On Thu, Dec 12, 2013 at 10:39:36AM +0100, Jan Kara wrote:
> On Thu 12-12-13 14:44:22, Zheng Liu wrote:
> > Hi Jan,
> >
> > On Tue, Dec 10, 2013 at 11:13:58AM +0100, Jan Kara wrote:
> > > Similarly as other ->write_begin functions in ext4, also
> > > ext4_da_write_inline_data_begin() should retry allocation if the
> > > conversion failed because of ENOSPC. This avoids returning ENOSPC
> > > prematurely because of uncommitted block deletions.
> >
> > I don't see why we need to try again here. If there is no enough space
> > in inline data, ext4_da_convert_inline_data_to_extent() just read the
> > inline data into a page and clear EXT4_STATE_MAY_INLINE_DATA flag. If
> > we try again, we will encounter an ENOSPC error again. So why do we
> > need to retry allocation?
> Umm, I don't think so. ext4_da_convert_inline_data_to_extent() calls
> ext4_da_get_block_prep() and that can falsely fail with ENOSPC if there are
> blocks freed in currently running transaction. So we call
> ext4_should_retry_alloc() which forces commit of the current transaction
> and then we retry the allocation.
Ah, I see. Thanks for your explanation.
- Zheng
>
> Honza
>
> > >
> > > Signed-off-by: Jan Kara <jack@xxxxxxx>
> > > ---
> > > fs/ext4/inline.c | 7 +++++++
> > > 1 file changed, 7 insertions(+)
> > >
> > > diff --git a/fs/ext4/inline.c b/fs/ext4/inline.c
> > > index bae987549dc3..ed6e71fe5e9d 100644
> > > --- a/fs/ext4/inline.c
> > > +++ b/fs/ext4/inline.c
> > > @@ -849,11 +849,13 @@ int ext4_da_write_inline_data_begin(struct address_space *mapping,
> > > handle_t *handle;
> > > struct page *page;
> > > struct ext4_iloc iloc;
> > > + int retries;
> > >
> > > ret = ext4_get_inode_loc(inode, &iloc);
> > > if (ret)
> > > return ret;
> > >
> > > +retry_journal:
> > > handle = ext4_journal_start(inode, EXT4_HT_INODE, 1);
> > > if (IS_ERR(handle)) {
> > > ret = PTR_ERR(handle);
> > > @@ -875,6 +877,11 @@ int ext4_da_write_inline_data_begin(struct address_space *mapping,
> > > inode,
> > > flags,
> > > fsdata);
> > > + ext4_journal_stop(handle);
> > > + handle = NULL;
> > > + if (ret == -ENOSPC &&
> > > + ext4_should_retry_alloc(inode->i_sb, &retries))
> > > + goto retry_journal;
> > > goto out;
> > > }
> > >
> > > --
> > > 1.8.1.4
> > >
> > > --
> > > To unsubscribe from this list: send the line "unsubscribe linux-ext4" in
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> --
> Jan Kara <jack@xxxxxxx>
> SUSE Labs, CR
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