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Mon, 24 Aug 2026 17:11:37 +0000 (UTC) Received: from dovecot-director2.suse.de ([2a07:de40:b281:106:10:150:64:167]) by imap1.dmz-prg2.suse.org with ESMTPSA id W0OjLkl7jGozNgAAD6G6ig (envelope-from ); Mon, 24 Aug 2026 17:11:37 +0000 Date: Mon, 24 Aug 2026 19:11:32 +0200 From: David Sterba To: Qu Wenruo Cc: linux-btrfs@vger.kernel.org Subject: Re: [PATCH v3 3/4] btrfs: dev-replace: fix the error handling in btrfs_dev_replace_finishing() Message-ID: <20260824171132.GG9053@twin.jikos.cz> Reply-To: dsterba@suse.cz References: Precedence: bulk X-Mailing-List: linux-btrfs@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.23.1-rc1 (2014-03-12) X-Spam-Score: -8.00 X-Spam-Level: X-Spam-Flag: NO X-Spamd-Result: default: False [-8.00 / 50.00]; REPLY(-4.00)[]; BAYES_HAM(-3.00)[100.00%]; NEURAL_HAM_LONG(-1.00)[-1.000]; HAS_REPLYTO(0.30)[dsterba@suse.cz]; NEURAL_HAM_SHORT(-0.20)[-0.999]; MIME_GOOD(-0.10)[text/plain]; RCVD_TLS_ALL(0.00)[]; ARC_NA(0.00)[]; MIME_TRACE(0.00)[0:+]; RCVD_VIA_SMTP_AUTH(0.00)[]; TO_DN_SOME(0.00)[]; RCPT_COUNT_TWO(0.00)[2]; DKIM_SIGNED(0.00)[suse.cz:s=susede2_rsa,suse.cz:s=susede2_ed25519]; TO_MATCH_ENVRCPT_ALL(0.00)[]; FROM_HAS_DN(0.00)[]; RCVD_COUNT_TWO(0.00)[2]; FROM_EQ_ENVFROM(0.00)[]; DBL_BLOCKED_OPENRESOLVER(0.00)[suse.cz:replyto,suse.com:email,imap1.dmz-prg2.suse.org:helo,twin.jikos.cz:mid]; REPLYTO_ADDR_EQ_FROM(0.00)[]; REPLYTO_DOM_NEQ_TO_DOM(0.00)[] On Mon, Aug 24, 2026 at 02:04:07PM +0930, Qu Wenruo wrote: > In btrfs_dev_replace_finishing(), we have the following error paths that > do not do any cleanup: > > - btrfs_start_delalloc_roots() error > - btrfs_start_transaction() error > > Both will error out directly, leaving the existing dev_replace > untouched, meaning the dev-replace will still be treated as running, > blocking future dev_replace. > > Fix the problem by letting the above errors to go to a new out label, > which will do the common dev_replace cleanup, with an error message > showing that dev-replace has failed. > > Signed-off-by: Qu Wenruo > --- > fs/btrfs/dev-replace.c | 39 +++++++++++++++++++++------------------ > 1 file changed, 21 insertions(+), 18 deletions(-) > > diff --git a/fs/btrfs/dev-replace.c b/fs/btrfs/dev-replace.c > index be4031a6ce1d..df048cf69621 100644 > --- a/fs/btrfs/dev-replace.c > +++ b/fs/btrfs/dev-replace.c > @@ -893,8 +893,9 @@ static int btrfs_dev_replace_finishing(struct btrfs_fs_info *fs_info, > */ > ret = btrfs_start_delalloc_roots(fs_info, LONG_MAX, false); > if (ret) { > - mutex_unlock(&dev_replace->lock_finishing_cancel_unmount); > - return ret; > + mutex_lock(&fs_devices->device_list_mutex); > + mutex_lock(&fs_info->chunk_mutex); The conditional locking inside an 'if' is not common, I don't see a better way how to do it so suggestion below > + goto out; > } > btrfs_wait_ordered_roots(fs_info, U64_MAX, NULL); > > @@ -906,8 +907,10 @@ static int btrfs_dev_replace_finishing(struct btrfs_fs_info *fs_info, > while (1) { > trans = btrfs_start_transaction(root, 0); > if (IS_ERR(trans)) { > - mutex_unlock(&dev_replace->lock_finishing_cancel_unmount); > - return PTR_ERR(trans); > + ret = PTR_ERR(trans); > + mutex_lock(&fs_devices->device_list_mutex); > + mutex_lock(&fs_info->chunk_mutex); > + goto out; > } > ret = btrfs_commit_transaction(trans); > WARN_ON(ret); > @@ -925,10 +928,8 @@ static int btrfs_dev_replace_finishing(struct btrfs_fs_info *fs_info, > } > } > > +out: Add lockdep_assert_held() so it's clear that all paths leading here will have the mutexes taken. > down_write(&dev_replace->rwsem); > - dev_replace->replace_state = > - scrub_ret ? BTRFS_IOCTL_DEV_REPLACE_STATE_CANCELED > - : BTRFS_IOCTL_DEV_REPLACE_STATE_FINISHED; > dev_replace->tgtdev = NULL; > dev_replace->srcdev = NULL; > dev_replace->time_stopped = ktime_get_real_seconds(); > @@ -938,14 +939,17 @@ static int btrfs_dev_replace_finishing(struct btrfs_fs_info *fs_info, > * Update allocation state in the new device and replace the old device > * with the new one in the mapping tree. > */ > - if (!scrub_ret) { > - scrub_ret = btrfs_set_target_alloc_state(src_device, tgt_device); > - if (scrub_ret) > - goto error; > - btrfs_dev_replace_update_device_in_mapping_tree(fs_info, > - src_device, > - tgt_device); > - } else { > + if (!scrub_ret && !ret) { > + ret = btrfs_set_target_alloc_state(src_device, tgt_device); > + if (!ret) > + btrfs_dev_replace_update_device_in_mapping_tree(fs_info, > + src_device, > + tgt_device); > + } > + dev_replace->replace_state = > + (scrub_ret || ret) ? BTRFS_IOCTL_DEV_REPLACE_STATE_CANCELED > + : BTRFS_IOCTL_DEV_REPLACE_STATE_FINISHED; > + if (scrub_ret || ret) { > if (scrub_ret == -ECANCELED) > btrfs_info(fs_info, > "dev_replace from %s (devid %llu) to %s canceled", > @@ -956,8 +960,7 @@ static int btrfs_dev_replace_finishing(struct btrfs_fs_info *fs_info, > "dev_replace from %s (devid %llu) to %s failed %d", > btrfs_dev_name(src_device), > src_device->devid, > - btrfs_dev_name(tgt_device), scrub_ret); > -error: > + btrfs_dev_name(tgt_device), scrub_ret ? scrub_ret : ret); > up_write(&dev_replace->rwsem); > mutex_unlock(&fs_info->chunk_mutex); > mutex_unlock(&fs_devices->device_list_mutex); > @@ -967,7 +970,7 @@ static int btrfs_dev_replace_finishing(struct btrfs_fs_info *fs_info, > btrfs_rm_dev_replace_unblocked(fs_info); > mutex_unlock(&dev_replace->lock_finishing_cancel_unmount); > > - return scrub_ret; > + return scrub_ret ? scrub_ret : ret; You can use the short form 'return scrub_ret ?: ret' > } > > btrfs_info(fs_info, > -- > 2.55.0 >