diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h index 906410719acb205eb680f50b32289ac5838d363c..b2c0336db69116dfbefa03ac78fb68ca56373367 100644 --- a/fs/btrfs/ctree.h +++ b/fs/btrfs/ctree.h @@ -1723,6 +1723,9 @@ struct btrfs_root { atomic_t log_commit[2]; atomic_t log_batch; int log_transid; + /* No matter the commit succeeds or not*/ + int log_transid_committed; + /* Just be updated when the commit succeeds. */ int last_log_commit; pid_t log_start_pid; bool log_multiple_pids; diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c index 44f52d280b7d4f06572202567a2925b8e2f0a8c8..dd52146035b3a183b3fcd3e7943a51c5217c3ae7 100644 --- a/fs/btrfs/disk-io.c +++ b/fs/btrfs/disk-io.c @@ -1209,6 +1209,7 @@ static void __setup_root(u32 nodesize, u32 leafsize, u32 sectorsize, atomic_set(&root->orphan_inodes, 0); atomic_set(&root->refs, 1); root->log_transid = 0; + root->log_transid_committed = -1; root->last_log_commit = 0; if (fs_info) extent_io_tree_init(&root->dirty_log_pages, @@ -1422,6 +1423,7 @@ int btrfs_add_log_tree(struct btrfs_trans_handle *trans, WARN_ON(root->log_root); root->log_root = log_root; root->log_transid = 0; + root->log_transid_committed = -1; root->last_log_commit = 0; return 0; } diff --git a/fs/btrfs/tree-log.c b/fs/btrfs/tree-log.c index da6da274dce3315fc6f3730046303c0d7987a044..57d4ca7fd5558667779a6ef80cb6f30c4174784c 100644 --- a/fs/btrfs/tree-log.c +++ b/fs/btrfs/tree-log.c @@ -156,6 +156,7 @@ static int start_log_trans(struct btrfs_trans_handle *trans, if (ctx) { index = root->log_transid % 2; list_add_tail(&ctx->list, &root->log_ctxs[index]); + ctx->log_transid = root->log_transid; } mutex_unlock(&root->log_mutex); return 0; @@ -181,6 +182,7 @@ static int start_log_trans(struct btrfs_trans_handle *trans, if (ctx) { index = root->log_transid % 2; list_add_tail(&ctx->list, &root->log_ctxs[index]); + ctx->log_transid = root->log_transid; } out: mutex_unlock(&root->log_mutex); @@ -2387,13 +2389,13 @@ static void wait_log_commit(struct btrfs_trans_handle *trans, &wait, TASK_UNINTERRUPTIBLE); mutex_unlock(&root->log_mutex); - if (root->log_transid < transid + 2 && + if (root->log_transid_committed < transid && atomic_read(&root->log_commit[index])) schedule(); finish_wait(&root->log_commit_wait[index], &wait); mutex_lock(&root->log_mutex); - } while (root->log_transid < transid + 2 && + } while (root->log_transid_committed < transid && atomic_read(&root->log_commit[index])); } @@ -2470,18 +2472,24 @@ int btrfs_sync_log(struct btrfs_trans_handle *trans, struct blk_plug plug; mutex_lock(&root->log_mutex); - log_transid = root->log_transid; - index1 = root->log_transid % 2; + log_transid = ctx->log_transid; + if (root->log_transid_committed >= log_transid) { + mutex_unlock(&root->log_mutex); + return ctx->log_ret; + } + + index1 = log_transid % 2; if (atomic_read(&root->log_commit[index1])) { - wait_log_commit(trans, root, root->log_transid); + wait_log_commit(trans, root, log_transid); mutex_unlock(&root->log_mutex); return ctx->log_ret; } + ASSERT(log_transid == root->log_transid); atomic_set(&root->log_commit[index1], 1); /* wait for previous tree log sync to complete */ if (atomic_read(&root->log_commit[(index1 + 1) % 2])) - wait_log_commit(trans, root, root->log_transid - 1); + wait_log_commit(trans, root, log_transid - 1); while (1) { int batch = atomic_read(&root->log_batch); @@ -2535,9 +2543,16 @@ int btrfs_sync_log(struct btrfs_trans_handle *trans, */ mutex_unlock(&root->log_mutex); + btrfs_init_log_ctx(&root_log_ctx); + mutex_lock(&log_root_tree->log_mutex); atomic_inc(&log_root_tree->log_batch); atomic_inc(&log_root_tree->log_writers); + + index2 = log_root_tree->log_transid % 2; + list_add_tail(&root_log_ctx.list, &log_root_tree->log_ctxs[index2]); + root_log_ctx.log_transid = log_root_tree->log_transid; + mutex_unlock(&log_root_tree->log_mutex); ret = update_log_root(trans, log); @@ -2550,6 +2565,9 @@ int btrfs_sync_log(struct btrfs_trans_handle *trans, } if (ret) { + if (!list_empty(&root_log_ctx.list)) + list_del_init(&root_log_ctx.list); + blk_finish_plug(&plug); if (ret != -ENOSPC) { btrfs_abort_transaction(trans, root, ret); @@ -2565,26 +2583,29 @@ int btrfs_sync_log(struct btrfs_trans_handle *trans, goto out; } - index2 = log_root_tree->log_transid % 2; - - btrfs_init_log_ctx(&root_log_ctx); - list_add_tail(&root_log_ctx.list, &log_root_tree->log_ctxs[index2]); + if (log_root_tree->log_transid_committed >= root_log_ctx.log_transid) { + mutex_unlock(&log_root_tree->log_mutex); + ret = root_log_ctx.log_ret; + goto out; + } + index2 = root_log_ctx.log_transid % 2; if (atomic_read(&log_root_tree->log_commit[index2])) { blk_finish_plug(&plug); btrfs_wait_marked_extents(log, &log->dirty_log_pages, mark); wait_log_commit(trans, log_root_tree, - log_root_tree->log_transid); + root_log_ctx.log_transid); btrfs_free_logged_extents(log, log_transid); mutex_unlock(&log_root_tree->log_mutex); ret = root_log_ctx.log_ret; goto out; } + ASSERT(root_log_ctx.log_transid == log_root_tree->log_transid); atomic_set(&log_root_tree->log_commit[index2], 1); if (atomic_read(&log_root_tree->log_commit[(index2 + 1) % 2])) { wait_log_commit(trans, log_root_tree, - log_root_tree->log_transid - 1); + root_log_ctx.log_transid - 1); } wait_for_writer(trans, log_root_tree); @@ -2652,26 +2673,22 @@ int btrfs_sync_log(struct btrfs_trans_handle *trans, */ btrfs_remove_all_log_ctxs(log_root_tree, index2, ret); - /* - * It is dangerous if log_commit is changed before we set - * ->log_ret of log ctx. Because the readers may not get - * the return value. - */ - smp_wmb(); - + mutex_lock(&log_root_tree->log_mutex); + log_root_tree->log_transid_committed++; atomic_set(&log_root_tree->log_commit[index2], 0); - smp_mb(); + mutex_unlock(&log_root_tree->log_mutex); + if (waitqueue_active(&log_root_tree->log_commit_wait[index2])) wake_up(&log_root_tree->log_commit_wait[index2]); out: /* See above. */ btrfs_remove_all_log_ctxs(root, index1, ret); - /* See above. */ - smp_wmb(); + mutex_lock(&root->log_mutex); + root->log_transid_committed++; atomic_set(&root->log_commit[index1], 0); + mutex_unlock(&root->log_mutex); - smp_mb(); if (waitqueue_active(&root->log_commit_wait[index1])) wake_up(&root->log_commit_wait[index1]); return ret; diff --git a/fs/btrfs/tree-log.h b/fs/btrfs/tree-log.h index 59c1edb31d19f0049987e2e920a0aceb805e1bad..91b145fce3336719a745085dc8497bed380405de 100644 --- a/fs/btrfs/tree-log.h +++ b/fs/btrfs/tree-log.h @@ -24,12 +24,14 @@ struct btrfs_log_ctx { int log_ret; + int log_transid; struct list_head list; }; static inline void btrfs_init_log_ctx(struct btrfs_log_ctx *ctx) { ctx->log_ret = 0; + ctx->log_transid = 0; INIT_LIST_HEAD(&ctx->list); }