diff options
Diffstat (limited to 'fs')
| -rw-r--r-- | fs/btrfs/ctree.h | 3 | ||||
| -rw-r--r-- | fs/btrfs/extent-tree.c | 46 | ||||
| -rw-r--r-- | fs/btrfs/inode.c | 111 |
3 files changed, 123 insertions, 37 deletions
diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h index 522a39b..f31aed7 100644 --- a/fs/btrfs/ctree.h +++ b/fs/btrfs/ctree.h @@ -2224,6 +2224,9 @@ int btrfs_block_rsv_migrate(struct btrfs_block_rsv *src_rsv, void btrfs_block_rsv_release(struct btrfs_root *root, struct btrfs_block_rsv *block_rsv, u64 num_bytes); +int btrfs_truncate_reserve_metadata(struct btrfs_trans_handle *trans, + struct btrfs_root *root, + struct btrfs_block_rsv *rsv); int btrfs_set_block_group_ro(struct btrfs_root *root, struct btrfs_block_group_cache *cache); int btrfs_set_block_group_rw(struct btrfs_root *root, diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c index ca59965..a2ca561 100644 --- a/fs/btrfs/extent-tree.c +++ b/fs/btrfs/extent-tree.c @@ -3980,6 +3980,37 @@ static u64 calc_trans_metadata_size(struct btrfs_root *root, int num_items) 3 * num_items; } +int btrfs_truncate_reserve_metadata(struct btrfs_trans_handle *trans, + struct btrfs_root *root, + struct btrfs_block_rsv *rsv) +{ + struct btrfs_block_rsv *trans_rsv = &root->fs_info->trans_block_rsv; + u64 num_bytes; + int ret; + + /* + * Truncate should be freeing data, but give us 2 items just in case it + * needs to use some space. We may want to be smarter about this in the + * future. + */ + num_bytes = calc_trans_metadata_size(root, 2); + + /* We already have enough bytes, just return */ + if (rsv->reserved >= num_bytes) + return 0; + + num_bytes -= rsv->reserved; + + /* + * You should have reserved enough space before hand to do this, so this + * should not fail. + */ + ret = block_rsv_migrate_bytes(trans_rsv, rsv, num_bytes); + BUG_ON(ret); + + return 0; +} + int btrfs_trans_reserve_metadata(struct btrfs_trans_handle *trans, struct btrfs_root *root, int num_items) @@ -4020,23 +4051,18 @@ int btrfs_orphan_reserve_metadata(struct btrfs_trans_handle *trans, struct btrfs_block_rsv *dst_rsv = root->orphan_block_rsv; /* - * one for deleting orphan item, one for updating inode and - * two for calling btrfs_truncate_inode_items. - * - * btrfs_truncate_inode_items is a delete operation, it frees - * more space than it uses in most cases. So two units of - * metadata space should be enough for calling it many times. - * If all of the metadata space is used, we can commit - * transaction and use space it freed. + * We need to hold space in order to delete our orphan item once we've + * added it, so this takes the reservation so we can release it later + * when we are truly done with the orphan item. */ - u64 num_bytes = calc_trans_metadata_size(root, 4); + u64 num_bytes = calc_trans_metadata_size(root, 1); return block_rsv_migrate_bytes(src_rsv, dst_rsv, num_bytes); } void btrfs_orphan_release_metadata(struct inode *inode) { struct btrfs_root *root = BTRFS_I(inode)->root; - u64 num_bytes = calc_trans_metadata_size(root, 4); + u64 num_bytes = calc_trans_metadata_size(root, 1); btrfs_block_rsv_release(root, root->orphan_block_rsv, num_bytes); } diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c index e47bdf0..bc12ba2 100644 --- a/fs/btrfs/inode.c +++ b/fs/btrfs/inode.c @@ -6591,6 +6591,7 @@ out: static int btrfs_truncate(struct inode *inode) { struct btrfs_root *root = BTRFS_I(inode)->root; + struct btrfs_block_rsv *rsv; int ret; int err = 0; struct btrfs_trans_handle *trans; @@ -6604,28 +6605,83 @@ static int btrfs_truncate(struct inode *inode) btrfs_wait_ordered_range(inode, inode->i_size & (~mask), (u64)-1); btrfs_ordered_update_i_size(inode, inode->i_size, NULL); - trans = btrfs_start_transaction(root, 5); - if (IS_ERR(trans)) - return PTR_ERR(trans); + /* + * Yes ladies and gentelment, this is indeed ugly. The fact is we have + * 3 things going on here + * + * 1) We need to reserve space for our orphan item and the space to + * delete our orphan item. Lord knows we don't want to have a dangling + * orphan item because we didn't reserve space to remove it. + * + * 2) We need to reserve space to update our inode. + * + * 3) We need to have something to cache all the space that is going to + * be free'd up by the truncate operation, but also have some slack + * space reserved in case it uses space during the truncate (thank you + * very much snapshotting). + * + * And we need these to all be seperate. The fact is we can use alot of + * space doing the truncate, and we have no earthly idea how much space + * we will use, so we need the truncate reservation to be seperate so it + * doesn't end up using space reserved for updating the inode or + * removing the orphan item. We also need to be able to stop the + * transaction and start a new one, which means we need to be able to + * update the inode several times, and we have no idea of knowing how + * many times that will be, so we can't just reserve 1 item for the + * entirety of the opration, so that has to be done seperately as well. + * Then there is the orphan item, which does indeed need to be held on + * to for the whole operation, and we need nobody to touch this reserved + * space except the orphan code. + * + * So that leaves us with + * + * 1) root->orphan_block_rsv - for the orphan deletion. + * 2) rsv - for the truncate reservation, which we will steal from the + * transaction reservation. + * 3) fs_info->trans_block_rsv - this will have 1 items worth left for + * updating the inode. + */ + rsv = btrfs_alloc_block_rsv(root); + if (!rsv) + return -ENOMEM; + btrfs_add_durable_block_rsv(root->fs_info, rsv); + + trans = btrfs_start_transaction(root, 4); + if (IS_ERR(trans)) { + err = PTR_ERR(trans); + goto out; + } btrfs_set_trans_block_group(trans, inode); + /* + * Reserve space for the truncate process. Truncate should be adding + * space, but if there are snapshots it may end up using space. + */ + ret = btrfs_truncate_reserve_metadata(trans, root, rsv); + BUG_ON(ret); + ret = btrfs_orphan_add(trans, inode); if (ret) { btrfs_end_transaction(trans, root); - return ret; + goto out; } nr = trans->blocks_used; btrfs_end_transaction(trans, root); btrfs_btree_balance_dirty(root, nr); - /* Now start a transaction for the truncate */ - trans = btrfs_start_transaction(root, 0); - if (IS_ERR(trans)) - return PTR_ERR(trans); + /* + * Ok so we've already migrated our bytes over for the truncate, so here + * just reserve the one slot we need for updating the inode. + */ + trans = btrfs_start_transaction(root, 1); + if (IS_ERR(trans)) { + err = PTR_ERR(trans); + goto out; + } btrfs_set_trans_block_group(trans, inode); - trans->block_rsv = root->orphan_block_rsv; + trans->block_rsv = rsv; /* * setattr is responsible for setting the ordered_data_close flag, @@ -6649,24 +6705,18 @@ static int btrfs_truncate(struct inode *inode) while (1) { if (!trans) { - trans = btrfs_start_transaction(root, 0); - if (IS_ERR(trans)) - return PTR_ERR(trans); - btrfs_set_trans_block_group(trans, inode); - trans->block_rsv = root->orphan_block_rsv; - } + trans = btrfs_start_transaction(root, 3); + if (IS_ERR(trans)) { + err = PTR_ERR(trans); + goto out; + } - ret = btrfs_block_rsv_check(trans, root, - root->orphan_block_rsv, 0, 5); - if (ret == -EAGAIN) { - ret = btrfs_commit_transaction(trans, root); - if (ret) - return ret; - trans = NULL; - continue; - } else if (ret) { - err = ret; - break; + ret = btrfs_truncate_reserve_metadata(trans, root, + rsv); + BUG_ON(ret); + + btrfs_set_trans_block_group(trans, inode); + trans->block_rsv = rsv; } ret = btrfs_truncate_inode_items(trans, root, inode, @@ -6677,6 +6727,7 @@ static int btrfs_truncate(struct inode *inode) break; } + trans->block_rsv = &root->fs_info->trans_block_rsv; ret = btrfs_update_inode(trans, root, inode); if (ret) { err = ret; @@ -6690,6 +6741,7 @@ static int btrfs_truncate(struct inode *inode) } if (ret == 0 && inode->i_nlink > 0) { + trans->block_rsv = root->orphan_block_rsv; ret = btrfs_orphan_del(trans, inode); if (ret) err = ret; @@ -6701,15 +6753,20 @@ static int btrfs_truncate(struct inode *inode) ret = btrfs_orphan_del(NULL, inode); } + trans->block_rsv = &root->fs_info->trans_block_rsv; ret = btrfs_update_inode(trans, root, inode); if (ret && !err) err = ret; nr = trans->blocks_used; ret = btrfs_end_transaction_throttle(trans, root); + btrfs_btree_balance_dirty(root, nr); + +out: + btrfs_free_block_rsv(root, rsv); + if (ret && !err) err = ret; - btrfs_btree_balance_dirty(root, nr); return err; } |
