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[63.231.237.45]) by smtp.gmail.com with ESMTPSA id o7-20020a92d4c7000000b0036576880ffcsm2430093ilm.85.2024.02.27.15.54.49 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Tue, 27 Feb 2024 15:54:50 -0800 (PST) Message-ID: Date: Tue, 27 Feb 2024 17:54:48 -0600 Precedence: bulk X-Mailing-List: linux-fsdevel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH] qnx4: convert qnx4 to use the new mount api Content-Language: en-US To: Christian Brauner , Bill O'Donnell Cc: linux-fsdevel@vger.kernel.org, al@alarsen.net References: <20240226224628.710547-1-bodonnel@redhat.com> <20240227-infrage-imperativ-53428d23802c@brauner> From: Eric Sandeen In-Reply-To: <20240227-infrage-imperativ-53428d23802c@brauner> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit On 2/27/24 6:26 AM, Christian Brauner wrote: > On Mon, Feb 26, 2024 at 04:46:28PM -0600, Bill O'Donnell wrote: >> Convert the qnx4 filesystem to use the new mount API. >> >> Tested mount, umount, and remount using a qnx4 boot image. >> >> Signed-off-by: Bill O'Donnell >> --- >> fs/qnx4/inode.c | 49 +++++++++++++++++++++++++++++++------------------ >> 1 file changed, 31 insertions(+), 18 deletions(-) >> >> diff --git a/fs/qnx4/inode.c b/fs/qnx4/inode.c >> index 6eb9bb369b57..c36fbe45a0e9 100644 >> --- a/fs/qnx4/inode.c >> +++ b/fs/qnx4/inode.c >> @@ -21,6 +21,7 @@ >> #include >> #include >> #include >> +#include >> #include "qnx4.h" >> >> #define QNX4_VERSION 4 >> @@ -30,28 +31,33 @@ static const struct super_operations qnx4_sops; >> >> static struct inode *qnx4_alloc_inode(struct super_block *sb); >> static void qnx4_free_inode(struct inode *inode); >> -static int qnx4_remount(struct super_block *sb, int *flags, char *data); >> static int qnx4_statfs(struct dentry *, struct kstatfs *); >> +static int qnx4_get_tree(struct fs_context *fc); >> >> static const struct super_operations qnx4_sops = >> { >> .alloc_inode = qnx4_alloc_inode, >> .free_inode = qnx4_free_inode, >> .statfs = qnx4_statfs, >> - .remount_fs = qnx4_remount, >> }; >> >> -static int qnx4_remount(struct super_block *sb, int *flags, char *data) >> +static int qnx4_reconfigure(struct fs_context *fc) >> { >> - struct qnx4_sb_info *qs; >> + struct super_block *sb = fc->root->d_sb; >> + struct qnx4_sb_info *qs = sb->s_fs_info; >> >> sync_filesystem(sb); >> qs = qnx4_sb(sb); >> qs->Version = QNX4_VERSION; >> - *flags |= SB_RDONLY; >> + fc->sb_flags |= SB_RDONLY; > > This confused me to no end because setting SB_RDONLY here > unconditionally would be wrong if it's not requested from userspace > during a remount. Because in that case the vfs wouldn't know that an > actual read-only remount request had been made which means that we don't > take the necessary protection steps to transition from read-write to > read-only. But qnx{4,6} are read-only so this is actually correct even > though it seems pretty weird. This seems to be how every only-read-only filesystem does it, see erofs, romfs, squashfs, cramfs ... -Eric