lk/linux-kernel-test
1
0
Fork 0
Code Issues Pull Requests Releases Wiki Activity

[patch 6/7] vfs: mountinfo: add /proc/<pid>/mountinfo

Browse Source 
[mszeredi@suse.cz] rewrite and split big patch into managable chunks

/proc/mounts in its current form lacks important information:

 - propagation state
 - root of mount for bind mounts
 - the st_dev value used within the filesystem
 - identifier for each mount and it's parent

It also suffers from the following problems:

 - not easily extendable
 - ambiguity of mountpoints within a chrooted environment
 - doesn't distinguish between filesystem dependent and independent options
 - doesn't distinguish between per mount and per super block options

This patch introduces /proc/<pid>/mountinfo which attempts to address
all these deficiencies.

Code shared between /proc/<pid>/mounts and /proc/<pid>/mountinfo is
extracted into separate functions.

Thanks to Al Viro for the help in getting the design right.

Signed-off-by: Ram Pai <linuxram@us.ibm.com>
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
This commit is contained in:
Ram Pai
2008-03-27 13:06:25 +01:00
committed by Al Viro
parent a1a2c409b6
commit 2d4d4864ac
4 changed files with 144 additions and 23 deletions
Download Patch File Download Diff File Expand all files Collapse all files

119
fs/namespace.c
View File

@ -746,20 +746,30 @@ static void m_stop(struct seq_file *m, void *v)
up_read(&namespace_sem);
}
static int show_vfsmnt(struct seq_file *m, void *v)
struct proc_fs_info {
int flag;
const char *str;
};
static void show_sb_opts(struct seq_file *m, struct super_block *sb)
{
struct vfsmount *mnt = list_entry(v, struct vfsmount, mnt_list);
int err = 0;
static struct proc_fs_info {
int flag;
char *str;
} fs_info[] = {
static const struct proc_fs_info fs_info[] = {
{ MS_SYNCHRONOUS, ",sync" },
{ MS_DIRSYNC, ",dirsync" },
{ MS_MANDLOCK, ",mand" },
{ 0, NULL }
};
static struct proc_fs_info mnt_info[] = {
const struct proc_fs_info *fs_infop;
for (fs_infop = fs_info; fs_infop->flag; fs_infop++) {
if (sb->s_flags & fs_infop->flag)
seq_puts(m, fs_infop->str);
}
}
static void show_mnt_opts(struct seq_file *m, struct vfsmount *mnt)
{
static const struct proc_fs_info mnt_info[] = {
{ MNT_NOSUID, ",nosuid" },
{ MNT_NODEV, ",nodev" },
{ MNT_NOEXEC, ",noexec" },
@ -768,27 +778,37 @@ static int show_vfsmnt(struct seq_file *m, void *v)
{ MNT_RELATIME, ",relatime" },
{ 0, NULL }
};
struct proc_fs_info *fs_infop;
const struct proc_fs_info *fs_infop;
for (fs_infop = mnt_info; fs_infop->flag; fs_infop++) {
if (mnt->mnt_flags & fs_infop->flag)
seq_puts(m, fs_infop->str);
}
}
static void show_type(struct seq_file *m, struct super_block *sb)
{
mangle(m, sb->s_type->name);
if (sb->s_subtype && sb->s_subtype[0]) {
seq_putc(m, '.');
mangle(m, sb->s_subtype);
}
}
static int show_vfsmnt(struct seq_file *m, void *v)
{
struct vfsmount *mnt = list_entry(v, struct vfsmount, mnt_list);
int err = 0;
struct path mnt_path = { .dentry = mnt->mnt_root, .mnt = mnt };
mangle(m, mnt->mnt_devname ? mnt->mnt_devname : "none");
seq_putc(m, ' ');
seq_path(m, &mnt_path, " \t\n\\");
seq_putc(m, ' ');
mangle(m, mnt->mnt_sb->s_type->name);
if (mnt->mnt_sb->s_subtype && mnt->mnt_sb->s_subtype[0]) {
seq_putc(m, '.');
mangle(m, mnt->mnt_sb->s_subtype);
}
show_type(m, mnt->mnt_sb);
seq_puts(m, __mnt_is_readonly(mnt) ? " ro" : " rw");
for (fs_infop = fs_info; fs_infop->flag; fs_infop++) {
if (mnt->mnt_sb->s_flags & fs_infop->flag)
seq_puts(m, fs_infop->str);
}
for (fs_infop = mnt_info; fs_infop->flag; fs_infop++) {
if (mnt->mnt_flags & fs_infop->flag)
seq_puts(m, fs_infop->str);
}
show_sb_opts(m, mnt->mnt_sb);
show_mnt_opts(m, mnt);
if (mnt->mnt_sb->s_op->show_options)
err = mnt->mnt_sb->s_op->show_options(m, mnt);
seq_puts(m, " 0 0\n");
@ -802,6 +822,59 @@ const struct seq_operations mounts_op = {
.show = show_vfsmnt
};
static int show_mountinfo(struct seq_file *m, void *v)
{
struct proc_mounts *p = m->private;
struct vfsmount *mnt = list_entry(v, struct vfsmount, mnt_list);
struct super_block *sb = mnt->mnt_sb;
struct path mnt_path = { .dentry = mnt->mnt_root, .mnt = mnt };
struct path root = p->root;
int err = 0;
seq_printf(m, "%i %i %u:%u ", mnt->mnt_id, mnt->mnt_parent->mnt_id,
MAJOR(sb->s_dev), MINOR(sb->s_dev));
seq_dentry(m, mnt->mnt_root, " \t\n\\");
seq_putc(m, ' ');
seq_path_root(m, &mnt_path, &root, " \t\n\\");
if (root.mnt != p->root.mnt || root.dentry != p->root.dentry) {
/*
* Mountpoint is outside root, discard that one. Ugly,
* but less so than trying to do that in iterator in a
* race-free way (due to renames).
*/
return SEQ_SKIP;
}
seq_puts(m, mnt->mnt_flags & MNT_READONLY ? " ro" : " rw");
show_mnt_opts(m, mnt);
/* Tagged fields ("foo:X" or "bar") */
if (IS_MNT_SHARED(mnt))
seq_printf(m, " shared:%i", mnt->mnt_group_id);
if (IS_MNT_SLAVE(mnt))
seq_printf(m, " master:%i", mnt->mnt_master->mnt_group_id);
if (IS_MNT_UNBINDABLE(mnt))
seq_puts(m, " unbindable");
/* Filesystem specific data */
seq_puts(m, " - ");
show_type(m, sb);
seq_putc(m, ' ');
mangle(m, mnt->mnt_devname ? mnt->mnt_devname : "none");
seq_puts(m, sb->s_flags & MS_RDONLY ? " ro" : " rw");
show_sb_opts(m, sb);
if (sb->s_op->show_options)
err = sb->s_op->show_options(m, mnt);
seq_putc(m, '\n');
return err;
}
const struct seq_operations mountinfo_op = {
.start = m_start,
.next = m_next,
.stop = m_stop,
.show = show_mountinfo,
};
static int show_vfsstat(struct seq_file *m, void *v)
{
struct vfsmount *mnt = list_entry(v, struct vfsmount, mnt_list);
@ -822,7 +895,7 @@ static int show_vfsstat(struct seq_file *m, void *v)
/* file system type */
seq_puts(m, "with fstype ");
mangle(m, mnt->mnt_sb->s_type->name);
show_type(m, mnt->mnt_sb);
/* optional statistics */
if (mnt->mnt_sb->s_op->show_stats) {