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authorRam Pai <linuxram@us.ibm.com>2008-03-27 13:06:25 +0100
committerAl Viro <viro@zeniv.linux.org.uk>2008-04-23 00:05:03 -0400
commit2d4d4864ac08caff5c204a752bd004eed4f08760 (patch)
treea8907c33afae589146fdcd06eacd740aff48c6a1 /fs
parenta1a2c409b666befc58c2db9c7fbddf200f153470 (diff)
[patch 6/7] vfs: mountinfo: add /proc/<pid>/mountinfo
[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>
Diffstat (limited to 'fs')
-rw-r--r--fs/namespace.c119
-rw-r--r--fs/proc/base.c15
2 files changed, 111 insertions, 23 deletions
diff --git a/fs/namespace.c b/fs/namespace.c
index dfdf51e81c1..c807b8d5f89 100644
--- a/fs/namespace.c
+++ b/fs/namespace.c
@@ -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) {
diff --git a/fs/proc/base.c b/fs/proc/base.c
index a04b3db7a29..c5e412a00b1 100644
--- a/fs/proc/base.c
+++ b/fs/proc/base.c
@@ -604,6 +604,19 @@ static const struct file_operations proc_mounts_operations = {
.poll = mounts_poll,
};
+static int mountinfo_open(struct inode *inode, struct file *file)
+{
+ return mounts_open_common(inode, file, &mountinfo_op);
+}
+
+static const struct file_operations proc_mountinfo_operations = {
+ .open = mountinfo_open,
+ .read = seq_read,
+ .llseek = seq_lseek,
+ .release = mounts_release,
+ .poll = mounts_poll,
+};
+
static int mountstats_open(struct inode *inode, struct file *file)
{
return mounts_open_common(inode, file, &mountstats_op);
@@ -2303,6 +2316,7 @@ static const struct pid_entry tgid_base_stuff[] = {
LNK("root", root),
LNK("exe", exe),
REG("mounts", S_IRUGO, mounts),
+ REG("mountinfo", S_IRUGO, mountinfo),
REG("mountstats", S_IRUSR, mountstats),
#ifdef CONFIG_PROC_PAGE_MONITOR
REG("clear_refs", S_IWUSR, clear_refs),
@@ -2635,6 +2649,7 @@ static const struct pid_entry tid_base_stuff[] = {
LNK("root", root),
LNK("exe", exe),
REG("mounts", S_IRUGO, mounts),
+ REG("mountinfo", S_IRUGO, mountinfo),
#ifdef CONFIG_PROC_PAGE_MONITOR
REG("clear_refs", S_IWUSR, clear_refs),
REG("smaps", S_IRUGO, smaps),