/* * 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); }