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>
diff --git a/fs/ext3/fsync.c b/fs/ext3/fsync.c
index 451d166..8209f26 100644
--- a/fs/ext3/fsync.c
+++ b/fs/ext3/fsync.c
@@ -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 @@
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