* Re: [PATCH] root mount failure emit filesystems attempted
2006-05-03 16:44 [PATCH] root mount failure emit filesystems attempted Andy Whitcroft
@ 2006-05-03 19:14 ` Jan Engelhardt
0 siblings, 0 replies; 2+ messages in thread
From: Jan Engelhardt @ 2006-05-03 19:14 UTC (permalink / raw)
To: Andy Whitcroft; +Cc: akpm, linux-kernel
>
>root mount failure emit filesystems attempted
Something better was already submitted earlier, but it did not get merged.
URL: http://tinyurl.com/pa4ap
Long URL: http://groups.google.com/group/linux.kernel/browse_thread/thread/81bfec7e96bd60cd/b3a7f8421fb7ca53?q=show+partitions+diff&rnum=1#b3a7f8421fb7ca53
What it does:
When we fail to mount from a valid root device list out the
block devices available.
>When we fail to mount from a valid root device list out the filesystems
>we have tried to mount it with. This gives the user vital diagnostics
>as to what is missing from their kernel.
I think both should be merged. An updated version of the print-partitions
patch that works with 2.6.17-rc3 is below.
> No filesystem could mount root, tried: reiserfs ext3 ext2 msdos vfat
> iso9660 jfs xfs
> Kernel panic - not syncing: VFS: Unable to mount root fs on unknown-block(8,1)
Your patch: Acked-by: Jan Engelhardt <jengelh@gmx.de>
Patch below: Signed-off-by: Jan Engelhardt <jengelh@gmx.de>
diff --fast -Ndpru linux-2.6.17-rc3~/block/genhd.c linux-2.6.17-rc3+/block/genhd.c
--- linux-2.6.17-rc3~/block/genhd.c 2006-04-27 04:19:25.000000000 +0200
+++ linux-2.6.17-rc3+/block/genhd.c 2006-05-01 18:50:14.326821000 +0200
@@ -214,6 +214,52 @@ struct gendisk *get_gendisk(dev_t dev, i
return kobj ? to_disk(kobj) : NULL;
}
+/*
+ * printk a full list of all partitions - intended for
+ * places where the root filesystem can't be mounted and thus
+ * to give the victim some idea of what went wrong
+ */
+void printk_all_partitions(void)
+{
+ int n;
+ struct gendisk* sgp;
+ down(&block_subsys_sem);
+
+ /* For each block device... */
+ list_for_each_entry(sgp,&block_subsys.kset.list, kobj.entry) {
+ char buf[BDEVNAME_SIZE];
+ /* Don't show empty devices or things that have been surpressed */
+ if (get_capacity(sgp) && !(sgp->flags & GENHD_FL_SUPPRESS_PARTITION_INFO)) {
+ /* Note, unlike /proc/partitions I'm showing the numbers in hex
+ in the same format as the root= option */
+ printk("%02x%02x %10llu %s",
+ sgp->major, sgp->first_minor,
+ (unsigned long long)get_capacity(sgp) >> 1,
+ disk_name(sgp, 0, buf));
+ if ((sgp->driverfs_dev) && (sgp->driverfs_dev->driver)) {
+ printk(" driver: %s\n", sgp->driverfs_dev->driver->name);
+ } else {
+ printk(" (driver?)\n");
+ }
+
+ /* now show the partitions */
+ for (n = 0; n < sgp->minors - 1; n++) {
+ if (!sgp->part[n])
+ continue;
+ if (sgp->part[n]->nr_sects == 0)
+ continue;
+ printk(" %02x%02x %10llu %s\n",
+ sgp->major, n + 1 + sgp->first_minor,
+ (unsigned long long)sgp->part[n]->nr_sects >> 1 ,
+ disk_name(sgp, n + 1, buf));
+ } /* partition subloop */
+ } /* Non 0 size, not surpressed */
+ } /* Block device loop */
+
+ up(&block_subsys_sem);
+
+}
+
#ifdef CONFIG_PROC_FS
/* iterator */
static void *part_start(struct seq_file *part, loff_t *pos)
diff --fast -Ndpru linux-2.6.17-rc3~/include/linux/genhd.h linux-2.6.17-rc3+/include/linux/genhd.h
--- linux-2.6.17-rc3~/include/linux/genhd.h 2006-04-27 04:19:25.000000000 +0200
+++ linux-2.6.17-rc3+/include/linux/genhd.h 2006-05-01 18:50:14.326821000 +0200
@@ -401,6 +401,7 @@ char *disk_name (struct gendisk *hd, int
extern int rescan_partitions(struct gendisk *disk, struct block_device *bdev);
extern void add_partition(struct gendisk *, int, sector_t, sector_t);
extern void delete_partition(struct gendisk *, int);
+extern void printk_all_partitions(void);
extern struct gendisk *alloc_disk_node(int minors, int node_id);
extern struct gendisk *alloc_disk(int minors);
diff --fast -Ndpru linux-2.6.17-rc3~/init/do_mounts.c linux-2.6.17-rc3+/init/do_mounts.c
--- linux-2.6.17-rc3~/init/do_mounts.c 2006-04-27 04:19:25.000000000 +0200
+++ linux-2.6.17-rc3+/init/do_mounts.c 2006-05-01 18:50:14.326821000 +0200
@@ -7,6 +7,7 @@
#include <linux/root_dev.h>
#include <linux/security.h>
#include <linux/delay.h>
+#include <linux/genhd.h>
#include <linux/mount.h>
#include <linux/nfs_fs.h>
@@ -302,14 +303,18 @@ retry:
/*
* Allow the user to distinguish between failed sys_open
* and bad superblock on root device
+ * and give them a list of the available devices
*/
__bdevname(ROOT_DEV, b);
printk("VFS: Cannot open root device \"%s\" or %s\n",
root_device_name, b);
- printk("Please append a correct \"root=\" boot option\n");
+ printk("Please append a correct \"root=\" boot option; here are the partitions available:\n");
+ printk_all_partitions();
panic("VFS: Unable to mount root fs on %s", b);
}
+ printk("List of all partitions:\n");
+ printk_all_partitions();
panic("VFS: Unable to mount root fs on %s", __bdevname(ROOT_DEV, b));
out:
putname(fs_names);
#<<eof>>
Jan Engelhardt
--
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