Oops, I haven't seen unmap_underlying_metadata code in __block_prepare_write so just forget this mail, sorry. 2010/1/27 丁定华 <dingdinghua85@xxxxxxxxx>: > Hi all: > The following is my analysis(if wrong, please point it out), > may be I can send a patch out if it's a bug. > If buffer_head belongs to comitting transaction, > jbd2_journal_forget do nothing except discard it from running > transaction. So this buffer will happily be inserted > into committing_transaction's checkpoint list and do write-back work, > then this buffer may be re-used as data-block, then there are two > buffer_heads maps to the same block, buffer aliasing occurs, and we > can't control the writeback order of the two buffer heads, fs may be > inconsistent. > The same thing will happen if buffer_head doesn't belongs to > running or committing transaction, but lays in checkpoint list. > > -- > 丁定华 > -- 丁定华 -- To unsubscribe from this list: send the line "unsubscribe linux-ext4" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
