From c7481d5c22cc50de58032304d67c23c844d7013a Mon Sep 17 00:00:00 2001 From: Luiz Capitulino Date: Mon, 27 Feb 2012 20:31:03 +0100 Subject: [PATCH 104/109] block: Keep track of devices' I/O status RH-Author: Luiz Capitulino Message-id: <1330374668-8838-2-git-send-email-lcapitulino@redhat.com> Patchwork-id: 37641 O-Subject: [PATCH RHEL6.3 qemu-kvm 1/6] block: Keep track of devices' I/O status Bugzilla: 797186 RH-Acked-by: Markus Armbruster RH-Acked-by: Paolo Bonzini RH-Acked-by: Kevin Wolf This commit adds support to the BlockDriverState type to keep track of devices' I/O status. There are three possible status: BDRV_IOS_OK (no error), BDRV_IOS_ENOSPC (no space error) and BDRV_IOS_FAILED (any other error). The distinction between no space and other errors is important because a management application may want to watch for no space in order to extend the space assigned to the VM and put it to run again. Qemu devices supporting the I/O status feature have to enable it explicitly by calling bdrv_iostatus_enable() _and_ have to be configured to stop the VM on errors (ie. werror=stop|enospc or rerror=stop). In case of multiple errors being triggered in sequence only the first one is stored. The I/O status is always reset to BDRV_IOS_OK when the 'cont' command is issued. Next commits will add support to some devices and extend the query-block/info block commands to return the I/O status information. Signed-off-by: Luiz Capitulino Reviewed-by: Markus Armbruster Signed-off-by: Kevin Wolf (cherry picked from commit 28a7282a5d5a15527e66d3a93c93c4ccc292f694) Conflicts: block.c Signed-off-by: Luiz Capitulino --- block.c | 40 ++++++++++++++++++++++++++++++++++++++++ block.h | 10 ++++++++++ block_int.h | 1 + monitor.c | 6 ++++++ 4 files changed, 57 insertions(+), 0 deletions(-) Signed-off-by: Michal Novotny --- block.c | 40 ++++++++++++++++++++++++++++++++++++++++ block.h | 10 ++++++++++ block_int.h | 1 + monitor.c | 6 ++++++ 4 files changed, 57 insertions(+), 0 deletions(-) diff --git a/block.c b/block.c index 4cb512e..24932e5 100644 --- a/block.c +++ b/block.c @@ -178,6 +178,7 @@ BlockDriverState *bdrv_new(const char *device_name) if (device_name[0] != '\0') { QTAILQ_INSERT_TAIL(&bdrv_states, bs, list); } + bdrv_iostatus_disable(bs); return bs; } @@ -726,6 +727,7 @@ int bdrv_attach_dev(BlockDriverState *bs, void *dev) return -EBUSY; } bs->dev = dev; + bdrv_iostatus_reset(bs); return 0; } @@ -2975,6 +2977,44 @@ void bdrv_reset_dirty(BlockDriverState *bs, int64_t cur_sector, set_dirty_bitmap(bs, cur_sector, nr_sectors, 0); } +void bdrv_iostatus_enable(BlockDriverState *bs) +{ + bs->iostatus = BDRV_IOS_OK; +} + +/* The I/O status is only enabled if the drive explicitly + * enables it _and_ the VM is configured to stop on errors */ +bool bdrv_iostatus_is_enabled(const BlockDriverState *bs) +{ + return (bs->iostatus != BDRV_IOS_INVAL && + (bs->on_write_error == BLOCK_ERR_STOP_ENOSPC || + bs->on_write_error == BLOCK_ERR_STOP_ANY || + bs->on_read_error == BLOCK_ERR_STOP_ANY)); +} + +void bdrv_iostatus_disable(BlockDriverState *bs) +{ + bs->iostatus = BDRV_IOS_INVAL; +} + +void bdrv_iostatus_reset(BlockDriverState *bs) +{ + if (bdrv_iostatus_is_enabled(bs)) { + bs->iostatus = BDRV_IOS_OK; + } +} + +/* XXX: Today this is set by device models because it makes the implementation + quite simple. However, the block layer knows about the error, so it's + possible to implement this without device models being involved */ +void bdrv_iostatus_set_err(BlockDriverState *bs, int error) +{ + if (bdrv_iostatus_is_enabled(bs) && bs->iostatus == BDRV_IOS_OK) { + assert(error >= 0); + bs->iostatus = error == ENOSPC ? BDRV_IOS_ENOSPC : BDRV_IOS_FAILED; + } +} + void bdrv_acct_start(BlockDriverState *bs, BlockAcctCookie *cookie, int64_t bytes, enum BlockAcctType type) diff --git a/block.h b/block.h index e561fef..cc198ef 100644 --- a/block.h +++ b/block.h @@ -87,6 +87,16 @@ typedef enum { BDRV_ACTION_REPORT, BDRV_ACTION_IGNORE, BDRV_ACTION_STOP } BlockMonEventAction; +typedef enum { + BDRV_IOS_INVAL, BDRV_IOS_OK, BDRV_IOS_FAILED, BDRV_IOS_ENOSPC, + BDRV_IOS_MAX +} BlockIOStatus; + +void bdrv_iostatus_enable(BlockDriverState *bs); +void bdrv_iostatus_reset(BlockDriverState *bs); +void bdrv_iostatus_disable(BlockDriverState *bs); +bool bdrv_iostatus_is_enabled(const BlockDriverState *bs); +void bdrv_iostatus_set_err(BlockDriverState *bs, int error); void bdrv_mon_event(const BlockDriverState *bdrv, BlockMonEventAction action, int error, int is_read); void bdrv_info_print(Monitor *mon, const QObject *data); diff --git a/block_int.h b/block_int.h index 11e2d90..239c547 100644 --- a/block_int.h +++ b/block_int.h @@ -202,6 +202,7 @@ struct BlockDriverState { int cyls, heads, secs, translation; int type; BlockErrorAction on_read_error, on_write_error; + BlockIOStatus iostatus; char device_name[32]; unsigned long *dirty_bitmap; int in_use; /* users other than guest access, eg. block migration */ diff --git a/monitor.c b/monitor.c index 0d62df7..8b9d3b8 100644 --- a/monitor.c +++ b/monitor.c @@ -1379,6 +1379,11 @@ struct bdrv_iterate_context { int err; }; +static void iostatus_bdrv_it(void *opaque, BlockDriverState *bs) +{ + bdrv_iostatus_reset(bs); +} + /** * do_cont(): Resume emulation. */ @@ -1395,6 +1400,7 @@ static int do_cont(Monitor *mon, const QDict *qdict, QObject **ret_data) return -1; } + bdrv_iterate(iostatus_bdrv_it, NULL); bdrv_iterate(encrypted_bdrv_it, &context); /* only resume the vm if all keys are set and valid */ if (!context.err) { -- 1.7.7.6