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Registered in England and Wales under Company Registration No. 3798903 Subject: [PATCH 10/14] ipc: Convert mqueue fs to fs_context [ver #6] From: David Howells To: viro@ZenIV.linux.org.uk Cc: linux-fsdevel@vger.kernel.org, mszeredi@redhat.com, linux-nfs@vger.kernel.org, linux-kernel@vger.kernel.org, jlayton@redhat.com Date: Fri, 06 Oct 2017 16:50:28 +0100 Message-ID: <150730502858.6182.8072842763914901286.stgit@warthog.procyon.org.uk> In-Reply-To: <150730494491.6182.5139368907374172391.stgit@warthog.procyon.org.uk> References: <150730494491.6182.5139368907374172391.stgit@warthog.procyon.org.uk> User-Agent: StGit/0.17.1-dirty MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.15 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.31]); Fri, 06 Oct 2017 15:50:30 +0000 (UTC) Sender: linux-fsdevel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP Convert the mqueue filesystem to use the filesystem context stuff. Notes: (1) The relevant ipc namespace is selected in when the context is initialised (and it defaults to the current task's ipc namespace). The caller can override this before calling vfs_get_tree(). (2) Rather than simply calling kern_mount_data(), mq_init_ns() creates a context, adjusts it and then does the rest of the mount procedure. Signed-off-by: David Howells --- ipc/mqueue.c | 90 ++++++++++++++++++++++++++++++++++++++++++++-------------- 1 file changed, 68 insertions(+), 22 deletions(-) diff --git a/ipc/mqueue.c b/ipc/mqueue.c index 9649ecd8a73a..561460675734 100644 --- a/ipc/mqueue.c +++ b/ipc/mqueue.c @@ -18,6 +18,7 @@ #include #include #include +#include #include #include #include @@ -42,6 +43,11 @@ #include #include "util.h" +struct mqueue_fs_context { + struct fs_context fc; + struct ipc_namespace *ipc_ns; +}; + #define MQUEUE_MAGIC 0x19800202 #define DIRENT_SIZE 20 #define FILENT_SIZE 80 @@ -90,6 +96,7 @@ struct mqueue_inode_info { static const struct inode_operations mqueue_dir_inode_operations; static const struct file_operations mqueue_file_operations; static const struct super_operations mqueue_super_ops; +static const struct fs_context_operations mqueue_fs_context_ops; static void remove_notification(struct mqueue_inode_info *info); static struct kmem_cache *mqueue_inode_cachep; @@ -305,7 +312,7 @@ static struct inode *mqueue_get_inode(struct super_block *sb, return ERR_PTR(ret); } -static int mqueue_fill_super(struct super_block *sb, void *data, int silent) +static int mqueue_fill_super(struct super_block *sb, struct fs_context *fc) { struct inode *inode; struct ipc_namespace *ns = sb->s_fs_info; @@ -326,18 +333,29 @@ static int mqueue_fill_super(struct super_block *sb, void *data, int silent) return 0; } -static struct dentry *mqueue_mount(struct file_system_type *fs_type, - int flags, const char *dev_name, - void *data) +static int mqueue_get_tree(struct fs_context *fc) { - struct ipc_namespace *ns; - if (flags & SB_KERNMOUNT) { - ns = data; - data = NULL; - } else { - ns = current->nsproxy->ipc_ns; - } - return mount_ns(fs_type, flags, data, ns, ns->user_ns, mqueue_fill_super); + struct mqueue_fs_context *ctx = container_of(fc, struct mqueue_fs_context, fc); + + ctx->fc.s_fs_info = ctx->ipc_ns; + return vfs_get_super(fc, vfs_get_keyed_super, mqueue_fill_super); +} + +static void mqueue_fs_context_free(struct fs_context *fc) +{ + struct mqueue_fs_context *ctx = container_of(fc, struct mqueue_fs_context, fc); + + if (ctx->ipc_ns) + put_ipc_ns(ctx->ipc_ns); +} + +static int mqueue_init_fs_context(struct fs_context *fc, struct super_block *src_sb) +{ + struct mqueue_fs_context *ctx = container_of(fc, struct mqueue_fs_context, fc); + + ctx->ipc_ns = get_ipc_ns(current->nsproxy->ipc_ns); + ctx->fc.ops = &mqueue_fs_context_ops; + return 0; } static void init_once(void *foo) @@ -1574,15 +1592,26 @@ static const struct super_operations mqueue_super_ops = { .statfs = simple_statfs, }; +static const struct fs_context_operations mqueue_fs_context_ops = { + .free = mqueue_fs_context_free, + .get_tree = mqueue_get_tree, +}; + static struct file_system_type mqueue_fs_type = { - .name = "mqueue", - .mount = mqueue_mount, - .kill_sb = kill_litter_super, - .fs_flags = FS_USERNS_MOUNT, + .name = "mqueue", + .fs_context_size = sizeof(struct mqueue_fs_context), + .init_fs_context = mqueue_init_fs_context, + .kill_sb = kill_litter_super, + .fs_flags = FS_USERNS_MOUNT, }; int mq_init_ns(struct ipc_namespace *ns) { + struct mqueue_fs_context *ctx; + struct fs_context *fc; + struct vfsmount *mnt; + int ret; + ns->mq_queues_count = 0; ns->mq_queues_max = DFLT_QUEUESMAX; ns->mq_msg_max = DFLT_MSGMAX; @@ -1590,13 +1619,30 @@ int mq_init_ns(struct ipc_namespace *ns) ns->mq_msg_default = DFLT_MSG; ns->mq_msgsize_default = DFLT_MSGSIZE; - ns->mq_mnt = kern_mount_data(&mqueue_fs_type, ns); - if (IS_ERR(ns->mq_mnt)) { - int err = PTR_ERR(ns->mq_mnt); - ns->mq_mnt = NULL; - return err; + fc = vfs_new_fs_context(&mqueue_fs_type, NULL, 0, + FS_CONTEXT_FOR_KERNEL_MOUNT); + if (IS_ERR(fc)) + return PTR_ERR(fc); + + ctx = container_of(fc, struct mqueue_fs_context, fc); + put_ipc_ns(ctx->ipc_ns); + ctx->ipc_ns = get_ipc_ns(ns); + + ret = vfs_get_tree(fc); + if (ret < 0) + goto out_fc; + + mnt = vfs_create_mount(fc); + if (IS_ERR(mnt)) { + ret = PTR_ERR(mnt); + goto out_fc; } - return 0; + + ns->mq_mnt = mnt; + ret = 0; +out_fc: + put_fs_context(fc); + return ret; } void mq_clear_sbinfo(struct ipc_namespace *ns)