From 20633f042fd0907300069714b98aaf607a8b5bf8 Mon Sep 17 00:00:00 2001 From: Weston Andros Adamson Date: Thu, 15 May 2014 11:56:47 -0400 Subject: [PATCH] nfs: page group syncing in write path Operations that modify state for a whole page must be syncronized across all requests within a page group. In the write path, this is calling end_page_writeback and removing the head request from an inode. Both of these operations 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/write.c | 32 ++++++++++++++++++++------------ include/linux/nfs_page.h | 2 ++ 3 files changed, 24 insertions(+), 12 deletions(-) diff --git a/fs/nfs/pagelist.c b/fs/nfs/pagelist.c index 18ee4e9..ceb4424 100644 --- a/fs/nfs/pagelist.c +++ b/fs/nfs/pagelist.c @@ -397,6 +397,8 @@ static void nfs_free_request(struct nfs_page *req) 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)); + WARN_ON_ONCE(test_bit(PG_WB_END, &req->wb_flags)); + WARN_ON_ONCE(test_bit(PG_REMOVE, &req->wb_flags)); /* Release struct file and open context */ nfs_clear_request(req); diff --git a/fs/nfs/write.c b/fs/nfs/write.c index d0f30f1..5d75276 100644 --- a/fs/nfs/write.c +++ b/fs/nfs/write.c @@ -201,12 +201,15 @@ static void nfs_set_page_writeback(struct page *page) } } -static void nfs_end_page_writeback(struct page *page) +static void nfs_end_page_writeback(struct nfs_page *req) { - struct inode *inode = page_file_mapping(page)->host; + struct inode *inode = page_file_mapping(req->wb_page)->host; struct nfs_server *nfss = NFS_SERVER(inode); - end_page_writeback(page); + if (!nfs_page_group_sync_on_bit(req, PG_WB_END)) + return; + + end_page_writeback(req->wb_page); if (atomic_long_dec_return(&nfss->writeback) < NFS_CONGESTION_OFF_THRESH) clear_bdi_congested(&nfss->backing_dev_info, BLK_RW_ASYNC); } @@ -397,15 +400,20 @@ static void nfs_inode_remove_request(struct nfs_page *req) { struct inode *inode = req->wb_context->dentry->d_inode; struct nfs_inode *nfsi = NFS_I(inode); + struct nfs_page *head; - spin_lock(&inode->i_lock); - if (likely(!PageSwapCache(req->wb_page))) { - set_page_private(req->wb_page, 0); - ClearPagePrivate(req->wb_page); - clear_bit(PG_MAPPED, &req->wb_flags); + if (nfs_page_group_sync_on_bit(req, PG_REMOVE)) { + head = req->wb_head; + + spin_lock(&inode->i_lock); + if (likely(!PageSwapCache(head->wb_page))) { + set_page_private(head->wb_page, 0); + ClearPagePrivate(head->wb_page); + clear_bit(PG_MAPPED, &head->wb_flags); + } + nfsi->npages--; + spin_unlock(&inode->i_lock); } - nfsi->npages--; - spin_unlock(&inode->i_lock); nfs_release_request(req); } @@ -599,7 +607,7 @@ remove_req: nfs_inode_remove_request(req); next: nfs_unlock_request(req); - nfs_end_page_writeback(req->wb_page); + nfs_end_page_writeback(req); do_destroy = !test_bit(NFS_IOHDR_NEED_COMMIT, &hdr->flags); nfs_release_request(req); } @@ -964,7 +972,7 @@ static void nfs_redirty_request(struct nfs_page *req) { nfs_mark_request_dirty(req); nfs_unlock_request(req); - nfs_end_page_writeback(req->wb_page); + nfs_end_page_writeback(req); nfs_release_request(req); } diff --git a/include/linux/nfs_page.h b/include/linux/nfs_page.h index 6385175..7d9096d 100644 --- a/include/linux/nfs_page.h +++ b/include/linux/nfs_page.h @@ -31,6 +31,8 @@ enum { 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 */ + PG_WB_END, /* page group sync bit in write path */ + PG_REMOVE, /* page group sync bit in write path */ }; struct nfs_inode; -- 2.7.4