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[PULL 4/6] virtiofsd: Save error code early at the failure callsite
From: |
Dr. David Alan Gilbert (git) |
Subject: |
[PULL 4/6] virtiofsd: Save error code early at the failure callsite |
Date: |
Tue, 16 Feb 2021 18:37:32 +0000 |
From: Vivek Goyal <vgoyal@redhat.com>
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 <vgoyal@redhat.com>
Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Message-Id: <20210208224024.43555-2-vgoyal@redhat.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
---
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 5f3afe8557..216c0bc026 100644
--- a/tools/virtiofsd/passthrough_ll.c
+++ b/tools/virtiofsd/passthrough_ll.c
@@ -698,6 +698,7 @@ 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;
}
}
@@ -707,6 +708,7 @@ 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;
}
}
@@ -718,16 +720,15 @@ 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;
@@ -760,6 +761,7 @@ 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;
}
}
@@ -768,7 +770,6 @@ 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);
}
--
2.29.2
- [PULL 0/6] virtiofs queue, Dr. David Alan Gilbert (git), 2021/02/16
- [PULL 1/6] virtiofsd: Allow to build it without the tools, Dr. David Alan Gilbert (git), 2021/02/16
- [PULL 2/6] virtiofsd: vu_dispatch locking should never fail, Dr. David Alan Gilbert (git), 2021/02/16
- [PULL 4/6] virtiofsd: Save error code early at the failure callsite,
Dr. David Alan Gilbert (git) <=
- [PULL 3/6] tools/virtiofsd: Replace the word 'whitelist', Dr. David Alan Gilbert (git), 2021/02/16
- [PULL 5/6] viriofsd: Add support for FUSE_HANDLE_KILLPRIV_V2, Dr. David Alan Gilbert (git), 2021/02/16
- [PULL 6/6] virtiofsd: Do not use a thread pool by default, Dr. David Alan Gilbert (git), 2021/02/16
- Re: [PULL 0/6] virtiofs queue, Peter Maydell, 2021/02/17