[Qemu-devel] IDE disk FLUSH take more than 30 secs, the SUSE guest reports "lost interrupt and the file system becomes read-only"

[Gonglei (Arei)]

In the case of physical hard disk's speed which processing IO (when grouping 
RAID) is very slow, I encountered a problem.
I dd big file in SUSE virtual machine, the command is
linux:/ # dd if=/dev/zero of=./info bs=1M count=5000;sync

but finally I get those message:
linux:~ # dmesg
[  174.804114] ata1: lost interrupt (Status 0x50)
[  174.812305] end_request: I/O error, dev sda, sector 12085270
[  174.812309] Buffer I/O error on device sda2, logical block 984530
[  174.812310] lost page write due to I/O error on sda2
[  174.813268] Aborting journal on device sda2.
[  174.828330] journal commit I/O error
[  174.828373] ext3_abort called.
[  174.828375] EXT3-fs error (device sda2): ext3_journal_start_sb: Detected 
aborted journal
[  174.828377] Remounting filesystem read-only
[  182.286424] __journal_remove_journal_head: freeing b_committed_data
[  182.286434] __journal_remove_journal_head: freeing b_committed_data
[  182.286442] __journal_remove_journal_head: freeing b_committed_data
[  182.286452] __journal_remove_journal_head: freeing b_committed_data
[  182.286472] __journal_remove_journal_head: freeing b_committed_data


Through analysis, I found that because the system call the fdatasync command in 
the Qemu over 30s, 
after the Guest's kernel thread detects the io transferation is timeout, went 
to check IDE disk state. 
But the IDE disk status is 0x50, rather than the BSY status, and then departed 
error process...

the path of kernel's action is :
scsi_softirq_done
 scsi_eh_scmd_add
   scsi_error_handler
     shost->transportt->eh_strategy_handler 
                ata_scsi_error 
                        ap->ops->lost_interrupt
                                ata_sff_lost_interrupt
Finally, the file system becomes read-only.

Why not set the IDE disk for the BSY status When 0xe7 command is executed in 
the Qemu?
Anyone know it? thanks!

Best Regards!
-Arei