413 lines
10 KiB
C
413 lines
10 KiB
C
/*
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* Ceph cache definitions.
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*
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* Copyright (C) 2013 by Adfin Solutions, Inc. All Rights Reserved.
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* Written by Milosz Tanski (milosz@adfin.com)
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2
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* as published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to:
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* Free Software Foundation
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* 51 Franklin Street, Fifth Floor
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* Boston, MA 02111-1301 USA
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*
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*/
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#include "super.h"
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#include "cache.h"
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struct ceph_aux_inode {
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u64 version;
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struct timespec mtime;
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loff_t size;
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};
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struct fscache_netfs ceph_cache_netfs = {
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.name = "ceph",
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.version = 0,
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};
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static DEFINE_MUTEX(ceph_fscache_lock);
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static LIST_HEAD(ceph_fscache_list);
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struct ceph_fscache_entry {
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struct list_head list;
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struct fscache_cookie *fscache;
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struct ceph_fsid fsid;
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size_t uniq_len;
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char uniquifier[0];
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};
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static uint16_t ceph_fscache_session_get_key(const void *cookie_netfs_data,
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void *buffer, uint16_t maxbuf)
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{
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const struct ceph_fs_client* fsc = cookie_netfs_data;
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const char *fscache_uniq = fsc->mount_options->fscache_uniq;
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uint16_t fsid_len, uniq_len;
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fsid_len = sizeof(fsc->client->fsid);
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uniq_len = fscache_uniq ? strlen(fscache_uniq) : 0;
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if (fsid_len + uniq_len > maxbuf)
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return 0;
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memcpy(buffer, &fsc->client->fsid, fsid_len);
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if (uniq_len)
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memcpy(buffer + fsid_len, fscache_uniq, uniq_len);
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return fsid_len + uniq_len;
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}
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static const struct fscache_cookie_def ceph_fscache_fsid_object_def = {
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.name = "CEPH.fsid",
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.type = FSCACHE_COOKIE_TYPE_INDEX,
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.get_key = ceph_fscache_session_get_key,
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};
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int ceph_fscache_register(void)
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{
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return fscache_register_netfs(&ceph_cache_netfs);
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}
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void ceph_fscache_unregister(void)
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{
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fscache_unregister_netfs(&ceph_cache_netfs);
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}
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int ceph_fscache_register_fs(struct ceph_fs_client* fsc)
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{
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const struct ceph_fsid *fsid = &fsc->client->fsid;
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const char *fscache_uniq = fsc->mount_options->fscache_uniq;
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size_t uniq_len = fscache_uniq ? strlen(fscache_uniq) : 0;
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struct ceph_fscache_entry *ent;
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int err = 0;
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mutex_lock(&ceph_fscache_lock);
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list_for_each_entry(ent, &ceph_fscache_list, list) {
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if (memcmp(&ent->fsid, fsid, sizeof(*fsid)))
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continue;
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if (ent->uniq_len != uniq_len)
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continue;
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if (uniq_len && memcmp(ent->uniquifier, fscache_uniq, uniq_len))
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continue;
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pr_err("fscache cookie already registered for fsid %pU\n", fsid);
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pr_err(" use fsc=%%s mount option to specify a uniquifier\n");
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err = -EBUSY;
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goto out_unlock;
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}
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ent = kzalloc(sizeof(*ent) + uniq_len, GFP_KERNEL);
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if (!ent) {
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err = -ENOMEM;
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goto out_unlock;
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}
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fsc->fscache = fscache_acquire_cookie(ceph_cache_netfs.primary_index,
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&ceph_fscache_fsid_object_def,
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fsc, true);
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if (fsc->fscache) {
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memcpy(&ent->fsid, fsid, sizeof(*fsid));
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if (uniq_len > 0) {
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memcpy(&ent->uniquifier, fscache_uniq, uniq_len);
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ent->uniq_len = uniq_len;
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}
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ent->fscache = fsc->fscache;
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list_add_tail(&ent->list, &ceph_fscache_list);
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} else {
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kfree(ent);
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pr_err("unable to register fscache cookie for fsid %pU\n",
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fsid);
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/* all other fs ignore this error */
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}
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out_unlock:
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mutex_unlock(&ceph_fscache_lock);
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return err;
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}
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static uint16_t ceph_fscache_inode_get_key(const void *cookie_netfs_data,
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void *buffer, uint16_t maxbuf)
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{
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const struct ceph_inode_info* ci = cookie_netfs_data;
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uint16_t klen;
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/* use ceph virtual inode (id + snapshot) */
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klen = sizeof(ci->i_vino);
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if (klen > maxbuf)
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return 0;
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memcpy(buffer, &ci->i_vino, klen);
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return klen;
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}
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static uint16_t ceph_fscache_inode_get_aux(const void *cookie_netfs_data,
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void *buffer, uint16_t bufmax)
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{
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struct ceph_aux_inode aux;
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const struct ceph_inode_info* ci = cookie_netfs_data;
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const struct inode* inode = &ci->vfs_inode;
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memset(&aux, 0, sizeof(aux));
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aux.version = ci->i_version;
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aux.mtime = inode->i_mtime;
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aux.size = i_size_read(inode);
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memcpy(buffer, &aux, sizeof(aux));
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return sizeof(aux);
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}
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static void ceph_fscache_inode_get_attr(const void *cookie_netfs_data,
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uint64_t *size)
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{
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const struct ceph_inode_info* ci = cookie_netfs_data;
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*size = i_size_read(&ci->vfs_inode);
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}
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static enum fscache_checkaux ceph_fscache_inode_check_aux(
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void *cookie_netfs_data, const void *data, uint16_t dlen)
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{
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struct ceph_aux_inode aux;
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struct ceph_inode_info* ci = cookie_netfs_data;
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struct inode* inode = &ci->vfs_inode;
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if (dlen != sizeof(aux))
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return FSCACHE_CHECKAUX_OBSOLETE;
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memset(&aux, 0, sizeof(aux));
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aux.version = ci->i_version;
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aux.mtime = inode->i_mtime;
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aux.size = i_size_read(inode);
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if (memcmp(data, &aux, sizeof(aux)) != 0)
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return FSCACHE_CHECKAUX_OBSOLETE;
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dout("ceph inode 0x%p cached okay", ci);
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return FSCACHE_CHECKAUX_OKAY;
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}
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static const struct fscache_cookie_def ceph_fscache_inode_object_def = {
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.name = "CEPH.inode",
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.type = FSCACHE_COOKIE_TYPE_DATAFILE,
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.get_key = ceph_fscache_inode_get_key,
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.get_attr = ceph_fscache_inode_get_attr,
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.get_aux = ceph_fscache_inode_get_aux,
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.check_aux = ceph_fscache_inode_check_aux,
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};
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void ceph_fscache_register_inode_cookie(struct inode *inode)
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{
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struct ceph_inode_info *ci = ceph_inode(inode);
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struct ceph_fs_client *fsc = ceph_inode_to_client(inode);
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/* No caching for filesystem */
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if (!fsc->fscache)
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return;
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/* Only cache for regular files that are read only */
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if (!S_ISREG(inode->i_mode))
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return;
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inode_lock_nested(inode, I_MUTEX_CHILD);
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if (!ci->fscache) {
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ci->fscache = fscache_acquire_cookie(fsc->fscache,
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&ceph_fscache_inode_object_def,
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ci, false);
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}
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inode_unlock(inode);
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}
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void ceph_fscache_unregister_inode_cookie(struct ceph_inode_info* ci)
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{
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struct fscache_cookie* cookie;
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if ((cookie = ci->fscache) == NULL)
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return;
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ci->fscache = NULL;
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fscache_uncache_all_inode_pages(cookie, &ci->vfs_inode);
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fscache_relinquish_cookie(cookie, 0);
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}
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static bool ceph_fscache_can_enable(void *data)
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{
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struct inode *inode = data;
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return !inode_is_open_for_write(inode);
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}
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void ceph_fscache_file_set_cookie(struct inode *inode, struct file *filp)
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{
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struct ceph_inode_info *ci = ceph_inode(inode);
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if (!fscache_cookie_valid(ci->fscache))
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return;
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if (inode_is_open_for_write(inode)) {
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dout("fscache_file_set_cookie %p %p disabling cache\n",
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inode, filp);
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fscache_disable_cookie(ci->fscache, false);
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fscache_uncache_all_inode_pages(ci->fscache, inode);
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} else {
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fscache_enable_cookie(ci->fscache, ceph_fscache_can_enable,
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inode);
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if (fscache_cookie_enabled(ci->fscache)) {
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dout("fscache_file_set_cookie %p %p enabling cache\n",
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inode, filp);
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}
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}
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}
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static void ceph_readpage_from_fscache_complete(struct page *page, void *data, int error)
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{
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if (!error)
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SetPageUptodate(page);
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unlock_page(page);
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}
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static inline bool cache_valid(struct ceph_inode_info *ci)
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{
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return ci->i_fscache_gen == ci->i_rdcache_gen;
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}
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/* Atempt to read from the fscache,
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*
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* This function is called from the readpage_nounlock context. DO NOT attempt to
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* unlock the page here (or in the callback).
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*/
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int ceph_readpage_from_fscache(struct inode *inode, struct page *page)
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{
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struct ceph_inode_info *ci = ceph_inode(inode);
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int ret;
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if (!cache_valid(ci))
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return -ENOBUFS;
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ret = fscache_read_or_alloc_page(ci->fscache, page,
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ceph_readpage_from_fscache_complete, NULL,
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GFP_KERNEL);
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switch (ret) {
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case 0: /* Page found */
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dout("page read submitted\n");
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return 0;
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case -ENOBUFS: /* Pages were not found, and can't be */
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case -ENODATA: /* Pages were not found */
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dout("page/inode not in cache\n");
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return ret;
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default:
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dout("%s: unknown error ret = %i\n", __func__, ret);
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return ret;
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}
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}
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int ceph_readpages_from_fscache(struct inode *inode,
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struct address_space *mapping,
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struct list_head *pages,
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unsigned *nr_pages)
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{
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struct ceph_inode_info *ci = ceph_inode(inode);
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int ret;
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if (!cache_valid(ci))
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return -ENOBUFS;
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ret = fscache_read_or_alloc_pages(ci->fscache, mapping, pages, nr_pages,
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ceph_readpage_from_fscache_complete,
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NULL, mapping_gfp_mask(mapping));
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switch (ret) {
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case 0: /* All pages found */
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dout("all-page read submitted\n");
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return 0;
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case -ENOBUFS: /* Some pages were not found, and can't be */
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case -ENODATA: /* some pages were not found */
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dout("page/inode not in cache\n");
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return ret;
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default:
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dout("%s: unknown error ret = %i\n", __func__, ret);
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return ret;
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}
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}
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void ceph_readpage_to_fscache(struct inode *inode, struct page *page)
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{
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struct ceph_inode_info *ci = ceph_inode(inode);
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int ret;
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if (!PageFsCache(page))
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return;
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if (!cache_valid(ci))
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return;
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ret = fscache_write_page(ci->fscache, page, GFP_KERNEL);
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if (ret)
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fscache_uncache_page(ci->fscache, page);
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}
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void ceph_invalidate_fscache_page(struct inode* inode, struct page *page)
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{
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struct ceph_inode_info *ci = ceph_inode(inode);
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if (!PageFsCache(page))
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return;
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fscache_wait_on_page_write(ci->fscache, page);
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fscache_uncache_page(ci->fscache, page);
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}
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void ceph_fscache_unregister_fs(struct ceph_fs_client* fsc)
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{
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if (fscache_cookie_valid(fsc->fscache)) {
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struct ceph_fscache_entry *ent;
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bool found = false;
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mutex_lock(&ceph_fscache_lock);
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list_for_each_entry(ent, &ceph_fscache_list, list) {
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if (ent->fscache == fsc->fscache) {
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list_del(&ent->list);
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kfree(ent);
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found = true;
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break;
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}
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}
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WARN_ON_ONCE(!found);
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mutex_unlock(&ceph_fscache_lock);
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__fscache_relinquish_cookie(fsc->fscache, 0);
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}
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fsc->fscache = NULL;
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}
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/*
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* caller should hold CEPH_CAP_FILE_{RD,CACHE}
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*/
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void ceph_fscache_revalidate_cookie(struct ceph_inode_info *ci)
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{
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if (cache_valid(ci))
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return;
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/* resue i_truncate_mutex. There should be no pending
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* truncate while the caller holds CEPH_CAP_FILE_RD */
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mutex_lock(&ci->i_truncate_mutex);
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if (!cache_valid(ci)) {
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if (fscache_check_consistency(ci->fscache))
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fscache_invalidate(ci->fscache);
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spin_lock(&ci->i_ceph_lock);
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ci->i_fscache_gen = ci->i_rdcache_gen;
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spin_unlock(&ci->i_ceph_lock);
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}
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mutex_unlock(&ci->i_truncate_mutex);
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}
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