bcacheadm: fix status and query-devs

[bcachefs-tools-debian] / bcache.c

diff --git a/bcache.c b/bcache.c
index fb3931ed54b65dd51beaa741bb098bf9ee0c1882..a69a46fb0ad6dacd37fd141d6568b311aaf0d2c5 100644 (file)
--- a/bcache.c
+++ b/bcache.c
@@ -906,30 +906,39 @@ void sysfs_attr_list() {
 struct cache_sb *query_dev(char *dev, bool force_csum,
                bool print_sb, bool uuid_only, char *dev_uuid)
 {
-       struct cache_sb sb_stack, *sb = &sb_stack;
-       size_t bytes = sizeof(*sb);
+       size_t bytes = 4096;
+       struct cache_sb *sb = aligned_alloc(bytes, bytes);
 
-       int fd = open(dev, O_RDONLY);
+       int fd = open(dev, O_RDONLY|O_DIRECT);
        if (fd < 0) {
                printf("Can't open dev %s: %s\n", dev, strerror(errno));
                return NULL;
        }
 
-       if (pread(fd, sb, bytes, SB_START) != bytes) {
-               fprintf(stderr, "Couldn't read\n");
-               return NULL;
-       }
-
-       if (sb->keys) {
-               bytes = sizeof(*sb) + sb->keys * sizeof(uint64_t);
-               sb = malloc(bytes);
-
-               if (pread(fd, sb, bytes, SB_START) != bytes) {
-                       fprintf(stderr, "Couldn't read\n");
+       while (true) {
+               int ret = pread(fd, sb, bytes, SB_START);
+               if (ret < 0) {
+                       fprintf(stderr, "Couldn't read superblock: %s\n",
+                                       strerror(errno));
+                       close(fd);
+                       free(sb);
                        return NULL;
+               } else if (bytes > sizeof(sb) + sb->keys * sizeof(u64)) {
+                       /* We read the whole superblock */
+                       break;
                }
+
+               /*
+                * otherwise double the size of our dest
+                * and read again
+                */
+               free(sb);
+               bytes *= 2;
+               sb = aligned_alloc(4096, bytes);
        }
 
+       close(fd);
+
        if(uuid_only) {
                show_uuid_only(sb, dev_uuid);
                return sb;
@@ -1061,6 +1070,8 @@ char *find_matching_uuid(char *stats_dir, char *subdir, const char *stats_dev_uu
                        sb = query_dev(devname, false, false, true, dev_uuid);
                        if(!sb)
                                return err;
+                       else
+                               free(sb);
 
                        if(!strcmp(stats_dev_uuid, dev_uuid)) {
                                strcat(subdir, intbuf);