| /* |
| * 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 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, |
| }; |
| |
| 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) |
| 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); |
| } |