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[2403:580d:fda1::299]) by smtp.gmail.com with ESMTPSA id 98e67ed59e1d1-30ad4d56976sm1737872a91.27.2025.05.08.02.29.06 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Thu, 08 May 2025 02:29:08 -0700 (PDT) Message-ID: <9a49247a-91dd-4c13-914a-36a5bfc718ba@suse.com> Date: Thu, 8 May 2025 18:59:04 +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 v3] btrfs_get_tree_subvol(): switch from fc_mount() to vfs_create_mount() To: Al Viro , linux-fsdevel@vger.kernel.org Cc: linux-btrfs@vger.kernel.org, Klara Modin References: <20250505030345.GD2023217@ZenIV> <20250506193405.GS2023217@ZenIV> <20250506195826.GU2023217@ZenIV> 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: <20250506195826.GU2023217@ZenIV> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit 在 2025/5/7 05:28, Al Viro 写道: > [Aaarghh...] > it's simpler to do btrfs_reconfigure_for_mount() right after vfs_get_tree() - > no need to mess with ->s_umount. > > [fix for braino(s) folded in - kudos to Klara Modin ] > Signed-off-by: Al Viro Reviewed-by: Qu Wenruo Test-by: Qu Wenruo Although the commit message can be enhanced a little, I can handle it at merge time, no need to re-send. Thanks, Qu > --- > diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c > index 7121d8c7a318..592ed044340c 100644 > --- a/fs/btrfs/super.c > +++ b/fs/btrfs/super.c > @@ -1984,17 +1984,13 @@ static int btrfs_get_tree_super(struct fs_context *fc) > * btrfs or not, setting the whole super block RO. To make per-subvolume mounting > * work with different options work we need to keep backward compatibility. > */ > -static int btrfs_reconfigure_for_mount(struct fs_context *fc, struct vfsmount *mnt) > +static int btrfs_reconfigure_for_mount(struct fs_context *fc) > { > int ret = 0; > > - if (fc->sb_flags & SB_RDONLY) > - return ret; > - > - down_write(&mnt->mnt_sb->s_umount); > - if (!(fc->sb_flags & SB_RDONLY) && (mnt->mnt_sb->s_flags & SB_RDONLY)) > + if (!(fc->sb_flags & SB_RDONLY) && (fc->root->d_sb->s_flags & SB_RDONLY)) > ret = btrfs_reconfigure(fc); > - up_write(&mnt->mnt_sb->s_umount); > + > return ret; > } > > @@ -2047,17 +2043,18 @@ static int btrfs_get_tree_subvol(struct fs_context *fc) > security_free_mnt_opts(&fc->security); > fc->security = NULL; > > - mnt = fc_mount(dup_fc); > - if (IS_ERR(mnt)) { > - put_fs_context(dup_fc); > - return PTR_ERR(mnt); > + ret = vfs_get_tree(dup_fc); > + if (!ret) { > + ret = btrfs_reconfigure_for_mount(dup_fc); > + up_write(&dup_fc->root->d_sb->s_umount); > } > - ret = btrfs_reconfigure_for_mount(dup_fc, mnt); > + if (!ret) > + mnt = vfs_create_mount(dup_fc); > + else > + mnt = ERR_PTR(ret); > put_fs_context(dup_fc); > - if (ret) { > - mntput(mnt); > - return ret; > - } > + if (IS_ERR(mnt)) > + return PTR_ERR(mnt); > > /* > * This free's ->subvol_name, because if it isn't set we have to >