Commit 55dc7db7 authored by Tejun Heo's avatar Tejun Heo Committed by Jens Axboe

init: DEBUG_BLOCK_EXT_DEVT requires explicit root= param

DEBUG_BLOCK_EXT_DEVT shuffles SCSI and IDE device numbers and root
device number set using rdev become meaningless.  Root devices should
be explicitly specified using textual names.  Warn about it if root
can't be found and DEBUG_BLOCK_EXT_DEVT is enabled.  Also, add warning
to the help text.
Signed-off-by: default avatarTejun Heo <tj@kernel.org>
Cc: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
Signed-off-by: default avatarJens Axboe <jens.axboe@oracle.com>
parent 2bbedcb4
...@@ -263,6 +263,10 @@ void __init mount_block_root(char *name, int flags) ...@@ -263,6 +263,10 @@ void __init mount_block_root(char *name, int flags)
printk("Please append a correct \"root=\" boot option; here are the available partitions:\n"); printk("Please append a correct \"root=\" boot option; here are the available partitions:\n");
printk_all_partitions(); printk_all_partitions();
#ifdef CONFIG_DEBUG_BLOCK_EXT_DEVT
printk("DEBUG_BLOCK_EXT_DEVT is enabled, you need to specify "
"explicit textual name for \"root=\" boot option.\n");
#endif
panic("VFS: Unable to mount root fs on %s", b); panic("VFS: Unable to mount root fs on %s", b);
} }
......
...@@ -638,6 +638,12 @@ config DEBUG_BLOCK_EXT_DEVT ...@@ -638,6 +638,12 @@ config DEBUG_BLOCK_EXT_DEVT
userland code paths which assume predetermined contiguous userland code paths which assume predetermined contiguous
device number allocation. device number allocation.
Note that turning on this debug option shuffles all the
device numbers for all IDE and SCSI devices including libata
ones, so root partition specified using device number
directly (via rdev or root=MAJ:MIN) won't work anymore.
Textual device names (root=/dev/sdXn) will continue to work.
Say N if you are unsure. Say N if you are unsure.
config LKDTM config LKDTM
......
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