diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c index e2e01a327108..32a4948b621c 100644 --- a/fs/btrfs/volumes.c +++ b/fs/btrfs/volumes.c @@ -4004,6 +4004,12 @@ int btrfs_num_copies(struct btrfs_fs_info *fs_info, u64 logical, u64 len) else ret = 1; free_extent_map(em); + + btrfs_dev_replace_lock(&fs_info->dev_replace); + if (btrfs_dev_replace_is_ongoing(&fs_info->dev_replace)) + ret++; + btrfs_dev_replace_unlock(&fs_info->dev_replace); + return ret; } @@ -4068,6 +4074,8 @@ static int __btrfs_map_block(struct btrfs_fs_info *fs_info, int rw, struct btrfs_dev_replace *dev_replace = &fs_info->dev_replace; int dev_replace_is_ongoing = 0; int num_alloc_stripes; + int patch_the_first_stripe_for_dev_replace = 0; + u64 physical_to_patch_in_first_stripe = 0; read_lock(&em_tree->lock); em = lookup_extent_mapping(em_tree, logical, *length); @@ -4084,9 +4092,6 @@ static int __btrfs_map_block(struct btrfs_fs_info *fs_info, int rw, map = (struct map_lookup *)em->bdev; offset = logical - em->start; - if (mirror_num > map->num_stripes) - mirror_num = 0; - stripe_nr = offset; /* * stripe_nr counts the total number of stripes we have to stride @@ -4118,6 +4123,88 @@ static int __btrfs_map_block(struct btrfs_fs_info *fs_info, int rw, if (!dev_replace_is_ongoing) btrfs_dev_replace_unlock(dev_replace); + if (dev_replace_is_ongoing && mirror_num == map->num_stripes + 1 && + !(rw & (REQ_WRITE | REQ_DISCARD | REQ_GET_READ_MIRRORS)) && + dev_replace->tgtdev != NULL) { + /* + * in dev-replace case, for repair case (that's the only + * case where the mirror is selected explicitly when + * calling btrfs_map_block), blocks left of the left cursor + * can also be read from the target drive. + * For REQ_GET_READ_MIRRORS, the target drive is added as + * the last one to the array of stripes. For READ, it also + * needs to be supported using the same mirror number. + * If the requested block is not left of the left cursor, + * EIO is returned. This can happen because btrfs_num_copies() + * returns one more in the dev-replace case. + */ + u64 tmp_length = *length; + struct btrfs_bio *tmp_bbio = NULL; + int tmp_num_stripes; + u64 srcdev_devid = dev_replace->srcdev->devid; + int index_srcdev = 0; + int found = 0; + u64 physical_of_found = 0; + + ret = __btrfs_map_block(fs_info, REQ_GET_READ_MIRRORS, + logical, &tmp_length, &tmp_bbio, 0); + if (ret) { + WARN_ON(tmp_bbio != NULL); + goto out; + } + + tmp_num_stripes = tmp_bbio->num_stripes; + if (mirror_num > tmp_num_stripes) { + /* + * REQ_GET_READ_MIRRORS does not contain this + * mirror, that means that the requested area + * is not left of the left cursor + */ + ret = -EIO; + kfree(tmp_bbio); + goto out; + } + + /* + * process the rest of the function using the mirror_num + * of the source drive. Therefore look it up first. + * At the end, patch the device pointer to the one of the + * target drive. + */ + for (i = 0; i < tmp_num_stripes; i++) { + if (tmp_bbio->stripes[i].dev->devid == srcdev_devid) { + /* + * In case of DUP, in order to keep it + * simple, only add the mirror with the + * lowest physical address + */ + if (found && + physical_of_found <= + tmp_bbio->stripes[i].physical) + continue; + index_srcdev = i; + found = 1; + physical_of_found = + tmp_bbio->stripes[i].physical; + } + } + + if (found) { + mirror_num = index_srcdev + 1; + patch_the_first_stripe_for_dev_replace = 1; + physical_to_patch_in_first_stripe = physical_of_found; + } else { + WARN_ON(1); + ret = -EIO; + kfree(tmp_bbio); + goto out; + } + + kfree(tmp_bbio); + } else if (mirror_num > map->num_stripes) { + mirror_num = 0; + } + num_stripes = 1; stripe_index = 0; stripe_nr_orig = stripe_nr; @@ -4188,8 +4275,12 @@ static int __btrfs_map_block(struct btrfs_fs_info *fs_info, int rw, BUG_ON(stripe_index >= map->num_stripes); num_alloc_stripes = num_stripes; - if (dev_replace_is_ongoing && (rw & (REQ_WRITE | REQ_DISCARD))) - num_alloc_stripes <<= 1; + if (dev_replace_is_ongoing) { + if (rw & (REQ_WRITE | REQ_DISCARD)) + num_alloc_stripes <<= 1; + if (rw & REQ_GET_READ_MIRRORS) + num_alloc_stripes++; + } bbio = kzalloc(btrfs_bio_size(num_alloc_stripes), GFP_NOFS); if (!bbio) { ret = -ENOMEM; @@ -4318,12 +4409,70 @@ static int __btrfs_map_block(struct btrfs_fs_info *fs_info, int rw, } } num_stripes = index_where_to_add; + } else if (dev_replace_is_ongoing && (rw & REQ_GET_READ_MIRRORS) && + dev_replace->tgtdev != NULL) { + u64 srcdev_devid = dev_replace->srcdev->devid; + int index_srcdev = 0; + int found = 0; + u64 physical_of_found = 0; + + /* + * During the dev-replace procedure, the target drive can + * also be used to read data in case it is needed to repair + * a corrupt block elsewhere. This is possible if the + * requested area is left of the left cursor. In this area, + * the target drive is a full copy of the source drive. + */ + for (i = 0; i < num_stripes; i++) { + if (bbio->stripes[i].dev->devid == srcdev_devid) { + /* + * In case of DUP, in order to keep it + * simple, only add the mirror with the + * lowest physical address + */ + if (found && + physical_of_found <= + bbio->stripes[i].physical) + continue; + index_srcdev = i; + found = 1; + physical_of_found = bbio->stripes[i].physical; + } + } + if (found) { + u64 length = map->stripe_len; + + if (physical_of_found + length <= + dev_replace->cursor_left) { + struct btrfs_bio_stripe *tgtdev_stripe = + bbio->stripes + num_stripes; + + tgtdev_stripe->physical = physical_of_found; + tgtdev_stripe->length = + bbio->stripes[index_srcdev].length; + tgtdev_stripe->dev = dev_replace->tgtdev; + + num_stripes++; + } + } } *bbio_ret = bbio; bbio->num_stripes = num_stripes; bbio->max_errors = max_errors; bbio->mirror_num = mirror_num; + + /* + * this is the case that REQ_READ && dev_replace_is_ongoing && + * mirror_num == num_stripes + 1 && dev_replace target drive is + * available as a mirror + */ + if (patch_the_first_stripe_for_dev_replace && num_stripes > 0) { + WARN_ON(num_stripes > 1); + bbio->stripes[0].dev = dev_replace->tgtdev; + bbio->stripes[0].physical = physical_to_patch_in_first_stripe; + bbio->mirror_num = map->num_stripes + 1; + } out: if (dev_replace_is_ongoing) btrfs_dev_replace_unlock(dev_replace);