From 9b3f26c9110dcea62716aca9b8c68ceb482227ef Mon Sep 17 00:00:00 2001 From: David Howells Date: Fri, 3 Apr 2009 16:42:41 +0100 Subject: FS-Cache: Make kAFS use FS-Cache The attached patch makes the kAFS filesystem in fs/afs/ use FS-Cache, and through it any attached caches. The kAFS filesystem will use caching automatically if it's available. Signed-off-by: David Howells Acked-by: Steve Dickson Acked-by: Trond Myklebust Acked-by: Al Viro Tested-by: Daire Byrne --- fs/afs/file.c | 220 ++++++++++++++++++++++++++++++++++++++-------------------- 1 file changed, 143 insertions(+), 77 deletions(-) (limited to 'fs/afs/file.c') diff --git a/fs/afs/file.c b/fs/afs/file.c index a3901769a96..7a1d942ef68 100644 --- a/fs/afs/file.c +++ b/fs/afs/file.c @@ -23,6 +23,9 @@ static void afs_invalidatepage(struct page *page, unsigned long offset); static int afs_releasepage(struct page *page, gfp_t gfp_flags); static int afs_launder_page(struct page *page); +static int afs_readpages(struct file *filp, struct address_space *mapping, + struct list_head *pages, unsigned nr_pages); + const struct file_operations afs_file_operations = { .open = afs_open, .release = afs_release, @@ -46,6 +49,7 @@ const struct inode_operations afs_file_inode_operations = { const struct address_space_operations afs_fs_aops = { .readpage = afs_readpage, + .readpages = afs_readpages, .set_page_dirty = afs_set_page_dirty, .launder_page = afs_launder_page, .releasepage = afs_releasepage, @@ -101,37 +105,18 @@ int afs_release(struct inode *inode, struct file *file) /* * deal with notification that a page was read from the cache */ -#ifdef AFS_CACHING_SUPPORT -static void afs_readpage_read_complete(void *cookie_data, - struct page *page, - void *data, - int error) +static void afs_file_readpage_read_complete(struct page *page, + void *data, + int error) { - _enter("%p,%p,%p,%d", cookie_data, page, data, error); + _enter("%p,%p,%d", page, data, error); - if (error) - SetPageError(page); - else + /* if the read completes with an error, we just unlock the page and let + * the VM reissue the readpage */ + if (!error) SetPageUptodate(page); unlock_page(page); - } -#endif - -/* - * deal with notification that a page was written to the cache - */ -#ifdef AFS_CACHING_SUPPORT -static void afs_readpage_write_complete(void *cookie_data, - struct page *page, - void *data, - int error) -{ - _enter("%p,%p,%p,%d", cookie_data, page, data, error); - - unlock_page(page); -} -#endif /* * AFS read page from file, directory or symlink @@ -161,9 +146,9 @@ static int afs_readpage(struct file *file, struct page *page) if (test_bit(AFS_VNODE_DELETED, &vnode->flags)) goto error; -#ifdef AFS_CACHING_SUPPORT /* is it cached? */ - ret = cachefs_read_or_alloc_page(vnode->cache, +#ifdef CONFIG_AFS_FSCACHE + ret = fscache_read_or_alloc_page(vnode->cache, page, afs_file_readpage_read_complete, NULL, @@ -171,20 +156,21 @@ static int afs_readpage(struct file *file, struct page *page) #else ret = -ENOBUFS; #endif - switch (ret) { - /* read BIO submitted and wb-journal entry found */ - case 1: - BUG(); // TODO - handle wb-journal match - /* read BIO submitted (page in cache) */ case 0: break; - /* no page available in cache */ - case -ENOBUFS: + /* page not yet cached */ case -ENODATA: + _debug("cache said ENODATA"); + goto go_on; + + /* page will not be cached */ + case -ENOBUFS: + _debug("cache said ENOBUFS"); default: + go_on: offset = page->index << PAGE_CACHE_SHIFT; len = min_t(size_t, i_size_read(inode) - offset, PAGE_SIZE); @@ -198,27 +184,25 @@ static int afs_readpage(struct file *file, struct page *page) set_bit(AFS_VNODE_DELETED, &vnode->flags); ret = -ESTALE; } -#ifdef AFS_CACHING_SUPPORT - cachefs_uncache_page(vnode->cache, page); + +#ifdef CONFIG_AFS_FSCACHE + fscache_uncache_page(vnode->cache, page); #endif + BUG_ON(PageFsCache(page)); goto error; } SetPageUptodate(page); -#ifdef AFS_CACHING_SUPPORT - if (cachefs_write_page(vnode->cache, - page, - afs_file_readpage_write_complete, - NULL, - GFP_KERNEL) != 0 - ) { - cachefs_uncache_page(vnode->cache, page); - unlock_page(page); + /* send the page to the cache */ +#ifdef CONFIG_AFS_FSCACHE + if (PageFsCache(page) && + fscache_write_page(vnode->cache, page, GFP_KERNEL) != 0) { + fscache_uncache_page(vnode->cache, page); + BUG_ON(PageFsCache(page)); } -#else - unlock_page(page); #endif + unlock_page(page); } _leave(" = 0"); @@ -232,34 +216,59 @@ error: } /* - * invalidate part or all of a page + * read a set of pages */ -static void afs_invalidatepage(struct page *page, unsigned long offset) +static int afs_readpages(struct file *file, struct address_space *mapping, + struct list_head *pages, unsigned nr_pages) { - int ret = 1; + struct afs_vnode *vnode; + int ret = 0; - _enter("{%lu},%lu", page->index, offset); + _enter(",{%lu},,%d", mapping->host->i_ino, nr_pages); - BUG_ON(!PageLocked(page)); + vnode = AFS_FS_I(mapping->host); + if (vnode->flags & AFS_VNODE_DELETED) { + _leave(" = -ESTALE"); + return -ESTALE; + } - if (PagePrivate(page)) { - /* We release buffers only if the entire page is being - * invalidated. - * The get_block cached value has been unconditionally - * invalidated, so real IO is not possible anymore. - */ - if (offset == 0) { - BUG_ON(!PageLocked(page)); - - ret = 0; - if (!PageWriteback(page)) - ret = page->mapping->a_ops->releasepage(page, - 0); - /* possibly should BUG_ON(!ret); - neilb */ - } + /* attempt to read as many of the pages as possible */ +#ifdef CONFIG_AFS_FSCACHE + ret = fscache_read_or_alloc_pages(vnode->cache, + mapping, + pages, + &nr_pages, + afs_file_readpage_read_complete, + NULL, + mapping_gfp_mask(mapping)); +#else + ret = -ENOBUFS; +#endif + + switch (ret) { + /* all pages are being read from the cache */ + case 0: + BUG_ON(!list_empty(pages)); + BUG_ON(nr_pages != 0); + _leave(" = 0 [reading all]"); + return 0; + + /* there were pages that couldn't be read from the cache */ + case -ENODATA: + case -ENOBUFS: + break; + + /* other error */ + default: + _leave(" = %d", ret); + return ret; } - _leave(" = %d", ret); + /* load the missing pages from the network */ + ret = read_cache_pages(mapping, pages, (void *) afs_readpage, file); + + _leave(" = %d [netting]", ret); + return ret; } /* @@ -273,25 +282,82 @@ static int afs_launder_page(struct page *page) } /* - * release a page and cleanup its private data + * invalidate part or all of a page + * - release a page and clean up its private data if offset is 0 (indicating + * the entire page) + */ +static void afs_invalidatepage(struct page *page, unsigned long offset) +{ + struct afs_writeback *wb = (struct afs_writeback *) page_private(page); + + _enter("{%lu},%lu", page->index, offset); + + BUG_ON(!PageLocked(page)); + + /* we clean up only if the entire page is being invalidated */ + if (offset == 0) { +#ifdef CONFIG_AFS_FSCACHE + if (PageFsCache(page)) { + struct afs_vnode *vnode = AFS_FS_I(page->mapping->host); + fscache_wait_on_page_write(vnode->cache, page); + fscache_uncache_page(vnode->cache, page); + ClearPageFsCache(page); + } +#endif + + if (PagePrivate(page)) { + if (wb && !PageWriteback(page)) { + set_page_private(page, 0); + afs_put_writeback(wb); + } + + if (!page_private(page)) + ClearPagePrivate(page); + } + } + + _leave(""); +} + +/* + * release a page and clean up its private state if it's not busy + * - return true if the page can now be released, false if not */ static int afs_releasepage(struct page *page, gfp_t gfp_flags) { + struct afs_writeback *wb = (struct afs_writeback *) page_private(page); struct afs_vnode *vnode = AFS_FS_I(page->mapping->host); - struct afs_writeback *wb; _enter("{{%x:%u}[%lu],%lx},%x", vnode->fid.vid, vnode->fid.vnode, page->index, page->flags, gfp_flags); + /* deny if page is being written to the cache and the caller hasn't + * elected to wait */ +#ifdef CONFIG_AFS_FSCACHE + if (PageFsCache(page)) { + if (fscache_check_page_write(vnode->cache, page)) { + if (!(gfp_flags & __GFP_WAIT)) { + _leave(" = F [cache busy]"); + return 0; + } + fscache_wait_on_page_write(vnode->cache, page); + } + + fscache_uncache_page(vnode->cache, page); + ClearPageFsCache(page); + } +#endif + if (PagePrivate(page)) { - wb = (struct afs_writeback *) page_private(page); - ASSERT(wb != NULL); - set_page_private(page, 0); + if (wb) { + set_page_private(page, 0); + afs_put_writeback(wb); + } ClearPagePrivate(page); - afs_put_writeback(wb); } - _leave(" = 0"); - return 0; + /* indicate that the page can be released */ + _leave(" = T"); + return 1; } -- cgit v1.2.3