On Mon, Jun 25, 2018 at 10:03:41AM -0700, Chris Mason wrote:
> The vm_fault_t conversion commit introduced a ret2 variable for tracking
> the integer return values from internal btrfs functions. It was
> sometimes returning VM_FAULT_LOCKED for pages that were actually invalid
> and had been removed from the radix. Something like this:
>
> ret2 = btrfs_delalloc_reserve_space() // returns zero on success
>
> lock_page(page)
> if (page->mapping != inode->i_mapping)
> goto out_unlock;
>
> ...
>
> out_unlock:
> if (!ret2) {
> ...
> return VM_FAULT_LOCKED;
> }
>
> This ends up triggering this WARNING in btrfs_destroy_inode()
> WARN_ON(BTRFS_I(inode)->block_rsv.size);
>
> xfstests generic/095 was able to reliably reproduce the errors.
>
> Since out_unlock: is only used for errors, this fix moves it below the
> if (!ret2) check we use to return VM_FAULT_LOCKED for success.
>
> Fixes: a528a2415087 (btrfs: change return type of btrfs_page_mkwrite to
> vm_fault_t)
> Signed-off-by: Chris Mason <c...@fb.com>
Reviewed-by: David Sterba <dste...@suse.com>
also passed the tests here standalone and with the fixup worker fixes.
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