From: Dave Wysochanski dwysocha@redhat.com
[ Upstream commit ba512c1bc3232124567a59a3995c773dc79716e8 ]
Earlier commits refactored some NFS read code and removed nfs_readpage_async(), but neglected to properly fixup nfs_readpage_from_fscache_complete(). The code path is only hit when something unusual occurs with the cachefiles backing filesystem, such as an IO error or while a cookie is being invalidated.
Mark page with PG_checked if fscache IO completes in error, unlock the page, and let the VM decide to re-issue based on PG_uptodate. When the VM reissues the readpage, PG_checked allows us to skip over fscache and read from the server.
Link: https://marc.info/?l=linux-nfs&m=162498209518739 Fixes: 1e83b173b266 ("NFS: Add nfs_pageio_complete_read() and remove nfs_readpage_async()") Signed-off-by: Dave Wysochanski dwysocha@redhat.com Signed-off-by: Trond Myklebust trond.myklebust@hammerspace.com Signed-off-by: Sasha Levin sashal@kernel.org --- fs/nfs/fscache.c | 18 +++++++++++++----- fs/nfs/read.c | 5 +++-- 2 files changed, 16 insertions(+), 7 deletions(-)
diff --git a/fs/nfs/fscache.c b/fs/nfs/fscache.c index c4c021c6ebbd..d743629e05e1 100644 --- a/fs/nfs/fscache.c +++ b/fs/nfs/fscache.c @@ -385,12 +385,15 @@ static void nfs_readpage_from_fscache_complete(struct page *page, "NFS: readpage_from_fscache_complete (0x%p/0x%p/%d)\n", page, context, error);
- /* if the read completes with an error, we just unlock the page and let - * the VM reissue the readpage */ - if (!error) { + /* + * If the read completes with an error, mark the page with PG_checked, + * unlock the page, and let the VM reissue the readpage. + */ + if (!error) SetPageUptodate(page); - unlock_page(page); - } + else + SetPageChecked(page); + unlock_page(page); }
/* @@ -405,6 +408,11 @@ int __nfs_readpage_from_fscache(struct nfs_open_context *ctx, "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)) { + ClearPageChecked(page); + return 1; + } + ret = fscache_read_or_alloc_page(nfs_i_fscache(inode), page, nfs_readpage_from_fscache_complete, diff --git a/fs/nfs/read.c b/fs/nfs/read.c index d2b6dce1f99f..4ca50b70a7b0 100644 --- a/fs/nfs/read.c +++ b/fs/nfs/read.c @@ -363,13 +363,13 @@ int nfs_readpage(struct file *file, struct page *page) } else 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; + goto out_wait; }
- xchg(&desc.ctx->error, 0); nfs_pageio_init_read(&desc.pgio, inode, false, &nfs_async_read_completion_ops);
@@ -379,6 +379,7 @@ int nfs_readpage(struct file *file, struct page *page) nfs_pageio_complete_read(&desc.pgio, inode);
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)