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[PATCH v2 098/109] virtiofsd: Reset O_DIRECT flag during file open
From: |
Dr. David Alan Gilbert (git) |
Subject: |
[PATCH v2 098/109] virtiofsd: Reset O_DIRECT flag during file open |
Date: |
Tue, 21 Jan 2020 12:24:22 +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>
Reviewed-by: Daniel P. Berrangé <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 4c3a48325f..cadfa676ca 100644
--- a/tools/virtiofsd/passthrough_ll.c
+++ b/tools/virtiofsd/passthrough_ll.c
@@ -1721,6 +1721,13 @@ 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;
@@ -1950,6 +1957,13 @@ 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) {
--
2.24.1
- [PATCH v2 087/109] virtiofsd: use fuse_lowlevel_is_virtio() in fuse_session_destroy(), (continued)
- [PATCH v2 087/109] virtiofsd: use fuse_lowlevel_is_virtio() in fuse_session_destroy(), Dr. David Alan Gilbert (git), 2020/01/21
- [PATCH v2 089/109] virtiofsd: make lo_release() atomic, Dr. David Alan Gilbert (git), 2020/01/21
- [PATCH v2 090/109] virtiofsd: prevent races with lo_dirp_put(), Dr. David Alan Gilbert (git), 2020/01/21
- [PATCH v2 091/109] virtiofsd: rename inode->refcount to inode->nlookup, Dr. David Alan Gilbert (git), 2020/01/21
- [PATCH v2 092/109] libvhost-user: Fix some memtable remap cases, Dr. David Alan Gilbert (git), 2020/01/21
- [PATCH v2 093/109] virtiofsd: add man page, Dr. David Alan Gilbert (git), 2020/01/21
- [PATCH v2 094/109] virtiofsd: passthrough_ll: fix refcounting on remove/rename, Dr. David Alan Gilbert (git), 2020/01/21
- [PATCH v2 095/109] virtiofsd: introduce inode refcount to prevent use-after-free, Dr. David Alan Gilbert (git), 2020/01/21
- [PATCH v2 096/109] virtiofsd: do not always set FUSE_FLOCK_LOCKS, Dr. David Alan Gilbert (git), 2020/01/21
- [PATCH v2 098/109] virtiofsd: Reset O_DIRECT flag during file open,
Dr. David Alan Gilbert (git) <=
- [PATCH v2 097/109] virtiofsd: convert more fprintf and perror to use fuse log infra, Dr. David Alan Gilbert (git), 2020/01/21
- [PATCH v2 100/109] virtiofsd: add definition of fuse_buf_writev(), Dr. David Alan Gilbert (git), 2020/01/21
- [PATCH v2 099/109] virtiofsd: Fix data corruption with O_APPEND write in writeback mode, Dr. David Alan Gilbert (git), 2020/01/21
- [PATCH v2 101/109] virtiofsd: use fuse_buf_writev to replace fuse_buf_write for better performance, Dr. David Alan Gilbert (git), 2020/01/21
- [PATCH v2 102/109] virtiofsd: process requests in a thread pool, Dr. David Alan Gilbert (git), 2020/01/21
- [PATCH v2 103/109] virtiofsd: prevent FUSE_INIT/FUSE_DESTROY races, Dr. David Alan Gilbert (git), 2020/01/21
- [PATCH v2 104/109] virtiofsd: fix lo_destroy() resource leaks, Dr. David Alan Gilbert (git), 2020/01/21
- [PATCH v2 105/109] virtiofsd: add --thread-pool-size=NUM option, Dr. David Alan Gilbert (git), 2020/01/21
- [PATCH v2 106/109] virtiofsd: Convert lo_destroy to take the lo->mutex lock itself, Dr. David Alan Gilbert (git), 2020/01/21