Btrfs-progs: cleanup error handling in btrfs-image

We use BUG_ON() everywhere in btrfs-image.  When users are going to use this
command things are pretty dire, so I'd rather have really good error messages so
I know what happened rather than figure out which one of the 20 BUG_ON()'s made
the stupid thing exit early.  Thanks,

Signed-off-by: Josef Bacik <jbacik@fusionio.com>

diff --git a/btrfs-image.c b/btrfs-image.c
index 5b0af28..ad4f94c 100644 (file)
--- a/btrfs-image.c
+++ b/btrfs-image.c
@@ -72,6 +72,7 @@ struct async_work {
        u64 size;
        u8 *buffer;
        size_t bufsize;
+       int error;
 };
 
 struct metadump_struct {
@@ -111,6 +112,7 @@ struct mdrestore_struct {
 
        int compress_method;
        int done;
+       int error;
 };
 
 static void csum_block(u8 *buf, size_t len)
@@ -219,7 +221,9 @@ static void *dump_worker(void *data)
                        ret = compress2(async->buffer,
                                         (unsigned long *)&async->bufsize,
                                         orig, async->size, md->compress_level);
-                       BUG_ON(ret != Z_OK);
+
+                       if (ret != Z_OK)
+                               async->error = 1;
 
                        free(orig);
                }
@@ -261,8 +265,11 @@ static int metadump_init(struct metadump_struct *md, struct btrfs_root *root,
        md->pending_start = (u64)-1;
        md->compress_level = compress_level;
        md->cluster = calloc(1, BLOCK_SIZE);
-       if (!md->cluster)
+       if (!md->cluster) {
+               pthread_cond_destroy(&md->cond);
+               pthread_mutex_destroy(&md->mutex);
                return -ENOMEM;
+       }
 
        meta_cluster_init(md, 0);
        if (!num_threads)
@@ -270,13 +277,34 @@ static int metadump_init(struct metadump_struct *md, struct btrfs_root *root,
 
        md->num_threads = num_threads;
        md->threads = calloc(num_threads, sizeof(pthread_t));
-       if (!md->threads)
+       if (!md->threads) {
+               free(md->cluster);
+               pthread_cond_destroy(&md->cond);
+               pthread_mutex_destroy(&md->mutex);
                return -ENOMEM;
+       }
+
        for (i = 0; i < num_threads; i++) {
                ret = pthread_create(md->threads + i, NULL, dump_worker, md);
                if (ret)
                        break;
        }
+
+       if (ret) {
+               pthread_mutex_lock(&md->mutex);
+               md->done = 1;
+               pthread_cond_broadcast(&md->cond);
+               pthread_mutex_unlock(&md->mutex);
+
+               for (i--; i >= 0; i--)
+                       pthread_join(md->threads[i], NULL);
+
+               pthread_cond_destroy(&md->cond);
+               pthread_mutex_destroy(&md->mutex);
+               free(md->cluster);
+               free(md->threads);
+       }
+
        return ret;
 }
 
@@ -311,6 +339,7 @@ static int write_buffers(struct metadump_struct *md, u64 *next)
        u64 bytenr = 0;
        u32 nritems = 0;
        int ret;
+       int err = 0;
 
        if (list_empty(&md->ordered))
                goto out;
@@ -336,7 +365,10 @@ static int write_buffers(struct metadump_struct *md, u64 *next)
        header->nritems = cpu_to_le32(nritems);
 
        ret = fwrite(md->cluster, BLOCK_SIZE, 1, md->out);
-       BUG_ON(ret != 1);
+       if (ret != 1) {
+               fprintf(stderr, "Error writing out cluster: %d\n", errno);
+               return -EIO;
+       }
 
        /* write buffers */
        bytenr += le64_to_cpu(header->bytenr) + BLOCK_SIZE;
@@ -346,24 +378,35 @@ static int write_buffers(struct metadump_struct *md, u64 *next)
                list_del_init(&async->ordered);
 
                bytenr += async->bufsize;
-               ret = fwrite(async->buffer, async->bufsize, 1, md->out);
-               BUG_ON(ret != 1);
+               if (!err)
+                       ret = fwrite(async->buffer, async->bufsize, 1,
+                                    md->out);
+               if (ret != 1) {
+                       err = -EIO;
+                       ret = 0;
+                       fprintf(stderr, "Error writing out cluster: %d\n",
+                               errno);
+               }
 
                free(async->buffer);
                free(async);
        }
 
        /* zero unused space in the last block */
-       if (bytenr & BLOCK_MASK) {
+       if (!err && bytenr & BLOCK_MASK) {
                size_t size = BLOCK_SIZE - (bytenr & BLOCK_MASK);
 
                bytenr += size;
                ret = write_zero(md->out, size);
-               BUG_ON(ret != 1);
+               if (ret != 1) {
+                       fprintf(stderr, "Error zeroing out buffer: %d\n",
+                               errno);
+                       err = -EIO;
+               }
        }
 out:
        *next = bytenr;
-       return 0;
+       return err;
 }
 
 static int flush_pending(struct metadump_struct *md, int done)
@@ -374,7 +417,7 @@ static int flush_pending(struct metadump_struct *md, int done)
        u64 start;
        u64 size;
        size_t offset;
-       int ret;
+       int ret = 0;
 
        if (md->pending_size) {
                async = calloc(1, sizeof(*async));
@@ -385,13 +428,22 @@ static int flush_pending(struct metadump_struct *md, int done)
                async->size = md->pending_size;
                async->bufsize = async->size;
                async->buffer = malloc(async->bufsize);
-
+               if (!async->buffer) {
+                       free(async);
+                       return -ENOMEM;
+               }
                offset = 0;
                start = async->start;
                size = async->size;
                while (size > 0) {
                        eb = read_tree_block(md->root, start, blocksize, 0);
-                       BUG_ON(!eb);
+                       if (!eb) {
+                               free(async->buffer);
+                               free(async);
+                               fprintf(stderr,
+                                       "Error reading metadata block\n");
+                               return -EIO;
+                       }
                        copy_buffer(async->buffer + offset, eb);
                        free_extent_buffer(eb);
                        start += blocksize;
@@ -418,11 +470,14 @@ static int flush_pending(struct metadump_struct *md, int done)
        }
        if (md->num_items >= ITEMS_PER_CLUSTER || done) {
                ret = write_buffers(md, &start);
-               BUG_ON(ret);
-               meta_cluster_init(md, start);
+               if (ret)
+                       fprintf(stderr, "Error writing buffers %d\n",
+                               errno);
+               else
+                       meta_cluster_init(md, start);
        }
        pthread_mutex_unlock(&md->mutex);
-       return 0;
+       return ret;
 }
 
 static int add_metadata(u64 start, u64 size, struct metadump_struct *md)
@@ -455,7 +510,8 @@ static int is_tree_block(struct btrfs_root *extent_root,
                path->slots[0]++;
                if (path->slots[0] >= btrfs_header_nritems(leaf)) {
                        ret = btrfs_next_leaf(extent_root, path);
-                       BUG_ON(ret < 0);
+                       if (ret < 0)
+                               return ret;
                        if (ret > 0)
                                break;
                        leaf = path->nodes[0];
@@ -481,7 +537,7 @@ static int create_metadump(const char *input, FILE *out, int num_threads,
 {
        struct btrfs_root *root;
        struct btrfs_root *extent_root;
-       struct btrfs_path *path;
+       struct btrfs_path *path = NULL;
        struct extent_buffer *leaf;
        struct btrfs_extent_item *ei;
        struct btrfs_key key;
@@ -489,38 +545,60 @@ static int create_metadump(const char *input, FILE *out, int num_threads,
        u64 bytenr;
        u64 num_bytes;
        int ret;
+       int err = 0;
 
        root = open_ctree(input, 0, 0);
        if (!root) {
                fprintf(stderr, "Open ctree failed\n");
-               exit(1);
+               return -EIO;
        }
 
        BUG_ON(root->nodesize != root->leafsize);
 
        ret = metadump_init(&metadump, root, out, num_threads,
                            compress_level);
-       BUG_ON(ret);
+       if (ret) {
+               fprintf(stderr, "Error initing metadump %d\n", ret);
+               close_ctree(root);
+               return ret;
+       }
 
        ret = add_metadata(BTRFS_SUPER_INFO_OFFSET, 4096, &metadump);
-       BUG_ON(ret);
+       if (ret) {
+               fprintf(stderr, "Error adding metadata %d\n", ret);
+               err = ret;
+               goto out;
+       }
 
        extent_root = root->fs_info->extent_root;
        path = btrfs_alloc_path();
-
+       if (!path) {
+               fprintf(stderr, "Out of memory allocing path\n");
+               err = -ENOMEM;
+               goto out;
+       }
        bytenr = BTRFS_SUPER_INFO_OFFSET + 4096;
        key.objectid = bytenr;
        key.type = BTRFS_EXTENT_ITEM_KEY;
        key.offset = 0;
 
        ret = btrfs_search_slot(NULL, extent_root, &key, path, 0, 0);
-       BUG_ON(ret < 0);
+       if (ret < 0) {
+               fprintf(stderr, "Error searching extent root %d\n", ret);
+               err = ret;
+               goto out;
+       }
 
        while (1) {
                leaf = path->nodes[0];
                if (path->slots[0] >= btrfs_header_nritems(leaf)) {
                        ret = btrfs_next_leaf(extent_root, path);
-                       BUG_ON(ret < 0);
+                       if (ret < 0) {
+                               fprintf(stderr, "Error going to next leaf %d"
+                                       "\n", ret);
+                               err = ret;
+                               goto out;
+                       }
                        if (ret > 0)
                                break;
                        leaf = path->nodes[0];
@@ -543,30 +621,56 @@ static int create_metadump(const char *input, FILE *out, int num_threads,
                            BTRFS_EXTENT_FLAG_TREE_BLOCK) {
                                ret = add_metadata(bytenr, num_bytes,
                                                   &metadump);
-                               BUG_ON(ret);
+                               if (ret) {
+                                       fprintf(stderr, "Error adding block "
+                                               "%d\n", ret);
+                                       err = ret;
+                                       goto out;
+                               }
                        }
                } else {
 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
-                       if (is_tree_block(extent_root, path, bytenr)) {
+                       ret = is_tree_block(extent_root, path, bytenr);
+                       if (ret < 0) {
+                               fprintf(stderr, "Error checking tree block "
+                                       "%d\n", ret);
+                               err = ret;
+                               goto out;
+                       }
+
+                       if (ret) {
                                ret = add_metadata(bytenr, num_bytes,
                                                   &metadump);
-                               BUG_ON(ret);
+                               if (ret) {
+                                       fprintf(stderr, "Error adding block "
+                                               "%d\n", ret);
+                                       err = ret;
+                                       goto out;
+                               }
                        }
 #else
-                       BUG_ON(1);
+                       fprintf(stderr, "Either extent tree corruption or "
+                               "you haven't built with V0 support\n");
+                       err = -EIO;
+                       goto out;
 #endif
                }
                bytenr += num_bytes;
        }
 
+out:
        ret = flush_pending(&metadump, 1);
-       BUG_ON(ret);
+       if (ret) {
+               if (!err)
+                       ret = err;
+               fprintf(stderr, "Error flushing pending %d\n", ret);
+       }
 
        metadump_destroy(&metadump);
 
        btrfs_free_path(path);
        ret = close_ctree(root);
-       return 0;
+       return err ? err : ret;
 }
 
 static void update_super(u8 *buffer)
@@ -616,9 +720,18 @@ static void *restore_worker(void *data)
 
        outfd = fileno(mdres->out);
        buffer = malloc(MAX_PENDING_SIZE * 2);
-       BUG_ON(!buffer);
+       if (!buffer) {
+               fprintf(stderr, "Error allocing buffer\n");
+               pthread_mutex_lock(&mdres->mutex);
+               if (!mdres->error)
+                       mdres->error = -ENOMEM;
+               pthread_mutex_unlock(&mdres->mutex);
+               goto out;
+       }
 
        while (1) {
+               int err = 0;
+
                pthread_mutex_lock(&mdres->mutex);
                while (list_empty(&mdres->list)) {
                        if (mdres->done) {
@@ -635,7 +748,11 @@ static void *restore_worker(void *data)
                        size = MAX_PENDING_SIZE * 2;
                        ret = uncompress(buffer, (unsigned long *)&size,
                                         async->buffer, async->bufsize);
-                       BUG_ON(ret != Z_OK);
+                       if (ret != Z_OK) {
+                               fprintf(stderr, "Error decompressing %d\n",
+                                       ret);
+                               err = -EIO;
+                       }
                        outbuf = buffer;
                } else {
                        outbuf = async->buffer;
@@ -646,9 +763,20 @@ static void *restore_worker(void *data)
                        update_super(outbuf);
 
                ret = pwrite64(outfd, outbuf, size, async->start);
-               BUG_ON(ret != size);
+               if (ret < size) {
+                       if (ret < 0) {
+                               fprintf(stderr, "Error writing to device %d\n",
+                                       errno);
+                               err = errno;
+                       } else {
+                               fprintf(stderr, "Short write\n");
+                               err = -EIO;
+                       }
+               }
 
                pthread_mutex_lock(&mdres->mutex);
+               if (err && !mdres->error)
+                       mdres->error = err;
                mdres->num_items--;
                pthread_mutex_unlock(&mdres->mutex);
 
@@ -660,6 +788,22 @@ out:
        pthread_exit(NULL);
 }
 
+static void mdrestore_destroy(struct mdrestore_struct *mdres)
+{
+       int i;
+       pthread_mutex_lock(&mdres->mutex);
+       mdres->done = 1;
+       pthread_cond_broadcast(&mdres->cond);
+       pthread_mutex_unlock(&mdres->mutex);
+
+       for (i = 0; i < mdres->num_threads; i++)
+               pthread_join(mdres->threads[i], NULL);
+
+       pthread_cond_destroy(&mdres->cond);
+       pthread_mutex_destroy(&mdres->mutex);
+       free(mdres->threads);
+}
+
 static int mdrestore_init(struct mdrestore_struct *mdres,
                          FILE *in, FILE *out, int num_threads)
 {
@@ -685,25 +829,11 @@ static int mdrestore_init(struct mdrestore_struct *mdres,
                if (ret)
                        break;
        }
+       if (ret)
+               mdrestore_destroy(mdres);
        return ret;
 }
 
-static void mdrestore_destroy(struct mdrestore_struct *mdres)
-{
-       int i;
-       pthread_mutex_lock(&mdres->mutex);
-       mdres->done = 1;
-       pthread_cond_broadcast(&mdres->cond);
-       pthread_mutex_unlock(&mdres->mutex);
-
-       for (i = 0; i < mdres->num_threads; i++)
-               pthread_join(mdres->threads[i], NULL);
-
-       pthread_cond_destroy(&mdres->cond);
-       pthread_mutex_destroy(&mdres->mutex);
-       free(mdres->threads);
-}
-
 static int add_cluster(struct meta_cluster *cluster,
                       struct mdrestore_struct *mdres, u64 *next)
 {
@@ -722,11 +852,25 @@ static int add_cluster(struct meta_cluster *cluster,
        for (i = 0; i < nritems; i++) {
                item = &cluster->items[i];
                async = calloc(1, sizeof(*async));
+               if (!async) {
+                       fprintf(stderr, "Error allocating async\n");
+                       return -ENOMEM;
+               }
                async->start = le64_to_cpu(item->bytenr);
                async->bufsize = le32_to_cpu(item->size);
                async->buffer = malloc(async->bufsize);
+               if (!async->buffer) {
+                       fprintf(stderr, "Error allocing async buffer\n");
+                       free(async);
+                       return -ENOMEM;
+               }
                ret = fread(async->buffer, async->bufsize, 1, mdres->in);
-               BUG_ON(ret != 1);
+               if (ret != 1) {
+                       fprintf(stderr, "Error reading buffer %d\n", errno);
+                       free(async->buffer);
+                       free(async);
+                       return -EIO;
+               }
                bytenr += async->bufsize;
 
                pthread_mutex_lock(&mdres->mutex);
@@ -741,7 +885,10 @@ static int add_cluster(struct meta_cluster *cluster,
 
                bytenr += size;
                ret = fread(buffer, size, 1, mdres->in);
-               BUG_ON(ret != 1);
+               if (ret != 1) {
+                       fprintf(stderr, "Error reading in buffer %d\n", errno);
+                       return -EIO;
+               }
        }
        *next = bytenr;
        return 0;
@@ -749,8 +896,11 @@ static int add_cluster(struct meta_cluster *cluster,
 
 static int wait_for_worker(struct mdrestore_struct *mdres)
 {
+       int ret = 0;
+
        pthread_mutex_lock(&mdres->mutex);
-       while (mdres->num_items > 0) {
+       ret = mdres->error;
+       while (!ret && mdres->num_items > 0) {
                struct timespec ts = {
                        .tv_sec = 0,
                        .tv_nsec = 10000000,
@@ -758,9 +908,10 @@ static int wait_for_worker(struct mdrestore_struct *mdres)
                pthread_mutex_unlock(&mdres->mutex);
                nanosleep(&ts, NULL);
                pthread_mutex_lock(&mdres->mutex);
+               ret = mdres->error;
        }
        pthread_mutex_unlock(&mdres->mutex);
-       return 0;
+       return ret;
 }
 
 static int restore_metadump(const char *input, FILE *out, int num_threads)
@@ -770,7 +921,7 @@ static int restore_metadump(const char *input, FILE *out, int num_threads)
        struct mdrestore_struct mdrestore;
        u64 bytenr = 0;
        FILE *in = NULL;
-       int ret;
+       int ret = 0;
 
        if (!strcmp(input, "-")) {
                in = stdin;
@@ -783,10 +934,21 @@ static int restore_metadump(const char *input, FILE *out, int num_threads)
        }
 
        cluster = malloc(BLOCK_SIZE);
-       BUG_ON(!cluster);
+       if (!cluster) {
+               fprintf(stderr, "Error allocating cluster\n");
+               if (in != stdin)
+                       fclose(in);
+               return -ENOMEM;
+       }
 
        ret = mdrestore_init(&mdrestore, in, out, num_threads);
-       BUG_ON(ret);
+       if (ret) {
+               fprintf(stderr, "Error initing mdrestore %d\n", ret);
+               if (in != stdin)
+                       fclose(in);
+               free(cluster);
+               return ret;
+       }
 
        while (1) {
                ret = fread(cluster, BLOCK_SIZE, 1, in);
@@ -797,15 +959,23 @@ static int restore_metadump(const char *input, FILE *out, int num_threads)
                if (le64_to_cpu(header->magic) != HEADER_MAGIC ||
                    le64_to_cpu(header->bytenr) != bytenr) {
                        fprintf(stderr, "bad header in metadump image\n");
-                       ret = 1;
-                       goto out;
+                       ret = -EIO;
+                       break;
                }
                ret = add_cluster(cluster, &mdrestore, &bytenr);
-               BUG_ON(ret);
+               if (ret) {
+                       fprintf(stderr, "Error adding cluster\n");
+                       break;
+               }
 
-               wait_for_worker(&mdrestore);
+               ret = wait_for_worker(&mdrestore);
+               if (ret) {
+                       fprintf(stderr, "One of the threads errored out %d\n",
+                               ret);
+                       break;
+               }
        }
-out:
+
        mdrestore_destroy(&mdrestore);
        free(cluster);
        if (in != stdin)
@@ -888,5 +1058,5 @@ int main(int argc, char *argv[])
        else
                fclose(out);
 
-       exit(ret);
+       return ret;
 }