diff options
Diffstat (limited to 'kernel/fs/9p/cache.c')
| -rw-r--r-- | kernel/fs/9p/cache.c | 414 |
1 files changed, 414 insertions, 0 deletions
diff --git a/kernel/fs/9p/cache.c b/kernel/fs/9p/cache.c new file mode 100644 index 000000000..a69260f27 --- /dev/null +++ b/kernel/fs/9p/cache.c @@ -0,0 +1,414 @@ +/* + * 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; + + spin_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); + + spin_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; + + spin_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); + + spin_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); +} |