We noticed that systemd has an issue about symlink unreliable caused by formatting filesystem and systemd operating on same device. Issue Link: https://github.com/systemd/systemd/issues/23746 According to systemd doc, a BSD flock needs to be acquired before formatting the device. Related Link: https://systemd.io/BLOCK_DEVICE_LOCKING/ So we acquire flock after opening the device but before writing superblock. Signed-off-by: wuguanghao <wuguanghao3@xxxxxxxxxx> --- mkfs/xfs_mkfs.c | 26 ++++++++++++++++++++++++++ 1 file changed, 26 insertions(+) diff --git a/mkfs/xfs_mkfs.c b/mkfs/xfs_mkfs.c index 9dd0e79c..b83cb043 100644 --- a/mkfs/xfs_mkfs.c +++ b/mkfs/xfs_mkfs.c @@ -13,6 +13,7 @@ #include "libfrog/crc32cselftest.h" #include "proto.h" #include <ini.h> +#include <sys/file.h> #define TERABYTES(count, blog) ((uint64_t)(count) << (40 - (blog))) #define GIGABYTES(count, blog) ((uint64_t)(count) << (30 - (blog))) @@ -2758,6 +2759,30 @@ _("log stripe unit (%d bytes) is too large (maximum is 256KiB)\n" } +static void +lock_device(dev_t dev, int flag, char *name) +{ + int fd = libxfs_device_to_fd(dev); + int readonly = flag & LIBXFS_ISREADONLY; + + if (!readonly && fd > 0) + if (flock(fd, LOCK_EX) != 0) { + fprintf(stderr, "%s: failed to get lock.\n", name); + exit(1); + } +} + +static void +lock_devices(struct libxfs_xinit *xi) +{ + if (!xi->disfile) + lock_device(xi->ddev, xi->dcreat, xi->dname); + if (xi->logdev && !xi->lisfile) + lock_device(xi->logdev, xi->lcreat, xi->logname); + if (xi->rtdev && !xi->risfile) + lock_device(xi->rtdev, xi->rcreat, xi->rtname); +} + static void open_devices( struct mkfs_params *cfg, @@ -4208,6 +4233,7 @@ main( * Open and validate the device configurations */ open_devices(&cfg, &xi); + lock_devices(&xi); validate_overwrite(dfile, force_overwrite); validate_datadev(&cfg, &cli); validate_logdev(&cfg, &cli, &logfile); -- 2.27.0
