diff options
| -rw-r--r-- | src/nspawn/nspawn.c | 14 |
1 files changed, 12 insertions, 2 deletions
diff --git a/src/nspawn/nspawn.c b/src/nspawn/nspawn.c index 295293858e..c56af6e6f4 100644 --- a/src/nspawn/nspawn.c +++ b/src/nspawn/nspawn.c @@ -2260,7 +2260,7 @@ static int dissect_image( static int mount_device(const char *what, const char *where, const char *directory, bool rw) { #ifdef HAVE_BLKID _cleanup_blkid_free_probe_ blkid_probe b = NULL; - const char *fstype, *p; + const char *fstype, *p, *options; int r; assert(what); @@ -2309,7 +2309,17 @@ static int mount_device(const char *what, const char *where, const char *directo return -EOPNOTSUPP; } - return mount_verbose(LOG_ERR, what, p, fstype, MS_NODEV|(rw ? 0 : MS_RDONLY), NULL); + /* If this is a loopback device then let's mount the image with discard, so that the underlying file remains + * sparse when possible. */ + if (STR_IN_SET(fstype, "btrfs", "ext4", "vfat", "xfs")) { + const char *l; + + l = path_startswith(what, "/dev"); + if (l && startswith(l, "loop")) + options = "discard"; + } + + return mount_verbose(LOG_ERR, what, p, fstype, MS_NODEV|(rw ? 0 : MS_RDONLY), options); #else log_error("--image= is not supported, compiled without blkid support."); return -EOPNOTSUPP; |