linux/fs/ceph/cache.c

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/*
* 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 {
struct timespec mtime;
loff_t size;
};
struct fscache_netfs ceph_cache_netfs = {
.name = "ceph",
.version = 0,
};
static uint16_t ceph_fscache_session_get_key(const void *cookie_netfs_data,
void *buffer, uint16_t maxbuf)
{
const struct ceph_fs_client* fsc = cookie_netfs_data;
uint16_t klen;
klen = sizeof(fsc->client->fsid);
if (klen > maxbuf)
return 0;
memcpy(buffer, &fsc->client->fsid, klen);
return klen;
}
static const struct fscache_cookie_def ceph_fscache_fsid_object_def = {
.name = "CEPH.fsid",
.type = FSCACHE_COOKIE_TYPE_INDEX,
.get_key = ceph_fscache_session_get_key,
};
int 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)
{
fsc->fscache = fscache_acquire_cookie(ceph_cache_netfs.primary_index,
&ceph_fscache_fsid_object_def,
fsc);
if (fsc->fscache == NULL) {
pr_err("Unable to resgister fsid: %p fscache cookie", fsc);
return 0;
}
fsc->revalidate_wq = alloc_workqueue("ceph-revalidate", 0, 1);
if (fsc->revalidate_wq == NULL)
return -ENOMEM;
return 0;
}
static uint16_t ceph_fscache_inode_get_key(const void *cookie_netfs_data,
void *buffer, uint16_t maxbuf)
{
const struct ceph_inode_info* ci = cookie_netfs_data;
uint16_t klen;
/* use ceph virtual inode (id + snaphot) */
klen = sizeof(ci->i_vino);
if (klen > maxbuf)
return 0;
memcpy(buffer, &ci->i_vino, klen);
return klen;
}
static uint16_t ceph_fscache_inode_get_aux(const void *cookie_netfs_data,
void *buffer, uint16_t bufmax)
{
struct ceph_aux_inode aux;
const struct ceph_inode_info* ci = cookie_netfs_data;
const struct inode* inode = &ci->vfs_inode;
memset(&aux, 0, sizeof(aux));
aux.mtime = inode->i_mtime;
aux.size = inode->i_size;
memcpy(buffer, &aux, sizeof(aux));
return sizeof(aux);
}
static void ceph_fscache_inode_get_attr(const void *cookie_netfs_data,
uint64_t *size)
{
const struct ceph_inode_info* ci = cookie_netfs_data;
const struct inode* inode = &ci->vfs_inode;
*size = inode->i_size;
}
static enum fscache_checkaux ceph_fscache_inode_check_aux(
void *cookie_netfs_data, const void *data, uint16_t dlen)
{
struct ceph_aux_inode aux;
struct ceph_inode_info* ci = cookie_netfs_data;
struct inode* inode = &ci->vfs_inode;
if (dlen != sizeof(aux))
return FSCACHE_CHECKAUX_OBSOLETE;
memset(&aux, 0, sizeof(aux));
aux.mtime = inode->i_mtime;
aux.size = inode->i_size;
if (memcmp(data, &aux, sizeof(aux)) != 0)
return FSCACHE_CHECKAUX_OBSOLETE;
dout("ceph inode 0x%p cached okay", ci);
return FSCACHE_CHECKAUX_OKAY;
}
static void ceph_fscache_inode_now_uncached(void* cookie_netfs_data)
{
struct ceph_inode_info* ci = cookie_netfs_data;
struct pagevec pvec;
pgoff_t first;
int loop, nr_pages;
pagevec_init(&pvec, 0);
first = 0;
dout("ceph inode 0x%p now uncached", ci);
while (1) {
nr_pages = pagevec_lookup(&pvec, ci->vfs_inode.i_mapping, first,
PAGEVEC_SIZE - pagevec_count(&pvec));
if (!nr_pages)
break;
for (loop = 0; loop < nr_pages; loop++)
ClearPageFsCache(pvec.pages[loop]);
first = pvec.pages[nr_pages - 1]->index + 1;
pvec.nr = nr_pages;
pagevec_release(&pvec);
cond_resched();
}
}
static const struct fscache_cookie_def ceph_fscache_inode_object_def = {
.name = "CEPH.inode",
.type = FSCACHE_COOKIE_TYPE_DATAFILE,
.get_key = ceph_fscache_inode_get_key,
.get_attr = ceph_fscache_inode_get_attr,
.get_aux = ceph_fscache_inode_get_aux,
.check_aux = ceph_fscache_inode_check_aux,
.now_uncached = ceph_fscache_inode_now_uncached,
};
void ceph_fscache_register_inode_cookie(struct ceph_fs_client* fsc,
struct ceph_inode_info* ci)
{
struct inode* inode = &ci->vfs_inode;
/* No caching for filesystem */
if (fsc->fscache == NULL)
return;
/* Only cache for regular files that are read only */
if ((ci->vfs_inode.i_mode & S_IFREG) == 0)
return;
/* Avoid multiple racing open requests */
mutex_lock(&inode->i_mutex);
if (ci->fscache)
goto done;
ci->fscache = fscache_acquire_cookie(fsc->fscache,
&ceph_fscache_inode_object_def,
ci);
done:
mutex_unlock(&inode->i_mutex);
}
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, 0);
}
static void ceph_vfs_readpage_complete(struct page *page, void *data, int error)
{
if (!error)
SetPageUptodate(page);
}
static void ceph_vfs_readpage_complete_unlock(struct page *page, void *data, int error)
{
if (!error)
SetPageUptodate(page);
unlock_page(page);
}
static inline int cache_valid(struct ceph_inode_info *ci)
{
return ((ceph_caps_issued(ci) & CEPH_CAP_FILE_CACHE) &&
(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_vfs_readpage_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_vfs_readpage_complete_unlock,
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, 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);
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 (fsc->revalidate_wq)
destroy_workqueue(fsc->revalidate_wq);
fscache_relinquish_cookie(fsc->fscache, 0);
fsc->fscache = NULL;
}
static void ceph_revalidate_work(struct work_struct *work)
{
int issued;
u32 orig_gen;
struct ceph_inode_info *ci = container_of(work, struct ceph_inode_info,
i_revalidate_work);
struct inode *inode = &ci->vfs_inode;
spin_lock(&ci->i_ceph_lock);
issued = __ceph_caps_issued(ci, NULL);
orig_gen = ci->i_rdcache_gen;
spin_unlock(&ci->i_ceph_lock);
if (!(issued & CEPH_CAP_FILE_CACHE)) {
dout("revalidate_work lost cache before validation %p\n",
inode);
goto out;
}
if (!fscache_check_consistency(ci->fscache))
fscache_invalidate(ci->fscache);
spin_lock(&ci->i_ceph_lock);
/* Update the new valid generation (backwards sanity check too) */
if (orig_gen > ci->i_fscache_gen) {
ci->i_fscache_gen = orig_gen;
}
spin_unlock(&ci->i_ceph_lock);
out:
iput(&ci->vfs_inode);
}
void ceph_queue_revalidate(struct inode *inode)
{
struct ceph_fs_client *fsc = ceph_sb_to_client(inode->i_sb);
struct ceph_inode_info *ci = ceph_inode(inode);
if (fsc->revalidate_wq == NULL || ci->fscache == NULL)
return;
ihold(inode);
if (queue_work(ceph_sb_to_client(inode->i_sb)->revalidate_wq,
&ci->i_revalidate_work)) {
dout("ceph_queue_revalidate %p\n", inode);
} else {
dout("ceph_queue_revalidate %p failed\n)", inode);
iput(inode);
}
}
void ceph_fscache_inode_init(struct ceph_inode_info *ci)
{
ci->fscache = NULL;
/* The first load is verifed cookie open time */
ci->i_fscache_gen = 1;
INIT_WORK(&ci->i_revalidate_work, ceph_revalidate_work);
}