rootfs pinning: On NFS, make file hidden but don't delete it

On NFS, avoid random names of the root pin file due to "NFS silly renaming" but use a fixed hidden name instead.
This commit is contained in:
Guido Jäkel 2018-04-06 09:35:21 +02:00 committed by GitHub
parent 83ffaa1d39
commit 63fc76c3e0
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@ -539,10 +539,11 @@ int run_script(const char *name, const char *section, const char *script, ...)
}
/* pin_rootfs
* if rootfs is a directory, then open ${rootfs}/lxc.hold for writing for
* if rootfs is a directory, then open ${rootfs}/.lxc-keep for writing for
* the duration of the container run, to prevent the container from marking
* the underlying fs readonly on shutdown. unlink the file immediately so
* no name pollution is happens
* no name pollution is happens.
* don't unlink on NFS to avoid random named stale handles.
* return -1 on error.
* return -2 if nothing needed to be pinned.
* return an open fd (>=0) if we pinned it.
@ -552,6 +553,7 @@ int pin_rootfs(const char *rootfs)
int fd, ret;
char absrootfs[MAXPATHLEN], absrootfspin[MAXPATHLEN];
struct stat s;
struct statfs sfs;
if (rootfs == NULL || strlen(rootfs) == 0)
return -2;
@ -570,7 +572,7 @@ int pin_rootfs(const char *rootfs)
if (!S_ISDIR(s.st_mode))
return -2;
ret = snprintf(absrootfspin, MAXPATHLEN, "%s/lxc.hold", absrootfs);
ret = snprintf(absrootfspin, MAXPATHLEN, "%s/.lxc-keep", absrootfs);
if (ret >= MAXPATHLEN)
return -1;
@ -578,6 +580,15 @@ int pin_rootfs(const char *rootfs)
if (fd < 0)
return fd;
if (fstatfs (fd, &sfs)) {
return -1;
}
if (sfs.f_type == NFS_SUPER_MAGIC) {
DEBUG("rootfs on NFS, not unlinking pin file \"%s\".", absrootfspin);
return fd;
}
(void)unlink(absrootfspin);
return fd;