diff options
author | Linus Torvalds <torvalds@linux-foundation.org> | 2009-03-27 16:23:12 -0700 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2009-03-27 16:23:12 -0700 |
commit | 3ae5080f4c2e293229508dabe7c8a90af4e4c460 (patch) | |
tree | 9cb11f26905a82b7fac9d3b8f9d61d58bc5c94b0 /fs/devpts/inode.c | |
parent | 2c9e15a011c55ff96b2b8d2b126d1b9a96abba20 (diff) | |
parent | aabb8fdb41128705fd1627f56fdd571e45fdbcdb (diff) |
Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs-2.6
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs-2.6: (37 commits)
fs: avoid I_NEW inodes
Merge code for single and multiple-instance mounts
Remove get_init_pts_sb()
Move common mknod_ptmx() calls into caller
Parse mount options just once and copy them to super block
Unroll essentials of do_remount_sb() into devpts
vfs: simple_set_mnt() should return void
fs: move bdev code out of buffer.c
constify dentry_operations: rest
constify dentry_operations: configfs
constify dentry_operations: sysfs
constify dentry_operations: JFS
constify dentry_operations: OCFS2
constify dentry_operations: GFS2
constify dentry_operations: FAT
constify dentry_operations: FUSE
constify dentry_operations: procfs
constify dentry_operations: ecryptfs
constify dentry_operations: CIFS
constify dentry_operations: AFS
...
Diffstat (limited to 'fs/devpts/inode.c')
-rw-r--r-- | fs/devpts/inode.c | 188 |
1 files changed, 46 insertions, 142 deletions
diff --git a/fs/devpts/inode.c b/fs/devpts/inode.c index bff4052b05e7..63a4a59e4148 100644 --- a/fs/devpts/inode.c +++ b/fs/devpts/inode.c @@ -322,177 +322,81 @@ static int compare_init_pts_sb(struct super_block *s, void *p) } /* - * Safely parse the mount options in @data and update @opts. + * devpts_get_sb() * - * devpts ends up parsing options two times during mount, due to the - * two modes of operation it supports. The first parse occurs in - * devpts_get_sb() when determining the mode (single-instance or - * multi-instance mode). The second parse happens in devpts_remount() - * or new_pts_mount() depending on the mode. + * If the '-o newinstance' mount option was specified, mount a new + * (private) instance of devpts. PTYs created in this instance are + * independent of the PTYs in other devpts instances. * - * Parsing of options modifies the @data making subsequent parsing - * incorrect. So make a local copy of @data and parse it. + * If the '-o newinstance' option was not specified, mount/remount the + * initial kernel mount of devpts. This type of mount gives the + * legacy, single-instance semantics. * - * Return: 0 On success, -errno on error - */ -static int safe_parse_mount_options(void *data, struct pts_mount_opts *opts) -{ - int rc; - void *datacp; - - if (!data) - return 0; - - /* Use kstrdup() ? */ - datacp = kmalloc(PAGE_SIZE, GFP_KERNEL); - if (!datacp) - return -ENOMEM; - - memcpy(datacp, data, PAGE_SIZE); - rc = parse_mount_options((char *)datacp, PARSE_MOUNT, opts); - kfree(datacp); - - return rc; -} - -/* - * Mount a new (private) instance of devpts. PTYs created in this - * instance are independent of the PTYs in other devpts instances. - */ -static int new_pts_mount(struct file_system_type *fs_type, int flags, - void *data, struct vfsmount *mnt) -{ - int err; - struct pts_fs_info *fsi; - struct pts_mount_opts *opts; - - err = get_sb_nodev(fs_type, flags, data, devpts_fill_super, mnt); - if (err) - return err; - - fsi = DEVPTS_SB(mnt->mnt_sb); - opts = &fsi->mount_opts; - - err = parse_mount_options(data, PARSE_MOUNT, opts); - if (err) - goto fail; - - err = mknod_ptmx(mnt->mnt_sb); - if (err) - goto fail; - - return 0; - -fail: - dput(mnt->mnt_sb->s_root); - deactivate_super(mnt->mnt_sb); - return err; -} - -/* - * Check if 'newinstance' mount option was specified in @data. + * The 'newinstance' option is needed to support multiple namespace + * semantics in devpts while preserving backward compatibility of the + * current 'single-namespace' semantics. i.e all mounts of devpts + * without the 'newinstance' mount option should bind to the initial + * kernel mount, like get_sb_single(). * - * Return: -errno on error (eg: invalid mount options specified) - * : 1 if 'newinstance' mount option was specified - * : 0 if 'newinstance' mount option was NOT specified - */ -static int is_new_instance_mount(void *data) -{ - int rc; - struct pts_mount_opts opts; - - if (!data) - return 0; - - rc = safe_parse_mount_options(data, &opts); - if (!rc) - rc = opts.newinstance; - - return rc; -} - -/* - * get_init_pts_sb() - * - * This interface is needed to support multiple namespace semantics in - * devpts while preserving backward compatibility of the current 'single- - * namespace' semantics. i.e all mounts of devpts without the 'newinstance' - * mount option should bind to the initial kernel mount, like - * get_sb_single(). + * Mounts with 'newinstance' option create a new, private namespace. * - * Mounts with 'newinstance' option create a new private namespace. + * NOTE: * - * But for single-mount semantics, devpts cannot use get_sb_single(), + * For single-mount semantics, devpts cannot use get_sb_single(), * because get_sb_single()/sget() find and use the super-block from * the most recent mount of devpts. But that recent mount may be a * 'newinstance' mount and get_sb_single() would pick the newinstance * super-block instead of the initial super-block. - * - * This interface is identical to get_sb_single() except that it - * consistently selects the 'single-namespace' superblock even in the - * presence of the private namespace (i.e 'newinstance') super-blocks. */ -static int get_init_pts_sb(struct file_system_type *fs_type, int flags, - void *data, struct vfsmount *mnt) +static int devpts_get_sb(struct file_system_type *fs_type, + int flags, const char *dev_name, void *data, struct vfsmount *mnt) { - struct super_block *s; int error; + struct pts_mount_opts opts; + struct super_block *s; + + memset(&opts, 0, sizeof(opts)); + if (data) { + error = parse_mount_options(data, PARSE_MOUNT, &opts); + if (error) + return error; + } + + if (opts.newinstance) + s = sget(fs_type, NULL, set_anon_super, NULL); + else + s = sget(fs_type, compare_init_pts_sb, set_anon_super, NULL); - s = sget(fs_type, compare_init_pts_sb, set_anon_super, NULL); if (IS_ERR(s)) return PTR_ERR(s); if (!s->s_root) { s->s_flags = flags; error = devpts_fill_super(s, data, flags & MS_SILENT ? 1 : 0); - if (error) { - up_write(&s->s_umount); - deactivate_super(s); - return error; - } + if (error) + goto out_undo_sget; s->s_flags |= MS_ACTIVE; } - do_remount_sb(s, flags, data, 0); - return simple_set_mnt(mnt, s); -} -/* - * Mount or remount the initial kernel mount of devpts. This type of - * mount maintains the legacy, single-instance semantics, while the - * kernel still allows multiple-instances. - */ -static int init_pts_mount(struct file_system_type *fs_type, int flags, - void *data, struct vfsmount *mnt) -{ - int err; + simple_set_mnt(mnt, s); - err = get_init_pts_sb(fs_type, flags, data, mnt); - if (err) - return err; + memcpy(&(DEVPTS_SB(s))->mount_opts, &opts, sizeof(opts)); - err = mknod_ptmx(mnt->mnt_sb); - if (err) { - dput(mnt->mnt_sb->s_root); - deactivate_super(mnt->mnt_sb); - } + error = mknod_ptmx(s); + if (error) + goto out_dput; - return err; -} - -static int devpts_get_sb(struct file_system_type *fs_type, - int flags, const char *dev_name, void *data, struct vfsmount *mnt) -{ - int new; - - new = is_new_instance_mount(data); - if (new < 0) - return new; + return 0; - if (new) - return new_pts_mount(fs_type, flags, data, mnt); +out_dput: + dput(s->s_root); - return init_pts_mount(fs_type, flags, data, mnt); +out_undo_sget: + up_write(&s->s_umount); + deactivate_super(s); + return error; } + #else /* * This supports only the legacy single-instance semantics (no |