From fc9dc401899ab280fe1849a0ca5800384726a793 Mon Sep 17 00:00:00 2001 From: Trond Myklebust Date: Mon, 8 Feb 2021 08:55:46 -0500 Subject: [PATCH] NFS: Optimise sparse writes past the end of file If we're doing a write, and the entire page lies beyond the end-of-file, then we can assume the write can be extended to cover the beginning of the page, since we know the data in that region will be all zeros. Signed-off-by: Trond Myklebust Signed-off-by: Anna Schumaker --- fs/nfs/file.c | 4 +--- fs/nfs/write.c | 20 ++++++++++++-------- 2 files changed, 13 insertions(+), 11 deletions(-) diff --git a/fs/nfs/file.c b/fs/nfs/file.c index d02a63af9c15..02795a01c7ef 100644 --- a/fs/nfs/file.c +++ b/fs/nfs/file.c @@ -626,13 +626,11 @@ ssize_t nfs_file_write(struct kiocb *iocb, struct iov_iter *from) /* * O_APPEND implies that we must revalidate the file length. */ - if (iocb->ki_flags & IOCB_APPEND) { + if (iocb->ki_flags & IOCB_APPEND || iocb->ki_pos > i_size_read(inode)) { result = nfs_revalidate_file_size(inode, file); if (result) goto out; } - if (iocb->ki_pos > i_size_read(inode)) - nfs_revalidate_mapping(inode, file->f_mapping); since = filemap_sample_wb_err(file->f_mapping); nfs_start_io_write(inode); diff --git a/fs/nfs/write.c b/fs/nfs/write.c index 639c34fec04a..6193350356a8 100644 --- a/fs/nfs/write.c +++ b/fs/nfs/write.c @@ -1278,19 +1278,21 @@ bool nfs_ctx_key_to_expire(struct nfs_open_context *ctx, struct inode *inode) * the PageUptodate() flag. In this case, we will need to turn off * write optimisations that depend on the page contents being correct. */ -static bool nfs_write_pageuptodate(struct page *page, struct inode *inode) +static bool nfs_write_pageuptodate(struct page *page, struct inode *inode, + unsigned int pagelen) { struct nfs_inode *nfsi = NFS_I(inode); if (nfs_have_delegated_attributes(inode)) goto out; - if (nfsi->cache_validity & NFS_INO_REVAL_PAGECACHE) + if (nfsi->cache_validity & + (NFS_INO_REVAL_PAGECACHE | NFS_INO_INVALID_SIZE)) return false; smp_rmb(); - if (test_bit(NFS_INO_INVALIDATING, &nfsi->flags)) + if (test_bit(NFS_INO_INVALIDATING, &nfsi->flags) && pagelen != 0) return false; out: - if (nfsi->cache_validity & NFS_INO_INVALID_DATA) + if (nfsi->cache_validity & NFS_INO_INVALID_DATA && pagelen != 0) return false; return PageUptodate(page) != 0; } @@ -1310,7 +1312,8 @@ is_whole_file_wrlock(struct file_lock *fl) * If the file is opened for synchronous writes then we can just skip the rest * of the checks. */ -static int nfs_can_extend_write(struct file *file, struct page *page, struct inode *inode) +static int nfs_can_extend_write(struct file *file, struct page *page, + struct inode *inode, unsigned int pagelen) { int ret; struct file_lock_context *flctx = inode->i_flctx; @@ -1318,7 +1321,7 @@ static int nfs_can_extend_write(struct file *file, struct page *page, struct ino if (file->f_flags & O_DSYNC) return 0; - if (!nfs_write_pageuptodate(page, inode)) + if (!nfs_write_pageuptodate(page, inode, pagelen)) return 0; if (NFS_PROTO(inode)->have_delegation(inode, FMODE_WRITE)) return 1; @@ -1356,6 +1359,7 @@ int nfs_updatepage(struct file *file, struct page *page, struct nfs_open_context *ctx = nfs_file_open_context(file); struct address_space *mapping = page_file_mapping(page); struct inode *inode = mapping->host; + unsigned int pagelen = nfs_page_length(page); int status = 0; nfs_inc_stats(inode, NFSIOS_VFSUPDATEPAGE); @@ -1366,8 +1370,8 @@ int nfs_updatepage(struct file *file, struct page *page, if (!count) goto out; - if (nfs_can_extend_write(file, page, inode)) { - count = max(count + offset, nfs_page_length(page)); + if (nfs_can_extend_write(file, page, inode, pagelen)) { + count = max(count + offset, pagelen); offset = 0; }