On Wed, Nov 06, 2002 at 12:25:00AM -0800, chrisl@vmware.com wrote:
> This should fix the ext3 htree rename problem. Please try it again.
I've looked over the patch, and I've got some comments....
> handle = ext3_journal_start(old_dir, 2 * EXT3_DATA_TRANS_BLOCKS +
> - EXT3_INDEX_EXTRA_TRANS_BLOCKS + 2);
> + EXT3_INDEX_EXTRA_TRANS_BLOCKS + 3);
There's no need to increase the number of blocks that might need to be
dirtied; if ext3_delete_entry() can't find the missing entry, it won't
dirty the block, so the number of blocks that might need to modified
remains constant.
> - ext3_delete_entry(handle, old_dir, old_de, old_bh);
> + retval = ext3_delete_entry(handle, old_dir, old_de, old_bh);
> + if (retval == -ENOENT) {
> + /*
> + * old_de can be moved during ext3_add_entry.
> + */
> + struct buffer_head * old_bh2;
> + struct ext3_dir_entry_2 * old_de2;
> + old_bh2 = ext3_find_entry (old_dentry, &old_de2);
> + if (old_bh2) {
> + retval = ext3_delete_entry(handle, old_dir, old_de2,
> + old_bh2);
> + brelse(old_bh2);
> + } else {
> + ext3_warning(old_dir->i_sb, "ext3_rename",
> + "Deleting old file not found (%lu), %d",
> + old_dir->i_ino, old_dir->i_nlink);
> + }
>
> + }
Simply retrying the ext3_delete_entry() isn't sufficient, since
another ext3_add_entry() could move the directory entry again while
you're reading in the blocks as part of ext3_find_entry(). OK, that
would be pretty rare, since enough other directory adds would have
to fill up enough that another split could happen, but *is* possible.
(Surely our scheduler isn't that unfair....)
Probably a better thing to do is use a while loop, and retry as long
(a) ext3_delete_entry fails, and (b) old_dir->i_version has changed.
In practice this will probably never happen, but I'll feel better with
that change.
Anyway, I plan to make these two changes to your patch, and then
submit it to Linus.
- Ted
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This archive was generated by hypermail 2b29 : Thu Nov 07 2002 - 22:00:45 EST