[v2,63/67] nfs: Implement cache I/O by accessing the cache directly

Message ID	163906981318.143852.17220018647843475985.stgit@warthog.procyon.org.uk (mailing list archive)
State	New, archived
Headers	show Return-Path: <linux-cifs-owner@kernel.org> Organization: Red Hat UK Ltd. Registered Address: Red Hat UK Ltd, Amberley Place, 107-111 Peascod Street, Windsor, Berkshire, SI4 1TE, United Kingdom. Registered in England and Wales under Company Registration No. 3798903 Subject: [PATCH v2 63/67] nfs: Implement cache I/O by accessing the cache directly From: David Howells <dhowells@redhat.com> To: linux-cachefs@redhat.com Cc: Dave Wysochanski <dwysocha@redhat.com>, Trond Myklebust <trond.myklebust@hammerspace.com>, Anna Schumaker <anna.schumaker@netapp.com>, linux-nfs@vger.kernel.org, dhowells@redhat.com, Trond Myklebust <trondmy@hammerspace.com>, Anna Schumaker <anna.schumaker@netapp.com>, Steve French <sfrench@samba.org>, Dominique Martinet <asmadeus@codewreck.org>, Jeff Layton <jlayton@kernel.org>, Matthew Wilcox <willy@infradead.org>, Alexander Viro <viro@zeniv.linux.org.uk>, Omar Sandoval <osandov@osandov.com>, JeffleXu <jefflexu@linux.alibaba.com>, Linus Torvalds <torvalds@linux-foundation.org>, linux-afs@lists.infradead.org, linux-nfs@vger.kernel.org, linux-cifs@vger.kernel.org, ceph-devel@vger.kernel.org, v9fs-developer@lists.sourceforge.net, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org Date: Thu, 09 Dec 2021 17:10:13 +0000 Message-ID: <163906981318.143852.17220018647843475985.stgit@warthog.procyon.org.uk> In-Reply-To: <163906878733.143852.5604115678965006622.stgit@warthog.procyon.org.uk> References: <163906878733.143852.5604115678965006622.stgit@warthog.procyon.org.uk> User-Agent: StGit/0.23 MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Precedence: bulk
Series	fscache, cachefiles: Rewrite \| expand [v2,00/67] fscache, cachefiles: Rewrite [v2,01/67] fscache, cachefiles: Disable configuration [v2,04/67] netfs: Display the netfs inode number in the netfs_read tracepoint [v2,05/67] netfs: Pass a flag to ->prepare_write() to say if there's no alloc'd space [v2,06/67] fscache: Introduce new driver [v2,07/67] fscache: Implement a hash function [v2,08/67] fscache: Implement cache registration [v2,09/67] fscache: Implement volume registration [v2,10/67] fscache: Implement cookie registration [v2,11/67] fscache: Implement cache-level access helpers [v2,12/67] fscache: Implement volume-level access helpers [v2,13/67] fscache: Implement cookie-level access helpers [v2,14/67] fscache: Implement functions add/remove a cache [v2,15/67] fscache: Provide and use cache methods to lookup/create/free a volume [v2,16/67] fscache: Add a function for a cache backend to note an I/O error [v2,17/67] fscache: Implement simple cookie state machine [v2,18/67] fscache: Implement cookie user counting and resource pinning [v2,19/67] fscache: Implement cookie invalidation [v2,20/67] fscache: Provide a means to begin an operation [v2,21/67] fscache: Count data storage objects in a cache [v2,22/67] fscache: Provide read/write stat counters for the cache [v2,23/67] fscache: Provide a function to let the netfs update its coherency data [v2,24/67] netfs: Pass more information on how to deal with a hole in the cache [v2,25/67] fscache: Implement raw I/O interface [v2,26/67] fscache: Implement higher-level write I/O interface [v2,27/67] vfs, fscache: Implement pinning of cache usage for writeback [v2,28/67] fscache: Provide a function to note the release of a page [v2,29/67] fscache: Provide a function to resize a cookie [v2,30/67] cachefiles: Introduce rewritten driver [v2,31/67] cachefiles: Define structs [v2,32/67] cachefiles: Add some error injection support [v2,33/67] cachefiles: Add a couple of tracepoints for logging errors [v2,34/67] cachefiles: Add cache error reporting macro [v2,35/67] cachefiles: Add security derivation [v2,36/67] cachefiles: Register a miscdev and parse commands over it [v2,37/67] cachefiles: Provide a function to check how much space there is [v2,38/67] vfs, cachefiles: Mark a backing file in use with an inode flag [v2,39/67] cachefiles: Implement a function to get/create a directory in the cache [v2,40/67] cachefiles: Implement cache registration and withdrawal [v2,41/67] cachefiles: Implement volume support [v2,42/67] cachefiles: Add tracepoints for calls to the VFS [v2,43/67] cachefiles: Implement object lifecycle funcs [v2,44/67] cachefiles: Implement key to filename encoding [v2,45/67] cachefiles: Implement metadata/coherency data storage in xattrs [v2,46/67] cachefiles: Mark a backing file in use with an inode flag [v2,47/67] cachefiles: Implement culling daemon commands [v2,48/67] cachefiles: Implement backing file wrangling [v2,49/67] cachefiles: Implement begin and end I/O operation [v2,50/67] cachefiles: Implement cookie resize for truncate [v2,51/67] cachefiles: Implement the I/O routines [v2,52/67] cachefiles: Allow cachefiles to actually function [v2,53/67] fscache, cachefiles: Display stats of no-space events [v2,54/67] fscache, cachefiles: Display stat of culling events [v2,55/67] afs: Handle len being extending over page end in write_begin/write_end [v2,56/67] afs: Fix afs_write_end() to handle len > page size [v2,57/67] afs: Convert afs to use the new fscache API [v2,58/67] afs: Copy local writes to the cache when writing to the server [v2,59/67] afs: Skip truncation on the server of data we haven't written yet [v2,60/67] 9p: Use fscache indexing rewrite and reenable caching [v2,61/67] 9p: Copy local writes to the cache when writing to the server [v2,62/67] nfs: Convert to new fscache volume/cookie API [v2,63/67] nfs: Implement cache I/O by accessing the cache directly [v2,64/67] cifs: Support fscache indexing rewrite (untested) [v2,65/67] ceph: conversion to new fscache API [v2,66/67] ceph: add fscache writeback support

diff --git a/fs/fscache/io.c b/fs/fscache/io.c index bed7628a5a9d..7a769ea57720 100644 --- a/fs/fscache/io.c +++ b/fs/fscache/io.c @@ -150,6 +150,14 @@ int __fscache_begin_read_operation(struct netfs_cache_resources *cres, } EXPORT_SYMBOL(__fscache_begin_read_operation); +int __fscache_begin_write_operation(struct netfs_cache_resources *cres, + struct fscache_cookie *cookie) +{ + return fscache_begin_operation(cres, cookie, FSCACHE_WANT_PARAMS, + fscache_access_io_write); +} +EXPORT_SYMBOL(__fscache_begin_write_operation); + /** * fscache_set_page_dirty - Mark page dirty and pin a cache object for writeback * @page: The page being dirtied diff --git a/fs/nfs/fscache.c b/fs/nfs/fscache.c index d10e50ab0b3d..aef777d2f308 100644 --- a/fs/nfs/fscache.c +++ b/fs/nfs/fscache.c @@ -249,48 +249,128 @@ void nfs_fscache_release_file(struct inode *inode, struct file *filp) } } +static inline void fscache_end_operation(struct netfs_cache_resources *cres) +{ + const struct netfs_cache_ops *ops = fscache_operation_valid(cres); + + if (ops) + ops->end_operation(cres); +} + +/* + * Fallback page reading interface. + */ +static int fscache_fallback_read_page(struct inode *inode, struct page *page) +{ + struct netfs_cache_resources cres; + struct fscache_cookie *cookie = nfs_i_fscache(inode); + struct iov_iter iter; + struct bio_vec bvec[1]; + int ret; + + memset(&cres, 0, sizeof(cres)); + bvec[0].bv_page = page; + bvec[0].bv_offset = 0; + bvec[0].bv_len = PAGE_SIZE; + iov_iter_bvec(&iter, READ, bvec, ARRAY_SIZE(bvec), PAGE_SIZE); + + ret = fscache_begin_read_operation(&cres, cookie); + if (ret < 0) + return ret; + + ret = fscache_read(&cres, page_offset(page), &iter, NETFS_READ_HOLE_FAIL, + NULL, NULL); + fscache_end_operation(&cres); + return ret; +} + +/* + * Fallback page writing interface. + */ +static int fscache_fallback_write_page(struct inode *inode, struct page *page, + bool no_space_allocated_yet) +{ + struct netfs_cache_resources cres; + struct fscache_cookie *cookie = nfs_i_fscache(inode); + struct iov_iter iter; + struct bio_vec bvec[1]; + loff_t start = page_offset(page); + size_t len = PAGE_SIZE; + int ret; + + memset(&cres, 0, sizeof(cres)); + bvec[0].bv_page = page; + bvec[0].bv_offset = 0; + bvec[0].bv_len = PAGE_SIZE; + iov_iter_bvec(&iter, WRITE, bvec, ARRAY_SIZE(bvec), PAGE_SIZE); + + ret = fscache_begin_write_operation(&cres, cookie); + if (ret < 0) + return ret; + + ret = cres.ops->prepare_write(&cres, &start, &len, i_size_read(inode), + no_space_allocated_yet); + if (ret == 0) + ret = fscache_write(&cres, page_offset(page), &iter, NULL, NULL); + fscache_end_operation(&cres); + return ret; +} + /* * Retrieve a page from fscache */ -int __nfs_readpage_from_fscache(struct nfs_open_context *ctx, - struct inode *inode, struct page *page) +int __nfs_readpage_from_fscache(struct inode *inode, struct page *page) { + int ret; + dfprintk(FSCACHE, "NFS: readpage_from_fscache(fsc:%p/p:%p(i:%lx f:%lx)/0x%p)\n", nfs_i_fscache(inode), page, page->index, page->flags, inode); if (PageChecked(page)) { + dfprintk(FSCACHE, "NFS: readpage_from_fscache: PageChecked\n"); ClearPageChecked(page); return 1; } - return -ENOBUFS; // TODO: Use netfslib -} - -/* - * Retrieve a set of pages from fscache - */ -int __nfs_readpages_from_fscache(struct nfs_open_context *ctx, - struct inode *inode, - struct address_space *mapping, - struct list_head *pages, - unsigned *nr_pages) -{ - dfprintk(FSCACHE, "NFS: nfs_getpages_from_fscache (0x%p/%u/0x%p)\n", - nfs_i_fscache(inode), *nr_pages, inode); + ret = fscache_fallback_read_page(inode, page); + if (ret < 0) { + nfs_inc_fscache_stats(inode, NFSIOS_FSCACHE_PAGES_READ_FAIL); + dfprintk(FSCACHE, + "NFS: readpage_from_fscache failed %d\n", ret); + SetPageChecked(page); + return ret; + } - return -ENOBUFS; // TODO: Use netfslib + /* Read completed synchronously */ + dfprintk(FSCACHE, "NFS: readpage_from_fscache: read successful\n"); + nfs_inc_fscache_stats(inode, NFSIOS_FSCACHE_PAGES_READ_OK); + SetPageUptodate(page); + return 0; } /* - * Store a newly fetched page in fscache - * - PG_fscache must be set on the page + * Store a newly fetched page in fscache. We can be certain there's no page + * stored in the cache as yet otherwise we would've read it from there. */ -void __nfs_readpage_to_fscache(struct inode *inode, struct page *page, int sync) +void __nfs_readpage_to_fscache(struct inode *inode, struct page *page) { + int ret; + dfprintk(FSCACHE, - "NFS: readpage_to_fscache(fsc:%p/p:%p(i:%lx f:%lx)/%d)\n", - nfs_i_fscache(inode), page, page->index, page->flags, sync); + "NFS: readpage_to_fscache(fsc:%p/p:%p(i:%lx f:%lx))\n", + nfs_i_fscache(inode), page, page->index, page->flags); - return; // TODO: Use netfslib + ret = fscache_fallback_write_page(inode, page, true); + + dfprintk(FSCACHE, + "NFS: readpage_to_fscache: p:%p(i:%lu f:%lx) ret %d\n", + page, page->index, page->flags, ret); + + if (ret != 0) { + nfs_inc_fscache_stats(inode, NFSIOS_FSCACHE_PAGES_WRITTEN_FAIL); + nfs_inc_fscache_stats(inode, NFSIOS_FSCACHE_PAGES_UNCACHED); + } else { + nfs_inc_fscache_stats(inode, NFSIOS_FSCACHE_PAGES_WRITTEN_OK); + } } diff --git a/fs/nfs/fscache.h b/fs/nfs/fscache.h index 26b6fb1cfd58..487e012363f5 100644 --- a/fs/nfs/fscache.h +++ b/fs/nfs/fscache.h @@ -44,14 +44,10 @@ extern void nfs_fscache_clear_inode(struct inode *); extern void nfs_fscache_open_file(struct inode *, struct file *); extern void nfs_fscache_release_file(struct inode *, struct file *); -extern void __nfs_fscache_invalidate_page(struct page *, struct inode *); - -extern int __nfs_readpage_from_fscache(struct nfs_open_context *, - struct inode *, struct page *); -extern int __nfs_readpages_from_fscache(struct nfs_open_context *, - struct inode *, struct address_space *, - struct list_head *, unsigned *); -extern void __nfs_readpage_to_fscache(struct inode *, struct page *, int); +extern int __nfs_readpage_from_fscache(struct inode *, struct page *); +extern void __nfs_read_completion_to_fscache(struct nfs_pgio_header *hdr, + unsigned long bytes); +extern void __nfs_readpage_to_fscache(struct inode *, struct page *); static inline int nfs_fscache_release_page(struct page *page, gfp_t gfp) { @@ -69,27 +65,11 @@ static inline int nfs_fscache_release_page(struct page *page, gfp_t gfp) /* * Retrieve a page from an inode data storage object. */ -static inline int nfs_readpage_from_fscache(struct nfs_open_context *ctx, - struct inode *inode, +static inline int nfs_readpage_from_fscache(struct inode *inode, struct page *page) { if (NFS_I(inode)->fscache) - return __nfs_readpage_from_fscache(ctx, inode, page); - return -ENOBUFS; -} - -/* - * Retrieve a set of pages from an inode data storage object. - */ -static inline int nfs_readpages_from_fscache(struct nfs_open_context *ctx, - struct inode *inode, - struct address_space *mapping, - struct list_head *pages, - unsigned *nr_pages) -{ - if (NFS_I(inode)->fscache) - return __nfs_readpages_from_fscache(ctx, inode, mapping, pages, - nr_pages); + return __nfs_readpage_from_fscache(inode, page); return -ENOBUFS; } @@ -98,11 +78,10 @@ static inline int nfs_readpages_from_fscache(struct nfs_open_context *ctx, * in the cache. */ static inline void nfs_readpage_to_fscache(struct inode *inode, - struct page *page, - int sync) + struct page *page) { - if (PageFsCache(page)) - __nfs_readpage_to_fscache(inode, page, sync); + if (NFS_I(inode)->fscache) + __nfs_readpage_to_fscache(inode, page); } static inline void nfs_fscache_update_auxdata(struct nfs_fscache_inode_auxdata *auxdata, @@ -151,26 +130,13 @@ static inline void nfs_fscache_clear_inode(struct inode *inode) {} static inline void nfs_fscache_open_file(struct inode *inode, struct file *filp) {} -static inline int nfs_fscache_release_page(struct page *page, gfp_t gfp) -{ - return 1; /* True: may release page */ -} -static inline int nfs_readpage_from_fscache(struct nfs_open_context *ctx, - struct inode *inode, +static inline int nfs_readpage_from_fscache(struct inode *inode, struct page *page) { return -ENOBUFS; } -static inline int nfs_readpages_from_fscache(struct nfs_open_context *ctx, - struct inode *inode, - struct address_space *mapping, - struct list_head *pages, - unsigned *nr_pages) -{ - return -ENOBUFS; -} static inline void nfs_readpage_to_fscache(struct inode *inode, - struct page *page, int sync) {} + struct page *page) {} static inline void nfs_fscache_invalidate(struct inode *inode, int flags) {} diff --git a/fs/nfs/read.c b/fs/nfs/read.c index d11af2a9299c..eb00229c1a50 100644 --- a/fs/nfs/read.c +++ b/fs/nfs/read.c @@ -123,7 +123,7 @@ static void nfs_readpage_release(struct nfs_page *req, int error) struct address_space *mapping = page_file_mapping(page); if (PageUptodate(page)) - nfs_readpage_to_fscache(inode, page, 0); + nfs_readpage_to_fscache(inode, page); else if (!PageError(page) && !PagePrivate(page)) generic_error_remove_page(mapping, page); unlock_page(page); @@ -305,6 +305,12 @@ readpage_async_filler(void *data, struct page *page) aligned_len = min_t(unsigned int, ALIGN(len, rsize), PAGE_SIZE); + if (!IS_SYNC(page->mapping->host)) { + error = nfs_readpage_from_fscache(page->mapping->host, page); + if (error == 0) + goto out_unlock; + } + new = nfs_create_request(desc->ctx, page, 0, aligned_len); if (IS_ERR(new)) goto out_error; @@ -320,6 +326,7 @@ readpage_async_filler(void *data, struct page *page) return 0; out_error: error = PTR_ERR(new); +out_unlock: unlock_page(page); out: return error; @@ -366,12 +373,6 @@ int nfs_readpage(struct file *file, struct page *page) desc.ctx = get_nfs_open_context(nfs_file_open_context(file)); xchg(&desc.ctx->error, 0); - if (!IS_SYNC(inode)) { - ret = nfs_readpage_from_fscache(desc.ctx, inode, page); - if (ret == 0) - goto out_wait; - } - nfs_pageio_init_read(&desc.pgio, inode, false, &nfs_async_read_completion_ops); @@ -381,7 +382,6 @@ int nfs_readpage(struct file *file, struct page *page) nfs_pageio_complete_read(&desc.pgio); ret = desc.pgio.pg_error < 0 ? desc.pgio.pg_error : 0; -out_wait: if (!ret) { ret = wait_on_page_locked_killable(page); if (!PageUptodate(page) && !ret) @@ -419,14 +419,6 @@ int nfs_readpages(struct file *file, struct address_space *mapping, } else desc.ctx = get_nfs_open_context(nfs_file_open_context(file)); - /* attempt to read as many of the pages as possible from the cache - * - this returns -ENOBUFS immediately if the cookie is negative - */ - ret = nfs_readpages_from_fscache(desc.ctx, inode, mapping, - pages, &nr_pages); - if (ret == 0) - goto read_complete; /* all pages were read */ - nfs_pageio_init_read(&desc.pgio, inode, false, &nfs_async_read_completion_ops); @@ -434,7 +426,6 @@ int nfs_readpages(struct file *file, struct address_space *mapping, nfs_pageio_complete_read(&desc.pgio); -read_complete: put_nfs_open_context(desc.ctx); out: trace_nfs_aop_readahead_done(inode, nr_pages, ret); diff --git a/fs/nfs/write.c b/fs/nfs/write.c index 2b322170372a..987a187bd39a 100644 --- a/fs/nfs/write.c +++ b/fs/nfs/write.c @@ -2126,8 +2126,11 @@ int nfs_migrate_page(struct address_space *mapping, struct page *newpage, if (PagePrivate(page)) return -EBUSY; - if (!nfs_fscache_release_page(page, GFP_KERNEL)) - return -EBUSY; + if (PageFsCache(page)) { + if (mode == MIGRATE_ASYNC) + return -EBUSY; + wait_on_page_fscache(page); + } return migrate_page(mapping, newpage, page, mode); } diff --git a/include/linux/fscache.h b/include/linux/fscache.h index b38d233c9fad..b28bedee28d9 100644 --- a/include/linux/fscache.h +++ b/include/linux/fscache.h @@ -165,6 +165,7 @@ extern void __fscache_relinquish_cookie(struct fscache_cookie *, bool); extern void __fscache_resize_cookie(struct fscache_cookie *, loff_t); extern void __fscache_invalidate(struct fscache_cookie *, const void *, loff_t, unsigned int); extern int __fscache_begin_read_operation(struct netfs_cache_resources *, struct fscache_cookie *); +extern int __fscache_begin_write_operation(struct netfs_cache_resources *, struct fscache_cookie *); extern void __fscache_write_to_cache(struct fscache_cookie *, struct address_space *, loff_t, size_t, loff_t, netfs_io_terminated_t, void *, @@ -493,6 +494,33 @@ int fscache_read(struct netfs_cache_resources *cres, term_func, term_func_priv); } +/** + * fscache_begin_write_operation - Begin a write operation for the netfs lib + * @cres: The cache resources for the write being performed + * @cookie: The cookie representing the cache object + * + * Begin a write operation on behalf of the netfs helper library. @cres + * indicates the cache resources to which the operation state should be + * attached; @cookie indicates the cache object that will be accessed. + * + * @cres->inval_counter is set from @cookie->inval_counter for comparison at + * the end of the operation. This allows invalidation during the operation to + * be detected by the caller. + * + * Returns: + * * 0 - Success + * * -ENOBUFS - No caching available + * * Other error code from the cache, such as -ENOMEM. + */ +static inline +int fscache_begin_write_operation(struct netfs_cache_resources *cres, + struct fscache_cookie *cookie) +{ + if (fscache_cookie_enabled(cookie)) + return __fscache_begin_write_operation(cres, cookie); + return -ENOBUFS; +} + /** * fscache_write - Start a write to the cache. * @cres: The cache resources to use

[v2,63/67] nfs: Implement cache I/O by accessing the cache directly

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Patch