From 2f7bf369b5f8699231398aef585cb680828f3ac9 Mon Sep 17 00:00:00 2001 From: Miklos Szeredi Date: Thu, 8 Feb 2018 15:17:38 +0100 Subject: [PATCH] fuse: atomic_o_trunc should truncate pagecache commit df0e91d488276086bc07da2e389986cae0048c37 upstream. Fuse has an "atomic_o_trunc" mode, where userspace filesystem uses the O_TRUNC flag in the OPEN request to truncate the file atomically with the open. In this mode there's no need to send a SETATTR request to userspace after the open, so fuse_do_setattr() checks this mode and returns. But this misses the important step of truncating the pagecache. Add the missing parts of truncation to the ATTR_OPEN branch. Reported-by: Chad Austin Fixes: 6ff958edbf39 ("fuse: add atomic open+truncate support") Signed-off-by: Miklos Szeredi Cc: Signed-off-by: Greg Kroah-Hartman --- fs/fuse/dir.c | 13 ++++++++++++- 1 file changed, 12 insertions(+), 1 deletion(-) diff --git a/fs/fuse/dir.c b/fs/fuse/dir.c index 2496738..7a980b44 100644 --- a/fs/fuse/dir.c +++ b/fs/fuse/dir.c @@ -1629,8 +1629,19 @@ int fuse_do_setattr(struct dentry *dentry, struct iattr *attr, return err; if (attr->ia_valid & ATTR_OPEN) { - if (fc->atomic_o_trunc) + /* This is coming from open(..., ... | O_TRUNC); */ + WARN_ON(!(attr->ia_valid & ATTR_SIZE)); + WARN_ON(attr->ia_size != 0); + if (fc->atomic_o_trunc) { + /* + * No need to send request to userspace, since actual + * truncation has already been done by OPEN. But still + * need to truncate page cache. + */ + i_size_write(inode, 0); + truncate_pagecache(inode, 0); return 0; + } file = NULL; } -- 2.7.4