Miao Xie
2012-Nov-01 07:32 UTC
[PATCH 1/5] Btrfs: fix joining the same transaction handler more than 2 times
If we flush inodes with pending delalloc in a transaction, we may join the same transaction handler more than 2 times. The reason is: Task use_count of trans handle commit_transaction 1 |-> btrfs_start_delalloc_inodes 1 |-> run_delalloc_nocow 1 |-> join_transaction 2 |-> cow_file_range 2 |-> join_transaction 3 In fact, cow_file_range needn''t join the transaction again because the caller have joined the transaction, so we fix this problem by this way. Reported-by: Liu Bo <bo.li.liu@oracle.com> Signed-off-by: Miao Xie <miaox@cn.fujitsu.com> --- fs/btrfs/inode.c | 77 +++++++++++++++++++++++++++++------------------ fs/btrfs/transaction.c | 1 + 2 files changed, 48 insertions(+), 30 deletions(-) diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c index 5fc0990..aadcdd6 100644 --- a/fs/btrfs/inode.c +++ b/fs/btrfs/inode.c @@ -803,14 +803,14 @@ static u64 get_extent_allocation_hint(struct inode *inode, u64 start, * required to start IO on it. It may be clean and already done with * IO when we return. */ -static noinline int cow_file_range(struct inode *inode, - struct page *locked_page, - u64 start, u64 end, int *page_started, - unsigned long *nr_written, - int unlock) +static noinline int __cow_file_range(struct btrfs_trans_handle *trans, + struct inode *inode, + struct btrfs_root *root, + struct page *locked_page, + u64 start, u64 end, int *page_started, + unsigned long *nr_written, + int unlock) { - struct btrfs_root *root = BTRFS_I(inode)->root; - struct btrfs_trans_handle *trans; u64 alloc_hint = 0; u64 num_bytes; unsigned long ram_size; @@ -823,25 +823,10 @@ static noinline int cow_file_range(struct inode *inode, int ret = 0; BUG_ON(btrfs_is_free_space_inode(inode)); - trans = btrfs_join_transaction(root); - if (IS_ERR(trans)) { - extent_clear_unlock_delalloc(inode, - &BTRFS_I(inode)->io_tree, - start, end, locked_page, - EXTENT_CLEAR_UNLOCK_PAGE | - EXTENT_CLEAR_UNLOCK | - EXTENT_CLEAR_DELALLOC | - EXTENT_CLEAR_DIRTY | - EXTENT_SET_WRITEBACK | - EXTENT_END_WRITEBACK); - return PTR_ERR(trans); - } - trans->block_rsv = &root->fs_info->delalloc_block_rsv; num_bytes = (end - start + blocksize) & ~(blocksize - 1); num_bytes = max(blocksize, num_bytes); disk_num_bytes = num_bytes; - ret = 0; /* if this is a small write inside eof, kick off defrag */ if (num_bytes < 64 * 1024 && @@ -952,11 +937,9 @@ static noinline int cow_file_range(struct inode *inode, alloc_hint = ins.objectid + ins.offset; start += cur_alloc_size; } - ret = 0; out: - btrfs_end_transaction(trans, root); - return ret; + out_unlock: extent_clear_unlock_delalloc(inode, &BTRFS_I(inode)->io_tree, @@ -971,6 +954,39 @@ out_unlock: goto out; } +static noinline int cow_file_range(struct inode *inode, + struct page *locked_page, + u64 start, u64 end, int *page_started, + unsigned long *nr_written, + int unlock) +{ + struct btrfs_trans_handle *trans; + struct btrfs_root *root = BTRFS_I(inode)->root; + int ret; + + trans = btrfs_join_transaction(root); + if (IS_ERR(trans)) { + extent_clear_unlock_delalloc(inode, + &BTRFS_I(inode)->io_tree, + start, end, locked_page, + EXTENT_CLEAR_UNLOCK_PAGE | + EXTENT_CLEAR_UNLOCK | + EXTENT_CLEAR_DELALLOC | + EXTENT_CLEAR_DIRTY | + EXTENT_SET_WRITEBACK | + EXTENT_END_WRITEBACK); + return PTR_ERR(trans); + } + trans->block_rsv = &root->fs_info->delalloc_block_rsv; + + ret = __cow_file_range(trans, inode, root, locked_page, start, end, + page_started, nr_written, unlock); + + btrfs_end_transaction(trans, root); + + return ret; +} + /* * work queue call back to started compression on a file and pages */ @@ -1281,9 +1297,9 @@ out_check: btrfs_release_path(path); if (cow_start != (u64)-1) { - ret = cow_file_range(inode, locked_page, cow_start, - found_key.offset - 1, page_started, - nr_written, 1); + ret = __cow_file_range(trans, inode, root, locked_page, + cow_start, found_key.offset - 1, + page_started, nr_written, 1); if (ret) { btrfs_abort_transaction(trans, root, ret); goto error; @@ -1352,8 +1368,9 @@ out_check: } if (cow_start != (u64)-1) { - ret = cow_file_range(inode, locked_page, cow_start, end, - page_started, nr_written, 1); + ret = __cow_file_range(trans, inode, root, locked_page, + cow_start, end, + page_started, nr_written, 1); if (ret) { btrfs_abort_transaction(trans, root, ret); goto error; diff --git a/fs/btrfs/transaction.c b/fs/btrfs/transaction.c index 04bbfb1..6d0d5a0 100644 --- a/fs/btrfs/transaction.c +++ b/fs/btrfs/transaction.c @@ -312,6 +312,7 @@ static struct btrfs_trans_handle *start_transaction(struct btrfs_root *root, WARN_ON(type != TRANS_JOIN && type != TRANS_JOIN_NOLOCK); h = current->journal_info; h->use_count++; + WARN_ON(h->use_count > 2); h->orig_rsv = h->block_rsv; h->block_rsv = NULL; goto got_it; -- 1.7.6.5 -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
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