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Merge code for single and multiple-instance mounts

Browse source 
new_pts_mount() (including the get_sb_nodev()), shares a lot of code
with init_pts_mount(). The only difference between them is the 'test-super'
function passed into sget().

Move all common code into devpts_get_sb() and remove the new_pts_mount() and
init_pts_mount() functions,

Changelog[v3]:
	[Serge Hallyn]: Remove unnecessary printk()s
Changelog[v2]:
	(Christoph Hellwig): Merge code in 'do_pts_mount()' into devpts_get_sb()

Signed-off-by: Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com>
Acked-by: Serge Hallyn <serue@us.ibm.com>
Tested-by: Serge Hallyn <serue@us.ibm.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
This commit is contained in:
Sukadev Bhattiprolu 2009-03-07 10:12:32 -08:00 committed by Al Viro
parent 289f00e225
commit 1bd7903560
1 changed files with 40 additions and 73 deletions
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113
fs/devpts/inode.c
View file

@ -322,85 +322,38 @@ static int compare_init_pts_sb(struct super_block *s, void *p)
} }
/* /*
* Mount a new (private) instance of devpts. PTYs created in this * devpts_get_sb()
* 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 pts_mount_opts *opts, struct vfsmount *mnt)
{
int err;
struct pts_fs_info *fsi;
err = get_sb_nodev(fs_type, flags, data, devpts_fill_super, mnt);
if (err)
return err;
fsi = DEVPTS_SB(mnt->mnt_sb);
memcpy(&fsi->mount_opts, opts, sizeof(opts));
return 0;
}
/*
* init_pts_mount()
* *
* Mount or remount the initial kernel mount of devpts. This type of * If the '-o newinstance' mount option was specified, mount a new
* mount maintains the legacy, single-instance semantics, while the * (private) instance of devpts. PTYs created in this instance are
* kernel still allows multiple-instances. * independent of the PTYs in other devpts instances.
* *
* This interface is needed to support multiple namespace semantics in * If the '-o newinstance' option was not specified, mount/remount the
* devpts while preserving backward compatibility of the current 'single- * initial kernel mount of devpts. This type of mount gives the
* namespace' semantics. i.e all mounts of devpts without the 'newinstance' * legacy, single-instance semantics.
* mount option should bind to the initial kernel mount, like
* get_sb_single().
* *
* Mounts with 'newinstance' option create a new private namespace. * 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().
* *
* But for single-mount semantics, devpts cannot use get_sb_single(), * Mounts with 'newinstance' option create a new, private namespace.
*
* NOTE:
*
* For single-mount semantics, devpts cannot use get_sb_single(),
* because get_sb_single()/sget() find and use the super-block from * 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 * the most recent mount of devpts. But that recent mount may be a
* 'newinstance' mount and get_sb_single() would pick the newinstance * 'newinstance' mount and get_sb_single() would pick the newinstance
* super-block instead of the initial super-block. * 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 init_pts_mount(struct file_system_type *fs_type, int flags,
void *data, struct pts_mount_opts *opts, struct vfsmount *mnt)
{
struct super_block *s;
struct pts_fs_info *fsi;
int error;
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;
}
s->s_flags |= MS_ACTIVE;
}
simple_set_mnt(mnt, s);
fsi = DEVPTS_SB(mnt->mnt_sb);
memcpy(&fsi->mount_opts, opts, sizeof(opts));
return 0;
}
static int devpts_get_sb(struct file_system_type *fs_type, static int devpts_get_sb(struct file_system_type *fs_type,
int flags, const char *dev_name, void *data, struct vfsmount *mnt) int flags, const char *dev_name, void *data, struct vfsmount *mnt)
{ {
int error; int error;
struct pts_mount_opts opts; struct pts_mount_opts opts;
struct super_block *s;
memset(&opts, 0, sizeof(opts)); memset(&opts, 0, sizeof(opts));
if (data) { if (data) {
@ -410,23 +363,37 @@ static int devpts_get_sb(struct file_system_type *fs_type,
} }
if (opts.newinstance) if (opts.newinstance)
error = new_pts_mount(fs_type, flags, data, &opts, mnt); s = sget(fs_type, NULL, set_anon_super, NULL);
else else
error = init_pts_mount(fs_type, flags, data, &opts, mnt); s = sget(fs_type, compare_init_pts_sb, set_anon_super, NULL);
if (error) if (IS_ERR(s))
return error; return PTR_ERR(s);
error = mknod_ptmx(mnt->mnt_sb); if (!s->s_root) {
s->s_flags = flags;
error = devpts_fill_super(s, data, flags & MS_SILENT ? 1 : 0);
if (error)
goto out_undo_sget;
s->s_flags |= MS_ACTIVE;
}
simple_set_mnt(mnt, s);
memcpy(&(DEVPTS_SB(s))->mount_opts, &opts, sizeof(opts));
error = mknod_ptmx(s);
if (error) if (error)
goto out_dput; goto out_dput;
return 0; return 0;
out_dput: out_dput:
dput(mnt->mnt_sb->s_root); dput(s->s_root);
up_write(&mnt->mnt_sb->s_umount);
deactivate_super(mnt->mnt_sb); out_undo_sget:
up_write(&s->s_umount);
deactivate_super(s);
return error; return error;
} }