btrfs-progs: report I/O errors when closing the filesystem
[platform/upstream/btrfs-progs.git] / volumes.c
index c38da6c..b350e25 100644 (file)
--- a/volumes.c
+++ b/volumes.c
@@ -15,8 +15,6 @@
  * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  * Boston, MA 021110-1307, USA.
  */
-#define _XOPEN_SOURCE 600
-#define __USE_XOPEN2K
 #include <stdio.h>
 #include <stdlib.h>
 #include <sys/types.h>
@@ -29,7 +27,7 @@
 #include "transaction.h"
 #include "print-tree.h"
 #include "volumes.h"
-#include "math.h"
+#include "utils.h"
 
 struct stripe {
        struct btrfs_device *dev;
@@ -116,6 +114,7 @@ static int device_list_add(const char *path,
                }
                device->fd = -1;
                device->devid = devid;
+               device->generation = found_transid;
                memcpy(device->uuid, disk_super->dev_item.uuid,
                       BTRFS_UUID_SIZE);
                device->name = kstrdup(path, GFP_NOFS);
@@ -160,29 +159,61 @@ static int device_list_add(const char *path,
 int btrfs_close_devices(struct btrfs_fs_devices *fs_devices)
 {
        struct btrfs_fs_devices *seed_devices;
-       struct list_head *cur;
        struct btrfs_device *device;
+       int ret = 0;
+
 again:
-       list_for_each(cur, &fs_devices->devices) {
-               device = list_entry(cur, struct btrfs_device, dev_list);
+       if (!fs_devices)
+               return 0;
+       while (!list_empty(&fs_devices->devices)) {
+               device = list_entry(fs_devices->devices.next,
+                                   struct btrfs_device, dev_list);
                if (device->fd != -1) {
-                       fsync(device->fd);
+                       if (fsync(device->fd) == -1) {
+                               warning("fsync on device %llu failed: %s",
+                                       device->devid, strerror(errno));
+                               ret = -errno;
+                       }
                        if (posix_fadvise(device->fd, 0, 0, POSIX_FADV_DONTNEED))
                                fprintf(stderr, "Warning, could not drop caches\n");
                        close(device->fd);
                        device->fd = -1;
                }
                device->writeable = 0;
+               list_del(&device->dev_list);
+               /* free the memory */
+               free(device->name);
+               free(device->label);
+               free(device);
        }
 
        seed_devices = fs_devices->seed;
        fs_devices->seed = NULL;
        if (seed_devices) {
+               struct btrfs_fs_devices *orig;
+
+               orig = fs_devices;
                fs_devices = seed_devices;
+               list_del(&orig->list);
+               free(orig);
                goto again;
+       } else {
+               list_del(&fs_devices->list);
+               free(fs_devices);
        }
 
-       return 0;
+       return ret;
+}
+
+void btrfs_close_all_devices(void)
+{
+       struct btrfs_fs_devices *fs_devices;
+
+       while (!list_empty(&fs_uuids)) {
+               fs_devices = list_entry(fs_uuids.next, struct btrfs_fs_devices,
+                                       list);
+               btrfs_close_devices(fs_devices);
+       }
 }
 
 int btrfs_open_devices(struct btrfs_fs_devices *fs_devices, int flags)
@@ -203,6 +234,8 @@ int btrfs_open_devices(struct btrfs_fs_devices *fs_devices, int flags)
                fd = open(device->name, flags);
                if (fd < 0) {
                        ret = -errno;
+                       error("cannot open device '%s': %s", device->name,
+                                       strerror(errno));
                        goto fail;
                }
 
@@ -214,7 +247,7 @@ int btrfs_open_devices(struct btrfs_fs_devices *fs_devices, int flags)
                if (device->devid == fs_devices->lowest_devid)
                        fs_devices->lowest_bdev = fd;
                device->fd = fd;
-               if (flags == O_RDWR)
+               if (flags & O_RDWR)
                        device->writeable = 1;
        }
        return 0;
@@ -225,24 +258,17 @@ fail:
 
 int btrfs_scan_one_device(int fd, const char *path,
                          struct btrfs_fs_devices **fs_devices_ret,
-                         u64 *total_devs, u64 super_offset)
+                         u64 *total_devs, u64 super_offset, unsigned sbflags)
 {
        struct btrfs_super_block *disk_super;
-       char *buf;
+       char buf[BTRFS_SUPER_INFO_SIZE];
        int ret;
        u64 devid;
 
-       buf = malloc(4096);
-       if (!buf) {
-               ret = -ENOMEM;
-               goto error;
-       }
        disk_super = (struct btrfs_super_block *)buf;
-       ret = btrfs_read_dev_super(fd, disk_super, super_offset);
-       if (ret < 0) {
-               ret = -EIO;
-               goto error_brelse;
-       }
+       ret = btrfs_read_dev_super(fd, disk_super, super_offset, sbflags);
+       if (ret < 0)
+               return -EIO;
        devid = btrfs_stack_device_id(&disk_super->dev_item);
        if (btrfs_super_flags(disk_super) & BTRFS_SUPER_FLAG_METADUMP)
                *total_devs = 1;
@@ -251,60 +277,83 @@ int btrfs_scan_one_device(int fd, const char *path,
 
        ret = device_list_add(path, disk_super, devid, fs_devices_ret);
 
-error_brelse:
-       free(buf);
-error:
        return ret;
 }
 
 /*
+ * find_free_dev_extent_start - find free space in the specified device
+ * @device:      the device which we search the free space in
+ * @num_bytes:   the size of the free space that we need
+ * @search_start: the position from which to begin the search
+ * @start:       store the start of the free space.
+ * @len:         the size of the free space. that we find, or the size
+ *               of the max free space if we don't find suitable free space
+ *
  * this uses a pretty simple search, the expectation is that it is
  * called very infrequently and that a given device has a small number
  * of extents
+ *
+ * @start is used to store the start of the free space if we find. But if we
+ * don't find suitable free space, it will be used to store the start position
+ * of the max free space.
+ *
+ * @len is used to store the size of the free space that we find.
+ * But if we don't find suitable free space, it is used to store the size of
+ * the max free space.
  */
-static int find_free_dev_extent(struct btrfs_trans_handle *trans,
-                               struct btrfs_device *device,
-                               struct btrfs_path *path,
-                               u64 num_bytes, u64 *start)
+static int find_free_dev_extent_start(struct btrfs_trans_handle *trans,
+                              struct btrfs_device *device, u64 num_bytes,
+                              u64 search_start, u64 *start, u64 *len)
 {
        struct btrfs_key key;
        struct btrfs_root *root = device->dev_root;
-       struct btrfs_dev_extent *dev_extent = NULL;
-       u64 hole_size = 0;
-       u64 last_byte = 0;
-       u64 search_start = root->fs_info->alloc_start;
+       struct btrfs_dev_extent *dev_extent;
+       struct btrfs_path *path;
+       u64 hole_size;
+       u64 max_hole_start;
+       u64 max_hole_size;
+       u64 extent_end;
        u64 search_end = device->total_bytes;
        int ret;
-       int slot = 0;
-       int start_found;
+       int slot;
        struct extent_buffer *l;
+       u64 min_search_start;
 
-       start_found = 0;
-       path->reada = 2;
+       /*
+        * We don't want to overwrite the superblock on the drive nor any area
+        * used by the boot loader (grub for example), so we make sure to start
+        * at an offset of at least 1MB.
+        */
+       min_search_start = max(root->fs_info->alloc_start, (u64)SZ_1M);
+       search_start = max(search_start, min_search_start);
 
-       /* FIXME use last free of some kind */
+       path = btrfs_alloc_path();
+       if (!path)
+               return -ENOMEM;
 
-       /* we don't want to overwrite the superblock on the drive,
-        * so we make sure to start at an offset of at least 1MB
-        */
-       search_start = max(BTRFS_BLOCK_RESERVED_1M_FOR_SUPER, search_start);
+       max_hole_start = search_start;
+       max_hole_size = 0;
 
        if (search_start >= search_end) {
                ret = -ENOSPC;
-               goto error;
+               goto out;
        }
 
+       path->reada = 2;
+
        key.objectid = device->devid;
        key.offset = search_start;
        key.type = BTRFS_DEV_EXTENT_KEY;
-       ret = btrfs_search_slot(trans, root, &key, path, 0, 0);
-       if (ret < 0)
-               goto error;
-       ret = btrfs_previous_item(root, path, 0, key.type);
+
+       ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
        if (ret < 0)
-               goto error;
-       l = path->nodes[0];
-       btrfs_item_key_to_cpu(l, &key, path->slots[0]);
+               goto out;
+       if (ret > 0) {
+               ret = btrfs_previous_item(root, path, key.objectid, key.type);
+               if (ret < 0)
+                       goto out;
+       }
+
        while (1) {
                l = path->nodes[0];
                slot = path->slots[0];
@@ -313,24 +362,9 @@ static int find_free_dev_extent(struct btrfs_trans_handle *trans,
                        if (ret == 0)
                                continue;
                        if (ret < 0)
-                               goto error;
-no_more_items:
-                       if (!start_found) {
-                               if (search_start >= search_end) {
-                                       ret = -ENOSPC;
-                                       goto error;
-                               }
-                               *start = search_start;
-                               start_found = 1;
-                               goto check_pending;
-                       }
-                       *start = last_byte > search_start ?
-                               last_byte : search_start;
-                       if (search_end <= *start) {
-                               ret = -ENOSPC;
-                               goto error;
-                       }
-                       goto check_pending;
+                               goto out;
+
+                       break;
                }
                btrfs_item_key_to_cpu(l, &key, slot);
 
@@ -338,54 +372,90 @@ no_more_items:
                        goto next;
 
                if (key.objectid > device->devid)
-                       goto no_more_items;
-
-               if (key.offset >= search_start && key.offset > last_byte &&
-                   start_found) {
-                       if (last_byte < search_start)
-                               last_byte = search_start;
-                       hole_size = key.offset - last_byte;
-                       if (key.offset > last_byte &&
-                           hole_size >= num_bytes) {
-                               *start = last_byte;
-                               goto check_pending;
-                       }
-               }
-               if (btrfs_key_type(&key) != BTRFS_DEV_EXTENT_KEY) {
+                       break;
+
+               if (key.type != BTRFS_DEV_EXTENT_KEY)
                        goto next;
+
+               if (key.offset > search_start) {
+                       hole_size = key.offset - search_start;
+
+                       /*
+                        * Have to check before we set max_hole_start, otherwise
+                        * we could end up sending back this offset anyway.
+                        */
+                       if (hole_size > max_hole_size) {
+                               max_hole_start = search_start;
+                               max_hole_size = hole_size;
+                       }
+
+                       /*
+                        * If this free space is greater than which we need,
+                        * it must be the max free space that we have found
+                        * until now, so max_hole_start must point to the start
+                        * of this free space and the length of this free space
+                        * is stored in max_hole_size. Thus, we return
+                        * max_hole_start and max_hole_size and go back to the
+                        * caller.
+                        */
+                       if (hole_size >= num_bytes) {
+                               ret = 0;
+                               goto out;
+                       }
                }
 
-               start_found = 1;
                dev_extent = btrfs_item_ptr(l, slot, struct btrfs_dev_extent);
-               last_byte = key.offset + btrfs_dev_extent_length(l, dev_extent);
+               extent_end = key.offset + btrfs_dev_extent_length(l,
+                                                                 dev_extent);
+               if (extent_end > search_start)
+                       search_start = extent_end;
 next:
                path->slots[0]++;
                cond_resched();
        }
-check_pending:
-       /* we have to make sure we didn't find an extent that has already
-        * been allocated by the map tree or the original allocation
+
+       /*
+        * At this point, search_start should be the end of
+        * allocated dev extents, and when shrinking the device,
+        * search_end may be smaller than search_start.
         */
-       btrfs_release_path(path);
-       BUG_ON(*start < search_start);
+       if (search_end > search_start) {
+               hole_size = search_end - search_start;
 
-       if (*start + num_bytes > search_end) {
-               ret = -ENOSPC;
-               goto error;
+               if (hole_size > max_hole_size) {
+                       max_hole_start = search_start;
+                       max_hole_size = hole_size;
+               }
        }
-       /* check for pending inserts here */
-       return 0;
 
-error:
-       btrfs_release_path(path);
+       /* See above. */
+       if (max_hole_size < num_bytes)
+               ret = -ENOSPC;
+       else
+               ret = 0;
+
+out:
+       btrfs_free_path(path);
+       *start = max_hole_start;
+       if (len)
+               *len = max_hole_size;
        return ret;
 }
 
+int find_free_dev_extent(struct btrfs_trans_handle *trans,
+                        struct btrfs_device *device, u64 num_bytes,
+                        u64 *start)
+{
+       /* FIXME use last free of some kind */
+       return find_free_dev_extent_start(trans, device,
+                                         num_bytes, 0, start, NULL);
+}
+
 static int btrfs_alloc_dev_extent(struct btrfs_trans_handle *trans,
                                  struct btrfs_device *device,
                                  u64 chunk_tree, u64 chunk_objectid,
                                  u64 chunk_offset,
-                                 u64 num_bytes, u64 *start)
+                                 u64 num_bytes, u64 *start, int convert)
 {
        int ret;
        struct btrfs_path *path;
@@ -398,9 +468,15 @@ static int btrfs_alloc_dev_extent(struct btrfs_trans_handle *trans,
        if (!path)
                return -ENOMEM;
 
-       ret = find_free_dev_extent(trans, device, path, num_bytes, start);
-       if (ret) {
-               goto err;
+       /*
+        * For convert case, just skip search free dev_extent, as caller
+        * is responsible to make sure it's free.
+        */
+       if (!convert) {
+               ret = find_free_dev_extent(trans, device, num_bytes,
+                                          start);
+               if (ret)
+                       goto err;
        }
 
        key.objectid = device->devid;
@@ -437,7 +513,8 @@ static int find_next_chunk(struct btrfs_root *root, u64 objectid, u64 *offset)
        struct btrfs_key found_key;
 
        path = btrfs_alloc_path();
-       BUG_ON(!path);
+       if (!path)
+               return -ENOMEM;
 
        key.objectid = objectid;
        key.offset = (u64)-1;
@@ -612,8 +689,7 @@ out:
        return ret;
 }
 
-int btrfs_add_system_chunk(struct btrfs_trans_handle *trans,
-                          struct btrfs_root *root,
+int btrfs_add_system_chunk(struct btrfs_root *root,
                           struct btrfs_key *key,
                           struct btrfs_chunk *chunk, int item_size)
 {
@@ -623,7 +699,8 @@ int btrfs_add_system_chunk(struct btrfs_trans_handle *trans,
        u8 *ptr;
 
        array_size = btrfs_super_sys_array_size(super_copy);
-       if (array_size + item_size > BTRFS_SYSTEM_CHUNK_ARRAY_SIZE)
+       if (array_size + item_size + sizeof(disk_key)
+                       > BTRFS_SYSTEM_CHUNK_ARRAY_SIZE)
                return -EFBIG;
 
        ptr = super_copy->sys_chunk_array + array_size;
@@ -655,7 +732,7 @@ static u64 chunk_bytes_by_type(u64 type, u64 calc_size, int num_stripes,
 static u32 find_raid56_stripe_len(u32 data_devices, u32 dev_stripe_target)
 {
        /* TODO, add a way to store the preferred stripe size */
-       return 64 * 1024;
+       return BTRFS_STRIPE_LEN;
 }
 
 /*
@@ -717,7 +794,7 @@ static int btrfs_device_avail_bytes(struct btrfs_trans_handle *trans,
                        goto next;
                if (key.objectid > device->devid)
                        break;
-               if (btrfs_key_type(&key) != BTRFS_DEV_EXTENT_KEY)
+               if (key.type != BTRFS_DEV_EXTENT_KEY)
                        goto next;
                if (key.offset > search_end)
                        break;
@@ -746,6 +823,16 @@ error:
        return ret;
 }
 
+#define BTRFS_MAX_DEVS(r) ((BTRFS_LEAF_DATA_SIZE(r)            \
+                       - sizeof(struct btrfs_item)             \
+                       - sizeof(struct btrfs_chunk))           \
+                       / sizeof(struct btrfs_stripe) + 1)
+
+#define BTRFS_MAX_DEVS_SYS_CHUNK ((BTRFS_SYSTEM_CHUNK_ARRAY_SIZE       \
+                               - 2 * sizeof(struct btrfs_disk_key)     \
+                               - 2 * sizeof(struct btrfs_chunk))       \
+                               / sizeof(struct btrfs_stripe) + 1)
+
 int btrfs_alloc_chunk(struct btrfs_trans_handle *trans,
                      struct btrfs_root *extent_root, u64 *start,
                      u64 *num_bytes, u64 type)
@@ -760,20 +847,21 @@ int btrfs_alloc_chunk(struct btrfs_trans_handle *trans,
        struct list_head *dev_list = &info->fs_devices->devices;
        struct list_head *cur;
        struct map_lookup *map;
-       int min_stripe_size = 1 * 1024 * 1024;
-       u64 calc_size = 8 * 1024 * 1024;
+       int min_stripe_size = SZ_1M;
+       u64 calc_size = SZ_8M;
        u64 min_free;
        u64 max_chunk_size = 4 * calc_size;
        u64 avail = 0;
        u64 max_avail = 0;
        u64 percent_max;
        int num_stripes = 1;
+       int max_stripes = 0;
        int min_stripes = 1;
        int sub_stripes = 0;
        int looped = 0;
        int ret;
        int index;
-       int stripe_len = 64 * 1024;
+       int stripe_len = BTRFS_STRIPE_LEN;
        struct btrfs_key key;
        u64 offset;
 
@@ -786,17 +874,20 @@ int btrfs_alloc_chunk(struct btrfs_trans_handle *trans,
                    BTRFS_BLOCK_GROUP_RAID10 |
                    BTRFS_BLOCK_GROUP_DUP)) {
                if (type & BTRFS_BLOCK_GROUP_SYSTEM) {
-                       calc_size = 8 * 1024 * 1024;
+                       calc_size = SZ_8M;
                        max_chunk_size = calc_size * 2;
-                       min_stripe_size = 1 * 1024 * 1024;
+                       min_stripe_size = SZ_1M;
+                       max_stripes = BTRFS_MAX_DEVS_SYS_CHUNK;
                } else if (type & BTRFS_BLOCK_GROUP_DATA) {
-                       calc_size = 1024 * 1024 * 1024;
+                       calc_size = SZ_1G;
                        max_chunk_size = 10 * calc_size;
-                       min_stripe_size = 64 * 1024 * 1024;
+                       min_stripe_size = SZ_64M;
+                       max_stripes = BTRFS_MAX_DEVS(chunk_root);
                } else if (type & BTRFS_BLOCK_GROUP_METADATA) {
-                       calc_size = 1024 * 1024 * 1024;
+                       calc_size = SZ_1G;
                        max_chunk_size = 4 * calc_size;
-                       min_stripe_size = 32 * 1024 * 1024;
+                       min_stripe_size = SZ_32M;
+                       max_stripes = BTRFS_MAX_DEVS(chunk_root);
                }
        }
        if (type & BTRFS_BLOCK_GROUP_RAID1) {
@@ -812,10 +903,14 @@ int btrfs_alloc_chunk(struct btrfs_trans_handle *trans,
        }
        if (type & (BTRFS_BLOCK_GROUP_RAID0)) {
                num_stripes = btrfs_super_num_devices(info->super_copy);
+               if (num_stripes > max_stripes)
+                       num_stripes = max_stripes;
                min_stripes = 2;
        }
        if (type & (BTRFS_BLOCK_GROUP_RAID10)) {
                num_stripes = btrfs_super_num_devices(info->super_copy);
+               if (num_stripes > max_stripes)
+                       num_stripes = max_stripes;
                if (num_stripes < 4)
                        return -ENOSPC;
                num_stripes &= ~(u32)1;
@@ -824,6 +919,8 @@ int btrfs_alloc_chunk(struct btrfs_trans_handle *trans,
        }
        if (type & (BTRFS_BLOCK_GROUP_RAID5)) {
                num_stripes = btrfs_super_num_devices(info->super_copy);
+               if (num_stripes > max_stripes)
+                       num_stripes = max_stripes;
                if (num_stripes < 2)
                        return -ENOSPC;
                min_stripes = 2;
@@ -832,6 +929,8 @@ int btrfs_alloc_chunk(struct btrfs_trans_handle *trans,
        }
        if (type & (BTRFS_BLOCK_GROUP_RAID6)) {
                num_stripes = btrfs_super_num_devices(info->super_copy);
+               if (num_stripes > max_stripes)
+                       num_stripes = max_stripes;
                if (num_stripes < 3)
                        return -ENOSPC;
                min_stripes = 3;
@@ -936,7 +1035,7 @@ again:
                ret = btrfs_alloc_dev_extent(trans, device,
                             info->chunk_root->root_key.objectid,
                             BTRFS_FIRST_CHUNK_TREE_OBJECTID, key.offset,
-                            calc_size, &dev_offset);
+                            calc_size, &dev_offset, 0);
                BUG_ON(ret);
 
                device->bytes_used += calc_size;
@@ -983,7 +1082,7 @@ again:
        BUG_ON(ret);
 
        if (type & BTRFS_BLOCK_GROUP_SYSTEM) {
-               ret = btrfs_add_system_chunk(trans, chunk_root, &key,
+               ret = btrfs_add_system_chunk(chunk_root, &key,
                                    chunk, btrfs_chunk_item_size(num_stripes));
                BUG_ON(ret);
        }
@@ -992,9 +1091,17 @@ again:
        return ret;
 }
 
+/*
+ * Alloc a DATA chunk with SINGLE profile.
+ *
+ * If 'convert' is set, it will alloc a chunk with 1:1 mapping
+ * (btrfs logical bytenr == on-disk bytenr)
+ * For that case, caller must make sure the chunk and dev_extent are not
+ * occupied.
+ */
 int btrfs_alloc_data_chunk(struct btrfs_trans_handle *trans,
                           struct btrfs_root *extent_root, u64 *start,
-                          u64 num_bytes, u64 type)
+                          u64 num_bytes, u64 type, int convert)
 {
        u64 dev_offset;
        struct btrfs_fs_info *info = extent_root->fs_info;
@@ -1005,20 +1112,34 @@ int btrfs_alloc_data_chunk(struct btrfs_trans_handle *trans,
        struct list_head *dev_list = &info->fs_devices->devices;
        struct list_head *cur;
        struct map_lookup *map;
-       u64 calc_size = 8 * 1024 * 1024;
+       u64 calc_size = SZ_8M;
        int num_stripes = 1;
        int sub_stripes = 0;
        int ret;
        int index;
-       int stripe_len = 64 * 1024;
+       int stripe_len = BTRFS_STRIPE_LEN;
        struct btrfs_key key;
 
        key.objectid = BTRFS_FIRST_CHUNK_TREE_OBJECTID;
        key.type = BTRFS_CHUNK_ITEM_KEY;
-       ret = find_next_chunk(chunk_root, BTRFS_FIRST_CHUNK_TREE_OBJECTID,
-                             &key.offset);
-       if (ret)
-               return ret;
+       if (convert) {
+               if (*start != round_down(*start, extent_root->sectorsize)) {
+                       error("DATA chunk start not sectorsize aligned: %llu",
+                                       (unsigned long long)*start);
+                       return -EINVAL;
+               }
+               key.offset = *start;
+               dev_offset = *start;
+       } else {
+               u64 tmp;
+
+               ret = find_next_chunk(chunk_root,
+                                     BTRFS_FIRST_CHUNK_TREE_OBJECTID,
+                                     &tmp);
+               key.offset = tmp;
+               if (ret)
+                       return ret;
+       }
 
        chunk = kmalloc(btrfs_chunk_item_size(num_stripes), GFP_NOFS);
        if (!chunk)
@@ -1043,7 +1164,7 @@ int btrfs_alloc_data_chunk(struct btrfs_trans_handle *trans,
                ret = btrfs_alloc_dev_extent(trans, device,
                             info->chunk_root->root_key.objectid,
                             BTRFS_FIRST_CHUNK_TREE_OBJECTID, key.offset,
-                            calc_size, &dev_offset);
+                            calc_size, &dev_offset, convert);
                BUG_ON(ret);
 
                device->bytes_used += calc_size;
@@ -1080,7 +1201,8 @@ int btrfs_alloc_data_chunk(struct btrfs_trans_handle *trans,
        ret = btrfs_insert_item(trans, chunk_root, &key, chunk,
                                btrfs_chunk_item_size(num_stripes));
        BUG_ON(ret);
-       *start = key.offset;
+       if (!convert)
+               *start = key.offset;
 
        map->ce.start = key.offset;
        map->ce.size = num_bytes;
@@ -1099,8 +1221,20 @@ int btrfs_num_copies(struct btrfs_mapping_tree *map_tree, u64 logical, u64 len)
        int ret;
 
        ce = search_cache_extent(&map_tree->cache_tree, logical);
-       BUG_ON(!ce);
-       BUG_ON(ce->start > logical || ce->start + ce->size < logical);
+       if (!ce) {
+               fprintf(stderr, "No mapping for %llu-%llu\n",
+                       (unsigned long long)logical,
+                       (unsigned long long)logical+len);
+               return 1;
+       }
+       if (ce->start > logical || ce->start + ce->size < logical) {
+               fprintf(stderr, "Invalid mapping for %llu-%llu, got "
+                       "%llu-%llu\n", (unsigned long long)logical,
+                       (unsigned long long)logical+len,
+                       (unsigned long long)ce->start,
+                       (unsigned long long)ce->start + ce->size);
+               return 1;
+       }
        map = container_of(ce, struct map_lookup, ce);
 
        if (map->type & (BTRFS_BLOCK_GROUP_DUP | BTRFS_BLOCK_GROUP_RAID1))
@@ -1116,21 +1250,30 @@ int btrfs_num_copies(struct btrfs_mapping_tree *map_tree, u64 logical, u64 len)
        return ret;
 }
 
-int btrfs_next_metadata(struct btrfs_mapping_tree *map_tree, u64 *logical,
-                       u64 *size)
+int btrfs_next_bg(struct btrfs_mapping_tree *map_tree, u64 *logical,
+                    u64 *size, u64 type)
 {
        struct cache_extent *ce;
        struct map_lookup *map;
+       u64 cur = *logical;
 
-       ce = search_cache_extent(&map_tree->cache_tree, *logical);
+       ce = search_cache_extent(&map_tree->cache_tree, cur);
 
        while (ce) {
-               ce = next_cache_extent(ce);
-               if (!ce)
-                       return -ENOENT;
+               /*
+                * only jump to next bg if our cur is not 0
+                * As the initial logical for btrfs_next_bg() is 0, and
+                * if we jump to next bg, we skipped a valid bg.
+                */
+               if (cur) {
+                       ce = next_cache_extent(ce);
+                       if (!ce)
+                               return -ENOENT;
+               }
 
+               cur = ce->start;
                map = container_of(ce, struct map_lookup, ce);
-               if (map->type & BTRFS_BLOCK_GROUP_METADATA) {
+               if (map->type & type) {
                        *logical = ce->start;
                        *size = ce->size;
                        return 0;
@@ -1267,13 +1410,13 @@ int __btrfs_map_block(struct btrfs_mapping_tree *map_tree, int rw,
 again:
        ce = search_cache_extent(&map_tree->cache_tree, logical);
        if (!ce) {
-               if (multi)
-                       kfree(multi);
+               kfree(multi);
+               *length = (u64)-1;
                return -ENOENT;
        }
-       if (ce->start > logical || ce->start + ce->size < logical) {
-               if (multi)
-                       kfree(multi);
+       if (ce->start > logical) {
+               kfree(multi);
+               *length = ce->start - logical;
                return -ENOENT;
        }
 
@@ -1462,7 +1605,8 @@ struct btrfs_device *btrfs_find_device(struct btrfs_root *root, u64 devid,
        cur_devices = root->fs_info->fs_devices;
        while (cur_devices) {
                if (!fsid ||
-                   !memcmp(cur_devices->fsid, fsid, BTRFS_UUID_SIZE)) {
+                   (!memcmp(cur_devices->fsid, fsid, BTRFS_UUID_SIZE) ||
+                    root->fs_info->ignore_fsid_mismatch)) {
                        device = __find_device(&cur_devices->devices,
                                               devid, uuid);
                        if (device)
@@ -1496,8 +1640,15 @@ int btrfs_chunk_readonly(struct btrfs_root *root, u64 chunk_offset)
        int readonly = 0;
        int i;
 
+       /*
+        * During chunk recovering, we may fail to find block group's
+        * corresponding chunk, we will rebuild it later
+        */
        ce = search_cache_extent(&map_tree->cache_tree, chunk_offset);
-       BUG_ON(!ce);
+       if (!root->fs_info->is_chunk_recover)
+               BUG_ON(!ce);
+       else
+               return 0;
 
        map = container_of(ce, struct map_lookup, ce);
        for (i = 0; i < map->num_stripes; i++) {
@@ -1520,9 +1671,99 @@ static struct btrfs_device *fill_missing_device(u64 devid)
        return device;
 }
 
+/*
+ * slot == -1: SYSTEM chunk
+ * return -EIO on error, otherwise return 0
+ */
+int btrfs_check_chunk_valid(struct btrfs_root *root,
+                           struct extent_buffer *leaf,
+                           struct btrfs_chunk *chunk,
+                           int slot, u64 logical)
+{
+       u64 length;
+       u64 stripe_len;
+       u16 num_stripes;
+       u16 sub_stripes;
+       u64 type;
+
+       length = btrfs_chunk_length(leaf, chunk);
+       stripe_len = btrfs_chunk_stripe_len(leaf, chunk);
+       num_stripes = btrfs_chunk_num_stripes(leaf, chunk);
+       sub_stripes = btrfs_chunk_sub_stripes(leaf, chunk);
+       type = btrfs_chunk_type(leaf, chunk);
+
+       /*
+        * These valid checks may be insufficient to cover every corner cases.
+        */
+       if (!IS_ALIGNED(logical, root->sectorsize)) {
+               error("invalid chunk logical %llu",  logical);
+               return -EIO;
+       }
+       if (btrfs_chunk_sector_size(leaf, chunk) != root->sectorsize) {
+               error("invalid chunk sectorsize %llu", 
+                     (unsigned long long)btrfs_chunk_sector_size(leaf, chunk));
+               return -EIO;
+       }
+       if (!length || !IS_ALIGNED(length, root->sectorsize)) {
+               error("invalid chunk length %llu",  length);
+               return -EIO;
+       }
+       if (stripe_len != BTRFS_STRIPE_LEN) {
+               error("invalid chunk stripe length: %llu", stripe_len);
+               return -EIO;
+       }
+       /* Check on chunk item type */
+       if (slot == -1 && (type & BTRFS_BLOCK_GROUP_SYSTEM) == 0) {
+               error("invalid chunk type %llu", type);
+               return -EIO;
+       }
+       if (type & ~(BTRFS_BLOCK_GROUP_TYPE_MASK |
+                    BTRFS_BLOCK_GROUP_PROFILE_MASK)) {
+               error("unrecognized chunk type: %llu",
+                     ~(BTRFS_BLOCK_GROUP_TYPE_MASK |
+                       BTRFS_BLOCK_GROUP_PROFILE_MASK) & type);
+               return -EIO;
+       }
+       /*
+        * Btrfs_chunk contains at least one stripe, and for sys_chunk
+        * it can't exceed the system chunk array size
+        * For normal chunk, it should match its chunk item size.
+        */
+       if (num_stripes < 1 ||
+           (slot == -1 && sizeof(struct btrfs_stripe) * num_stripes >
+            BTRFS_SYSTEM_CHUNK_ARRAY_SIZE) ||
+           (slot >= 0 && sizeof(struct btrfs_stripe) * (num_stripes - 1) >
+            btrfs_item_size_nr(leaf, slot))) {
+               error("invalid num_stripes: %u", num_stripes);
+               return -EIO;
+       }
+       /*
+        * Device number check against profile
+        */
+       if ((type & BTRFS_BLOCK_GROUP_RAID10 && sub_stripes == 0) ||
+           (type & BTRFS_BLOCK_GROUP_RAID1 && num_stripes < 1) ||
+           (type & BTRFS_BLOCK_GROUP_RAID5 && num_stripes < 2) ||
+           (type & BTRFS_BLOCK_GROUP_RAID6 && num_stripes < 3) ||
+           (type & BTRFS_BLOCK_GROUP_DUP && num_stripes > 2) ||
+           ((type & BTRFS_BLOCK_GROUP_PROFILE_MASK) == 0 &&
+            num_stripes != 1)) {
+               error("Invalid num_stripes:sub_stripes %u:%u for profile %llu",
+                     num_stripes, sub_stripes,
+                     type & BTRFS_BLOCK_GROUP_PROFILE_MASK);
+               return -EIO;
+       }
+
+       return 0;
+}
+
+/*
+ * Slot is used to verify the chunk item is valid
+ *
+ * For sys chunk in superblock, pass -1 to indicate sys chunk.
+ */
 static int read_one_chunk(struct btrfs_root *root, struct btrfs_key *key,
                          struct extent_buffer *leaf,
-                         struct btrfs_chunk *chunk)
+                         struct btrfs_chunk *chunk, int slot)
 {
        struct btrfs_mapping_tree *map_tree = &root->fs_info->mapping_tree;
        struct map_lookup *map;
@@ -1537,6 +1778,15 @@ static int read_one_chunk(struct btrfs_root *root, struct btrfs_key *key,
 
        logical = key->offset;
        length = btrfs_chunk_length(leaf, chunk);
+       num_stripes = btrfs_chunk_num_stripes(leaf, chunk);
+       /* Validation check */
+       ret = btrfs_check_chunk_valid(root, leaf, chunk, slot, logical);
+       if (ret) {
+               error("%s checksums match, but it has an invalid chunk, %s",
+                     (slot == -1) ? "Superblock" : "Metadata",
+                     (slot == -1) ? "try btrfsck --repair -s <superblock> ie, 0,1,2" : "");
+               return ret;
+       }
 
        ce = search_cache_extent(&map_tree->cache_tree, logical);
 
@@ -1545,7 +1795,6 @@ static int read_one_chunk(struct btrfs_root *root, struct btrfs_key *key,
                return 0;
        }
 
-       num_stripes = btrfs_chunk_num_stripes(leaf, chunk);
        map = kmalloc(btrfs_map_lookup_size(num_stripes), GFP_NOFS);
        if (!map)
                return -ENOMEM;
@@ -1573,6 +1822,8 @@ static int read_one_chunk(struct btrfs_root *root, struct btrfs_key *key,
                        map->stripes[i].dev = fill_missing_device(devid);
                        printf("warning, device %llu is missing\n",
                               (unsigned long long)devid);
+                       list_add(&map->stripes[i].dev->dev_list,
+                                &root->fs_info->fs_devices->devices);
                }
 
        }
@@ -1618,8 +1869,15 @@ static int open_seed_devices(struct btrfs_root *root, u8 *fsid)
 
        fs_devices = find_fsid(fsid);
        if (!fs_devices) {
-               ret = -ENOENT;
-               goto out;
+               /* missing all seed devices */
+               fs_devices = kzalloc(sizeof(*fs_devices), GFP_NOFS);
+               if (!fs_devices) {
+                       ret = -ENOMEM;
+                       goto out;
+               }
+               INIT_LIST_HEAD(&fs_devices->devices);
+               list_add(&fs_devices->list, &fs_uuids);
+               memcpy(fs_devices->fsid, fsid, BTRFS_FSID_SIZE);
        }
 
        ret = btrfs_open_devices(fs_devices, O_RDONLY);
@@ -1658,8 +1916,6 @@ static int read_one_dev(struct btrfs_root *root,
 
        device = btrfs_find_device(root, devid, dev_uuid, fs_uuid);
        if (!device) {
-               printk("warning devid %llu not found already\n",
-                       (unsigned long long)devid);
                device = kzalloc(sizeof(*device), GFP_NOFS);
                if (!device)
                        return -ENOMEM;
@@ -1679,50 +1935,85 @@ int btrfs_read_sys_array(struct btrfs_root *root)
        struct extent_buffer *sb;
        struct btrfs_disk_key *disk_key;
        struct btrfs_chunk *chunk;
-       struct btrfs_key key;
+       u8 *array_ptr;
+       unsigned long sb_array_offset;
+       int ret = 0;
        u32 num_stripes;
+       u32 array_size;
        u32 len = 0;
-       u8 *ptr;
-       u8 *array_end;
-       int ret = 0;
+       u32 cur_offset;
+       struct btrfs_key key;
 
-       sb = btrfs_find_create_tree_block(root, BTRFS_SUPER_INFO_OFFSET,
+       sb = btrfs_find_create_tree_block(root->fs_info,
+                                         BTRFS_SUPER_INFO_OFFSET,
                                          BTRFS_SUPER_INFO_SIZE);
        if (!sb)
                return -ENOMEM;
        btrfs_set_buffer_uptodate(sb);
        write_extent_buffer(sb, super_copy, 0, sizeof(*super_copy));
-       array_end = ((u8 *)super_copy->sys_chunk_array) +
-                   btrfs_super_sys_array_size(super_copy);
+       array_size = btrfs_super_sys_array_size(super_copy);
 
-       /*
-        * we do this loop twice, once for the device items and
-        * once for all of the chunks.  This way there are device
-        * structs filled in for every chunk
-        */
-       ptr = super_copy->sys_chunk_array;
+       array_ptr = super_copy->sys_chunk_array;
+       sb_array_offset = offsetof(struct btrfs_super_block, sys_chunk_array);
+       cur_offset = 0;
+
+       while (cur_offset < array_size) {
+               disk_key = (struct btrfs_disk_key *)array_ptr;
+               len = sizeof(*disk_key);
+               if (cur_offset + len > array_size)
+                       goto out_short_read;
 
-       while (ptr < array_end) {
-               disk_key = (struct btrfs_disk_key *)ptr;
                btrfs_disk_key_to_cpu(&key, disk_key);
 
-               len = sizeof(*disk_key);
-               ptr += len;
+               array_ptr += len;
+               sb_array_offset += len;
+               cur_offset += len;
 
                if (key.type == BTRFS_CHUNK_ITEM_KEY) {
-                       chunk = (struct btrfs_chunk *)(ptr - (u8 *)super_copy);
-                       ret = read_one_chunk(root, &key, sb, chunk);
-                       if (ret)
-                               break;
+                       chunk = (struct btrfs_chunk *)sb_array_offset;
+                       /*
+                        * At least one btrfs_chunk with one stripe must be
+                        * present, exact stripe count check comes afterwards
+                        */
+                       len = btrfs_chunk_item_size(1);
+                       if (cur_offset + len > array_size)
+                               goto out_short_read;
+
                        num_stripes = btrfs_chunk_num_stripes(sb, chunk);
+                       if (!num_stripes) {
+                               printk(
+           "ERROR: invalid number of stripes %u in sys_array at offset %u\n",
+                                       num_stripes, cur_offset);
+                               ret = -EIO;
+                               break;
+                       }
+
                        len = btrfs_chunk_item_size(num_stripes);
+                       if (cur_offset + len > array_size)
+                               goto out_short_read;
+
+                       ret = read_one_chunk(root, &key, sb, chunk, -1);
+                       if (ret)
+                               break;
                } else {
-                       BUG();
+                       printk(
+               "ERROR: unexpected item type %u in sys_array at offset %u\n",
+                               (u32)key.type, cur_offset);
+                       ret = -EIO;
+                       break;
                }
-               ptr += len;
+               array_ptr += len;
+               sb_array_offset += len;
+               cur_offset += len;
        }
        free_extent_buffer(sb);
        return ret;
+
+out_short_read:
+       printk("ERROR: sys_array too short to read %u bytes at offset %u\n",
+                       len, cur_offset);
+       free_extent_buffer(sb);
+       return -EIO;
 }
 
 int btrfs_read_chunk_tree(struct btrfs_root *root)
@@ -1773,7 +2064,8 @@ int btrfs_read_chunk_tree(struct btrfs_root *root)
                } else if (found_key.type == BTRFS_CHUNK_ITEM_KEY) {
                        struct btrfs_chunk *chunk;
                        chunk = btrfs_item_ptr(leaf, slot, struct btrfs_chunk);
-                       ret = read_one_chunk(root, &found_key, leaf, chunk);
+                       ret = read_one_chunk(root, &found_key, leaf, chunk,
+                                            slot);
                        BUG_ON(ret);
                }
                path->slots[0]++;
@@ -1825,26 +2117,39 @@ static int rmw_eb(struct btrfs_fs_info *info,
        return 0;
 }
 
-static void split_eb_for_raid56(struct btrfs_fs_info *info,
-                               struct extent_buffer *orig_eb,
+static int split_eb_for_raid56(struct btrfs_fs_info *info,
+                              struct extent_buffer *orig_eb,
                               struct extent_buffer **ebs,
                               u64 stripe_len, u64 *raid_map,
                               int num_stripes)
 {
-       struct extent_buffer *eb;
+       struct extent_buffer **tmp_ebs;
        u64 start = orig_eb->start;
        u64 this_eb_start;
        int i;
-       int ret;
+       int ret = 0;
+
+       tmp_ebs = calloc(num_stripes, sizeof(*tmp_ebs));
+       if (!tmp_ebs)
+               return -ENOMEM;
 
+       /* Alloc memory in a row for data stripes */
        for (i = 0; i < num_stripes; i++) {
                if (raid_map[i] >= BTRFS_RAID5_P_STRIPE)
                        break;
 
-               eb = malloc(sizeof(struct extent_buffer) + stripe_len);
-               if (!eb)
-                       BUG();
-               memset(eb, 0, sizeof(struct extent_buffer) + stripe_len);
+               tmp_ebs[i] = calloc(1, sizeof(**tmp_ebs) + stripe_len);
+               if (!tmp_ebs[i]) {
+                       ret = -ENOMEM;
+                       goto clean_up;
+               }
+       }
+
+       for (i = 0; i < num_stripes; i++) {
+               struct extent_buffer *eb = tmp_ebs[i];
+
+               if (raid_map[i] >= BTRFS_RAID5_P_STRIPE)
+                       break;
 
                eb->start = raid_map[i];
                eb->len = stripe_len;
@@ -1858,12 +2163,21 @@ static void split_eb_for_raid56(struct btrfs_fs_info *info,
                if (start > this_eb_start ||
                    start + orig_eb->len < this_eb_start + stripe_len) {
                        ret = rmw_eb(info, eb, orig_eb);
-                       BUG_ON(ret);
+                       if (ret)
+                               goto clean_up;
                } else {
-                       memcpy(eb->data, orig_eb->data + eb->start - start, stripe_len);
+                       memcpy(eb->data, orig_eb->data + eb->start - start,
+                              stripe_len);
                }
                ebs[i] = eb;
        }
+       free(tmp_ebs);
+       return ret;
+clean_up:
+       for (i = 0; i < num_stripes; i++)
+               free(tmp_ebs[i]);
+       free(tmp_ebs);
+       return ret;
 }
 
 int write_raid56_with_parity(struct btrfs_fs_info *info,
@@ -1873,18 +2187,25 @@ int write_raid56_with_parity(struct btrfs_fs_info *info,
 {
        struct extent_buffer **ebs, *p_eb = NULL, *q_eb = NULL;
        int i;
-       int j;
        int ret;
        int alloc_size = eb->len;
+       void **pointers;
 
-       ebs = kmalloc(sizeof(*ebs) * multi->num_stripes, GFP_NOFS);
-       BUG_ON(!ebs);
+       ebs = malloc(sizeof(*ebs) * multi->num_stripes);
+       pointers = malloc(sizeof(*pointers) * multi->num_stripes);
+       if (!ebs || !pointers) {
+               free(ebs);
+               free(pointers);
+               return -ENOMEM;
+       }
 
        if (stripe_len > alloc_size)
                alloc_size = stripe_len;
 
-       split_eb_for_raid56(info, eb, ebs, stripe_len, raid_map,
-                           multi->num_stripes);
+       ret = split_eb_for_raid56(info, eb, ebs, stripe_len, raid_map,
+                                 multi->num_stripes);
+       if (ret)
+               goto out;
 
        for (i = 0; i < multi->num_stripes; i++) {
                struct extent_buffer *new_eb;
@@ -1892,11 +2213,17 @@ int write_raid56_with_parity(struct btrfs_fs_info *info,
                        ebs[i]->dev_bytenr = multi->stripes[i].physical;
                        ebs[i]->fd = multi->stripes[i].dev->fd;
                        multi->stripes[i].dev->total_ios++;
-                       BUG_ON(ebs[i]->start != raid_map[i]);
+                       if (ebs[i]->start != raid_map[i]) {
+                               ret = -EINVAL;
+                               goto out_free_split;
+                       }
                        continue;
                }
-               new_eb = kmalloc(sizeof(*eb) + alloc_size, GFP_NOFS);
-               BUG_ON(!new_eb);
+               new_eb = malloc(sizeof(*eb) + alloc_size);
+               if (!new_eb) {
+                       ret = -ENOMEM;
+                       goto out_free_split;
+               }
                new_eb->dev_bytenr = multi->stripes[i].physical;
                new_eb->fd = multi->stripes[i].dev->fd;
                multi->stripes[i].dev->total_ios++;
@@ -1908,12 +2235,6 @@ int write_raid56_with_parity(struct btrfs_fs_info *info,
                        q_eb = new_eb;
        }
        if (q_eb) {
-               void **pointers;
-
-               pointers = kmalloc(sizeof(*pointers) * multi->num_stripes,
-                                  GFP_NOFS);
-               BUG_ON(!pointers);
-
                ebs[multi->num_stripes - 2] = p_eb;
                ebs[multi->num_stripes - 1] = q_eb;
 
@@ -1921,26 +2242,30 @@ int write_raid56_with_parity(struct btrfs_fs_info *info,
                        pointers[i] = ebs[i]->data;
 
                raid6_gen_syndrome(multi->num_stripes, stripe_len, pointers);
-               kfree(pointers);
        } else {
                ebs[multi->num_stripes - 1] = p_eb;
-               memcpy(p_eb->data, ebs[0]->data, stripe_len);
-               for (j = 1; j < multi->num_stripes - 1; j++) {
-                       for (i = 0; i < stripe_len; i += sizeof(unsigned long)) {
-                               *(unsigned long *)(p_eb->data + i) ^=
-                                       *(unsigned long *)(ebs[j]->data + i);
-                       }
-               }
+               for (i = 0; i < multi->num_stripes; i++)
+                       pointers[i] = ebs[i]->data;
+               ret = raid5_gen_result(multi->num_stripes, stripe_len,
+                                      multi->num_stripes - 1, pointers);
+               if (ret < 0)
+                       goto out_free_split;
        }
 
        for (i = 0; i < multi->num_stripes; i++) {
                ret = write_extent_to_disk(ebs[i]);
-               BUG_ON(ret);
-               if (ebs[i] != eb)
-                       kfree(ebs[i]);
+               if (ret < 0)
+                       goto out_free_split;
        }
 
-       kfree(ebs);
+out_free_split:
+       for (i = 0; i < multi->num_stripes; i++) {
+               if (ebs[i] != eb)
+                       free(ebs[i]);
+       }
+out:
+       free(ebs);
+       free(pointers);
 
-       return 0;
+       return ret;
 }