From 22fe525a532619088a135c0f5f80bde12da68109 Mon Sep 17 00:00:00 2001 From: "Dr. David Alan Gilbert" Date: Thu, 4 Mar 2021 15:49:00 -0500 Subject: [PATCH 3/4] virtiofsd: Save error code early at the failure callsite RH-Author: Dr. David Alan Gilbert Message-id: <20210304154901.47930-2-dgilbert@redhat.com> Patchwork-id: 101304 O-Subject: [RHEL-AV-8.4.0 qemu-kvm PATCH 1/2] virtiofsd: Save error code early at the failure callsite Bugzilla: 1935071 RH-Acked-by: Connor Kuehl RH-Acked-by: Laszlo Ersek RH-Acked-by: Stefan Hajnoczi From: Vivek Goyal Change error code handling slightly in lo_setattr(). Right now we seem to jump to out_err and assume that "errno" is valid and use that to send reply. But if caller has to do some other operations before jumping to out_err, then it does the dance of first saving errno to saverr and the restore errno before jumping to out_err. This makes it more confusing. I am about to make more changes where caller will have to do some work after error before jumping to out_err. I found it easier to change the convention a bit. That is caller saves error in "saverr" before jumping to out_err. And out_err uses "saverr" to send error back and does not rely on "errno" having actual error. v3: Resolved conflicts in lo_setattr() due to lo_inode_open() changes. Signed-off-by: Vivek Goyal Reviewed-by: Dr. David Alan Gilbert Message-Id: <20210208224024.43555-2-vgoyal@redhat.com> (cherry picked from commit 1e08f164e9fdc9528ad6990012301b9a04b0bc90) Signed-off-by: Dr. David Alan Gilbert Signed-off-by: Danilo C. L. de Paula --- tools/virtiofsd/passthrough_ll.c | 9 +++++---- 1 file changed, 5 insertions(+), 4 deletions(-) diff --git a/tools/virtiofsd/passthrough_ll.c b/tools/virtiofsd/passthrough_ll.c index 03c5e0d13c..f06074d81f 100644 --- a/tools/virtiofsd/passthrough_ll.c +++ b/tools/virtiofsd/passthrough_ll.c @@ -710,6 +710,7 @@ static void lo_setattr(fuse_req_t req, fuse_ino_t ino, struct stat *attr, res = fchmodat(lo->proc_self_fd, procname, attr->st_mode, 0); } if (res == -1) { + saverr = errno; goto out_err; } } @@ -719,6 +720,7 @@ static void lo_setattr(fuse_req_t req, fuse_ino_t ino, struct stat *attr, res = fchownat(ifd, "", uid, gid, AT_EMPTY_PATH | AT_SYMLINK_NOFOLLOW); if (res == -1) { + saverr = errno; goto out_err; } } @@ -730,16 +732,15 @@ static void lo_setattr(fuse_req_t req, fuse_ino_t ino, struct stat *attr, } else { truncfd = lo_inode_open(lo, inode, O_RDWR); if (truncfd < 0) { - errno = -truncfd; + saverr = -truncfd; goto out_err; } } res = ftruncate(truncfd, attr->st_size); + saverr = res == -1 ? errno : 0; if (!fi) { - saverr = errno; close(truncfd); - errno = saverr; } if (res == -1) { goto out_err; @@ -772,6 +773,7 @@ static void lo_setattr(fuse_req_t req, fuse_ino_t ino, struct stat *attr, res = utimensat(lo->proc_self_fd, procname, tv, 0); } if (res == -1) { + saverr = errno; goto out_err; } } @@ -780,7 +782,6 @@ static void lo_setattr(fuse_req_t req, fuse_ino_t ino, struct stat *attr, return lo_getattr(req, ino, fi); out_err: - saverr = errno; lo_inode_put(lo, &inode); fuse_reply_err(req, saverr); } -- 2.27.0