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[PATCH 096/104] virtiofsd: Reset O_DIRECT flag during file open
From: |
Dr. David Alan Gilbert (git) |
Subject: |
[PATCH 096/104] virtiofsd: Reset O_DIRECT flag during file open |
Date: |
Thu, 12 Dec 2019 16:38:56 +0000 |
From: Vivek Goyal <address@hidden>
If an application wants to do direct IO and opens a file with O_DIRECT
in guest, that does not necessarily mean that we need to bypass page
cache on host as well. So reset this flag on host.
If somebody needs to bypass page cache on host as well (and it is safe to
do so), we can add a knob in daemon later to control this behavior.
I check virtio-9p and they do reset O_DIRECT flag.
Signed-off-by: Vivek Goyal <address@hidden>
---
tools/virtiofsd/passthrough_ll.c | 14 ++++++++++++++
1 file changed, 14 insertions(+)
diff --git a/tools/virtiofsd/passthrough_ll.c b/tools/virtiofsd/passthrough_ll.c
index cf6b548eee..6b3d396b6f 100644
--- a/tools/virtiofsd/passthrough_ll.c
+++ b/tools/virtiofsd/passthrough_ll.c
@@ -1705,6 +1705,13 @@ static void lo_create(fuse_req_t req, fuse_ino_t parent,
const char *name,
goto out;
}
+ /*
+ * O_DIRECT in guest should not necessarily mean bypassing page
+ * cache on host as well. If somebody needs that behavior, it
+ * probably should be a configuration knob in daemon.
+ */
+ fi->flags &= ~O_DIRECT;
+
fd = openat(parent_inode->fd, name, (fi->flags | O_CREAT) & ~O_NOFOLLOW,
mode);
err = fd == -1 ? errno : 0;
@@ -1934,6 +1941,13 @@ static void lo_open(fuse_req_t req, fuse_ino_t ino,
struct fuse_file_info *fi)
fi->flags &= ~O_APPEND;
}
+ /*
+ * O_DIRECT in guest should not necessarily mean bypassing page
+ * cache on host as well. If somebody needs that behavior, it
+ * probably should be a configuration knob in daemon.
+ */
+ fi->flags &= ~O_DIRECT;
+
sprintf(buf, "%i", lo_fd(req, ino));
fd = openat(lo->proc_self_fd, buf, fi->flags & ~O_NOFOLLOW);
if (fd == -1) {
--
2.23.0
- [PATCH 089/104] virtiofsd: prevent races with lo_dirp_put(), (continued)
- [PATCH 089/104] virtiofsd: prevent races with lo_dirp_put(), Dr. David Alan Gilbert (git), 2019/12/12
- [PATCH 088/104] virtiofsd: make lo_release() atomic, Dr. David Alan Gilbert (git), 2019/12/12
- [PATCH 091/104] libvhost-user: Fix some memtable remap cases, Dr. David Alan Gilbert (git), 2019/12/12
- [PATCH 090/104] virtiofsd: rename inode->refcount to inode->nlookup, Dr. David Alan Gilbert (git), 2019/12/12
- [PATCH 092/104] virtiofsd: add man page, Dr. David Alan Gilbert (git), 2019/12/12
- [PATCH 094/104] virtiofsd: do not always set FUSE_FLOCK_LOCKS, Dr. David Alan Gilbert (git), 2019/12/12
- [PATCH 095/104] virtiofsd: convert more fprintf and perror to use fuse log infra, Dr. David Alan Gilbert (git), 2019/12/12
- [PATCH 093/104] virtiofsd: introduce inode refcount to prevent use-after-free, Dr. David Alan Gilbert (git), 2019/12/12
- [PATCH 096/104] virtiofsd: Reset O_DIRECT flag during file open,
Dr. David Alan Gilbert (git) <=
- [PATCH 097/104] virtiofsd: Fix data corruption with O_APPEND wirte in writeback mode, Dr. David Alan Gilbert (git), 2019/12/12
- [PATCH 098/104] virtiofsd: add definition of fuse_buf_writev(), Dr. David Alan Gilbert (git), 2019/12/12
- [PATCH 099/104] virtiofsd: use fuse_buf_writev to replace fuse_buf_write for better performance, Dr. David Alan Gilbert (git), 2019/12/12
- [PATCH 102/104] virtiofsd: fix lo_destroy() resource leaks, Dr. David Alan Gilbert (git), 2019/12/12
- [PATCH 103/104] virtiofsd: add --thread-pool-size=NUM option, Dr. David Alan Gilbert (git), 2019/12/12
- [PATCH 101/104] virtiofsd: prevent FUSE_INIT/FUSE_DESTROY races, Dr. David Alan Gilbert (git), 2019/12/12
- [PATCH 100/104] virtiofsd: process requests in a thread pool, Dr. David Alan Gilbert (git), 2019/12/12
- [PATCH 104/104] virtiofsd: Convert lo_destroy to take the lo->mutex lock itself, Dr. David Alan Gilbert (git), 2019/12/12
- Re: [PATCH 000/104] virtiofs daemon [all], no-reply, 2019/12/12