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[2403:580d:fda1::299]) by smtp.gmail.com with ESMTPSA id d9443c01a7336-2364e702d9dsm265605ad.180.2025.06.11.14.28.56 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Wed, 11 Jun 2025 14:28:59 -0700 (PDT) Message-ID: Date: Thu, 12 Jun 2025 06:58:53 +0930 Precedence: bulk X-Mailing-List: linux-btrfs@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v2 1/5] btrfs: always open the device read-only in btrfs_scan_one_device To: Johannes Thumshirn , linux-btrfs@vger.kernel.org Cc: Boris Burkov , Christoph Hellwig , David Sterba , Josef Bacik , Johannes Thumshirn References: <20250611100303.110311-1-jth@kernel.org> <20250611100303.110311-2-jth@kernel.org> Content-Language: en-US From: Qu Wenruo Autocrypt: addr=wqu@suse.com; keydata= xsBNBFnVga8BCACyhFP3ExcTIuB73jDIBA/vSoYcTyysFQzPvez64TUSCv1SgXEByR7fju3o 8RfaWuHCnkkea5luuTZMqfgTXrun2dqNVYDNOV6RIVrc4YuG20yhC1epnV55fJCThqij0MRL 1NxPKXIlEdHvN0Kov3CtWA+R1iNN0RCeVun7rmOrrjBK573aWC5sgP7YsBOLK79H3tmUtz6b 9Imuj0ZyEsa76Xg9PX9Hn2myKj1hfWGS+5og9Va4hrwQC8ipjXik6NKR5GDV+hOZkktU81G5 gkQtGB9jOAYRs86QG/b7PtIlbd3+pppT0gaS+wvwMs8cuNG+Pu6KO1oC4jgdseFLu7NpABEB AAHNGFF1IFdlbnJ1byA8d3F1QHN1c2UuY29tPsLAlAQTAQgAPgIbAwULCQgHAgYVCAkKCwIE FgIDAQIeAQIXgBYhBC3fcuWlpVuonapC4cI9kfOhJf6oBQJnEXVgBQkQ/lqxAAoJEMI9kfOh Jf6o+jIH/2KhFmyOw4XWAYbnnijuYqb/obGae8HhcJO2KIGcxbsinK+KQFTSZnkFxnbsQ+VY fvtWBHGt8WfHcNmfjdejmy9si2jyy8smQV2jiB60a8iqQXGmsrkuR+AM2V360oEbMF3gVvim 2VSX2IiW9KERuhifjseNV1HLk0SHw5NnXiWh1THTqtvFFY+CwnLN2GqiMaSLF6gATW05/sEd V17MdI1z4+WSk7D57FlLjp50F3ow2WJtXwG8yG8d6S40dytZpH9iFuk12Sbg7lrtQxPPOIEU rpmZLfCNJJoZj603613w/M8EiZw6MohzikTWcFc55RLYJPBWQ+9puZtx1DopW2jOwE0EWdWB rwEIAKpT62HgSzL9zwGe+WIUCMB+nOEjXAfvoUPUwk+YCEDcOdfkkM5FyBoJs8TCEuPXGXBO Cl5P5B8OYYnkHkGWutAVlUTV8KESOIm/KJIA7jJA+Ss9VhMjtePfgWexw+P8itFRSRrrwyUf E+0WcAevblUi45LjWWZgpg3A80tHP0iToOZ5MbdYk7YFBE29cDSleskfV80ZKxFv6koQocq0 vXzTfHvXNDELAuH7Ms/WJcdUzmPyBf3Oq6mKBBH8J6XZc9LjjNZwNbyvsHSrV5bgmu/THX2n g/3be+iqf6OggCiy3I1NSMJ5KtR0q2H2Nx2Vqb1fYPOID8McMV9Ll6rh8S8AEQEAAcLAfAQY AQgAJgIbDBYhBC3fcuWlpVuonapC4cI9kfOhJf6oBQJnEXWBBQkQ/lrSAAoJEMI9kfOhJf6o cakH+QHwDszsoYvmrNq36MFGgvAHRjdlrHRBa4A1V1kzd4kOUokongcrOOgHY9yfglcvZqlJ qfa4l+1oxs1BvCi29psteQTtw+memmcGruKi+YHD7793zNCMtAtYidDmQ2pWaLfqSaryjlzR /3tBWMyvIeWZKURnZbBzWRREB7iWxEbZ014B3gICqZPDRwwitHpH8Om3eZr7ygZck6bBa4MU o1XgbZcspyCGqu1xF/bMAY2iCDcq6ULKQceuKkbeQ8qxvt9hVxJC2W3lHq8dlK1pkHPDg9wO JoAXek8MF37R8gpLoGWl41FIUb3hFiu3zhDDvslYM4BmzI18QgQTQnotJH8= In-Reply-To: <20250611100303.110311-2-jth@kernel.org> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit 在 2025/6/11 19:32, Johannes Thumshirn 写道: > From: Christoph Hellwig > > 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 > Signed-off-by: Johannes Thumshirn Reviewed-by: Qu Wenruo Thanks, Qu > --- > 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 2d0d8c6e77b4..b9e08a59da4e 100644 > --- a/fs/btrfs/super.c > +++ b/fs/btrfs/super.c > @@ -364,10 +364,9 @@ 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 = btrfs_open_mode(fc); > > 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); > @@ -1855,7 +1854,7 @@ 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); > @@ -2233,7 +2232,7 @@ 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; > @@ -2251,7 +2250,7 @@ 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); > if (IS_ERR(device)) > diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c > index 1535a425e8f9..1ebfc69012a2 100644 > --- a/fs/btrfs/volumes.c > +++ b/fs/btrfs/volumes.c > @@ -1440,7 +1440,7 @@ static bool btrfs_skip_registration(struct btrfs_super_block *disk_super, > * 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; > @@ -1461,7 +1461,7 @@ 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_file = bdev_file_open_by_path(path, flags, NULL, NULL); > + bdev_file = bdev_file_open_by_path(path, BLK_OPEN_READ, NULL, NULL); > if (IS_ERR(bdev_file)) > return ERR_CAST(bdev_file); > > diff --git a/fs/btrfs/volumes.h b/fs/btrfs/volumes.h > index 6d8b1f38e3ee..afa71d315c46 100644 > --- a/fs/btrfs/volumes.h > +++ b/fs/btrfs/volumes.h > @@ -719,7 +719,7 @@ 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);