bdfd667883
Current virtiofsd has problems about xattr operations and
they does not work properly for directory/symlink/special file.
The fundamental cause is that virtiofsd uses openat() + f...xattr()
systemcalls for xattr operation but we should not open symlink/special
file in the daemon. Therefore the function is restricted.
Fix this problem by:
1. during setup of each thread, call unshare(CLONE_FS)
2. in xattr operations (i.e. lo_getxattr), if inode is not a regular
file or directory, use fchdir(proc_loot_fd) + ...xattr() +
fchdir(root.fd) instead of openat() + f...xattr()
(Note: for a regular file/directory openat() + f...xattr()
is still used for performance reason)
With this patch, xfstests generic/062 passes on virtiofs.
This fix is suggested by Miklos Szeredi and Stefan Hajnoczi.
The original discussion can be found here:
https://www.redhat.com/archives/virtio-fs/2019-October/msg00046.html
Signed-off-by: Misono Tomohiro <misono.tomohiro@jp.fujitsu.com>
Message-Id: <20200227055927.24566-3-misono.tomohiro@jp.fujitsu.com>
Acked-by: Vivek Goyal <vgoyal@redhat.com>
Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
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| .. | ||
| 50-qemu-virtiofsd.json.in | ||
| buffer.c | ||
| fuse_common.h | ||
| fuse_i.h | ||
| fuse_log.c | ||
| fuse_log.h | ||
| fuse_lowlevel.c | ||
| fuse_lowlevel.h | ||
| fuse_misc.h | ||
| fuse_opt.c | ||
| fuse_opt.h | ||
| fuse_signals.c | ||
| fuse_virtio.c | ||
| fuse_virtio.h | ||
| helper.c | ||
| Makefile.objs | ||
| passthrough_helpers.h | ||
| passthrough_ll.c | ||
| seccomp.c | ||
| seccomp.h | ||