/* * 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;	struct timespec	mtime;	loff_t          size;}; 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;	struct ceph_fsid fsid;	size_t uniq_len;	char uniquifier[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;	const char *fscache_uniq = fsc->mount_options->fscache_uniq;	uint16_t fsid_len, uniq_len; 	fsid_len = sizeof(fsc->client->fsid);	uniq_len = fscache_uniq ? strlen(fscache_uniq) : 0;	if (fsid_len + uniq_len > maxbuf)		return 0; 	memcpy(buffer, &fsc->client->fsid, fsid_len);	if (uniq_len)		memcpy(buffer + fsid_len, fscache_uniq, uniq_len); 	return fsid_len + uniq_len;} 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){	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;	} 	fsc->fscache = fscache_acquire_cookie(ceph_cache_netfs.primary_index,					      &ceph_fscache_fsid_object_def,					      fsc, true); 	if (fsc->fscache) {		memcpy(&ent->fsid, fsid, sizeof(*fsid));		if (uniq_len > 0) {			memcpy(&ent->uniquifier, fscache_uniq, uniq_len);			ent->uniq_len = uniq_len;		}		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 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 + snapshot) */	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.version = ci->i_version;	aux.mtime = inode->i_mtime;	aux.size = i_size_read(inode); 	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;	*size = i_size_read(&ci->vfs_inode);} 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.version = ci->i_version;	aux.mtime = inode->i_mtime;	aux.size = i_size_read(inode); 	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 inode *inode){	struct ceph_inode_info *ci = ceph_inode(inode);	struct ceph_fs_client *fsc = ceph_inode_to_client(inode); 	/* No caching for filesystem */	if (fsc->fscache == NULL)		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) {		ci->fscache = fscache_acquire_cookie(fsc->fscache,					&ceph_fscache_inode_object_def,					ci, 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, 0);} 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, false);		fscache_uncache_all_inode_pages(ci->fscache, inode);	} else {		fscache_enable_cookie(ci->fscache, 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, 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, 0);	}	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))			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);}