From 67d0338edd71db9a4f406d8778f7c525d31e9f7f Mon Sep 17 00:00:00 2001 From: Weston Andros Adamson Date: Thu, 15 May 2014 11:56:46 -0400 Subject: [PATCH] nfs: page group syncing in read path Operations that modify state for a whole page must be syncronized across all requests within a page group. In the read path, this is calling unlock_page and SetPageUptodate. Both of these functions should not be called until all requests in a page group have reached the point where they would call them. This patch should have no effect yet since all page groups currently have one request, but will come into play when pg_test functions are modified to split pages into sub-page regions. Signed-off-by: Weston Andros Adamson Signed-off-by: Trond Myklebust --- fs/nfs/pagelist.c | 2 ++ fs/nfs/read.c | 22 +++++++++++++++++----- include/linux/nfs_page.h | 2 ++ 3 files changed, 21 insertions(+), 5 deletions(-) diff --git a/fs/nfs/pagelist.c b/fs/nfs/pagelist.c index 015fb7b48df..18ee4e99347 100644 --- a/fs/nfs/pagelist.c +++ b/fs/nfs/pagelist.c @@ -395,6 +395,8 @@ static void nfs_free_request(struct nfs_page *req) /* extra debug: make sure no sync bits are still set */ WARN_ON_ONCE(test_bit(PG_TEARDOWN, &req->wb_flags)); + WARN_ON_ONCE(test_bit(PG_UNLOCKPAGE, &req->wb_flags)); + WARN_ON_ONCE(test_bit(PG_UPTODATE, &req->wb_flags)); /* Release struct file and open context */ nfs_clear_request(req); diff --git a/fs/nfs/read.c b/fs/nfs/read.c index 902ba2c63d0..53d5b83611c 100644 --- a/fs/nfs/read.c +++ b/fs/nfs/read.c @@ -105,10 +105,16 @@ static void nfs_readpage_release(struct nfs_page *req) { struct inode *d_inode = req->wb_context->dentry->d_inode; - if (PageUptodate(req->wb_page)) - nfs_readpage_to_fscache(d_inode, req->wb_page, 0); + dprintk("NFS: read done (%s/%llu %d@%lld)\n", d_inode->i_sb->s_id, + (unsigned long long)NFS_FILEID(d_inode), req->wb_bytes, + (long long)req_offset(req)); - unlock_page(req->wb_page); + if (nfs_page_group_sync_on_bit(req, PG_UNLOCKPAGE)) { + if (PageUptodate(req->wb_page)) + nfs_readpage_to_fscache(d_inode, req->wb_page, 0); + + unlock_page(req->wb_page); + } dprintk("NFS: read done (%s/%Lu %d@%Ld)\n", req->wb_context->dentry->d_inode->i_sb->s_id, @@ -118,6 +124,12 @@ static void nfs_readpage_release(struct nfs_page *req) nfs_release_request(req); } +static void nfs_page_group_set_uptodate(struct nfs_page *req) +{ + if (nfs_page_group_sync_on_bit(req, PG_UPTODATE)) + SetPageUptodate(req->wb_page); +} + /* Note io was page aligned */ static void nfs_read_completion(struct nfs_pgio_header *hdr) { @@ -140,9 +152,9 @@ static void nfs_read_completion(struct nfs_pgio_header *hdr) bytes += req->wb_bytes; if (test_bit(NFS_IOHDR_ERROR, &hdr->flags)) { if (bytes <= hdr->good_bytes) - SetPageUptodate(page); + nfs_page_group_set_uptodate(req); } else - SetPageUptodate(page); + nfs_page_group_set_uptodate(req); nfs_list_remove_request(req); nfs_readpage_release(req); } diff --git a/include/linux/nfs_page.h b/include/linux/nfs_page.h index 986c0c279d0..6385175a127 100644 --- a/include/linux/nfs_page.h +++ b/include/linux/nfs_page.h @@ -29,6 +29,8 @@ enum { PG_INODE_REF, /* extra ref held by inode (head req only) */ PG_HEADLOCK, /* page group lock of wb_head */ PG_TEARDOWN, /* page group sync for destroy */ + PG_UNLOCKPAGE, /* page group sync bit in read path */ + PG_UPTODATE, /* page group sync bit in read path */ }; struct nfs_inode; -- 2.41.0