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338 lines
8.1 KiB
338 lines
8.1 KiB
// SPDX-License-Identifier: GPL-2.0-only |
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/* |
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* V9FS cache definitions. |
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* |
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* Copyright (C) 2009 by Abhishek Kulkarni <[email protected]> |
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*/ |
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#include <linux/jiffies.h> |
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#include <linux/file.h> |
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#include <linux/slab.h> |
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#include <linux/stat.h> |
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#include <linux/sched.h> |
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#include <linux/fs.h> |
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#include <net/9p/9p.h> |
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#include "v9fs.h" |
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#include "cache.h" |
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#define CACHETAG_LEN 11 |
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struct fscache_netfs v9fs_cache_netfs = { |
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.name = "9p", |
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.version = 0, |
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}; |
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/** |
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* v9fs_random_cachetag - Generate a random tag to be associated |
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* with a new cache session. |
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* |
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* The value of jiffies is used for a fairly randomly cache tag. |
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*/ |
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static |
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int v9fs_random_cachetag(struct v9fs_session_info *v9ses) |
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{ |
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v9ses->cachetag = kmalloc(CACHETAG_LEN, GFP_KERNEL); |
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if (!v9ses->cachetag) |
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return -ENOMEM; |
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return scnprintf(v9ses->cachetag, CACHETAG_LEN, "%lu", jiffies); |
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} |
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const struct fscache_cookie_def v9fs_cache_session_index_def = { |
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.name = "9P.session", |
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.type = FSCACHE_COOKIE_TYPE_INDEX, |
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}; |
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void v9fs_cache_session_get_cookie(struct v9fs_session_info *v9ses) |
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{ |
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/* If no cache session tag was specified, we generate a random one. */ |
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if (!v9ses->cachetag) { |
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if (v9fs_random_cachetag(v9ses) < 0) { |
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v9ses->fscache = NULL; |
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kfree(v9ses->cachetag); |
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v9ses->cachetag = NULL; |
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return; |
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} |
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} |
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v9ses->fscache = fscache_acquire_cookie(v9fs_cache_netfs.primary_index, |
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&v9fs_cache_session_index_def, |
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v9ses->cachetag, |
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strlen(v9ses->cachetag), |
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NULL, 0, |
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v9ses, 0, true); |
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p9_debug(P9_DEBUG_FSC, "session %p get cookie %p\n", |
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v9ses, v9ses->fscache); |
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} |
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void v9fs_cache_session_put_cookie(struct v9fs_session_info *v9ses) |
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{ |
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p9_debug(P9_DEBUG_FSC, "session %p put cookie %p\n", |
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v9ses, v9ses->fscache); |
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fscache_relinquish_cookie(v9ses->fscache, NULL, false); |
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v9ses->fscache = NULL; |
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} |
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static enum |
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fscache_checkaux v9fs_cache_inode_check_aux(void *cookie_netfs_data, |
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const void *buffer, |
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uint16_t buflen, |
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loff_t object_size) |
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{ |
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const struct v9fs_inode *v9inode = cookie_netfs_data; |
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if (buflen != sizeof(v9inode->qid.version)) |
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return FSCACHE_CHECKAUX_OBSOLETE; |
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if (memcmp(buffer, &v9inode->qid.version, |
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sizeof(v9inode->qid.version))) |
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return FSCACHE_CHECKAUX_OBSOLETE; |
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return FSCACHE_CHECKAUX_OKAY; |
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} |
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const struct fscache_cookie_def v9fs_cache_inode_index_def = { |
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.name = "9p.inode", |
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.type = FSCACHE_COOKIE_TYPE_DATAFILE, |
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.check_aux = v9fs_cache_inode_check_aux, |
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}; |
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void v9fs_cache_inode_get_cookie(struct inode *inode) |
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{ |
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struct v9fs_inode *v9inode; |
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struct v9fs_session_info *v9ses; |
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if (!S_ISREG(inode->i_mode)) |
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return; |
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v9inode = V9FS_I(inode); |
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if (v9inode->fscache) |
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return; |
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v9ses = v9fs_inode2v9ses(inode); |
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v9inode->fscache = fscache_acquire_cookie(v9ses->fscache, |
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&v9fs_cache_inode_index_def, |
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&v9inode->qid.path, |
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sizeof(v9inode->qid.path), |
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&v9inode->qid.version, |
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sizeof(v9inode->qid.version), |
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v9inode, |
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i_size_read(&v9inode->vfs_inode), |
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true); |
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p9_debug(P9_DEBUG_FSC, "inode %p get cookie %p\n", |
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inode, v9inode->fscache); |
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} |
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void v9fs_cache_inode_put_cookie(struct inode *inode) |
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{ |
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struct v9fs_inode *v9inode = V9FS_I(inode); |
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if (!v9inode->fscache) |
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return; |
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p9_debug(P9_DEBUG_FSC, "inode %p put cookie %p\n", |
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inode, v9inode->fscache); |
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fscache_relinquish_cookie(v9inode->fscache, &v9inode->qid.version, |
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false); |
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v9inode->fscache = NULL; |
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} |
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void v9fs_cache_inode_flush_cookie(struct inode *inode) |
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{ |
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struct v9fs_inode *v9inode = V9FS_I(inode); |
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if (!v9inode->fscache) |
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return; |
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p9_debug(P9_DEBUG_FSC, "inode %p flush cookie %p\n", |
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inode, v9inode->fscache); |
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fscache_relinquish_cookie(v9inode->fscache, NULL, true); |
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v9inode->fscache = NULL; |
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} |
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void v9fs_cache_inode_set_cookie(struct inode *inode, struct file *filp) |
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{ |
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struct v9fs_inode *v9inode = V9FS_I(inode); |
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if (!v9inode->fscache) |
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return; |
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mutex_lock(&v9inode->fscache_lock); |
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if ((filp->f_flags & O_ACCMODE) != O_RDONLY) |
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v9fs_cache_inode_flush_cookie(inode); |
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else |
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v9fs_cache_inode_get_cookie(inode); |
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mutex_unlock(&v9inode->fscache_lock); |
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} |
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void v9fs_cache_inode_reset_cookie(struct inode *inode) |
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{ |
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struct v9fs_inode *v9inode = V9FS_I(inode); |
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struct v9fs_session_info *v9ses; |
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struct fscache_cookie *old; |
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if (!v9inode->fscache) |
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return; |
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old = v9inode->fscache; |
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mutex_lock(&v9inode->fscache_lock); |
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fscache_relinquish_cookie(v9inode->fscache, NULL, true); |
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v9ses = v9fs_inode2v9ses(inode); |
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v9inode->fscache = fscache_acquire_cookie(v9ses->fscache, |
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&v9fs_cache_inode_index_def, |
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&v9inode->qid.path, |
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sizeof(v9inode->qid.path), |
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&v9inode->qid.version, |
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sizeof(v9inode->qid.version), |
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v9inode, |
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i_size_read(&v9inode->vfs_inode), |
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true); |
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p9_debug(P9_DEBUG_FSC, "inode %p revalidating cookie old %p new %p\n", |
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inode, old, v9inode->fscache); |
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mutex_unlock(&v9inode->fscache_lock); |
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} |
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int __v9fs_fscache_release_page(struct page *page, gfp_t gfp) |
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{ |
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struct inode *inode = page->mapping->host; |
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struct v9fs_inode *v9inode = V9FS_I(inode); |
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BUG_ON(!v9inode->fscache); |
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return fscache_maybe_release_page(v9inode->fscache, page, gfp); |
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} |
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void __v9fs_fscache_invalidate_page(struct page *page) |
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{ |
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struct inode *inode = page->mapping->host; |
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struct v9fs_inode *v9inode = V9FS_I(inode); |
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BUG_ON(!v9inode->fscache); |
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if (PageFsCache(page)) { |
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fscache_wait_on_page_write(v9inode->fscache, page); |
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BUG_ON(!PageLocked(page)); |
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fscache_uncache_page(v9inode->fscache, page); |
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} |
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} |
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static void v9fs_vfs_readpage_complete(struct page *page, void *data, |
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int error) |
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{ |
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if (!error) |
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SetPageUptodate(page); |
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unlock_page(page); |
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} |
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/** |
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* __v9fs_readpage_from_fscache - read a page from cache |
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* |
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* Returns 0 if the pages are in cache and a BIO is submitted, |
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* 1 if the pages are not in cache and -error otherwise. |
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*/ |
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int __v9fs_readpage_from_fscache(struct inode *inode, struct page *page) |
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{ |
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int ret; |
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const struct v9fs_inode *v9inode = V9FS_I(inode); |
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p9_debug(P9_DEBUG_FSC, "inode %p page %p\n", inode, page); |
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if (!v9inode->fscache) |
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return -ENOBUFS; |
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ret = fscache_read_or_alloc_page(v9inode->fscache, |
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page, |
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v9fs_vfs_readpage_complete, |
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NULL, |
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GFP_KERNEL); |
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switch (ret) { |
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case -ENOBUFS: |
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case -ENODATA: |
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p9_debug(P9_DEBUG_FSC, "page/inode not in cache %d\n", ret); |
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return 1; |
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case 0: |
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p9_debug(P9_DEBUG_FSC, "BIO submitted\n"); |
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return ret; |
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default: |
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p9_debug(P9_DEBUG_FSC, "ret %d\n", ret); |
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return ret; |
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} |
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} |
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/** |
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* __v9fs_readpages_from_fscache - read multiple pages from cache |
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* |
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* Returns 0 if the pages are in cache and a BIO is submitted, |
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* 1 if the pages are not in cache and -error otherwise. |
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*/ |
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int __v9fs_readpages_from_fscache(struct inode *inode, |
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struct address_space *mapping, |
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struct list_head *pages, |
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unsigned *nr_pages) |
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{ |
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int ret; |
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const struct v9fs_inode *v9inode = V9FS_I(inode); |
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p9_debug(P9_DEBUG_FSC, "inode %p pages %u\n", inode, *nr_pages); |
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if (!v9inode->fscache) |
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return -ENOBUFS; |
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ret = fscache_read_or_alloc_pages(v9inode->fscache, |
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mapping, pages, nr_pages, |
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v9fs_vfs_readpage_complete, |
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NULL, |
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mapping_gfp_mask(mapping)); |
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switch (ret) { |
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case -ENOBUFS: |
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case -ENODATA: |
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p9_debug(P9_DEBUG_FSC, "pages/inodes not in cache %d\n", ret); |
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return 1; |
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case 0: |
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BUG_ON(!list_empty(pages)); |
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BUG_ON(*nr_pages != 0); |
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p9_debug(P9_DEBUG_FSC, "BIO submitted\n"); |
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return ret; |
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default: |
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p9_debug(P9_DEBUG_FSC, "ret %d\n", ret); |
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return ret; |
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} |
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} |
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/** |
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* __v9fs_readpage_to_fscache - write a page to the cache |
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* |
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*/ |
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void __v9fs_readpage_to_fscache(struct inode *inode, struct page *page) |
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{ |
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int ret; |
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const struct v9fs_inode *v9inode = V9FS_I(inode); |
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p9_debug(P9_DEBUG_FSC, "inode %p page %p\n", inode, page); |
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ret = fscache_write_page(v9inode->fscache, page, |
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i_size_read(&v9inode->vfs_inode), GFP_KERNEL); |
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p9_debug(P9_DEBUG_FSC, "ret = %d\n", ret); |
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if (ret != 0) |
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v9fs_uncache_page(inode, page); |
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} |
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/* |
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* wait for a page to complete writing to the cache |
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*/ |
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void __v9fs_fscache_wait_on_page_write(struct inode *inode, struct page *page) |
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{ |
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const struct v9fs_inode *v9inode = V9FS_I(inode); |
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p9_debug(P9_DEBUG_FSC, "inode %p page %p\n", inode, page); |
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if (PageFsCache(page)) |
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fscache_wait_on_page_write(v9inode->fscache, page); |
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}
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