Re: [PATCH -next v5 28/32] ext4: set DISKSIZE_GROW_PENDING after zeroing unaligned EOF block

> From: Zhang Yi <[email protected]>
> 
> In the iomap buffered I/O path, data=ordered mode is not used, so the
> zeroed EOF block has no implicit ordering with later i_disksize updates.
> Without the pending state being set, i_disksize can be advanced past the
> zeroed block before writeback completes, exposing stale data after a
> crash.
> 
> Previous patches added the consumer side of the
> disksize-grow-pending mechanism: the state bit, clear and wait helpers,
> and ioend tagging. Now add ext4_iomap_mark_disksize_pending() and call
> it from ext4_block_zero_eof() after zeroing the tail of the block that
> straddles i_disksize.
> 
> The helper locks the folio, waits for any in-flight writeback on it to
> complete, then sets EXT4_STATE_DISKSIZE_GROW_PENDING only if the folio
> is still dirty. Waiting for writeback prevents folio_test_dirty() from
> returning false mid-writeback, which would cause us to skip the pending
> state while zeroed data is still in flight. The dirty check then avoids
> setting the bit when the data has already been written back.
> 
> Suggested-by: Jan Kara <[email protected]>
> Signed-off-by: Zhang Yi <[email protected]>

Sashiko has reviewed this patch and found no issues. It looks great!

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Sashiko AI review · https://sashiko.dev/#/patchset/[email protected]?part=28