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1d8f83604c
Current ceph uses FSID as primary index key of fscache data. This allows ceph to retain cached data across remount. But this causes problem (kernel opps, fscache does not support sharing data) when a filesystem get mounted several times (with fscache enabled, with different mount options). The fix is adding a new mount option, which specifies uniquifier for fscache. Signed-off-by: "Yan, Zheng" <zyan@redhat.com> Acked-by: Jeff Layton <jlayton@redhat.com> Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
450 lines
11 KiB
C
450 lines
11 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 void ceph_fscache_inode_now_uncached(void* cookie_netfs_data)
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{
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struct ceph_inode_info* ci = cookie_netfs_data;
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struct pagevec pvec;
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pgoff_t first;
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int loop, nr_pages;
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pagevec_init(&pvec, 0);
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first = 0;
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dout("ceph inode 0x%p now uncached", ci);
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while (1) {
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nr_pages = pagevec_lookup(&pvec, ci->vfs_inode.i_mapping, first,
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PAGEVEC_SIZE - pagevec_count(&pvec));
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if (!nr_pages)
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break;
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for (loop = 0; loop < nr_pages; loop++)
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ClearPageFsCache(pvec.pages[loop]);
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first = pvec.pages[nr_pages - 1]->index + 1;
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pvec.nr = nr_pages;
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pagevec_release(&pvec);
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cond_resched();
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}
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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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.now_uncached = ceph_fscache_inode_now_uncached,
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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 == NULL)
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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_vfs_readpage_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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}
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static void ceph_vfs_readpage_complete_unlock(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_vfs_readpage_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_vfs_readpage_complete_unlock,
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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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