vfs: new superblock methods to override /proc/*/mount{s,info}
a) ->show_devname(m, mnt) - what to put into devname columns in mounts,
mountinfo and mountstats
b) ->show_path(m, mnt) - what to put into relative path column in mountinfo
Leaving those NULL gives old behaviour. NFS switched to using those.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/fs/namespace.c b/fs/namespace.c
index dffe6f4..75d843a 100644
--- a/fs/namespace.c
+++ b/fs/namespace.c
@@ -978,7 +978,13 @@
int err = 0;
struct path mnt_path = { .dentry = mnt->mnt_root, .mnt = mnt };
- mangle(m, mnt->mnt_devname ? mnt->mnt_devname : "none");
+ if (mnt->mnt_sb->s_op->show_devname) {
+ err = mnt->mnt_sb->s_op->show_devname(m, mnt);
+ if (err)
+ goto out;
+ } else {
+ mangle(m, mnt->mnt_devname ? mnt->mnt_devname : "none");
+ }
seq_putc(m, ' ');
seq_path(m, &mnt_path, " \t\n\\");
seq_putc(m, ' ');
@@ -1025,7 +1031,12 @@
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\\");
+ if (sb->s_op->show_path)
+ err = sb->s_op->show_path(m, mnt);
+ else
+ seq_dentry(m, mnt->mnt_root, " \t\n\\");
+ if (err)
+ goto out;
seq_putc(m, ' ');
seq_path_root(m, &mnt_path, &root, " \t\n\\");
if (root.mnt != p->root.mnt || root.dentry != p->root.dentry) {
@@ -1060,7 +1071,12 @@
seq_puts(m, " - ");
show_type(m, sb);
seq_putc(m, ' ');
- mangle(m, mnt->mnt_devname ? mnt->mnt_devname : "none");
+ if (sb->s_op->show_devname)
+ err = sb->s_op->show_devname(m, mnt);
+ else
+ mangle(m, mnt->mnt_devname ? mnt->mnt_devname : "none");
+ if (err)
+ goto out;
seq_puts(m, sb->s_flags & MS_RDONLY ? " ro" : " rw");
err = show_sb_opts(m, sb);
if (err)
@@ -1086,11 +1102,15 @@
int err = 0;
/* device */
- if (mnt->mnt_devname) {
- seq_puts(m, "device ");
- mangle(m, mnt->mnt_devname);
- } else
- seq_puts(m, "no device");
+ if (mnt->mnt_sb->s_op->show_devname) {
+ err = mnt->mnt_sb->s_op->show_devname(m, mnt);
+ } else {
+ if (mnt->mnt_devname) {
+ seq_puts(m, "device ");
+ mangle(m, mnt->mnt_devname);
+ } else
+ seq_puts(m, "no device");
+ }
/* mount point */
seq_puts(m, " mounted on ");
@@ -1104,7 +1124,8 @@
/* optional statistics */
if (mnt->mnt_sb->s_op->show_stats) {
seq_putc(m, ' ');
- err = mnt->mnt_sb->s_op->show_stats(m, mnt);
+ if (!err)
+ err = mnt->mnt_sb->s_op->show_stats(m, mnt);
}
seq_putc(m, '\n');
diff --git a/fs/nfs/super.c b/fs/nfs/super.c
index a6ab483..79bc61f 100644
--- a/fs/nfs/super.c
+++ b/fs/nfs/super.c
@@ -263,6 +263,8 @@
static void nfs_umount_begin(struct super_block *);
static int nfs_statfs(struct dentry *, struct kstatfs *);
static int nfs_show_options(struct seq_file *, struct vfsmount *);
+static int nfs_show_devname(struct seq_file *, struct vfsmount *);
+static int nfs_show_path(struct seq_file *, struct vfsmount *);
static int nfs_show_stats(struct seq_file *, struct vfsmount *);
static int nfs_get_sb(struct file_system_type *, int, const char *, void *, struct vfsmount *);
static struct dentry *nfs_xdev_mount(struct file_system_type *fs_type,
@@ -296,6 +298,8 @@
.evict_inode = nfs_evict_inode,
.umount_begin = nfs_umount_begin,
.show_options = nfs_show_options,
+ .show_devname = nfs_show_devname,
+ .show_path = nfs_show_path,
.show_stats = nfs_show_stats,
.remount_fs = nfs_remount,
};
@@ -366,6 +370,8 @@
.evict_inode = nfs4_evict_inode,
.umount_begin = nfs_umount_begin,
.show_options = nfs_show_options,
+ .show_devname = nfs_show_devname,
+ .show_path = nfs_show_path,
.show_stats = nfs_show_stats,
.remount_fs = nfs_remount,
};
@@ -726,6 +732,28 @@
return 0;
}
+static int nfs_show_devname(struct seq_file *m, struct vfsmount *mnt)
+{
+ char *page = (char *) __get_free_page(GFP_KERNEL);
+ char *devname, *dummy;
+ int err = 0;
+ if (!page)
+ return -ENOMEM;
+ devname = nfs_path(&dummy, mnt->mnt_root, page, PAGE_SIZE);
+ if (IS_ERR(devname))
+ err = PTR_ERR(devname);
+ else
+ seq_escape(m, devname, " \t\n\\");
+ free_page((unsigned long)page);
+ return err;
+}
+
+static int nfs_show_path(struct seq_file *m, struct vfsmount *mnt)
+{
+ seq_puts(m, "/");
+ return 0;
+}
+
/*
* Present statistical information for this VFS mountpoint
*/
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 13df14e..e6d3fe4 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -1632,6 +1632,8 @@
void (*umount_begin) (struct super_block *);
int (*show_options)(struct seq_file *, struct vfsmount *);
+ int (*show_devname)(struct seq_file *, struct vfsmount *);
+ int (*show_path)(struct seq_file *, struct vfsmount *);
int (*show_stats)(struct seq_file *, struct vfsmount *);
#ifdef CONFIG_QUOTA
ssize_t (*quota_read)(struct super_block *, int, char *, size_t, loff_t);