#endif /* USABLE_KERNEL_PAGE_SYMLINK_CACHE */
#if defined(AFS_CACHE_BYPASS)
-static inline int
-afs_linux_can_bypass(struct inode *ip) {
- switch(cache_bypass_strategy) {
- case NEVER_BYPASS_CACHE:
- return 0;
- case ALWAYS_BYPASS_CACHE:
- return 1;
- case LARGE_FILES_BYPASS_CACHE:
- if(i_size_read(ip) > cache_bypass_threshold)
- return 1;
- default:
- }
- return 0;
-}
-
-static int
-afs_linux_cache_bypass_read(struct file *fp, struct address_space *mapping,
- struct list_head *page_list, unsigned num_pages)
-{
- afs_int32 page_ix;
- uio_t *auio;
- afs_offs_t offset;
- struct iovec* iovecp;
- struct nocache_read_request *ancr;
- struct page *pp, *ppt;
- struct pagevec lrupv;
- afs_int32 code = 0;
-
- cred_t *credp;
- struct inode *ip = FILE_INODE(fp);
- struct vcache *avc = VTOAFS(ip);
- afs_int32 bypasscache = 0; /* bypass for this read */
- afs_int32 base_index = 0;
- afs_int32 page_count = 0;
- afs_int32 isize;
-
- /* background thread must free: iovecp, auio, ancr */
- iovecp = osi_Alloc(num_pages * sizeof(struct iovec));
-
- auio = osi_Alloc(sizeof(uio_t));
- auio->uio_iov = iovecp;
- auio->uio_iovcnt = num_pages;
- auio->uio_flag = UIO_READ;
- auio->uio_seg = AFS_UIOSYS;
- auio->uio_resid = num_pages * PAGE_SIZE;
-
- ancr = osi_Alloc(sizeof(struct nocache_read_request));
- ancr->auio = auio;
- ancr->offset = auio->uio_offset;
- ancr->length = auio->uio_resid;
-
- pagevec_init(&lrupv, 0);
-
- for(page_ix = 0; page_ix < num_pages; ++page_ix) {
-
- if(list_empty(page_list))
- break;
-
- pp = list_entry(page_list->prev, struct page, lru);
- /* If we allocate a page and don't remove it from page_list,
- * the page cache gets upset. */
- list_del(&pp->lru);
- isize = (i_size_read(fp->f_mapping->host) - 1) >> PAGE_CACHE_SHIFT;
- if(pp->index > isize) {
- if(PageLocked(pp))
- UnlockPage(pp);
- continue;
- }
-
- if(page_ix == 0) {
- offset = ((loff_t) pp->index) << PAGE_CACHE_SHIFT;
- auio->uio_offset = offset;
- base_index = pp->index;
- }
- iovecp[page_ix].iov_len = PAGE_SIZE;
- code = add_to_page_cache(pp, mapping, pp->index, GFP_KERNEL);
- if(base_index != pp->index) {
- if(PageLocked(pp))
- UnlockPage(pp);
- page_cache_release(pp);
- iovecp[page_ix].iov_base = (void *) 0;
- base_index++;
- continue;
- }
- base_index++;
- if(code) {
- if(PageLocked(pp))
- UnlockPage(pp);
- page_cache_release(pp);
- iovecp[page_ix].iov_base = (void *) 0;
- } else {
- page_count++;
- if(!PageLocked(pp)) {
- LockPage(pp);
- }
-
- /* save the page for background map */
- iovecp[page_ix].iov_base = (void*) pp;
-
- /* and put it on the LRU cache */
- if (!pagevec_add(&lrupv, pp))
- __pagevec_lru_add(&lrupv);
- }
- }
-
- /* If there were useful pages in the page list, make sure all pages
- * are in the LRU cache, then schedule the read */
- if(page_count) {
- pagevec_lru_add(&lrupv);
- credp = crref();
- code = afs_ReadNoCache(avc, ancr, credp);
- crfree(credp);
- } else {
- /* If there is nothing for the background thread to handle,
- * it won't be freeing the things that we never gave it */
- osi_Free(iovecp, num_pages * sizeof(struct iovec));
- osi_Free(auio, sizeof(uio_t));
- osi_Free(ancr, sizeof(struct nocache_read_request));
- }
- /* we do not flush, release, or unmap pages--that will be
- * done for us by the background thread as each page comes in
- * from the fileserver */
-out:
- return afs_convert_code(code);
-}
-
#endif /* defined(AFS_CACHE_BYPASS */
+/* Populate a page by filling it from the cache file pointed at by cachefp
+ * (which contains indicated chunk)
+ * If task is NULL, the page copy occurs syncronously, and the routine
+ * returns with page still locked. If task is non-NULL, then page copies
+ * may occur in the background, and the page will be unlocked when it is
+ * ready for use.
+ */
static int
afs_linux_read_cache(struct file *cachefp, struct page *page,
int chunk, struct pagevec *lrupv,
copy_highpage(page, cachepage);
flush_dcache_page(page);
SetPageUptodate(page);
- UnlockPage(page);
+
+ if (task)
+ UnlockPage(page);
} else if (task) {
afs_pagecopy_queue_page(task, cachepage, page);
} else {
}
}
- if (code) {
+ if (code && task) {
UnlockPage(page);
}
}
/* afs_linux_readpage
- * all reads come through here. A strategy-like read call.
+ *
+ * This function is split into two, because prepare_write/begin_write
+ * require a readpage call which doesn't unlock the resulting page upon
+ * success.
*/
static int
-afs_linux_readpage(struct file *fp, struct page *pp)
+afs_linux_fillpage(struct file *fp, struct page *pp)
{
afs_int32 code;
char *address;
- afs_offs_t offset = ((loff_t) pp->index) << PAGE_CACHE_SHIFT;
-#if defined(AFS_CACHE_BYPASS)
- afs_int32 bypasscache = 0; /* bypass for this read */
- struct nocache_read_request *ancr;
- afs_int32 isize;
-#endif
uio_t *auio;
struct iovec *iovecp;
struct inode *ip = FILE_INODE(fp);
afs_int32 cnt = page_count(pp);
struct vcache *avc = VTOAFS(ip);
+ afs_offs_t offset = page_offset(pp);
cred_t *credp;
AFS_GLOCK();
address = kmap(pp);
ClearPageError(pp);
- /* if bypasscache, receiver frees, else we do */
auio = osi_Alloc(sizeof(uio_t));
iovecp = osi_Alloc(sizeof(struct iovec));
setup_uio(auio, iovecp, (char *)address, offset, PAGE_SIZE, UIO_READ,
- AFS_UIOSYS);
+ AFS_UIOSYS);
-#if defined(AFS_CACHE_BYPASS)
- bypasscache = afs_linux_can_bypass(ip);
-
- /* In the new incarnation of selective caching, a file's caching policy
- * can change, eg because file size exceeds threshold, etc. */
- trydo_cache_transition(avc, credp, bypasscache);
-
- if(bypasscache) {
- if(address)
- kunmap(pp);
- /* save the page for background map */
- auio->uio_iov->iov_base = (void*) pp;
- /* the background thread will free this */
- ancr = osi_Alloc(sizeof(struct nocache_read_request));
- ancr->auio = auio;
- ancr->offset = offset;
- ancr->length = PAGE_SIZE;
-
- afs_maybe_lock_kernel();
- code = afs_ReadNoCache(avc, ancr, credp);
- afs_maybe_unlock_kernel();
-
- goto done; /* skips release page, doing it in bg thread */
- }
-#endif
-
afs_maybe_lock_kernel();
AFS_GLOCK();
AFS_DISCON_LOCK();
} /* !code */
kunmap(pp);
- UnlockPage(pp);
-#if defined(AFS_CACHE_BYPASS)
- /* do not call afs_GetDCache if cache is bypassed */
- if(bypasscache)
- goto done;
-#endif
-
- /* free if not bypassing cache */
osi_Free(auio, sizeof(uio_t));
osi_Free(iovecp, sizeof(struct iovec));
- if (!code && AFS_CHUNKOFFSET(offset) == 0) {
+ crfree(credp);
+ return afs_convert_code(code);
+}
+
+static int
+afs_linux_prefetch(struct file *fp, struct page *pp)
+{
+ int code = 0;
+ struct vcache *avc = VTOAFS(FILE_INODE(fp));
+ afs_offs_t offset = page_offset(pp);
+
+ if (AFS_CHUNKOFFSET(offset) == 0) {
struct dcache *tdc;
struct vrequest treq;
+ cred_t *credp;
+ credp = crref();
AFS_GLOCK();
code = afs_InitReq(&treq, credp);
if (!code && !NBObtainWriteLock(&avc->lock, 534)) {
ReleaseWriteLock(&avc->lock);
}
AFS_GUNLOCK();
+ crfree(credp);
}
+ return afs_convert_code(code);
+
+}
#if defined(AFS_CACHE_BYPASS)
-done:
-#endif
+
+static int
+afs_linux_bypass_readpages(struct file *fp, struct address_space *mapping,
+ struct list_head *page_list, unsigned num_pages)
+{
+ afs_int32 page_ix;
+ uio_t *auio;
+ afs_offs_t offset;
+ struct iovec* iovecp;
+ struct nocache_read_request *ancr;
+ struct page *pp, *ppt;
+ struct pagevec lrupv;
+ afs_int32 code = 0;
+
+ cred_t *credp;
+ struct inode *ip = FILE_INODE(fp);
+ struct vcache *avc = VTOAFS(ip);
+ afs_int32 base_index = 0;
+ afs_int32 page_count = 0;
+ afs_int32 isize;
+
+ /* background thread must free: iovecp, auio, ancr */
+ iovecp = osi_Alloc(num_pages * sizeof(struct iovec));
+
+ auio = osi_Alloc(sizeof(uio_t));
+ auio->uio_iov = iovecp;
+ auio->uio_iovcnt = num_pages;
+ auio->uio_flag = UIO_READ;
+ auio->uio_seg = AFS_UIOSYS;
+ auio->uio_resid = num_pages * PAGE_SIZE;
+
+ ancr = osi_Alloc(sizeof(struct nocache_read_request));
+ ancr->auio = auio;
+ ancr->offset = auio->uio_offset;
+ ancr->length = auio->uio_resid;
+
+ pagevec_init(&lrupv, 0);
+
+ for(page_ix = 0; page_ix < num_pages; ++page_ix) {
+
+ if(list_empty(page_list))
+ break;
+
+ pp = list_entry(page_list->prev, struct page, lru);
+ /* If we allocate a page and don't remove it from page_list,
+ * the page cache gets upset. */
+ list_del(&pp->lru);
+ isize = (i_size_read(fp->f_mapping->host) - 1) >> PAGE_CACHE_SHIFT;
+ if(pp->index > isize) {
+ if(PageLocked(pp))
+ UnlockPage(pp);
+ continue;
+ }
+
+ if(page_ix == 0) {
+ offset = ((lof_t) pp->index) << PAGE_CACHE_SHIFT;
+ auio->uio_offset = offset;
+ base_index = pp->index;
+ }
+ iovecp[page_ix].iov_len = PAGE_SIZE;
+ code = add_to_page_cache(pp, mapping, pp->index, GFP_KERNEL);
+ if(base_index != pp->index) {
+ if(PageLocked(pp))
+ UnlockPage(pp);
+ page_cache_release(pp);
+ iovecp[page_ix].iov_base = (void *) 0;
+ base_index++;
+ continue;
+ }
+ base_index++;
+ if(code) {
+ if(PageLocked(pp))
+ UnlockPage(pp);
+ page_cache_release(pp);
+ iovecp[page_ix].iov_base = (void *) 0;
+ } else {
+ page_count++;
+ if(!PageLocked(pp)) {
+ LockPage(pp);
+ }
+
+ /* save the page for background map */
+ iovecp[page_ix].iov_base = (void*) pp;
+
+ /* and put it on the LRU cache */
+ if (!pagevec_add(&lrupv, pp))
+ __pagevec_lru_add(&lrupv);
+ }
+ }
+
+ /* If there were useful pages in the page list, make sure all pages
+ * are in the LRU cache, then schedule the read */
+ if(page_count) {
+ pagevec_lru_add(&lrupv);
+ credp = crref();
+ code = afs_ReadNoCache(avc, ancr, credp);
+ crfree(credp);
+ } else {
+ /* If there is nothing for the background thread to handle,
+ * it won't be freeing the things that we never gave it */
+ osi_Free(iovecp, num_pages * sizeof(struct iovec));
+ osi_Free(auio, sizeof(uio_t));
+ osi_Free(ancr, sizeof(struct nocache_read_request));
+ }
+ /* we do not flush, release, or unmap pages--that will be
+ * done for us by the background thread as each page comes in
+ * from the fileserver */
+out:
+ return afs_convert_code(code);
+}
+
+
+static int
+afs_linux_bypass_readpage(struct file *fp, struct page *pp)
+{
+ cred_t *credp = NULL;
+ uio_t *auio;
+ struct iovec *iovecp;
+ struct nocache_read_request *ancr;
+ afs_int32 isize;
+
+ ClearPageError(pp);
+
+ /* If the page is past the end of the file, skip it */
+ isize = (i_size_read(fp->f_mapping->host) - 1) >> PAGE_CACHE_SHIFT;
+ if(pp->index > isize) {
+ if (PageLocked(pp))
+ UnlockPage(pp);
+ return 0;
+ }
+ /* receiver frees */
+ auio = osi_Alloc(sizeof(uio_t));
+ iovecp = osi_Alloc(sizeof(struct iovec));
+
+ /* address can be NULL, because we overwrite it with 'pp', below */
+ setup_uio(auio, iovecp, NULL, (pp->index << PAGE_CACHE_SHIFT),
+ PAGE_SIZE, UIO_READ, AFS_UIOSYS);
+
+ /* save the page for background map */
+ /* XXX - Shouldn't we get a reference count here? */
+ auio->uio_iov->iov_base = (void*) pp;
+ /* the background thread will free this */
+ ancr = osi_Alloc(sizeof(struct nocache_read_request));
+ ancr->auio = auio;
+ ancr->offset = offset;
+ ancr->length = PAGE_SIZE;
+
+ credp = crref();
+ afs_maybe_lock_kernel();
+ code = afs_ReadNoCache(VTOAFS(FILE_INODE(fp)), ancr, credp);
+ afs_maybe_unlock_kernel();
crfree(credp);
+
return afs_convert_code(code);
}
+static inline int
+afs_linux_can_bypass(struct inode *ip) {
+ switch(cache_bypass_strategy) {
+ case NEVER_BYPASS_CACHE:
+ return 0;
+ case ALWAYS_BYPASS_CACHE:
+ return 1;
+ case LARGE_FILES_BYPASS_CACHE:
+ if(i_size_read(ip) > cache_bypass_threshold)
+ return 1;
+ default:
+ }
+ return 0;
+}
+
+/* Check if a file is permitted to bypass the cache by policy, and modify
+ * the cache bypass state recorded for that file */
+
+static inline int
+afs_linux_bypass_check(struct inode *ip) {
+ struct cred* credp;
+
+ int bypass = afs_linux_can_bypass(ip);
+
+ credp = crref();
+ trydo_cache_transition(VTOAFS(ip)), credp, bypass);
+ crfree(credp);
+
+ return bypass;
+}
+
+#else
+static inline int
+afs_linux_bypass_check(struct inode *ip) {
+ return 0;
+}
+static inline int
+afs_linux_bypass_readpage(struct file *fp, struct page *pp) {
+ return 0;
+}
+static inline int
+afs_linux_bypass_readpages(struct file *fp, struct address_space *mapping,
+ struct list_head *page_list, unsigned int num_pages) {
+ return 0;
+}
+#endif
+
+static int
+afs_linux_readpage(struct file *fp, struct page *pp)
+{
+ int code;
+
+ if (afs_linux_bypass_check(FILE_INODE(fp))) {
+ code = afs_linux_bypass_readpage(fp, pp);
+ } else {
+ code = afs_linux_fillpage(fp, pp);
+ if (!code)
+ code = afs_linux_prefetch(fp, pp);
+ UnlockPage(pp);
+ }
+
+ return code;
+}
+
/* Readpages reads a number of pages for a particular file. We use
* this to optimise the reading, by limiting the number of times upon which
* we have to lookup, lock and open vcaches and dcaches
struct pagevec lrupv;
struct afs_pagecopy_task *task;
-#if defined(AFS_CACHE_BYPASS)
- bypasscache = afs_linux_can_bypass(ip);
-
- /* In the new incarnation of selective caching, a file's caching policy
- * can change, eg because file size exceeds threshold, etc. */
- trydo_cache_transition(avc, credp, bypasscache);
-
- if (bypasscache)
- return afs_linux_cache_bypass_read(ip, mapping, page_list, num_pages);
-#endif
+ if (afs_linux_bypass_check(inode))
+ return afs_linux_bypass_readpages(fp, mapping, page_list, num_pages);
AFS_GLOCK();
if ((code = afs_linux_VerifyVCache(avc, NULL))) {
git://git.openafs.org / openafs.git / commitdiff