[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>
diff --git a/fs/proc/base.c b/fs/proc/base.c
index a04b3db..c5e412a 100644
--- a/fs/proc/base.c
+++ b/fs/proc/base.c
@@ -604,6 +604,19 @@
.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 @@
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 @@
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),
