From patchwork Fri Nov 11 06:48:18 2011 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Supriya Kannery X-Patchwork-Id: 125099 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from lists.gnu.org (lists.gnu.org [140.186.70.17]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (Client did not present a certificate) by ozlabs.org (Postfix) with ESMTPS id F299C1007D1 for ; Fri, 11 Nov 2011 17:49:20 +1100 (EST) Received: from localhost ([::1]:40269 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ROkvG-0008Sh-63 for incoming@patchwork.ozlabs.org; Fri, 11 Nov 2011 01:49:10 -0500 Received: from eggs.gnu.org ([140.186.70.92]:60098) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ROkv9-0008RW-L2 for qemu-devel@nongnu.org; Fri, 11 Nov 2011 01:49:04 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1ROkv8-0002op-97 for qemu-devel@nongnu.org; Fri, 11 Nov 2011 01:49:03 -0500 Received: from e3.ny.us.ibm.com ([32.97.182.143]:45039) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ROkv7-0002oj-W3 for qemu-devel@nongnu.org; Fri, 11 Nov 2011 01:49:02 -0500 Received: from /spool/local by e3.ny.us.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! 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X-Received-From: 32.97.182.143 Cc: Kevin Wolf , Stefan Hajnoczi , Christoph Hellwig , Luiz Capitulino Subject: [Qemu-devel] [v9 Patch 5/6]Qemu: Framework for reopening images safely X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org Sender: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org Struct BDRVReopenState along with three reopen related functions introduced for handling reopen state of images safely. This can be extended by each of the block drivers to reopen respective image files. Signed-off-by: Supriya Kannery Index: qemu/block.c =================================================================== --- qemu.orig/block.c +++ qemu/block.c @@ -696,10 +696,33 @@ unlink_and_fail: return ret; } +int bdrv_reopen_prepare(BlockDriverState *bs, BDRVReopenState **prs, int flags) +{ + BlockDriver *drv = bs->drv; + + return drv->bdrv_reopen_prepare(bs, prs, flags); +} + +void bdrv_reopen_commit(BlockDriverState *bs, BDRVReopenState *rs, int flags) +{ + BlockDriver *drv = bs->drv; + + drv->bdrv_reopen_commit(bs, rs, flags); + bs->open_flags = flags; +} + +void bdrv_reopen_abort(BlockDriverState *bs, BDRVReopenState *rs) +{ + BlockDriver *drv = bs->drv; + + drv->bdrv_reopen_abort(bs, rs); +} + int bdrv_reopen(BlockDriverState *bs, int bdrv_flags) { BlockDriver *drv = bs->drv; int ret = 0, open_flags; + BDRVReopenState *reopen_state = NULL; /* Quiesce IO for the given block device */ qemu_aio_flush(); @@ -708,17 +731,31 @@ int bdrv_reopen(BlockDriverState *bs, in qerror_report(QERR_DATA_SYNC_FAILED, bs->device_name); return ret; } - open_flags = bs->open_flags; - bdrv_close(bs); - ret = bdrv_open(bs, bs->filename, bdrv_flags, drv); - if (ret < 0) { - /* Reopen failed. Try to open with original flags */ - qerror_report(QERR_REOPEN_FILE_FAILED, bs->filename); - ret = bdrv_open(bs, bs->filename, open_flags, drv); + /* Use driver specific reopen() if available */ + if (drv->bdrv_reopen_prepare) { + ret = bdrv_reopen_prepare(bs, &reopen_state, bdrv_flags); + if (ret < 0) { + bdrv_reopen_abort(bs, reopen_state); + qerror_report(QERR_REOPEN_FILE_FAILED, bs->filename); + return ret; + } + + bdrv_reopen_commit(bs, reopen_state, bdrv_flags); + + } else { + open_flags = bs->open_flags; + bdrv_close(bs); + + ret = bdrv_open(bs, bs->filename, bdrv_flags, drv); if (ret < 0) { - /* Reopen failed with orig and modified flags */ - abort(); + /* Reopen failed. Try to open with original flags */ + qerror_report(QERR_REOPEN_FILE_FAILED, bs->filename); + ret = bdrv_open(bs, bs->filename, open_flags, drv); + if (ret < 0) { + /* Reopen failed with orig and modified flags */ + bs->drv = NULL; + } } } Index: qemu/block_int.h =================================================================== --- qemu.orig/block_int.h +++ qemu/block_int.h @@ -56,6 +56,14 @@ struct BlockDriver { int (*bdrv_probe)(const uint8_t *buf, int buf_size, const char *filename); int (*bdrv_probe_device)(const char *filename); int (*bdrv_open)(BlockDriverState *bs, int flags); + + /* For handling image reopen for split or non-split files */ + int (*bdrv_reopen_prepare)(BlockDriverState *bs, + BDRVReopenState **prs, + int flags); + void (*bdrv_reopen_commit)(BlockDriverState *bs, BDRVReopenState *rs, + int flags); + void (*bdrv_reopen_abort)(BlockDriverState *bs, BDRVReopenState *rs); int (*bdrv_file_open)(BlockDriverState *bs, const char *filename, int flags); int (*bdrv_read)(BlockDriverState *bs, int64_t sector_num, uint8_t *buf, int nb_sectors); @@ -213,6 +221,11 @@ struct BlockDriverState { void *private; }; +struct BDRVReopenState { + BlockDriverState *bs; + int reopen_flags; +}; + struct BlockDriverAIOCB { AIOPool *pool; BlockDriverState *bs; Index: qemu/qemu-common.h =================================================================== --- qemu.orig/qemu-common.h +++ qemu/qemu-common.h @@ -203,6 +203,7 @@ typedef struct NICInfo NICInfo; typedef struct HCIInfo HCIInfo; typedef struct AudioState AudioState; typedef struct BlockDriverState BlockDriverState; +typedef struct BDRVReopenState BDRVReopenState; typedef struct DriveInfo DriveInfo; typedef struct DisplayState DisplayState; typedef struct DisplayChangeListener DisplayChangeListener; Index: qemu/block.h =================================================================== --- qemu.orig/block.h +++ qemu/block.h @@ -105,6 +105,9 @@ int bdrv_file_open(BlockDriverState **pb int bdrv_open(BlockDriverState *bs, const char *filename, int flags, BlockDriver *drv); int bdrv_reopen(BlockDriverState *bs, int bdrv_flags); +int bdrv_reopen_prepare(BlockDriverState *bs, BDRVReopenState **prs, int flags); +void bdrv_reopen_commit(BlockDriverState *bs, BDRVReopenState *rs, int flags); +void bdrv_reopen_abort(BlockDriverState *bs, BDRVReopenState *rs); void bdrv_close(BlockDriverState *bs); int bdrv_attach_dev(BlockDriverState *bs, void *dev); void bdrv_attach_dev_nofail(BlockDriverState *bs, void *dev);