lkml.org 
[lkml]   [2009]   [Jan]   [16]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    Date
    From
    SubjectRe: ext3: call blkdev_issue_flush on fsync
    On Fri 16-01-09 22:55:01, Fernando Luis Vázquez Cao wrote:
    > To ensure that bits are truly on-disk after an fsync or fdatasync, we
    > should force a disk flush explicitly when there is dirty data/metadata
    > and the journal didn't emit a write barrier (either because metadata is
    > not being synched or barriers are disabled).
    >
    > Signed-off-by: Fernando Luis Vazquez Cao <fernando@oss.ntt.co.jp>
    > ---
    Only two minor nits:

    > --- linux-2.6.29-rc1-orig/fs/ext3/fsync.c 2008-12-25 08:26:37.000000000 +0900
    > +++ linux-2.6.29-rc1/fs/ext3/fsync.c 2009-01-16 22:18:53.000000000 +0900
    > @@ -27,6 +27,7 @@
    > #include <linux/sched.h>
    > #include <linux/writeback.h>
    > #include <linux/jbd.h>
    > +#include <linux/blkdev.h>
    > #include <linux/ext3_fs.h>
    > #include <linux/ext3_jbd.h>
    >
    > @@ -45,6 +46,8 @@
    > int ext3_sync_file(struct file * file, struct dentry *dentry, int datasync)
    > {
    > struct inode *inode = dentry->d_inode;
    > + journal_t *journal = EXT3_SB(inode->i_sb)->s_journal;
    > + unsigned long i_state = inode->i_state;
    > int ret = 0;
    >
    > J_ASSERT(ext3_journal_current_handle() == NULL);
    > @@ -69,23 +72,33 @@ int ext3_sync_file(struct file * file, s
    > */
    > if (ext3_should_journal_data(inode)) {
    > ret = ext3_force_commit(inode->i_sb);
    > + if (!(journal->j_flags & JFS_BARRIER))
    > + goto no_journal_barrier;
    > goto out;
    > }
    >
    > - if (datasync && !(inode->i_state & I_DIRTY_DATASYNC))
    > - goto out;
    > + if (datasync && !(i_state & I_DIRTY_DATASYNC))
    > + goto flush_blkdev;
    >
    > /*
    > * 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)) {
    > + if (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 (journal && !(journal->j_flags & JFS_BARRIER))
    > + goto no_journal_barrier;
    I cannot imagine "journal" will be NULL here.
    And we can also optimize here a bit and do "goto out" because here
    we know the barrier has been issued.

    > }
    > +
    > +flush_blkdev:
    > + if (!(i_state & I_DIRTY_PAGES))
    > + goto out;
    > +no_journal_barrier:
    > + blkdev_issue_flush(inode->i_sb->s_bdev, NULL);
    > out:
    > return ret;
    > }

    Honza
    --
    Jan Kara <jack@suse.cz>
    SUSE Labs, CR
    --
    To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
    the body of a message to majordomo@vger.kernel.org
    More majordomo info at http://vger.kernel.org/majordomo-info.html
    Please read the FAQ at http://www.tux.org/lkml/

    \
     
     \ /
      Last update: 2009-01-16 17:33    [W:0.052 / U:0.436 seconds]
    ©2003-2016 Jasper Spaans. hosted at Digital OceanAdvertise on this site