raid6check: Check return value of lseek64()

If lseek64() failed it was still writing to the disks, which would introduce
data corruption.

Signed-off-by: Bernd Schubert <bernd.schubert@fastmail.fm>
Signed-off-by: NeilBrown <neilb@suse.de>

diff --git a/raid6check.c b/raid6check.c
index 45d808d45305a71765c28bf34024325f08a2f888..aa6ce234e37805b7fa34a2174872d23e8f4a296b 100644 (file)
--- a/raid6check.c
+++ b/raid6check.c
@@ -185,11 +185,19 @@ int check_stripes(struct mdinfo *info, int *source, unsigned long long *offsets,
                        goto exitCheck;
                }
                for (i = 0 ; i < raid_disks ; i++) {
-                       lseek64(source[i], offsets[i] + start * chunk_size, 0);
+                       off64_t seek_res = lseek64(source[i], offsets[i] + start * chunk_size,
+                                                  SEEK_SET);
+                       if (seek_res < 0) {
+                               fprintf(stderr, "lseek to source %d failed\n", i);
+                               unlock_all_stripes(info, sig);
+                               err = -1;
+                               goto exitCheck;
+                       }
                        int read_res = read(source[i], stripes[i], chunk_size);
                        if (read_res < chunk_size) {
                                fprintf(stderr, "Failed to read complete chunk disk %d, aborting\n", i);
                                unlock_all_stripes(info, sig);
+                               err = -1;
                                goto exitCheck;
                        }
                }
@@ -288,17 +296,33 @@ int check_stripes(struct mdinfo *info, int *source, unsigned long long *offsets,
                        }
 
                        int write_res1, write_res2;
+                       off64_t seek_res;
 
-                       lseek64(source[failed_disk1], offsets[failed_disk1] + start * chunk_size, 0);
+                       seek_res = lseek64(source[failed_disk1],
+                                          offsets[failed_disk1] + start * chunk_size, SEEK_SET);
+                       if (seek_res < 0) {
+                               fprintf(stderr, "lseek failed for failed_disk1\n");
+                               unlock_all_stripes(info, sig);
+                               err = -1;
+                               goto exitCheck;
+                       }
                        write_res1 = write(source[failed_disk1], stripes[failed_disk1], chunk_size);
-                       lseek64(source[failed_disk2], offsets[failed_disk2] + start * chunk_size, 0);
+
+
+                       seek_res = lseek64(source[failed_disk2],
+                                          offsets[failed_disk2] + start * chunk_size, SEEK_SET);
+                       if (seek_res < 0) {
+                               fprintf(stderr, "lseek failed for failed_disk1\n");
+                               unlock_all_stripes(info, sig);
+                               err = -1;
+                               goto exitCheck;
+                       }
                        write_res2 = write(source[failed_disk2], stripes[failed_disk2], chunk_size);
 
                        err = unlock_all_stripes(info, sig);
                        if(err != 0)
                                goto exitCheck;
 
-
                        if (write_res1 != chunk_size || write_res2 != chunk_size) {
                                fprintf(stderr, "Failed to write a complete chunk.\n");
                                goto exitCheck;