alistair23-linux/fs/ext3/fsync.c
Jan Kara 5277970878 ext3: Fix waiting on transaction during fsync
log_start_commit() returns 1 only when it started a transaction
commit. Thus in case transaction commit is already running, we
fail to wait for the commit to finish. Fix the issue by always
waiting for the commit regardless of the log_start_commit return
value.

Signed-off-by: Jan Kara <jack@suse.cz>
2010-05-21 19:30:41 +02:00

96 lines
2.9 KiB
C

/*
* linux/fs/ext3/fsync.c
*
* Copyright (C) 1993 Stephen Tweedie (sct@redhat.com)
* from
* Copyright (C) 1992 Remy Card (card@masi.ibp.fr)
* Laboratoire MASI - Institut Blaise Pascal
* Universite Pierre et Marie Curie (Paris VI)
* from
* linux/fs/minix/truncate.c Copyright (C) 1991, 1992 Linus Torvalds
*
* ext3fs fsync primitive
*
* Big-endian to little-endian byte-swapping/bitmaps by
* David S. Miller (davem@caip.rutgers.edu), 1995
*
* Removed unnecessary code duplication for little endian machines
* and excessive __inline__s.
* Andi Kleen, 1997
*
* Major simplications and cleanup - we only need to do the metadata, because
* we can depend on generic_block_fdatasync() to sync the data blocks.
*/
#include <linux/time.h>
#include <linux/blkdev.h>
#include <linux/fs.h>
#include <linux/sched.h>
#include <linux/writeback.h>
#include <linux/jbd.h>
#include <linux/ext3_fs.h>
#include <linux/ext3_jbd.h>
/*
* akpm: A new design for ext3_sync_file().
*
* This is only called from sys_fsync(), sys_fdatasync() and sys_msync().
* There cannot be a transaction open by this task.
* Another task could have dirtied this inode. Its data can be in any
* state in the journalling system.
*
* What we do is just kick off a commit and wait on it. This will snapshot the
* inode to disk.
*/
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, needs_barrier = 0;
tid_t commit_tid;
if (inode->i_sb->s_flags & MS_RDONLY)
return 0;
J_ASSERT(ext3_journal_current_handle() == NULL);
/*
* data=writeback,ordered:
* The caller's filemap_fdatawrite()/wait will sync the data.
* 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).
* ext3_force_commit will write the file data into the journal and
* will wait on that.
* filemap_fdatawait() will encounter a ton of newly-dirtied pages
* (they were dirtied by commit). But that's OK - the blocks are
* safe in-journal, which is all fsync() needs to ensure.
*/
if (ext3_should_journal_data(inode))
return ext3_force_commit(inode->i_sb);
if (datasync)
commit_tid = atomic_read(&ei->i_datasync_tid);
else
commit_tid = atomic_read(&ei->i_sync_tid);
if (test_opt(inode->i_sb, BARRIER) &&
!journal_trans_will_send_data_barrier(journal, commit_tid))
needs_barrier = 1;
log_start_commit(journal, commit_tid);
ret = log_wait_commit(journal, commit_tid);
/*
* In case we didn't commit a transaction, we have to flush
* disk caches manually so that data really is on persistent
* storage
*/
if (needs_barrier)
blkdev_issue_flush(inode->i_sb->s_bdev, NULL);
return ret;
}