw-r--r--fs/ceph/cache.c364
1 files changed, 364 insertions, 0 deletions
diff --git a/fs/ceph/cache.c b/fs/ceph/cache.c
new file mode 100644
index 000000000..1bf3502bd
--- /dev/null
+++ b/fs/ceph/cache.c
@@ -0,0 +1,364 @@
+/*
+ * Ceph cache definitions.
+ *
+ * Copyright (C) 2013 by Adfin Solutions, Inc. All Rights Reserved.
+ * Written by Milosz Tanski (milosz@adfin.com)
+ *
+ * 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 "super.h"
+#include "cache.h"
+
+struct ceph_aux_inode {
+ u64 version;
+ u64 mtime_sec;
+ u64 mtime_nsec;
+};
+
+struct fscache_netfs ceph_cache_netfs = {
+ .name = "ceph",
+ .version = 0,
+};
+
+static DEFINE_MUTEX(ceph_fscache_lock);
+static LIST_HEAD(ceph_fscache_list);
+
+struct ceph_fscache_entry {
+ struct list_head list;
+ struct fscache_cookie *fscache;
+ size_t uniq_len;
+ /* The following members must be last */
+ struct ceph_fsid fsid;
+ char uniquifier[0];
+};
+
+static const struct fscache_cookie_def ceph_fscache_fsid_object_def = {
+ .name = "CEPH.fsid",
+ .type = FSCACHE_COOKIE_TYPE_INDEX,
+};
+
+int __init ceph_fscache_register(void)
+{
+ return fscache_register_netfs(&ceph_cache_netfs);
+}
+
+void ceph_fscache_unregister(void)
+{
+ fscache_unregister_netfs(&ceph_cache_netfs);
+}
+
+int ceph_fscache_register_fs(struct ceph_fs_client* fsc)
+{
+ const struct ceph_fsid *fsid = &fsc->client->fsid;
+ const char *fscache_uniq = fsc->mount_options->fscache_uniq;
+ size_t uniq_len = fscache_uniq ? strlen(fscache_uniq) : 0;
+ struct ceph_fscache_entry *ent;
+ int err = 0;
+
+ mutex_lock(&ceph_fscache_lock);
+ list_for_each_entry(ent, &ceph_fscache_list, list) {
+ if (memcmp(&ent->fsid, fsid, sizeof(*fsid)))
+ continue;
+ if (ent->uniq_len != uniq_len)
+ continue;
+ if (uniq_len && memcmp(ent->uniquifier, fscache_uniq, uniq_len))
+ continue;
+
+ pr_err("fscache cookie already registered for fsid %pU\n", fsid);
+ pr_err(" use fsc=%%s mount option to specify a uniquifier\n");
+ err = -EBUSY;
+ goto out_unlock;
+ }
+
+ ent = kzalloc(sizeof(*ent) + uniq_len, GFP_KERNEL);
+ if (!ent) {
+ err = -ENOMEM;
+ goto out_unlock;
+ }
+
+ memcpy(&ent->fsid, fsid, sizeof(*fsid));
+ if (uniq_len > 0) {
+ memcpy(&ent->uniquifier, fscache_uniq, uniq_len);
+ ent->uniq_len = uniq_len;
+ }
+
+ fsc->fscache = fscache_acquire_cookie(ceph_cache_netfs.primary_index,
+ &ceph_fscache_fsid_object_def,
+ &ent->fsid, sizeof(ent->fsid) + uniq_len,
+ NULL, 0,
+ fsc, 0, true);
+
+ if (fsc->fscache) {
+ ent->fscache = fsc->fscache;
+ list_add_tail(&ent->list, &ceph_fscache_list);
+ } else {
+ kfree(ent);
+ pr_err("unable to register fscache cookie for fsid %pU\n",
+ fsid);
+ /* all other fs ignore this error */
+ }
+out_unlock:
+ mutex_unlock(&ceph_fscache_lock);
+ return err;
+}
+
+static enum fscache_checkaux ceph_fscache_inode_check_aux(
+ void *cookie_netfs_data, const void *data, uint16_t dlen,
+ loff_t object_size)
+{
+ struct ceph_aux_inode aux;
+ struct ceph_inode_info* ci = cookie_netfs_data;
+ struct inode* inode = &ci->vfs_inode;
+
+ if (dlen != sizeof(aux) ||
+ i_size_read(inode) != object_size)
+ return FSCACHE_CHECKAUX_OBSOLETE;
+
+ memset(&aux, 0, sizeof(aux));
+ aux.version = ci->i_version;
+ aux.mtime_sec = inode->i_mtime.tv_sec;
+ aux.mtime_nsec = inode->i_mtime.tv_nsec;
+
+ if (memcmp(data, &aux, sizeof(aux)) != 0)
+ return FSCACHE_CHECKAUX_OBSOLETE;
+
+ dout("ceph inode 0x%p cached okay\n", ci);
+ return FSCACHE_CHECKAUX_OKAY;
+}
+
+static const struct fscache_cookie_def ceph_fscache_inode_object_def = {
+ .name = "CEPH.inode",
+ .type = FSCACHE_COOKIE_TYPE_DATAFILE,
+ .check_aux = ceph_fscache_inode_check_aux,
+};
+
+void ceph_fscache_register_inode_cookie(struct inode *inode)
+{
+ struct ceph_inode_info *ci = ceph_inode(inode);
+ struct ceph_fs_client *fsc = ceph_inode_to_client(inode);
+ struct ceph_aux_inode aux;
+
+ /* No caching for filesystem */
+ if (!fsc->fscache)
+ return;
+
+ /* Only cache for regular files that are read only */
+ if (!S_ISREG(inode->i_mode))
+ return;
+
+ inode_lock_nested(inode, I_MUTEX_CHILD);
+ if (!ci->fscache) {
+ memset(&aux, 0, sizeof(aux));
+ aux.version = ci->i_version;
+ aux.mtime_sec = inode->i_mtime.tv_sec;
+ aux.mtime_nsec = inode->i_mtime.tv_nsec;
+ ci->fscache = fscache_acquire_cookie(fsc->fscache,
+ &ceph_fscache_inode_object_def,
+ &ci->i_vino, sizeof(ci->i_vino),
+ &aux, sizeof(aux),
+ ci, i_size_read(inode), false);
+ }
+ inode_unlock(inode);
+}
+
+void ceph_fscache_unregister_inode_cookie(struct ceph_inode_info* ci)
+{
+ struct fscache_cookie* cookie;
+
+ if ((cookie = ci->fscache) == NULL)
+ return;
+
+ ci->fscache = NULL;
+
+ fscache_uncache_all_inode_pages(cookie, &ci->vfs_inode);
+ fscache_relinquish_cookie(cookie, &ci->i_vino, false);
+}
+
+static bool ceph_fscache_can_enable(void *data)
+{
+ struct inode *inode = data;
+ return !inode_is_open_for_write(inode);
+}
+
+void ceph_fscache_file_set_cookie(struct inode *inode, struct file *filp)
+{
+ struct ceph_inode_info *ci = ceph_inode(inode);
+
+ if (!fscache_cookie_valid(ci->fscache))
+ return;
+
+ if (inode_is_open_for_write(inode)) {
+ dout("fscache_file_set_cookie %p %p disabling cache\n",
+ inode, filp);
+ fscache_disable_cookie(ci->fscache, &ci->i_vino, false);
+ fscache_uncache_all_inode_pages(ci->fscache, inode);
+ } else {
+ fscache_enable_cookie(ci->fscache, &ci->i_vino, i_size_read(inode),
+ ceph_fscache_can_enable, inode);
+ if (fscache_cookie_enabled(ci->fscache)) {
+ dout("fscache_file_set_cookie %p %p enabling cache\n",
+ inode, filp);
+ }
+ }
+}
+
+static void ceph_readpage_from_fscache_complete(struct page *page, void *data, int error)
+{
+ if (!error)
+ SetPageUptodate(page);
+
+ unlock_page(page);
+}
+
+static inline bool cache_valid(struct ceph_inode_info *ci)
+{
+ return ci->i_fscache_gen == ci->i_rdcache_gen;
+}
+
+
+/* Atempt to read from the fscache,
+ *
+ * This function is called from the readpage_nounlock context. DO NOT attempt to
+ * unlock the page here (or in the callback).
+ */
+int ceph_readpage_from_fscache(struct inode *inode, struct page *page)
+{
+ struct ceph_inode_info *ci = ceph_inode(inode);
+ int ret;
+
+ if (!cache_valid(ci))
+ return -ENOBUFS;
+
+ ret = fscache_read_or_alloc_page(ci->fscache, page,
+ ceph_readpage_from_fscache_complete, NULL,
+ GFP_KERNEL);
+
+ switch (ret) {
+ case 0: /* Page found */
+ dout("page read submitted\n");
+ return 0;
+ case -ENOBUFS: /* Pages were not found, and can't be */
+ case -ENODATA: /* Pages were not found */
+ dout("page/inode not in cache\n");
+ return ret;
+ default:
+ dout("%s: unknown error ret = %i\n", __func__, ret);
+ return ret;
+ }
+}
+
+int ceph_readpages_from_fscache(struct inode *inode,
+ struct address_space *mapping,
+ struct list_head *pages,
+ unsigned *nr_pages)
+{
+ struct ceph_inode_info *ci = ceph_inode(inode);
+ int ret;
+
+ if (!cache_valid(ci))
+ return -ENOBUFS;
+
+ ret = fscache_read_or_alloc_pages(ci->fscache, mapping, pages, nr_pages,
+ ceph_readpage_from_fscache_complete,
+ NULL, mapping_gfp_mask(mapping));
+
+ switch (ret) {
+ case 0: /* All pages found */
+ dout("all-page read submitted\n");
+ return 0;
+ case -ENOBUFS: /* Some pages were not found, and can't be */
+ case -ENODATA: /* some pages were not found */
+ dout("page/inode not in cache\n");
+ return ret;
+ default:
+ dout("%s: unknown error ret = %i\n", __func__, ret);
+ return ret;
+ }
+}
+
+void ceph_readpage_to_fscache(struct inode *inode, struct page *page)
+{
+ struct ceph_inode_info *ci = ceph_inode(inode);
+ int ret;
+
+ if (!PageFsCache(page))
+ return;
+
+ if (!cache_valid(ci))
+ return;
+
+ ret = fscache_write_page(ci->fscache, page, i_size_read(inode),
+ GFP_KERNEL);
+ if (ret)
+ fscache_uncache_page(ci->fscache, page);
+}
+
+void ceph_invalidate_fscache_page(struct inode* inode, struct page *page)
+{
+ struct ceph_inode_info *ci = ceph_inode(inode);
+
+ if (!PageFsCache(page))
+ return;
+
+ fscache_wait_on_page_write(ci->fscache, page);
+ fscache_uncache_page(ci->fscache, page);
+}
+
+void ceph_fscache_unregister_fs(struct ceph_fs_client* fsc)
+{
+ if (fscache_cookie_valid(fsc->fscache)) {
+ struct ceph_fscache_entry *ent;
+ bool found = false;
+
+ mutex_lock(&ceph_fscache_lock);
+ list_for_each_entry(ent, &ceph_fscache_list, list) {
+ if (ent->fscache == fsc->fscache) {
+ list_del(&ent->list);
+ kfree(ent);
+ found = true;
+ break;
+ }
+ }
+ WARN_ON_ONCE(!found);
+ mutex_unlock(&ceph_fscache_lock);
+
+ __fscache_relinquish_cookie(fsc->fscache, NULL, false);
+ }
+ fsc->fscache = NULL;
+}
+
+/*
+ * caller should hold CEPH_CAP_FILE_{RD,CACHE}
+ */
+void ceph_fscache_revalidate_cookie(struct ceph_inode_info *ci)
+{
+ if (cache_valid(ci))
+ return;
+
+ /* resue i_truncate_mutex. There should be no pending
+ * truncate while the caller holds CEPH_CAP_FILE_RD */
+ mutex_lock(&ci->i_truncate_mutex);
+ if (!cache_valid(ci)) {
+ if (fscache_check_consistency(ci->fscache, &ci->i_vino))
+ fscache_invalidate(ci->fscache);
+ spin_lock(&ci->i_ceph_lock);
+ ci->i_fscache_gen = ci->i_rdcache_gen;
+ spin_unlock(&ci->i_ceph_lock);
+ }
+ mutex_unlock(&ci->i_truncate_mutex);
+}
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