[PATCH] ext4: fix #11321: create /proc/ext4/*/stats et al more carefully

[Alexey Dobriyan <adobriyan@gmail.com>]

Ralf, please confirm.



[PATCH] ext4: fix #11321: create /proc/ext4/*/stats more carefully

ext4 creates per-suberblock directory in /proc/ext4/ . Name used as
basis is taken from bdevname, which, surprise, can contain slash.

However, proc while allowing to use proc_create("a/b", parent) form of
PDE creation, assumes that parent/a was already created.

bdevname in question is 'cciss/c0d0p9', directory is not created and all
this stuff goes directly into /proc (which is real bug).

Warning comes when _second_ partition is mounted.

http://bugzilla.kernel.org/show_bug.cgi?id=11321

Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
---

 fs/ext4/mballoc.c |    9 +++++++++
 1 file changed, 9 insertions(+)

--- a/fs/ext4/mballoc.c
+++ b/fs/ext4/mballoc.c
@@ -2792,6 +2792,15 @@ static int ext4_mb_init_per_dev_proc(struct super_block *sb)
 		return -EINVAL;
 	}
 	bdevname(sb->s_bdev, devname);
+	{
+		char *p = devname;
+
+		while (*p != '\0') {
+			if (*p == '/')
+				*p = '!';
+			p++;
+		}
+	}
 	sbi->s_mb_proc = proc_mkdir(devname, proc_root_ext4);
 
 	MB_PROC_HANDLER(EXT4_MB_STATS_NAME, stats);