[PATCH v2] Allow core dumps to block devices as well as regular files.

["Richard W.M. Jones" <rjones@redhat.com>]

Allow core dumps to block devices by allowing the user to name a block
device in core_pattern.  This change also removes the historical
comment which would no longer be accurate.

This is extremely useful when running the kernel in a "captive"
appliance.  There is not necessarily a writable, mounted filesystem
that can be used to catch a core dump, so instead we set aside a
virtual disk for core dumps and allow the kernel to write a core to
that.

This patch was tested by running the modified kernel under qemu (using
libguestfs) and forcing various core dumps to attached virtual disks.

Signed-off-by: Richard W.M. Jones <rjones@redhat.com>
---
 fs/exec.c |    6 +-----
 1 files changed, 1 insertions(+), 5 deletions(-)

diff --git a/fs/exec.c b/fs/exec.c
index ba99e1a..ee8051a 100644
--- a/fs/exec.c
+++ b/fs/exec.c
@@ -2052,11 +2052,7 @@ void do_coredump(long signr, int exit_code, struct pt_regs *regs)
 			goto close_fail;
 		if (d_unhashed(cprm.file->f_path.dentry))
 			goto close_fail;
-		/*
-		 * AK: actually i see no reason to not allow this for named
-		 * pipes etc, but keep the previous behaviour for now.
-		 */
-		if (!S_ISREG(inode->i_mode))
+		if (!S_ISREG(inode->i_mode) && !S_ISBLK(inode->i_mode))
 			goto close_fail;
 		/*
 		 * Dont allow local users get cute and trick others to coredump
-- 
1.7.4