motorhead/qemu
1
0
Fork 0
mirror of https://github.com/Motorhead1991/qemu.git synced 2025-08-04 08:13:54 -06:00
Code Issues Projects Releases Packages Wiki Activity Actions

block: add enable_write_cache flag

Browse source 
Add a enable_write_cache flag in the block driver state, and use it to
decide if we claim to have a volatile write cache that needs controlled
flushing from the guest.  The flag is off if cache=writethrough is
defined because O_DSYNC guarantees that every write goes to stable
storage, and it is on for cache=none and cache=writeback.

Both scsi-disk and ide now use the new flage, changing from their
defaults of always off (ide) or always on (scsi-disk).

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
This commit is contained in:
Christoph Hellwig 2009-09-04 19:01:15 +02:00 • committed by Anthony Liguori
parent b8193adbda
commit e900a7b748
5 changed files with 27 additions and 3 deletions
Download patch file Download diff file Expand all files Collapse all files

4
hw/scsi-disk.c
View file

@ -709,7 +709,9 @@ static int32_t scsi_send_command(SCSIDevice *d, uint32_t tag,
memset(p,0,20);
p[0] = 8;
p[1] = 0x12;
p[2] = 4; /* WCE */
if (bdrv_enable_write_cache(s->dinfo->bdrv)) {
p[2] = 4; /* WCE */
}
p += 20;
}
if ((page == 0x3f || page == 0x2a)