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Message-Id: <1256023478-746-5-git-send-email-jack@suse.cz>
Date: Tue, 20 Oct 2009 09:24:38 +0200
From: Jan Kara <jack@...e.cz>
To: linux-ext4@...r.kernel.org
Cc: tytso@....edu, chris.mason@...cle.com, Jan Kara <jack@...e.cz>
Subject: [PATCH 4/4] ext4: Wait for proper transaction commit on fsync
We cannot rely on buffer dirty bits during fsync because pdflush can come
before fsync is called and clear dirty bits without forcing a transaction
commit. What we do is that we track which transaction has last changed
the inode and which transaction last changed allocation and force it to
disk on fsync.
Signed-off-by: Jan Kara <jack@...e.cz>
---
fs/ext4/ext4.h | 7 +++++++
fs/ext4/extents.c | 5 +++++
fs/ext4/fsync.c | 40 +++++++++++++++++-----------------------
fs/ext4/inode.c | 34 ++++++++++++++++++++++++++++++++++
4 files changed, 63 insertions(+), 23 deletions(-)
diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
index 984ca0c..5639f30 100644
--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h
@@ -702,6 +702,13 @@ struct ext4_inode_info {
struct list_head i_aio_dio_complete_list;
/* current io_end structure for async DIO write*/
ext4_io_end_t *cur_aio_dio;
+
+ /*
+ * Transactions that contain inode's metadata needed to complete
+ * fsync and fdatasync, respectively.
+ */
+ atomic_t i_sync_tid;
+ atomic_t i_datasync_tid;
};
/*
diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c
index 10539e3..3e167f6 100644
--- a/fs/ext4/extents.c
+++ b/fs/ext4/extents.c
@@ -3315,6 +3315,11 @@ int ext4_ext_get_blocks(handle_t *handle, struct inode *inode,
newblock = ext_pblock(&newex);
allocated = ext4_ext_get_actual_len(&newex);
set_buffer_new(bh_result);
+
+ atomic_set(&EXT4_I(inode)->i_sync_tid, handle->h_transaction->t_tid);
+ atomic_set(&EXT4_I(inode)->i_datasync_tid,
+ handle->h_transaction->t_tid);
+ printk("Datasync tid %u\n", handle->h_transaction->t_tid);
/* Cache only when it is _not_ an uninitialized extent */
if ((flags & EXT4_GET_BLOCKS_UNINIT_EXT) == 0)
diff --git a/fs/ext4/fsync.c b/fs/ext4/fsync.c
index 2bf9413..03e0fe9 100644
--- a/fs/ext4/fsync.c
+++ b/fs/ext4/fsync.c
@@ -51,25 +51,26 @@
int ext4_sync_file(struct file *file, struct dentry *dentry, int datasync)
{
struct inode *inode = dentry->d_inode;
+ struct ext4_inode_info *ei = EXT4_I(inode);
journal_t *journal = EXT4_SB(inode->i_sb)->s_journal;
- int err, ret = 0;
+ int ret = 0;
+ tid_t commit_tid;
J_ASSERT(ext4_journal_current_handle() == NULL);
trace_ext4_sync_file(file, dentry, datasync);
+ if (inode->i_sb->s_flags & MS_RDONLY)
+ goto out;
+
ret = flush_aio_dio_completed_IO(inode);
if (ret < 0)
goto out;
/*
- * data=writeback:
+ * data=writeback,ordered:
* The caller's filemap_fdatawrite()/wait will sync the data.
- * sync_inode() will sync the metadata
- *
- * data=ordered:
- * The caller's filemap_fdatawrite() will write the data and
- * sync_inode() will write the inode if it is dirty. Then the caller's
- * filemap_fdatawait() will wait on the pages.
+ * Metadata is in the journal, we wait for proper transaction to
+ * commit here.
*
* data=journal:
* filemap_fdatawrite won't do anything (the buffers are clean).
@@ -87,23 +88,16 @@ int ext4_sync_file(struct file *file, struct dentry *dentry, int datasync)
if (!journal)
ret = sync_mapping_buffers(inode->i_mapping);
- if (datasync && !(inode->i_state & I_DIRTY_DATASYNC))
- goto flush;
+ if (datasync)
+ commit_tid = atomic_read(&ei->i_datasync_tid);
+ else
+ commit_tid = atomic_read(&ei->i_sync_tid);
- /*
- * The VFS has written the file data. If the inode is unaltered
- * then we need not start a commit.
- */
- if (inode->i_state & (I_DIRTY_SYNC|I_DIRTY_DATASYNC)) {
- struct writeback_control wbc = {
- .sync_mode = WB_SYNC_ALL,
- .nr_to_write = 0, /* sys_fsync did this */
- };
- err = sync_inode(inode, &wbc);
- if (ret == 0)
- ret = err;
+ if (jbd2_log_start_commit(journal, commit_tid)) {
+ jbd2_log_wait_commit(journal, commit_tid);
+ goto out;
}
-flush:
+
if (journal && (journal->j_flags & JBD2_BARRIER))
blkdev_issue_flush(inode->i_sb->s_bdev, NULL);
out:
diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index 9105f40..412de4e 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -1024,6 +1024,10 @@ static int ext4_ind_get_blocks(handle_t *handle, struct inode *inode,
goto cleanup;
set_buffer_new(bh_result);
+
+ atomic_set(&EXT4_I(inode)->i_sync_tid, handle->h_transaction->t_tid);
+ atomic_set(&EXT4_I(inode)->i_datasync_tid,
+ handle->h_transaction->t_tid);
got_it:
map_bh(bh_result, inode->i_sb, le32_to_cpu(chain[depth-1].key));
if (count > blocks_to_boundary)
@@ -4777,6 +4781,7 @@ struct inode *ext4_iget(struct super_block *sb, unsigned long ino)
struct ext4_inode_info *ei;
struct buffer_head *bh;
struct inode *inode;
+ journal_t *journal = EXT4_SB(sb)->s_journal;
long ret;
int block;
@@ -4842,6 +4847,34 @@ struct inode *ext4_iget(struct super_block *sb, unsigned long ino)
ei->i_data[block] = raw_inode->i_block[block];
INIT_LIST_HEAD(&ei->i_orphan);
+ /*
+ * Set transaction id's of transactions that have to be committed
+ * to finish f[data]sync. We set them to currently running transaction
+ * as we cannot be sure that the inode or some of its metadata isn't
+ * part of the transaction - the inode could have been reclaimed and
+ * now it is reread from disk.
+ */
+ if (journal) {
+ transaction_t *transaction;
+ tid_t tid;
+
+ spin_lock(&journal->j_state_lock);
+ if (journal->j_running_transaction)
+ transaction = journal->j_running_transaction;
+ else
+ transaction = journal->j_committing_transaction;
+ if (transaction)
+ tid = transaction->t_tid;
+ else
+ tid = journal->j_commit_sequence;
+ spin_unlock(&journal->j_state_lock);
+ atomic_set(&ei->i_sync_tid, tid);
+ atomic_set(&ei->i_datasync_tid, tid);
+ } else {
+ atomic_set(&ei->i_sync_tid, 0);
+ atomic_set(&ei->i_datasync_tid, 0);
+ }
+
if (EXT4_INODE_SIZE(inode->i_sb) > EXT4_GOOD_OLD_INODE_SIZE) {
ei->i_extra_isize = le16_to_cpu(raw_inode->i_extra_isize);
if (EXT4_GOOD_OLD_INODE_SIZE + ei->i_extra_isize >
@@ -5102,6 +5135,7 @@ static int ext4_do_update_inode(handle_t *handle,
err = rc;
ei->i_state &= ~EXT4_STATE_NEW;
+ atomic_set(&ei->i_sync_tid, handle->h_transaction->t_tid);
out_brelse:
brelse(bh);
ext4_std_error(inode->i_sb, err);
--
1.6.0.2
--
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