From eb497943fa215897f2f60fd28aa6fe52da27ca6c Mon Sep 17 00:00:00 2001 From: David Howells Date: Tue, 2 Nov 2021 08:29:55 +0000 Subject: 9p: Convert to using the netfs helper lib to do reads and caching Convert the 9p filesystem to use the netfs helper lib to handle readpage, readahead and write_begin, converting those into a common issue_op for the filesystem itself to handle. The netfs helper lib also handles reading from fscache if a cache is available, and interleaving reads from both sources. This change also switches from the old fscache I/O API to the new one, meaning that fscache no longer keeps track of netfs pages and instead does async DIO between the backing files and the 9p file pagecache. As a part of this change, the handling of PG_fscache changes. It now just means that the cache has a write I/O operation in progress on a page (PG_locked is used for a read I/O op). Note that this is a cut-down version of the fscache rewrite and does not change any of the cookie and cache coherency handling. Changes ======= ver #4: - Rebase on top of folios. - Don't use wait_on_page_bit_killable(). ver #3: - v9fs_req_issue_op() needs to terminate the subrequest. - v9fs_write_end() needs to call SetPageUptodate() a bit more often. - It's not CONFIG_{AFS,V9FS}_FSCACHE[1] - v9fs_init_rreq() should take a ref on the p9_fid and the cleanup should drop it [from Dominique Martinet]. Signed-off-by: David Howells Reviewed-and-tested-by: Dominique Martinet cc: v9fs-developer@lists.sourceforge.net cc: linux-cachefs@redhat.com Link: https://lore.kernel.org/r/YUm+xucHxED+1MJp@codewreck.org/ [1] Link: https://lore.kernel.org/r/163162772646.438332.16323773205855053535.stgit@warthog.procyon.org.uk/ # rfc Link: https://lore.kernel.org/r/163189109885.2509237.7153668924503399173.stgit@warthog.procyon.org.uk/ # rfc v2 Link: https://lore.kernel.org/r/163363943896.1980952.1226527304649419689.stgit@warthog.procyon.org.uk/ # v3 Link: https://lore.kernel.org/r/163551662876.1877519.14706391695553204156.stgit@warthog.procyon.org.uk/ # v4 Link: https://lore.kernel.org/r/163584179557.4023316.11089762304657644342.stgit@warthog.procyon.org.uk # rebase on folio Signed-off-by: Dominique Martinet --- fs/9p/cache.c | 137 ---------------------------------------------------------- 1 file changed, 137 deletions(-) (limited to 'fs/9p/cache.c') diff --git a/fs/9p/cache.c b/fs/9p/cache.c index 1769a44f4819..077f0a40aa01 100644 --- a/fs/9p/cache.c +++ b/fs/9p/cache.c @@ -199,140 +199,3 @@ void v9fs_cache_inode_reset_cookie(struct inode *inode) 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, - i_size_read(&v9inode->vfs_inode), 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); -} -- cgit v1.2.3