ext3: 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@suse.cz>
Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
This commit is contained in:
Jan Kara 2009-10-16 19:26:15 +02:00
parent ea0174a713
commit fe8bc91c4c
4 changed files with 57 additions and 21 deletions

View File

@ -46,19 +46,21 @@
int ext3_sync_file(struct file * file, struct dentry *dentry, int datasync)
{
struct inode *inode = dentry->d_inode;
struct ext3_inode_info *ei = EXT3_I(inode);
journal_t *journal = EXT3_SB(inode->i_sb)->s_journal;
int ret = 0;
tid_t commit_tid;
if (inode->i_sb->s_flags & MS_RDONLY)
return 0;
J_ASSERT(ext3_journal_current_handle() == NULL);
/*
* 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 a proper transaction
* to commit here.
*
* data=journal:
* filemap_fdatawrite won't do anything (the buffers are clean).
@ -73,22 +75,16 @@ int ext3_sync_file(struct file * file, struct dentry *dentry, int datasync)
goto out;
}
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 */
};
ret = sync_inode(inode, &wbc);
if (log_start_commit(journal, commit_tid)) {
log_wait_commit(journal, commit_tid);
goto out;
}
flush:
/*
* In case we didn't commit a transaction, we have to flush
* disk caches manually so that data really is on persistent

View File

@ -699,8 +699,9 @@ static int ext3_splice_branch(handle_t *handle, struct inode *inode,
int err = 0;
struct ext3_block_alloc_info *block_i;
ext3_fsblk_t current_block;
struct ext3_inode_info *ei = EXT3_I(inode);
block_i = EXT3_I(inode)->i_block_alloc_info;
block_i = ei->i_block_alloc_info;
/*
* If we're splicing into a [td]indirect block (as opposed to the
* inode) then we need to get write access to the [td]indirect block
@ -741,6 +742,8 @@ static int ext3_splice_branch(handle_t *handle, struct inode *inode,
inode->i_ctime = CURRENT_TIME_SEC;
ext3_mark_inode_dirty(handle, inode);
/* ext3_mark_inode_dirty already updated i_sync_tid */
atomic_set(&ei->i_datasync_tid, handle->h_transaction->t_tid);
/* had we spliced it onto indirect block? */
if (where->bh) {
@ -2754,6 +2757,8 @@ struct inode *ext3_iget(struct super_block *sb, unsigned long ino)
struct ext3_inode_info *ei;
struct buffer_head *bh;
struct inode *inode;
journal_t *journal = EXT3_SB(sb)->s_journal;
transaction_t *transaction;
long ret;
int block;
@ -2831,6 +2836,30 @@ struct inode *ext3_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) {
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);
}
if (inode->i_ino >= EXT3_FIRST_INO(inode->i_sb) + 1 &&
EXT3_INODE_SIZE(inode->i_sb) > EXT3_GOOD_OLD_INODE_SIZE) {
/*
@ -3015,6 +3044,7 @@ again:
err = rc;
ei->i_state &= ~EXT3_STATE_NEW;
atomic_set(&ei->i_sync_tid, handle->h_transaction->t_tid);
out_brelse:
brelse (bh);
ext3_std_error(inode->i_sb, err);

View File

@ -466,6 +466,8 @@ static struct inode *ext3_alloc_inode(struct super_block *sb)
return NULL;
ei->i_block_alloc_info = NULL;
ei->vfs_inode.i_version = 1;
atomic_set(&ei->i_datasync_tid, 0);
atomic_set(&ei->i_sync_tid, 0);
return &ei->vfs_inode;
}

View File

@ -137,6 +137,14 @@ struct ext3_inode_info {
* by other means, so we have truncate_mutex.
*/
struct mutex truncate_mutex;
/*
* Transactions that contain inode's metadata needed to complete
* fsync and fdatasync, respectively.
*/
atomic_t i_sync_tid;
atomic_t i_datasync_tid;
struct inode vfs_inode;
};