From 6013efd8860bf15c1f86f365332642cfe557152f Mon Sep 17 00:00:00 2001 From: Tejun Heo Date: Thu, 19 Nov 2009 15:36:45 +0900 Subject: libata: retry failed FLUSH if device didn't fail it If ATA device failed FLUSH, it means that the device failed to write out some amount of data and the error needs to be reported to upper layers. As retries can't recover the lost data, FLUSH failures need to be reported immediately in general. However, if FLUSH fails due to transmission errors, the FLUSH needs to be retried; otherwise, filesystems may switch to RO mode and/or raid array may drop a drive for a random transmission glitch. This condition can be rather easily reproduced on certain ahci controllers which go through a PHY event after powersave mode switch + ext4 combination. Powersave mode switch is often closely followed by flush from the filesystem failing the FLUSH with ATA bus error which makes the filesystem code believe that data is lost and drop to RO mode. This was reported in the following bugzilla bug. http://bugzilla.kernel.org/show_bug.cgi?id=14543 This patch makes libata EH retry FLUSH if it wasn't failed by the device. Signed-off-by: Tejun Heo Reported-by: Andrey Vihrov Signed-off-by: Jeff Garzik --- include/linux/libata.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'include/linux/libata.h') diff --git a/include/linux/libata.h b/include/linux/libata.h index 87698640c091..ba07e84c9840 100644 --- a/include/linux/libata.h +++ b/include/linux/libata.h @@ -365,7 +365,7 @@ enum { /* This should match the actual table size of * ata_eh_cmd_timeout_table in libata-eh.c. */ - ATA_EH_CMD_TIMEOUT_TABLE_SIZE = 5, + ATA_EH_CMD_TIMEOUT_TABLE_SIZE = 6, /* Horkage types. May be set by libata or controller on drives (some horkage may be drive/controller pair dependant */ -- cgit v1.2.3