From patchwork Mon Dec 18 04:49:29 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Christoph Hellwig X-Patchwork-Id: 13496177 Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 0F0695680 for ; Mon, 18 Dec 2023 04:49:40 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=lst.de Authentication-Results: smtp.subspace.kernel.org; spf=none smtp.mailfrom=bombadil.srs.infradead.org Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="B6e07KHJ" DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20210309; h=Content-Transfer-Encoding: MIME-Version:References:In-Reply-To:Message-Id:Date:Subject:Cc:To:From:Sender :Reply-To:Content-Type:Content-ID:Content-Description; bh=jGpmtEB+cn2F/3PfIxw2xWkhull+ZgQeedcokwukZ0w=; b=B6e07KHJL7rSr5IjVFnr6f2eTP PHRu/ZR3qwVZfzo/E8HNV3qb1k4YYUlLlP3VgjwmUyMN16NwJizhbeXmwZgtG8IG4MraD7wbfeoMJ WKajxRh10BZWJxV72sII2Yrj/rfBujGW0QGkfKhvMHr7g7aQIqVQAo0KBVMxuJNldsJ3dgXw98Z8Y DY0Th/t8Oqv+LWe8QqPyjYnfm5z7EbBZFCdAIt2SG59wh+M+4lqU99CMY/SsmDK20GFQhX8+F99D0 gFWS9cWqs6MfHphZQFOZ9yTkjX1/w00JZv78kdxtviT8fEAIug8Oq1wxS2/PfKIUoJTAKtaj7kAzO GV0M2xyw==; Received: from 2a02-8389-2341-5b80-39d3-4735-9a3c-88d8.cable.dynamic.v6.surfer.at ([2a02:8389:2341:5b80:39d3:4735:9a3c:88d8] helo=localhost) by bombadil.infradead.org with esmtpsa (Exim 4.96 #2 (Red Hat Linux)) id 1rF5ZS-0094Dh-1P; Mon, 18 Dec 2023 04:49:38 +0000 From: Christoph Hellwig To: Chris Mason , Josef Bacik , David Sterba Cc: linux-btrfs@vger.kernel.org, Christian Brauner , Eric Biggers Subject: [PATCH 1/5] btrfs: always open the device read-only in btrfs_scan_one_device Date: Mon, 18 Dec 2023 05:49:29 +0100 Message-Id: <20231218044933.706042-2-hch@lst.de> X-Mailer: git-send-email 2.39.2 In-Reply-To: <20231218044933.706042-1-hch@lst.de> References: <20231218044933.706042-1-hch@lst.de> Precedence: bulk X-Mailing-List: linux-btrfs@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-SRS-Rewrite: SMTP reverse-path rewritten from by bombadil.infradead.org. See http://www.infradead.org/rpr.html btrfs_scan_one_device opens the block device only to read the super block. Instead of passing a blk_mode_t argument to sometimes open it for writing, just hard code BLK_OPEN_READ as it will never write to the device or hand the block_device out to someone else. Signed-off-by: Christoph Hellwig --- fs/btrfs/super.c | 9 ++++----- fs/btrfs/volumes.c | 4 ++-- fs/btrfs/volumes.h | 2 +- 3 files changed, 7 insertions(+), 8 deletions(-) diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c index 3a677b808f0f75..ba16ade1d79aea 100644 --- a/fs/btrfs/super.c +++ b/fs/btrfs/super.c @@ -295,10 +295,9 @@ static int btrfs_parse_param(struct fs_context *fc, struct fs_parameter *param) break; case Opt_device: { struct btrfs_device *device; - blk_mode_t mode = sb_open_mode(fc->sb_flags); mutex_lock(&uuid_mutex); - device = btrfs_scan_one_device(param->string, mode, false); + device = btrfs_scan_one_device(param->string, false); mutex_unlock(&uuid_mutex); if (IS_ERR(device)) return PTR_ERR(device); @@ -1796,7 +1795,7 @@ static int btrfs_get_tree_super(struct fs_context *fc) * With 'true' passed to btrfs_scan_one_device() (mount time) we expect * either a valid device or an error. */ - device = btrfs_scan_one_device(fc->source, mode, true); + device = btrfs_scan_one_device(fc->source, true); ASSERT(device != NULL); if (IS_ERR(device)) { mutex_unlock(&uuid_mutex); @@ -2198,7 +2197,7 @@ static long btrfs_control_ioctl(struct file *file, unsigned int cmd, * Scanning outside of mount can return NULL which would turn * into 0 error code. */ - device = btrfs_scan_one_device(vol->name, BLK_OPEN_READ, false); + device = btrfs_scan_one_device(vol->name, false); ret = PTR_ERR_OR_ZERO(device); mutex_unlock(&uuid_mutex); break; @@ -2216,7 +2215,7 @@ static long btrfs_control_ioctl(struct file *file, unsigned int cmd, * Scanning outside of mount can return NULL which would turn * into 0 error code. */ - device = btrfs_scan_one_device(vol->name, BLK_OPEN_READ, false); + device = btrfs_scan_one_device(vol->name, false); if (IS_ERR_OR_NULL(device)) { mutex_unlock(&uuid_mutex); ret = PTR_ERR(device); diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c index 4c32497311d2ff..02b61757798366 100644 --- a/fs/btrfs/volumes.c +++ b/fs/btrfs/volumes.c @@ -1310,7 +1310,7 @@ int btrfs_forget_devices(dev_t devt) * the device or return an error. Multi-device and seeding devices are registered * in both cases. */ -struct btrfs_device *btrfs_scan_one_device(const char *path, blk_mode_t flags, +struct btrfs_device *btrfs_scan_one_device(const char *path, bool mount_arg_dev) { struct btrfs_super_block *disk_super; @@ -1339,7 +1339,7 @@ struct btrfs_device *btrfs_scan_one_device(const char *path, blk_mode_t flags, * values temporarily, as the device paths of the fsid are the only * required information for assembling the volume. */ - bdev_handle = bdev_open_by_path(path, flags, NULL, NULL); + bdev_handle = bdev_open_by_path(path, BLK_OPEN_READ, NULL, NULL); if (IS_ERR(bdev_handle)) return ERR_CAST(bdev_handle); diff --git a/fs/btrfs/volumes.h b/fs/btrfs/volumes.h index 53f87f398da779..3d35c4b92efb94 100644 --- a/fs/btrfs/volumes.h +++ b/fs/btrfs/volumes.h @@ -642,7 +642,7 @@ struct btrfs_block_group *btrfs_create_chunk(struct btrfs_trans_handle *trans, void btrfs_mapping_tree_free(struct btrfs_fs_info *fs_info); int btrfs_open_devices(struct btrfs_fs_devices *fs_devices, blk_mode_t flags, void *holder); -struct btrfs_device *btrfs_scan_one_device(const char *path, blk_mode_t flags, +struct btrfs_device *btrfs_scan_one_device(const char *path, bool mount_arg_dev); int btrfs_forget_devices(dev_t devt); void btrfs_close_devices(struct btrfs_fs_devices *fs_devices); From patchwork Mon Dec 18 04:49:30 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Christoph Hellwig X-Patchwork-Id: 13496178 Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id EF85163AE for ; Mon, 18 Dec 2023 04:49:43 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=lst.de Authentication-Results: smtp.subspace.kernel.org; spf=none smtp.mailfrom=bombadil.srs.infradead.org Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="4kM8A5Ru" DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20210309; h=Content-Transfer-Encoding: MIME-Version:References:In-Reply-To:Message-Id:Date:Subject:Cc:To:From:Sender :Reply-To:Content-Type:Content-ID:Content-Description; bh=6+/tPB8H2ZpOMp6KNaaRjHjXsRE9V5S6wwFc2IkV/vo=; b=4kM8A5Rufr/JJ7L9t+FrWAYFZF zdUdRkWLKfvysbVPVpJj0OWXRiv9aAX3+BEdaTA/aBIEI1XDT42Zl95wqoBIQwv1cpELMQU0COPMQ bszehWU7FoJF8flOR3y+SnKNIzYrktGepGfXtd7WFg8rDSda80vEp22ErxXCz6OqF2Y8HNMDQAGl8 KuFfbLGR5nRqLRVo9MS4Zv8G5JcoGErJbYKEYXWt7sgy7mmg94KAm0fwOPorcCEeUJk+NKS2orqi5 qES3hKb1YWtF5QWQ9zTxsAzQCfrQ1FP3+BeqKuqTohXEZQNpCJU2Y78im+xLKZnTePExg3Ke+IX7X oicn2olg==; Received: from 2a02-8389-2341-5b80-39d3-4735-9a3c-88d8.cable.dynamic.v6.surfer.at ([2a02:8389:2341:5b80:39d3:4735:9a3c:88d8] helo=localhost) by bombadil.infradead.org with esmtpsa (Exim 4.96 #2 (Red Hat Linux)) id 1rF5ZV-0094ES-0M; Mon, 18 Dec 2023 04:49:41 +0000 From: Christoph Hellwig To: Chris Mason , Josef Bacik , David Sterba Cc: linux-btrfs@vger.kernel.org, Christian Brauner , Eric Biggers Subject: [PATCH 2/5] btrfs: call btrfs_close_devices from ->kill_sb Date: Mon, 18 Dec 2023 05:49:30 +0100 Message-Id: <20231218044933.706042-3-hch@lst.de> X-Mailer: git-send-email 2.39.2 In-Reply-To: <20231218044933.706042-1-hch@lst.de> References: <20231218044933.706042-1-hch@lst.de> Precedence: bulk X-Mailing-List: linux-btrfs@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-SRS-Rewrite: SMTP reverse-path rewritten from by bombadil.infradead.org. See http://www.infradead.org/rpr.html blkdev_put must not be called under sb->s_umount to avoid a lock order reversal with disk->open_mutex once call backs from block devices to the file system using the holder ops are supported. Move the call to btrfs_close_devices into btrfs_free_fs_info so that it is closed from ->kill_sb (which is also called from the mount failure handling path unlike ->put_super) as well as when an fs_info is freed because an existing superblock already exists. Signed-off-by: Christoph Hellwig --- fs/btrfs/disk-io.c | 4 ++-- fs/btrfs/super.c | 27 ++++++++++++++------------- 2 files changed, 16 insertions(+), 15 deletions(-) diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c index c6907d533fe839..c2f57c986069b7 100644 --- a/fs/btrfs/disk-io.c +++ b/fs/btrfs/disk-io.c @@ -1265,6 +1265,8 @@ static void free_global_roots(struct btrfs_fs_info *fs_info) void btrfs_free_fs_info(struct btrfs_fs_info *fs_info) { + if (fs_info->fs_devices) + btrfs_close_devices(fs_info->fs_devices); percpu_counter_destroy(&fs_info->dirty_metadata_bytes); percpu_counter_destroy(&fs_info->delalloc_bytes); percpu_counter_destroy(&fs_info->ordered_bytes); @@ -3597,7 +3599,6 @@ int __cold open_ctree(struct super_block *sb, struct btrfs_fs_devices *fs_device iput(fs_info->btree_inode); fail: - btrfs_close_devices(fs_info->fs_devices); ASSERT(ret < 0); return ret; } @@ -4377,7 +4378,6 @@ void __cold close_ctree(struct btrfs_fs_info *fs_info) iput(fs_info->btree_inode); btrfs_mapping_tree_free(fs_info); - btrfs_close_devices(fs_info->fs_devices); } void btrfs_mark_buffer_dirty(struct btrfs_trans_handle *trans, diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c index ba16ade1d79aea..7d38f973e991f6 100644 --- a/fs/btrfs/super.c +++ b/fs/btrfs/super.c @@ -1810,10 +1810,8 @@ static int btrfs_get_tree_super(struct fs_context *fc) if (ret) return ret; - if (!(fc->sb_flags & SB_RDONLY) && fs_devices->rw_devices == 0) { - ret = -EACCES; - goto error; - } + if (!(fc->sb_flags & SB_RDONLY) && fs_devices->rw_devices == 0) + return -EACCES; bdev = fs_devices->latest_dev->bdev; @@ -1827,15 +1825,12 @@ static int btrfs_get_tree_super(struct fs_context *fc) * otherwise it's tied to the lifetime of the super_block. */ sb = sget_fc(fc, btrfs_fc_test_super, set_anon_super_fc); - if (IS_ERR(sb)) { - ret = PTR_ERR(sb); - goto error; - } + if (IS_ERR(sb)) + return PTR_ERR(sb); set_device_specific_options(fs_info); if (sb->s_root) { - btrfs_close_devices(fs_devices); if ((fc->sb_flags ^ sb->s_flags) & SB_RDONLY) ret = -EBUSY; } else { @@ -1854,10 +1849,6 @@ static int btrfs_get_tree_super(struct fs_context *fc) fc->root = dget(sb->s_root); return 0; - -error: - btrfs_close_devices(fs_devices); - return ret; } /* @@ -1950,10 +1941,20 @@ static int btrfs_get_tree_super(struct fs_context *fc) */ static struct vfsmount *btrfs_reconfigure_for_mount(struct fs_context *fc) { + struct btrfs_fs_info *fs_info = fc->s_fs_info; struct vfsmount *mnt; int ret; const bool ro2rw = !(fc->sb_flags & SB_RDONLY); + /* + * We got a reference to our fs_devices, so we need to close it here to + * make sure we don't leak our reference on the fs_devices. + */ + if (fs_info->fs_devices) { + btrfs_close_devices(fs_info->fs_devices); + fs_info->fs_devices = NULL; + } + /* * We got an EBUSY because our SB_RDONLY flag didn't match the existing * super block, so invert our setting here and retry the mount so we From patchwork Mon Dec 18 04:49:31 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Christoph Hellwig X-Patchwork-Id: 13496179 Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 5E36863AF for ; Mon, 18 Dec 2023 04:49:45 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=lst.de Authentication-Results: smtp.subspace.kernel.org; spf=none smtp.mailfrom=bombadil.srs.infradead.org Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="msLql90W" DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20210309; h=Content-Transfer-Encoding: MIME-Version:References:In-Reply-To:Message-Id:Date:Subject:Cc:To:From:Sender :Reply-To:Content-Type:Content-ID:Content-Description; bh=1XSDTqCZ2FQPKqku3okcR5aMoAlJT6ybFxP3/+al0fo=; b=msLql90WeG99x7qxU5f+H+U6zH 9ukGRVv2NeillPZha3brHuvTxQnER7rM7NShHVYKpWLT2XmYHJkIZYmCV1G9jryga/g/FXQ5cEuGh NiBDl6sUEbNcdBLnsD4QAlWBPZIEFEOyAUIRNEujnnLQSY2u6IRFONJaWVtaPpCVcEyW41wLtOP4x p9MkB0YmX5dRg7b21dAKC+5/LcdWzNEgisGOIZ2EP24QvMURXrvCjcQ7NHPClfnJf7eaBbfsGYCov b4+Pef0rD/P6mqXtsZxeIINJVgLzXzWiKsAK6ifvumSr9usQf7ZCG//pQHSZBDUadzSyEDxayijYL hnHbPY+g==; Received: from 2a02-8389-2341-5b80-39d3-4735-9a3c-88d8.cable.dynamic.v6.surfer.at ([2a02:8389:2341:5b80:39d3:4735:9a3c:88d8] helo=localhost) by bombadil.infradead.org with esmtpsa (Exim 4.96 #2 (Red Hat Linux)) id 1rF5ZX-0094Eg-1s; Mon, 18 Dec 2023 04:49:43 +0000 From: Christoph Hellwig To: Chris Mason , Josef Bacik , David Sterba Cc: linux-btrfs@vger.kernel.org, Christian Brauner , Eric Biggers Subject: [PATCH 3/5] btrfs: split btrfs_fs_devices.opened Date: Mon, 18 Dec 2023 05:49:31 +0100 Message-Id: <20231218044933.706042-4-hch@lst.de> X-Mailer: git-send-email 2.39.2 In-Reply-To: <20231218044933.706042-1-hch@lst.de> References: <20231218044933.706042-1-hch@lst.de> Precedence: bulk X-Mailing-List: linux-btrfs@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-SRS-Rewrite: SMTP reverse-path rewritten from by bombadil.infradead.org. See http://www.infradead.org/rpr.html The btrfs_fs_devices.opened member mixes an in use counter for the fs_devices structure that prevents it from being garbage collected with a flag if the underlying devices were actually opened. This not only makes the code hard to follow, but also prevents btrfs from switching to opening the block device only after super block creation. Split it into an in_use counter and an is_open boolean flag instead. Signed-off-by: Christoph Hellwig --- fs/btrfs/volumes.c | 51 ++++++++++++++++++++++++++-------------------- fs/btrfs/volumes.h | 6 ++++-- 2 files changed, 33 insertions(+), 24 deletions(-) diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c index 02b61757798366..65d28c79402091 100644 --- a/fs/btrfs/volumes.c +++ b/fs/btrfs/volumes.c @@ -414,7 +414,8 @@ static void free_fs_devices(struct btrfs_fs_devices *fs_devices) { struct btrfs_device *device; - WARN_ON(fs_devices->opened); + WARN_ON_ONCE(fs_devices->in_use); + WARN_ON_ONCE(fs_devices->is_open); while (!list_empty(&fs_devices->devices)) { device = list_entry(fs_devices->devices.next, struct btrfs_device, dev_list); @@ -537,7 +538,7 @@ static int btrfs_free_stale_devices(dev_t devt, struct btrfs_device *skip_device continue; if (devt && devt != device->devt) continue; - if (fs_devices->opened) { + if (fs_devices->in_use) { if (devt) ret = -EBUSY; break; @@ -609,7 +610,7 @@ static struct btrfs_fs_devices *find_fsid_by_device( if (found_by_devt) { /* Existing device. */ if (fsid_fs_devices == NULL) { - if (devt_fs_devices->opened == 0) { + if (devt_fs_devices->in_use == 0) { /* Stale device. */ return NULL; } else { @@ -797,7 +798,7 @@ static noinline struct btrfs_device *device_list_add(const char *path, if (!device) { unsigned int nofs_flag; - if (fs_devices->opened) { + if (fs_devices->in_use) { btrfs_err(NULL, "device %s belongs to fsid %pU, and the fs is already mounted, scanned by %s (%d)", path, fs_devices->fsid, current->comm, @@ -862,7 +863,7 @@ static noinline struct btrfs_device *device_list_add(const char *path, * tracking a problem where systems fail mount by subvolume id * when we reject replacement on a mounted FS. */ - if (!fs_devices->opened && found_transid < device->generation) { + if (!fs_devices->in_use && found_transid < device->generation) { /* * That is if the FS is _not_ mounted and if you * are here, that means there is more than one @@ -923,7 +924,7 @@ static noinline struct btrfs_device *device_list_add(const char *path, * it back. We need it to pick the disk with largest generation * (as above). */ - if (!fs_devices->opened) { + if (!fs_devices->in_use) { device->generation = found_transid; fs_devices->latest_generation = max_t(u64, found_transid, fs_devices->latest_generation); @@ -1122,15 +1123,19 @@ static void close_fs_devices(struct btrfs_fs_devices *fs_devices) lockdep_assert_held(&uuid_mutex); - if (--fs_devices->opened > 0) + if (--fs_devices->in_use > 0) return; + if (!fs_devices->is_open) + goto done; + list_for_each_entry_safe(device, tmp, &fs_devices->devices, dev_list) btrfs_close_one_device(device); WARN_ON(fs_devices->open_devices); WARN_ON(fs_devices->rw_devices); - fs_devices->opened = 0; + fs_devices->is_open = false; +done: fs_devices->seeding = false; fs_devices->fs_info = NULL; } @@ -1142,7 +1147,7 @@ void btrfs_close_devices(struct btrfs_fs_devices *fs_devices) mutex_lock(&uuid_mutex); close_fs_devices(fs_devices); - if (!fs_devices->opened) { + if (!fs_devices->in_use) { list_splice_init(&fs_devices->seed_list, &list); /* @@ -1190,7 +1195,7 @@ static int open_fs_devices(struct btrfs_fs_devices *fs_devices, if (fs_devices->open_devices == 0) return -EINVAL; - fs_devices->opened = 1; + fs_devices->is_open = true; fs_devices->latest_dev = latest_dev; fs_devices->total_rw_bytes = 0; fs_devices->chunk_alloc_policy = BTRFS_CHUNK_ALLOC_REGULAR; @@ -1227,16 +1232,14 @@ int btrfs_open_devices(struct btrfs_fs_devices *fs_devices, * We also don't need the lock here as this is called during mount and * exclusion is provided by uuid_mutex */ - - if (fs_devices->opened) { - fs_devices->opened++; - ret = 0; - } else { + if (!fs_devices->is_open) { list_sort(NULL, &fs_devices->devices, devid_cmp); ret = open_fs_devices(fs_devices, flags, holder); + if (ret) + return ret; } - - return ret; + fs_devices->in_use++; + return 0; } void btrfs_release_disk_super(struct btrfs_super_block *super) @@ -2203,13 +2206,14 @@ int btrfs_rm_device(struct btrfs_fs_info *fs_info, * This can happen if cur_devices is the private seed devices list. We * cannot call close_fs_devices() here because it expects the uuid_mutex * to be held, but in fact we don't need that for the private - * seed_devices, we can simply decrement cur_devices->opened and then + * seed_devices, we can simply decrement cur_devices->in_use and then * remove it from our list and free the fs_devices. */ if (cur_devices->num_devices == 0) { list_del_init(&cur_devices->seed_list); - ASSERT(cur_devices->opened == 1); - cur_devices->opened--; + ASSERT(cur_devices->in_use == 1); + cur_devices->in_use--; + cur_devices->is_open = false; free_fs_devices(cur_devices); } @@ -2439,7 +2443,8 @@ static struct btrfs_fs_devices *btrfs_init_sprout(struct btrfs_fs_info *fs_info) list_add(&old_devices->fs_list, &fs_uuids); memcpy(seed_devices, fs_devices, sizeof(*seed_devices)); - seed_devices->opened = 1; + seed_devices->in_use = 1; + seed_devices->is_open = true; INIT_LIST_HEAD(&seed_devices->devices); INIT_LIST_HEAD(&seed_devices->alloc_list); mutex_init(&seed_devices->device_list_mutex); @@ -7109,7 +7114,8 @@ static struct btrfs_fs_devices *open_seed_devices(struct btrfs_fs_info *fs_info, return fs_devices; fs_devices->seeding = true; - fs_devices->opened = 1; + fs_devices->in_use = 1; + fs_devices->is_open = true; return fs_devices; } @@ -7126,6 +7132,7 @@ static struct btrfs_fs_devices *open_seed_devices(struct btrfs_fs_info *fs_info, free_fs_devices(fs_devices); return ERR_PTR(ret); } + fs_devices->in_use = 1; if (!fs_devices->seeding) { close_fs_devices(fs_devices); diff --git a/fs/btrfs/volumes.h b/fs/btrfs/volumes.h index 3d35c4b92efb94..a136205044898c 100644 --- a/fs/btrfs/volumes.h +++ b/fs/btrfs/volumes.h @@ -357,8 +357,10 @@ struct btrfs_fs_devices { struct list_head seed_list; - /* Count fs-devices opened. */ - int opened; + /* Count if fs_device is in used. */ + unsigned int in_use; + /* True if the devices were opened. */ + bool is_open; /* Set when we find or add a device that doesn't have the nonrot flag set. */ bool rotating; From patchwork Mon Dec 18 04:49:32 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Christoph Hellwig X-Patchwork-Id: 13496180 Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 1E5C86AA8 for ; Mon, 18 Dec 2023 04:49:48 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=lst.de Authentication-Results: smtp.subspace.kernel.org; spf=none smtp.mailfrom=bombadil.srs.infradead.org Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="HWXfn1Kr" DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20210309; h=Content-Transfer-Encoding: MIME-Version:References:In-Reply-To:Message-Id:Date:Subject:Cc:To:From:Sender :Reply-To:Content-Type:Content-ID:Content-Description; bh=y1ClTYqVSi47swoAkDvhns1CIwMW3vg5a53Yp5NWlUA=; b=HWXfn1KrTbgenx4BfCMN58sx75 nSLb9qRGjqdPRVyhzJcv6/0QA+AtC1dbncK1Jyrgr0yoafhkJfprDeTnCb54s9kMJofd/LZ93EpQB EPlNiKn3/QCrncwaM8xFYbMnSo6Slu3yLYwrFz4cccw8ABf7+Pr/MUW+6j9AA+LKYaNYizUFQLFFW Xp0PBpIfVULVZsFlPetoahnM9tUz/88GCfFFM9SIyfHU8i1Nd1jO3do7KHaByJDQzf4me5W/GXnr4 PZpjUY/P/YeqgHZLrcQJ4nu348MgFnqZXf7MUL3d6SEVZWTO1OlBmOtJnMvRMP8/1h79FfvR8/sCR lB94jX8w==; Received: from 2a02-8389-2341-5b80-39d3-4735-9a3c-88d8.cable.dynamic.v6.surfer.at ([2a02:8389:2341:5b80:39d3:4735:9a3c:88d8] helo=localhost) by bombadil.infradead.org with esmtpsa (Exim 4.96 #2 (Red Hat Linux)) id 1rF5ZZ-0094F1-38; Mon, 18 Dec 2023 04:49:46 +0000 From: Christoph Hellwig To: Chris Mason , Josef Bacik , David Sterba Cc: linux-btrfs@vger.kernel.org, Christian Brauner , Eric Biggers Subject: [PATCH 4/5] btrfs: open block devices after superblock creation Date: Mon, 18 Dec 2023 05:49:32 +0100 Message-Id: <20231218044933.706042-5-hch@lst.de> X-Mailer: git-send-email 2.39.2 In-Reply-To: <20231218044933.706042-1-hch@lst.de> References: <20231218044933.706042-1-hch@lst.de> Precedence: bulk X-Mailing-List: linux-btrfs@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-SRS-Rewrite: SMTP reverse-path rewritten from by bombadil.infradead.org. See http://www.infradead.org/rpr.html Currently btrfs_mount_root opens the block devices before committing to allocating a super block. That creates problems for restricting the number of writers to a device, and also leads to a unusual and not very helpful holder (the fs_type). Reorganize the code to first check whether the superblock for a particular fsid does already exist and open the block devices only if it doesn't, mirroring the recent changes to the VFS mount helpers. To do this the increment of the in_use counter moves out of btrfs_open_devices and into the only caller in btrfs_mount_root so that it happens before dropping uuid_mutex around the call to sget. Signed-off-by: Christoph Hellwig --- fs/btrfs/super.c | 41 +++++++++++++++++++++++++---------------- fs/btrfs/volumes.c | 15 +++++---------- 2 files changed, 30 insertions(+), 26 deletions(-) diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c index 7d38f973e991f6..62a933b47e03c3 100644 --- a/fs/btrfs/super.c +++ b/fs/btrfs/super.c @@ -1782,7 +1782,6 @@ static int btrfs_get_tree_super(struct fs_context *fc) struct btrfs_fs_info *fs_info = fc->s_fs_info; struct btrfs_fs_context *ctx = fc->fs_private; struct btrfs_fs_devices *fs_devices = NULL; - struct block_device *bdev; struct btrfs_device *device; struct super_block *sb; blk_mode_t mode = sb_open_mode(fc->sb_flags); @@ -1805,15 +1804,8 @@ static int btrfs_get_tree_super(struct fs_context *fc) fs_devices = device->fs_devices; fs_info->fs_devices = fs_devices; - ret = btrfs_open_devices(fs_devices, mode, &btrfs_fs_type); + fs_devices->in_use++; mutex_unlock(&uuid_mutex); - if (ret) - return ret; - - if (!(fc->sb_flags & SB_RDONLY) && fs_devices->rw_devices == 0) - return -EACCES; - - bdev = fs_devices->latest_dev->bdev; /* * From now on the error handling is not straightforward. @@ -1831,24 +1823,41 @@ static int btrfs_get_tree_super(struct fs_context *fc) set_device_specific_options(fs_info); if (sb->s_root) { - if ((fc->sb_flags ^ sb->s_flags) & SB_RDONLY) + if ((fc->sb_flags ^ sb->s_flags) & SB_RDONLY) { ret = -EBUSY; + goto error_deactivate; + } } else { - snprintf(sb->s_id, sizeof(sb->s_id), "%pg", bdev); + struct btrfs_fs_devices *fs_devices = fs_info->fs_devices; + + mutex_lock(&uuid_mutex); + ret = btrfs_open_devices(fs_devices, mode, &btrfs_fs_type); + mutex_unlock(&uuid_mutex); + if (ret) + goto error_deactivate; + + if (!(fc->sb_flags & SB_RDONLY) && !fs_devices->rw_devices) { + ret = -EACCES; + goto error_deactivate; + } + + snprintf(sb->s_id, sizeof(sb->s_id), "%pg", + fs_devices->latest_dev->bdev); shrinker_debugfs_rename(sb->s_shrink, "sb-btrfs:%s", sb->s_id); btrfs_sb(sb)->bdev_holder = &btrfs_fs_type; ret = btrfs_fill_super(sb, fs_devices, NULL); - } - - if (ret) { - deactivate_locked_super(sb); - return ret; + if (ret) + goto error_deactivate; } btrfs_clear_oneshot_options(fs_info); fc->root = dget(sb->s_root); return 0; + +error_deactivate: + deactivate_locked_super(sb); + return ret; } /* diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c index 65d28c79402091..5ab1b7c2fa3967 100644 --- a/fs/btrfs/volumes.c +++ b/fs/btrfs/volumes.c @@ -1222,8 +1222,6 @@ static int devid_cmp(void *priv, const struct list_head *a, int btrfs_open_devices(struct btrfs_fs_devices *fs_devices, blk_mode_t flags, void *holder) { - int ret; - lockdep_assert_held(&uuid_mutex); /* * The device_list_mutex cannot be taken here in case opening the @@ -1232,14 +1230,11 @@ int btrfs_open_devices(struct btrfs_fs_devices *fs_devices, * We also don't need the lock here as this is called during mount and * exclusion is provided by uuid_mutex */ - if (!fs_devices->is_open) { - list_sort(NULL, &fs_devices->devices, devid_cmp); - ret = open_fs_devices(fs_devices, flags, holder); - if (ret) - return ret; - } - fs_devices->in_use++; - return 0; + ASSERT(fs_devices->in_use); + if (fs_devices->is_open) + return 0; + list_sort(NULL, &fs_devices->devices, devid_cmp); + return open_fs_devices(fs_devices, flags, holder); } void btrfs_release_disk_super(struct btrfs_super_block *super) From patchwork Mon Dec 18 04:49:33 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Christoph Hellwig X-Patchwork-Id: 13496181 Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 2C33C613C for ; Mon, 18 Dec 2023 04:49:50 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=lst.de Authentication-Results: smtp.subspace.kernel.org; spf=none smtp.mailfrom=bombadil.srs.infradead.org Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="sEbVv17w" DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20210309; h=Content-Transfer-Encoding: MIME-Version:References:In-Reply-To:Message-Id:Date:Subject:Cc:To:From:Sender :Reply-To:Content-Type:Content-ID:Content-Description; bh=LDrDeV/kHy3r/3w2Doo9aEjmT8I+Ne0frQ9VVRfffHU=; b=sEbVv17weiFVYW4uC3vcXO72Or iHe5On6foSxOHr1K/hovLNVbTonQILzJu6+PhenHGz11UfW8oxfgg8EiAE9tuR59DIv4GNU3o/qMj 4ZxoGgl23nzGnFkZe0eyPIpB/mSzfHM34vItwV3ys/VrDLOMDq6GqZ+YuD6BB2kcLoTfrTDGo94FR MtNAek5tEamP5/T+Vd0+OwpnlNBQmcE2cnWoqvVNpuKyr73BETciYKPkaDsRwfrnvM/SjHZ8/eyiC Dzfxdh93lmesuCVzgO+bUhg/iwxctdCPIgROztZ89vXZ2XGByZVJ6f6U4m5Qa4uANiQCFQIWaQLPX cDrTOTaw==; Received: from 2a02-8389-2341-5b80-39d3-4735-9a3c-88d8.cable.dynamic.v6.surfer.at ([2a02:8389:2341:5b80:39d3:4735:9a3c:88d8] helo=localhost) by bombadil.infradead.org with esmtpsa (Exim 4.96 #2 (Red Hat Linux)) id 1rF5Zc-0094FV-0u; Mon, 18 Dec 2023 04:49:48 +0000 From: Christoph Hellwig To: Chris Mason , Josef Bacik , David Sterba Cc: linux-btrfs@vger.kernel.org, Christian Brauner , Eric Biggers Subject: [PATCH 5/5] btrfs: use the super_block as holder when mounting file systems Date: Mon, 18 Dec 2023 05:49:33 +0100 Message-Id: <20231218044933.706042-6-hch@lst.de> X-Mailer: git-send-email 2.39.2 In-Reply-To: <20231218044933.706042-1-hch@lst.de> References: <20231218044933.706042-1-hch@lst.de> Precedence: bulk X-Mailing-List: linux-btrfs@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-SRS-Rewrite: SMTP reverse-path rewritten from by bombadil.infradead.org. See http://www.infradead.org/rpr.html The file system type is not a very useful holder as it doesn't allow us to go back to the actual file system instance. Pass the super_block instead which is useful when passed back to the file system driver. This matches what is done for all other block device based file systems. Signed-off-by: Christoph Hellwig --- fs/btrfs/super.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c index 62a933b47e03c3..2dfa2274b19387 100644 --- a/fs/btrfs/super.c +++ b/fs/btrfs/super.c @@ -1831,7 +1831,7 @@ static int btrfs_get_tree_super(struct fs_context *fc) struct btrfs_fs_devices *fs_devices = fs_info->fs_devices; mutex_lock(&uuid_mutex); - ret = btrfs_open_devices(fs_devices, mode, &btrfs_fs_type); + ret = btrfs_open_devices(fs_devices, mode, sb); mutex_unlock(&uuid_mutex); if (ret) goto error_deactivate; @@ -1844,7 +1844,7 @@ static int btrfs_get_tree_super(struct fs_context *fc) snprintf(sb->s_id, sizeof(sb->s_id), "%pg", fs_devices->latest_dev->bdev); shrinker_debugfs_rename(sb->s_shrink, "sb-btrfs:%s", sb->s_id); - btrfs_sb(sb)->bdev_holder = &btrfs_fs_type; + btrfs_sb(sb)->bdev_holder = sb; ret = btrfs_fill_super(sb, fs_devices, NULL); if (ret) goto error_deactivate;