[PATCH 04/12] Btrfs: introduce first sub trans
From: Liu Bo <hidden>
Date: 2011-06-30 07:36:24
Subsystem:
btrfs file system, filesystems (vfs and infrastructure), the rest · Maintainers:
Chris Mason, David Sterba, Alexander Viro, Christian Brauner, Linus Torvalds
In multi-thread situations, writeback of a file may span across several sub transactions, and we need to introduce first_sub_trans to get sub_transid of teh first sub transaction recorded, so that log code can skip file extents which have been logged or committed onto disk. Signed-off-by: Liu Bo <redacted> --- fs/btrfs/btrfs_inode.h | 9 +++++++++ fs/btrfs/inode.c | 13 ++++++++++++- fs/btrfs/transaction.h | 17 ++++++++++++++++- 3 files changed, 37 insertions(+), 2 deletions(-)
diff --git a/fs/btrfs/btrfs_inode.h b/fs/btrfs/btrfs_inode.h
index 52d7eca..8eca5de 100644
--- a/fs/btrfs/btrfs_inode.h
+++ b/fs/btrfs/btrfs_inode.h@@ -80,6 +80,15 @@ struct btrfs_inode { /* sequence number for NFS changes */ u64 sequence; + /* used to avoid race of first_sub_trans */ + spinlock_t sub_trans_lock; + + /* + * sub transid of the trans that first modified this inode before + * a trans commit or a log sync + */ + u64 first_sub_trans; + /* * transid of the trans_handle that last modified this inode */
diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index ff9d4d1..93c9d22 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c@@ -6468,7 +6468,16 @@ again: set_page_dirty(page); SetPageUptodate(page); - BTRFS_I(inode)->last_trans = root->fs_info->generation; + spin_lock(&BTRFS_I(inode)->sub_trans_lock); + + if (BTRFS_I(inode)->first_sub_trans > root->fs_info->sub_generation || + BTRFS_I(inode)->last_trans <= BTRFS_I(inode)->logged_trans || + BTRFS_I(inode)->last_trans <= root->fs_info->last_trans_committed) + BTRFS_I(inode)->first_sub_trans = root->fs_info->sub_generation; + + spin_unlock(&BTRFS_I(inode)->sub_trans_lock); + + BTRFS_I(inode)->last_trans = root->fs_info->sub_generation; BTRFS_I(inode)->last_sub_trans = BTRFS_I(inode)->root->log_transid; unlock_extent_cached(io_tree, page_start, page_end, &cached_state, GFP_NOFS);
@@ -6714,6 +6723,7 @@ struct inode *btrfs_alloc_inode(struct super_block *sb) ei->space_info = NULL; ei->generation = 0; ei->sequence = 0; + ei->first_sub_trans = 0; ei->last_trans = 0; ei->last_sub_trans = 0; ei->logged_trans = 0;
@@ -6740,6 +6750,7 @@ struct inode *btrfs_alloc_inode(struct super_block *sb) extent_io_tree_init(&ei->io_tree, &inode->i_data); extent_io_tree_init(&ei->io_failure_tree, &inode->i_data); mutex_init(&ei->log_mutex); + spin_lock_init(&ei->sub_trans_lock); btrfs_ordered_inode_tree_init(&ei->ordered_tree); INIT_LIST_HEAD(&ei->i_orphan); INIT_LIST_HEAD(&ei->delalloc_inodes);
diff --git a/fs/btrfs/transaction.h b/fs/btrfs/transaction.h
index 45876b0..f5ca0fd 100644
--- a/fs/btrfs/transaction.h
+++ b/fs/btrfs/transaction.h@@ -73,7 +73,22 @@ struct btrfs_pending_snapshot { static inline void btrfs_set_inode_last_trans(struct btrfs_trans_handle *trans, struct inode *inode) { - BTRFS_I(inode)->last_trans = trans->transaction->transid; + spin_lock(&BTRFS_I(inode)->sub_trans_lock); + + /* + * We have joined in a transaction, so btrfs_commit_transaction will + * definitely wait for us and it does not need to add a extra + * trans_mutex lock here. + */ + if (BTRFS_I(inode)->first_sub_trans > trans->transid || + BTRFS_I(inode)->last_trans <= BTRFS_I(inode)->logged_trans || + BTRFS_I(inode)->last_trans <= + BTRFS_I(inode)->root->fs_info->last_trans_committed) + BTRFS_I(inode)->first_sub_trans = trans->transid; + + spin_unlock(&BTRFS_I(inode)->sub_trans_lock); + + BTRFS_I(inode)->last_trans = trans->transid; BTRFS_I(inode)->last_sub_trans = BTRFS_I(inode)->root->log_transid; }
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1.6.5.2