From: Benjamin Coddington Date: Mon, 18 Jul 2016 14:41:57 +0000 (-0400) Subject: nfs: don't create zero-length requests X-Git-Tag: firefly_0821_release~176^2~4^2~31^2~383 X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=3d6562fded3ce875b8a7fc30eeed73b16366d77e;p=firefly-linux-kernel-4.4.55.git nfs: don't create zero-length requests commit 149a4fddd0a72d526abbeac0c8deaab03559836a upstream. NFS doesn't expect requests with wb_bytes set to zero and may make unexpected decisions about how to handle that request at the page IO layer. Skip request creation if we won't have any wb_bytes in the request. Signed-off-by: Benjamin Coddington Signed-off-by: Alexey Dobriyan Reviewed-by: Weston Andros Adamson Signed-off-by: Trond Myklebust Signed-off-by: Greg Kroah-Hartman --- diff --git a/fs/nfs/write.c b/fs/nfs/write.c index 7b9316406930..7a9b6e347249 100644 --- a/fs/nfs/write.c +++ b/fs/nfs/write.c @@ -1261,6 +1261,9 @@ int nfs_updatepage(struct file *file, struct page *page, dprintk("NFS: nfs_updatepage(%pD2 %d@%lld)\n", file, count, (long long)(page_file_offset(page) + offset)); + if (!count) + goto out; + if (nfs_can_extend_write(file, page, inode)) { count = max(count + offset, nfs_page_length(page)); offset = 0; @@ -1271,7 +1274,7 @@ int nfs_updatepage(struct file *file, struct page *page, nfs_set_pageerror(page); else __set_page_dirty_nobuffers(page); - +out: dprintk("NFS: nfs_updatepage returns %d (isize %lld)\n", status, (long long)i_size_read(inode)); return status;