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envelope-from=andrey.shinkevich@virtuozzo.com; helo=EUR05-AM6-obe.outbound.protection.outlook.com X-detected-operating-system: by eggs.gnu.org: First seen = 2020/08/23 15:35:43 X-ACL-Warn: Detected OS = Windows NT kernel [generic] [fuzzy] X-Spam_score_int: -41 X-Spam_score: -4.2 X-Spam_bar: ---- X-Spam_report: (-4.2 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, MSGID_FROM_MTA_HEADER=0.001, NICE_REPLY_A=-1.381, RCVD_IN_DNSWL_LOW=-0.7, RCVD_IN_MSPIKE_H2=-0.001, SPF_HELO_PASS=-0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: kwolf@redhat.com, armbru@redhat.com, qemu-devel@nongnu.org, den@openvz.org, mreitz@redhat.com, jsnow@redhat.com Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On 19.08.2020 13:21, Vladimir Sementsov-Ogievskiy wrote: > 19.08.2020 00:24, Andrey Shinkevich wrote: >> Provide API for the COR-filter insertion/removal. >> Also, drop the filter child permissions for an inactive state when the >> filter node is being removed. >> >> Signed-off-by: Andrey Shinkevich >> --- >>   block/copy-on-read.c | 103 >> +++++++++++++++++++++++++++++++++++++++++++++++++++ >>   block/copy-on-read.h |  36 ++++++++++++++++++ >>   2 files changed, 139 insertions(+) >>   create mode 100644 block/copy-on-read.h >> >> diff --git a/block/copy-on-read.c b/block/copy-on-read.c >> index cb03e0f..150d9b7 100644 >> --- a/block/copy-on-read.c >> +++ b/block/copy-on-read.c >> @@ -23,11 +23,21 @@ >>   #include "qemu/osdep.h" >>   #include "block/block_int.h" >>   #include "qemu/module.h" >> +#include "qapi/error.h" >> +#include "qapi/qmp/qdict.h" >> +#include "block/copy-on-read.h" >> + >> + >> +typedef struct BDRVStateCOR { >> +    bool active; >> +} BDRVStateCOR; >>       static int cor_open(BlockDriverState *bs, QDict *options, int >> flags, >>                       Error **errp) >>   { >> +    BDRVStateCOR *state = bs->opaque; >> + >>       bs->file = bdrv_open_child(NULL, options, "file", bs, >> &child_of_bds, >>                                  BDRV_CHILD_FILTERED | >> BDRV_CHILD_PRIMARY, >>                                  false, errp); >> @@ -42,6 +52,8 @@ static int cor_open(BlockDriverState *bs, QDict >> *options, int flags, >>           ((BDRV_REQ_FUA | BDRV_REQ_MAY_UNMAP | BDRV_REQ_NO_FALLBACK) & >>               bs->file->bs->supported_zero_flags); >>   +    state->active = true; > > We don't need to call bdrv_child_refresh_perms() here, as permissions > will be > updated soon, when the filter node get its parent, yes? > > Let's add at least a comment on this. > >> + >>       return 0; >>   } >>   @@ -57,6 +69,17 @@ static void cor_child_perm(BlockDriverState *bs, >> BdrvChild *c, >>                              uint64_t perm, uint64_t shared, >>                              uint64_t *nperm, uint64_t *nshared) >>   { >> +    BDRVStateCOR *s = bs->opaque; >> + >> +    if (!s->active) { >> +        /* >> +         * While the filter is being removed >> +         */ >> +        *nperm = 0; >> +        *nshared = BLK_PERM_ALL; >> +        return; >> +    } >> + >>       *nperm = perm & PERM_PASSTHROUGH; >>       *nshared = (shared & PERM_PASSTHROUGH) | PERM_UNCHANGED; >>   @@ -135,6 +158,7 @@ static void cor_lock_medium(BlockDriverState >> *bs, bool locked) >>     static BlockDriver bdrv_copy_on_read = { >>       .format_name                        = "copy-on-read", >> +    .instance_size                      = sizeof(BDRVStateCOR), >>         .bdrv_open                          = cor_open, >>       .bdrv_child_perm                    = cor_child_perm, >> @@ -159,4 +183,83 @@ static void bdrv_copy_on_read_init(void) >>       bdrv_register(&bdrv_copy_on_read); >>   } >>   + >> +static BlockDriverState *create_filter_node(BlockDriverState *bs, >> +                                            const char >> *filter_node_name, >> +                                            Error **errp) >> +{ >> +    QDict *opts = qdict_new(); >> + >> +    qdict_put_str(opts, "driver", "copy-on-read"); >> +    qdict_put_str(opts, "file", bdrv_get_node_name(bs)); >> +    if (filter_node_name) { >> +        qdict_put_str(opts, "node-name", filter_node_name); >> +    } >> + >> +    return bdrv_open(NULL, NULL, opts, BDRV_O_RDWR, errp); >> +} >> + >> + >> +BlockDriverState *bdrv_cor_filter_append(BlockDriverState *bs, >> +                                         const char *filter_node_name, >> +                                         Error **errp) >> +{ >> +    BlockDriverState *cor_filter_bs; >> +    BDRVStateCOR *state; >> +    Error *local_err = NULL; >> + >> +    cor_filter_bs = create_filter_node(bs, filter_node_name, errp); >> +    if (cor_filter_bs == NULL) { >> +        error_prepend(errp, "Could not create filter node: "); >> +        return NULL; >> +    } >> + >> +    if (!filter_node_name) { >> +        cor_filter_bs->implicit = true; >> +    } >> + >> +    bdrv_drained_begin(bs); >> +    bdrv_replace_node(bs, cor_filter_bs, &local_err); >> +    bdrv_drained_end(bs); >> + >> +    if (local_err) { >> +        bdrv_unref(cor_filter_bs); >> +        error_propagate(errp, local_err); >> +        return NULL; >> +    } >> + >> +    state = cor_filter_bs->opaque; >> +    state->active = true; > > hmm stop. it's already active, after create_filter_node, so you don't > need to set it again, isn't it? I will remove the extra assignment from the cor_open() for consistancy. Andrey > >> + >> +    return cor_filter_bs; >> +} >> + >> + >> +void bdrv_cor_filter_drop(BlockDriverState *cor_filter_bs) >> +{ >> +    BdrvChild *child; >> +    BlockDriverState *bs; >> +    BDRVStateCOR *s = cor_filter_bs->opaque; >> + >> +    child = bdrv_filter_child(cor_filter_bs); >> +    if (!child) { >> +        return; >> +    } >> +    bs = child->bs; >> + >> +    /* Retain the BDS until we complete the graph change. */ >> +    bdrv_ref(bs); >> +    /* Hold a guest back from writing while permissions are being >> reset. */ >> +    bdrv_drained_begin(bs); >> +    /* Drop permissions before the graph change. */ >> +    s->active = false; >> +    bdrv_child_refresh_perms(cor_filter_bs, child, &error_abort); >> +    bdrv_replace_node(cor_filter_bs, bs, &error_abort); >> + >> +    bdrv_drained_end(bs); >> +    bdrv_unref(bs); >> +    bdrv_unref(cor_filter_bs); >> +} >> + >> + >>   block_init(bdrv_copy_on_read_init); >> diff --git a/block/copy-on-read.h b/block/copy-on-read.h >> new file mode 100644 >> index 0000000..db03c6c >> --- /dev/null >> +++ b/block/copy-on-read.h >> @@ -0,0 +1,36 @@ >> +/* >> + * Copy-on-read filter block driver >> + * >> + * The filter driver performs Copy-On-Read (COR) operations >> + * >> + * Copyright (c) 2018-2020 Virtuozzo International GmbH. >> + * >> + * Author: >> + *   Andrey Shinkevich >> + * >> + * This program is free software; you can redistribute it and/or modify >> + * it under the terms of the GNU General Public License as published by >> + * the Free Software Foundation; either version 2 of the License, or >> + * (at your option) any later version. >> + * >> + * This program is distributed in the hope that it will be useful, >> + * but WITHOUT ANY WARRANTY; without even the implied warranty of >> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the >> + * GNU General Public License for more details. >> + * >> + * You should have received a copy of the GNU General Public License >> + * along with this program. If not, see . >> + */ >> + >> +#ifndef COPY_ON_READ_FILTER >> +#define COPY_ON_READ_FILTER >> + >> +#include "block/block_int.h" >> +#include "block/block-copy.h" > > do you really need block-copy.h ? > >> + >> +BlockDriverState *bdrv_cor_filter_append(BlockDriverState *bs, >> +                                         const char *filter_node_name, >> +                                         Error **errp); >> +void bdrv_cor_filter_drop(BlockDriverState *cor_filter_bs); >> + >> +#endif /* COPY_ON_READ_FILTER */ >> > > Code seems correct to me, with extra "state->active = true;" dropped: > Reviewed-by: Vladimir Sementsov-Ogievskiy >