pstore: Create a convenient mount point for pstore

Using /dev/pstore as a mount point for the pstore filesystem is slightly
awkward.  We don't normally mount filesystems in /dev/ and the /dev/pstore
file isn't created automatically by anything.  While this method will
still work, we can create a persistent mount point in sysfs.  This will
put pstore on par with things like cgroups and efivarfs.

Signed-off-by: Josh Boyer <jwboyer@redhat.com>
Acked-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Tony Luck <tony.luck@intel.com>

diff --git a/Documentation/ABI/testing/pstore b/Documentation/ABI/testing/pstore
index ff1df4e3b05962741195df437d8ec2891f3e29af..5fca9f5e10a3aa8bc1b84069904fd99c00f6db58 100644 (file)
--- a/Documentation/ABI/testing/pstore
+++ b/Documentation/ABI/testing/pstore
@@ -1,4 +1,4 @@
-Where:         /dev/pstore/...
+Where:         /sys/fs/pstore/... (or /dev/pstore/...)
 Date:          March 2011
 Kernel Version: 2.6.39
 Contact:       tony.luck@intel.com
@@ -11,9 +11,9 @@ Description:  Generic interface to platform dependent persistent storage.
                of the console log is captured, but other interesting
                data can also be saved.
 
-               # mount -t pstore -o kmsg_bytes=8000 - /dev/pstore
+               # mount -t pstore -o kmsg_bytes=8000 - /sys/fs/pstore
 
-               $ ls -l /dev/pstore
+               $ ls -l /sys/fs/pstore/
                total 0
                -r--r--r-- 1 root root 7896 Nov 30 15:38 dmesg-erst-1
 
@@ -27,9 +27,9 @@ Description:  Generic interface to platform dependent persistent storage.
                the file will signal to the underlying persistent storage
                device that it can reclaim the space for later re-use.
 
-               $ rm /dev/pstore/dmesg-erst-1
+               $ rm /sys/fs/pstore/dmesg-erst-1
 
-               The expectation is that all files in /dev/pstore
+               The expectation is that all files in /sys/fs/pstore/
                will be saved elsewhere and erased from persistent store
                soon after boot to free up space ready for the next
                catastrophe.

diff --git a/fs/pstore/inode.c b/fs/pstore/inode.c
index 67de74ca85f4a992d94f5ef3450aa5767be231ee..e4bcb2cf055a1dc8f81df7cbb38e8cdab4add0b0 100644 (file)
--- a/fs/pstore/inode.c
+++ b/fs/pstore/inode.c
@@ -418,9 +418,25 @@ static struct file_system_type pstore_fs_type = {
        .kill_sb        = pstore_kill_sb,
 };
 
+static struct kobject *pstore_kobj;
+
 static int __init init_pstore_fs(void)
 {
-       return register_filesystem(&pstore_fs_type);
+       int err = 0;
+
+       /* Create a convenient mount point for people to access pstore */
+       pstore_kobj = kobject_create_and_add("pstore", fs_kobj);
+       if (!pstore_kobj) {
+               err = -ENOMEM;
+               goto out;
+       }
+
+       err = register_filesystem(&pstore_fs_type);
+       if (err < 0)
+               kobject_put(pstore_kobj);
+
+out:
+       return err;
 }
 module_init(init_pstore_fs)