On Thu, Feb 21, 2019 at 11:27 AM Francesco Ruggeri <fruggeri@xxxxxxxxxx> wrote: > > __find_get_block_slow() and grow_buffers() use different methods to compute > a page index for a given block: __find_get_block_slow() computes it from > bd_inode->i_blkbits, while grow_buffers() computes it from the block size > argument. > The two can get out of sync, for example if bd_inode->i_blkbits is modified > while a isofs_fill_super() (in mount) is between sb_min_blocksize() and > sb_read/__bread_gfp/__getblk_gfp/__getblk_slow. > The script below can reproduce such a scenario, resulting in an infinite > loop in __getblk_slow(), as grow_buffers() allocates a page but > __find_get_block() keeps looking for a different one. > This patch changes __find_get_block_slow() to also use the block size. > It implicitly relies on size being a power of 2 in the 256..PAGE_SIZE > range. > Any comments? Thanks, Francesco Ruggeri
