Hello,

Block layer didn't consider failfast status while merging requests and
it led to premature failure of normal (non-failfast) IOs. Niel
Lambrechts could trigger the problem semi-reliably on ext4 when
resuming from STR. ext4 uses readahead when reading inodes and
combined with the deterministic extra SATA PHY exception cycle during
resume on the specific configuration, non-readahead inode read would
fail causing ext4 errors. Please read the following thread for
details.

[ message continues ]

bio and request use the same set of failfast bits. This patch makes
the following changes to simplify things.

* enumify BIO_RW* bits and reorder bits such that BIOS_RW_FAILFAST_*
bits coincide with __REQ_FAILFAST_* bits.

* The above pushes BIO_RW_AHEAD out of sync with __REQ_FAILFAST_DEV
but the matching is useless anyway. init_request_from_bio() is
responsible for setting FAILFAST bits on FS requests and non-FS
requests never use BIO_RW_AHEAD. Drop the code and comment from
blk_rq_...

Update scsi_io_completion() such that it only fails requests till the
next error boundary and retry the leftover. This enables block layer
to merge requests with different failfast settings and still behave
correctly on errors. Allow merge of requests of different failfast
settings.

As SCSI is currently the only subsystem which follows failfast status,
there's no need to worry about other block drivers for now.

Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Jens Axboe <axboe@kernel.dk&g...

Hi,

Checked aacraid drivers, initialzing and reset device at _aac_rx_init(),
at the begin of function, set @adapter_enable_int to aac_rx_disable_interrupt(),
when device status it KERNEL_PANIC, driver will try to reset device,
before reset device, it will check device health or no by call
aac_rx_check_health(), then aac_rx_check_health()->rx_sync_cmd() will use the
aac_rx_disable_interrupt() to restore interrupt mask, is that the right
action? if need to replace it to aac_rx_enable_interrupt_...