/* * V9FS cache definitions. * * Copyright (C) 2009 by Abhishek Kulkarni <adkulkar@umail.iu.edu> * * 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 <linux/jiffies.h> #include <linux/file.h> #include <linux/slab.h> #include <linux/stat.h> #include <linux/sched.h> #include <linux/fs.h> #include <net/9p/9p.h> #include "v9fs.h" #include "cache.h" #define CACHETAG_LEN 11 struct fscache_netfs v9fs_cache_netfs = { .name = "9p", .version = 0, }; /** * v9fs_random_cachetag - Generate a random tag to be associated * with a new cache session. * * The value of jiffies is used for a fairly randomly cache tag. */ static int v9fs_random_cachetag(struct v9fs_session_info *v9ses) { v9ses->cachetag = kmalloc(CACHETAG_LEN, GFP_KERNEL); if (!v9ses->cachetag) return -ENOMEM; return scnprintf(v9ses->cachetag, CACHETAG_LEN, "%lu", jiffies); } static uint16_t v9fs_cache_session_get_key(const void *cookie_netfs_data, void *buffer, uint16_t bufmax) { struct v9fs_session_info *v9ses; uint16_t klen = 0; v9ses = (struct v9fs_session_info *)cookie_netfs_data; p9_debug(P9_DEBUG_FSC, "session %p buf %p size %u\n", v9ses, buffer, bufmax); if (v9ses->cachetag) klen = strlen(v9ses->cachetag); if (klen > bufmax) return 0; memcpy(buffer, v9ses->cachetag, klen); p9_debug(P9_DEBUG_FSC, "cache session tag %s\n", v9ses->cachetag); return klen; } const struct fscache_cookie_def v9fs_cache_session_index_def = { .name = "9P.session", .type = FSCACHE_COOKIE_TYPE_INDEX, .get_key = v9fs_cache_session_get_key, }; void v9fs_cache_session_get_cookie(struct v9fs_session_info *v9ses) { /* If no cache session tag was specified, we generate a random one. */ if (!v9ses->cachetag) v9fs_random_cachetag(v9ses); v9ses->fscache = fscache_acquire_cookie(v9fs_cache_netfs.primary_index, &v9fs_cache_session_index_def, v9ses, true); p9_debug(P9_DEBUG_FSC, "session %p get cookie %p\n", v9ses, v9ses->fscache); } void v9fs_cache_session_put_cookie(struct v9fs_session_info *v9ses) { p9_debug(P9_DEBUG_FSC, "session %p put cookie %p\n", v9ses, v9ses->fscache); fscache_relinquish_cookie(v9ses->fscache, 0); v9ses->fscache = NULL; } static uint16_t v9fs_cache_inode_get_key(const void *cookie_netfs_data, void *buffer, uint16_t bufmax) { const struct v9fs_inode *v9inode = cookie_netfs_data; memcpy(buffer, &v9inode->qid.path, sizeof(v9inode->qid.path)); p9_debug(P9_DEBUG_FSC, "inode %p get key %llu\n", &v9inode->vfs_inode, v9inode->qid.path); return sizeof(v9inode->qid.path); } static void v9fs_cache_inode_get_attr(const void *cookie_netfs_data, uint64_t *size) { const struct v9fs_inode *v9inode = cookie_netfs_data; *size = i_size_read(&v9inode->vfs_inode); p9_debug(P9_DEBUG_FSC, "inode %p get attr %llu\n", &v9inode->vfs_inode, *size); } static uint16_t v9fs_cache_inode_get_aux(const void *cookie_netfs_data, void *buffer, uint16_t buflen) { const struct v9fs_inode *v9inode = cookie_netfs_data; memcpy(buffer, &v9inode->qid.version, sizeof(v9inode->qid.version)); p9_debug(P9_DEBUG_FSC, "inode %p get aux %u\n", &v9inode->vfs_inode, v9inode->qid.version); return sizeof(v9inode->qid.version); } static enum fscache_checkaux v9fs_cache_inode_check_aux(void *cookie_netfs_data, const void *buffer, uint16_t buflen) { const struct v9fs_inode *v9inode = cookie_netfs_data; if (buflen != sizeof(v9inode->qid.version)) return FSCACHE_CHECKAUX_OBSOLETE; if (memcmp(buffer, &v9inode->qid.version, sizeof(v9inode->qid.version))) return FSCACHE_CHECKAUX_OBSOLETE; return FSCACHE_CHECKAUX_OKAY; } static void v9fs_cache_inode_now_uncached(void *cookie_netfs_data) { struct v9fs_inode *v9inode = cookie_netfs_data; struct pagevec pvec; pgoff_t first; int loop, nr_pages; pagevec_init(&pvec, 0); first = 0; for (;;) { nr_pages = pagevec_lookup(&pvec, v9inode->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(); } } const struct fscache_cookie_def v9fs_cache_inode_index_def = { .name = "9p.inode", .type = FSCACHE_COOKIE_TYPE_DATAFILE, .get_key = v9fs_cache_inode_get_key, .get_attr = v9fs_cache_inode_get_attr, .get_aux = v9fs_cache_inode_get_aux, .check_aux = v9fs_cache_inode_check_aux, .now_uncached = v9fs_cache_inode_now_uncached, }; void v9fs_cache_inode_get_cookie(struct inode *inode) { struct v9fs_inode *v9inode; struct v9fs_session_info *v9ses; if (!S_ISREG(inode->i_mode)) return; v9inode = V9FS_I(inode); if (v9inode->fscache) return; v9ses = v9fs_inode2v9ses(inode); v9inode->fscache = fscache_acquire_cookie(v9ses->fscache, &v9fs_cache_inode_index_def, v9inode, true); p9_debug(P9_DEBUG_FSC, "inode %p get cookie %p\n", inode, v9inode->fscache); } void v9fs_cache_inode_put_cookie(struct inode *inode) { struct v9fs_inode *v9inode = V9FS_I(inode); if (!v9inode->fscache) return; p9_debug(P9_DEBUG_FSC, "inode %p put cookie %p\n", inode, v9inode->fscache); fscache_relinquish_cookie(v9inode->fscache, 0); v9inode->fscache = NULL; } void v9fs_cache_inode_flush_cookie(struct inode *inode) { struct v9fs_inode *v9inode = V9FS_I(inode); if (!v9inode->fscache) return; p9_debug(P9_DEBUG_FSC, "inode %p flush cookie %p\n", inode, v9inode->fscache); fscache_relinquish_cookie(v9inode->fscache, 1); v9inode->fscache = NULL; } void v9fs_cache_inode_set_cookie(struct inode *inode, struct file *filp) { struct v9fs_inode *v9inode = V9FS_I(inode); if (!v9inode->fscache) return; mutex_lock(&v9inode->fscache_lock); if ((filp->f_flags & O_ACCMODE) != O_RDONLY) v9fs_cache_inode_flush_cookie(inode); else v9fs_cache_inode_get_cookie(inode); mutex_unlock(&v9inode->fscache_lock); } void v9fs_cache_inode_reset_cookie(struct inode *inode) { struct v9fs_inode *v9inode = V9FS_I(inode); struct v9fs_session_info *v9ses; struct fscache_cookie *old; if (!v9inode->fscache) return; old = v9inode->fscache; mutex_lock(&v9inode->fscache_lock); fscache_relinquish_cookie(v9inode->fscache, 1); v9ses = v9fs_inode2v9ses(inode); v9inode->fscache = fscache_acquire_cookie(v9ses->fscache, &v9fs_cache_inode_index_def, v9inode, true); p9_debug(P9_DEBUG_FSC, "inode %p revalidating cookie old %p new %p\n", inode, old, v9inode->fscache); mutex_unlock(&v9inode->fscache_lock); } int __v9fs_fscache_release_page(struct page *page, gfp_t gfp) { struct inode *inode = page->mapping->host; struct v9fs_inode *v9inode = V9FS_I(inode); BUG_ON(!v9inode->fscache); return fscache_maybe_release_page(v9inode->fscache, page, gfp); } void __v9fs_fscache_invalidate_page(struct page *page) { struct inode *inode = page->mapping->host; struct v9fs_inode *v9inode = V9FS_I(inode); BUG_ON(!v9inode->fscache); if (PageFsCache(page)) { fscache_wait_on_page_write(v9inode->fscache, page); BUG_ON(!PageLocked(page)); fscache_uncache_page(v9inode->fscache, page); } } static void v9fs_vfs_readpage_complete(struct page *page, void *data, int error) { if (!error) SetPageUptodate(page); unlock_page(page); } /** * __v9fs_readpage_from_fscache - read a page from cache * * Returns 0 if the pages are in cache and a BIO is submitted, * 1 if the pages are not in cache and -error otherwise. */ int __v9fs_readpage_from_fscache(struct inode *inode, struct page *page) { int ret; const struct v9fs_inode *v9inode = V9FS_I(inode); p9_debug(P9_DEBUG_FSC, "inode %p page %p\n", inode, page); if (!v9inode->fscache) return -ENOBUFS; ret = fscache_read_or_alloc_page(v9inode->fscache, page, v9fs_vfs_readpage_complete, NULL, GFP_KERNEL); switch (ret) { case -ENOBUFS: case -ENODATA: p9_debug(P9_DEBUG_FSC, "page/inode not in cache %d\n", ret); return 1; case 0: p9_debug(P9_DEBUG_FSC, "BIO submitted\n"); return ret; default: p9_debug(P9_DEBUG_FSC, "ret %d\n", ret); return ret; } } /** * __v9fs_readpages_from_fscache - read multiple pages from cache * * Returns 0 if the pages are in cache and a BIO is submitted, * 1 if the pages are not in cache and -error otherwise. */ int __v9fs_readpages_from_fscache(struct inode *inode, struct address_space *mapping, struct list_head *pages, unsigned *nr_pages) { int ret; const struct v9fs_inode *v9inode = V9FS_I(inode); p9_debug(P9_DEBUG_FSC, "inode %p pages %u\n", inode, *nr_pages); if (!v9inode->fscache) return -ENOBUFS; ret = fscache_read_or_alloc_pages(v9inode->fscache, mapping, pages, nr_pages, v9fs_vfs_readpage_complete, NULL, mapping_gfp_mask(mapping)); switch (ret) { case -ENOBUFS: case -ENODATA: p9_debug(P9_DEBUG_FSC, "pages/inodes not in cache %d\n", ret); return 1; case 0: BUG_ON(!list_empty(pages)); BUG_ON(*nr_pages != 0); p9_debug(P9_DEBUG_FSC, "BIO submitted\n"); return ret; default: p9_debug(P9_DEBUG_FSC, "ret %d\n", ret); return ret; } } /** * __v9fs_readpage_to_fscache - write a page to the cache * */ void __v9fs_readpage_to_fscache(struct inode *inode, struct page *page) { int ret; const struct v9fs_inode *v9inode = V9FS_I(inode); p9_debug(P9_DEBUG_FSC, "inode %p page %p\n", inode, page); ret = fscache_write_page(v9inode->fscache, page, GFP_KERNEL); p9_debug(P9_DEBUG_FSC, "ret = %d\n", ret); if (ret != 0) v9fs_uncache_page(inode, page); } /* * wait for a page to complete writing to the cache */ void __v9fs_fscache_wait_on_page_write(struct inode *inode, struct page *page) { const struct v9fs_inode *v9inode = V9FS_I(inode); p9_debug(P9_DEBUG_FSC, "inode %p page %p\n", inode, page); if (PageFsCache(page)) fscache_wait_on_page_write(v9inode->fscache, page); }