LU-9936 utils: Improve ldiskfs_write_dd() writing mount data

Writing the mount data to a file used buffered stream I/O missing a
flush operation with incomplete error handling.

This patch replaces buffered stream I/O with the Unix I/O API and adds
error handling.

Signed-off-by: Marc Vef <mvef@whamcloud.com>
Change-Id: Ia7dfc186b1c6f581dee461bd277f07dcc2eabafa
Reviewed-on: https://review.whamcloud.com/c/fs/lustre-release/+/56408
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>
Reviewed-by: Mikhail Pershin <mpershin@whamcloud.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>

diff --git a/lustre/utils/libmount_utils_ldiskfs.c b/lustre/utils/libmount_utils_ldiskfs.c
index 1721bf9..dc40f43 100644 (file)
--- a/lustre/utils/libmount_utils_ldiskfs.c
+++ b/lustre/utils/libmount_utils_ldiskfs.c
@@ -143,9 +143,10 @@ int ldiskfs_write_ldd(struct mkfs_opts *mop)
        char mntpt[] = "/tmp/mntXXXXXX";
        char filepnm[192];
        char *dev;
-       FILE *filep;
        int ret = 0;
-       size_t num;
+       int fd;
+       size_t total_written;
+       size_t write_cnt;
 
        /* Mount this device temporarily in order to write these files */
        if (!mkdtemp(mntpt)) {
@@ -173,8 +174,7 @@ int ldiskfs_write_ldd(struct mkfs_opts *mop)
                                ret = run_command(command, sizeof(filepnm));
                                if (ret)
                                        fprintf(stderr,
-                                               "%s: Unable to set 'mmp' "
-                                               "on %s: %d\n",
+                                               "%s: Unable to set 'mmp' on %s: %d\n",
                                                progname, dev, ret);
                        } else {
                                disp_old_e2fsprogs_msg("mmp", 1);
@@ -207,6 +207,7 @@ int ldiskfs_write_ldd(struct mkfs_opts *mop)
        if ((ret != 0) && (errno != EEXIST)) {
                fprintf(stderr, "%s: Can't make configs dir %s (%s)\n",
                        progname, filepnm, strerror(errno));
+               ret = errno;
                goto out_umnt;
        } else if (errno == EEXIST) {
                ret = 0;
@@ -216,22 +217,40 @@ int ldiskfs_write_ldd(struct mkfs_opts *mop)
           this file to get the real mount options. */
        vprint("Writing %s\n", MOUNT_DATA_FILE);
        sprintf(filepnm, "%s/%s", mntpt, MOUNT_DATA_FILE);
-       filep = fopen(filepnm, "w");
-       if (!filep) {
-               fprintf(stderr, "%s: Unable to create %s file: %s\n",
-                       progname, filepnm, strerror(errno));
+       fd = open(filepnm, O_WRONLY | O_CREAT | O_TRUNC, 0644);
+       if (fd < 0) {
+               fprintf(stderr, "%s: Unable to create %s file: %s\n", progname,
+                       filepnm, strerror(errno));
+               ret = errno;
                goto out_umnt;
        }
-       num = fwrite(&mop->mo_ldd, sizeof(mop->mo_ldd), 1, filep);
-       if (num < 1 && ferror(filep)) {
-               fprintf(stderr, "%s: Unable to write to file (%s): %s\n",
-                       progname, filepnm, strerror(errno));
-               fclose(filep);
-               goto out_umnt;
+       total_written = 0;
+       while (total_written < sizeof(mop->mo_ldd)) {
+               write_cnt = write(fd, &mop->mo_ldd + total_written,
+                                 sizeof(mop->mo_ldd) - total_written);
+               if (write_cnt < 0) {
+                       fprintf(stderr,
+                               "%s: Unable to write to file (%s): %s\n",
+                               progname, filepnm, strerror(errno));
+                       ret = errno;
+                       goto close_fd;
+               }
+               total_written += write_cnt;
+       }
+       if (fsync(fd) < 0) {
+               fprintf(stderr, "%s: Unable to fsync file (%s): %s\n", progname,
+                       filepnm, strerror(errno));
+               ret = errno;
        }
-       fsync(filep->_fileno);
-       fclose(filep);
 
+close_fd:
+       if (close(fd) < 0) {
+               fprintf(stderr, "%s: Error while closing file (%s): %s\n",
+                       progname, filepnm, strerror(errno));
+               /* Don't overwrite errno if already set in previous failure */
+               if (ret == 0)
+                       ret = errno;
+       }
 out_umnt:
        umount(mntpt);
 out_rmdir:
@@ -411,7 +430,8 @@ static bool is_e2fsprogs_feature_supp(const char *feature)
                   strncmp(feature, "-O ", 3) ? feature : feature + 3))
                return true;
 
-       if ((fd = mkstemp(imgname)) < 0)
+       fd = mkstemp(imgname);
+       if (fd < 0)
                return false;
 
        close(fd);