From: Mark Doffman <mark.doffman@xxxxxxxxxxxxxxx>
Analogous to NFS add a new root device option, the ability
to boot using the Ceph networked file system as the root fs.
This patch adds a new root device option '/dev/ceph' that
uses a ceph networked file system. File system parameters
are passed using a new kernel parameter: 'cephroot'.
The 'cephroot' parameters are very similar to 'nfsroot'.
Signed-off-by: Mark Doffman <mark.doffman@xxxxxxxxxxxxxxx>
Reviewed-by: Ian Molton <ian.molton@xxxxxxxxxxxxxxx>
---
fs/ceph/Kconfig | 10 +++
fs/ceph/Makefile | 1 +
fs/ceph/root.c | 176 +++++++++++++++++++++++++++++++++++++++++
include/linux/ceph/ceph_root.h | 10 +++
include/linux/root_dev.h | 1 +
init/do_mounts.c | 32 +++++++-
net/ipv4/ipconfig.c | 10 ++-
7 files changed, 237 insertions(+), 3 deletions(-)
create mode 100644 fs/ceph/root.c
create mode 100644 include/linux/ceph/ceph_root.h
diff --git a/fs/ceph/Kconfig b/fs/ceph/Kconfig
index ac9a2ef..325e83d 100644
--- a/fs/ceph/Kconfig
+++ b/fs/ceph/Kconfig
@@ -25,3 +25,13 @@ config CEPH_FSCACHE
caching support for Ceph clients using FS-Cache
endif
+
+config ROOT_CEPH
+ bool "Root file system on Ceph FS"
+ depends on CEPH_FS=y && IP_PNP
+ help
+ If you want your system to mount its root file system via CEPH,
+ choose Y here. For details, read
+ <file:Documentation/filesystems/ceph/cephroot.txt>.
+
+ If unsure say N.
diff --git a/fs/ceph/Makefile b/fs/ceph/Makefile
index 32e3010..af2dcbf 100644
--- a/fs/ceph/Makefile
+++ b/fs/ceph/Makefile
@@ -10,3 +10,4 @@ ceph-y := super.o inode.o dir.o file.o locks.o addr.o ioctl.o \
debugfs.o
ceph-$(CONFIG_CEPH_FSCACHE) += cache.o
+ceph-$(CONFIG_ROOT_CEPH) += root.o
diff --git a/fs/ceph/root.c b/fs/ceph/root.c
new file mode 100644
index 0000000..1559c19
--- /dev/null
+++ b/fs/ceph/root.c
@@ -0,0 +1,176 @@
+/*
+ * Copyright (C) 2012 Codethink Ltd. <mark.doffman@xxxxxxxxxxxxxxx>
+ *
+ * This file is released under the GPL v2
+ *
+ * Allow a CephFS filesystem to be mounted as root.
+ */
+
+#include <linux/kernel.h>
+#include <linux/types.h>
+#include <linux/string.h>
+#include <linux/init.h>
+#include <linux/slab.h>
+#include <linux/utsname.h>
+#include <linux/root_dev.h>
+#include <linux/in.h>
+#include <net/ipconfig.h>
+#include <linux/ceph/ceph_root.h>
+
+#define MAXPATHLEN 1024
+
+/* Parameters passed from the kernel command line */
+static char ceph_command_line_params[256] __initdata;
+
+/* server:path string passed to mount */
+static char ceph_root_device[MAXPATHLEN + 1] __initdata;
+
+/* Name of directory to mount */
+static char ceph_export_path[MAXPATHLEN + 1] __initdata;
+
+/* Mount options */
+static char ceph_root_options[256] __initdata;
+
+/*
+ * Parse CephFS server and directory information passed on the kernel
+ * command line.
+ *
+ * cephroot=[<server-ip>][,<server-ips>]:<root-dir>[,<cephfs-options>]
+ */
+static int __init ceph_root_setup(char *line)
+{
+ ROOT_DEV = Root_CEPH;
+
+ strlcpy(ceph_command_line_params, line,
+ sizeof(ceph_command_line_params));
+
+ return 1;
+}
+
+__setup("cephroot=", ceph_root_setup);
+
+/*
+ * ceph_root_append - Concatenates an options or address string
+ * adding a ',' delimiter if neccessary.
+ *
+ * Returns 0 on success -E2BIG if the resulting string is too long.
+ */
+static int __init ceph_root_append(char *incoming,
+ char *dest,
+ const size_t destlen)
+{
+ int res = 0;
+
+ if (incoming != NULL && *incoming != '\0') {
+ size_t len = strlen(dest);
+
+ if (len && dest[len - 1] != ',') {
+ if (strlcat(dest, ",", destlen) > destlen)
+ res = -E2BIG;
+ }
+
+ if (strlcat(dest, incoming, destlen) > destlen)
+ res = -E2BIG;
+
+ }
+ return res;
+}
+
+/*
+ * ceph_root_parse_params - Parse out root export path and mount options from
+ * passed-in string @incoming.
+ *
+ * Copy the path into @path.
+ *
+ * Returns 0 on success -E2BIG if the resulting options string or device
+ * string are too long.
+ */
+static int __init ceph_root_parse_params(char *incoming, char *outpath,
+ const size_t outpathlen)
+{
+ int res = -EINVAL;
+ char *options;
+ char *path;
+
+ options = strstr(incoming, ":/");
+ if (options == NULL)
+ options = strstr(incoming, "default");
+
+ if (options != NULL) {
+ path = strsep(&options, ",");
+ if (*path != '\0' && strcmp(path, "default") != 0)
+ strlcpy(outpath, path, outpathlen);
+ res = ceph_root_append(options, ceph_root_options,
+ sizeof(ceph_root_options));
+
+ if (res == 0) {
+ *path = '\0';
+ res = ceph_root_append(incoming, ceph_root_device,
+ sizeof(ceph_root_device));
+ }
+ }
+
+ return res;
+}
+
+/*
+ * ceph_root_data - Return mount device and data for CEPHROOT mount.
+ *
+ * @root_device: OUT: Address of string containing CEPHROOT device.
+ * @root_data: OUT: Address of string containing CEPHROOT mount options.
+ *
+ * Returns: 0 and sets @root_device and @root_data if successful.
+ * error code if unsuccessful.
+ */
+int __init ceph_root_data(char **root_device, char **root_data)
+{
+ char *tmp_root_path = NULL;
+ const size_t tmplen = sizeof(ceph_export_path);
+ int len;
+ int res = -E2BIG;
+
+ tmp_root_path = kzalloc(tmplen, GFP_KERNEL);
+ if (tmp_root_path == NULL)
+ return -ENOMEM;
+
+ if (root_server_path[0] != '\0') {
+ if (ceph_root_parse_params(root_server_path, tmp_root_path,
+ tmplen))
+ goto out;
+ }
+
+ if (ceph_command_line_params[0] != '\0') {
+ if (ceph_root_parse_params(ceph_command_line_params,
+ tmp_root_path, tmplen))
+ goto out;
+ }
+
+ /*
+ * Set up ceph_root_device. This looks like: server:/path
+ *
+ * At this point, utsname()->nodename contains our local
+ * IP address or hostname, set by ipconfig. If "%s" exists
+ * in tmp_root_path, substitute the nodename, then shovel the whole
+ * mess into ceph_root_device.
+ */
+ len = snprintf(ceph_export_path, sizeof(ceph_export_path),
+ tmp_root_path, utsname()->nodename);
+ if (len > (int)sizeof(ceph_export_path))
+ goto out;
+
+ len = strlcat(ceph_root_device, ceph_export_path,
+ sizeof(ceph_root_device));
+ if (len > (int)sizeof(ceph_root_device))
+ goto out;
+
+ pr_debug("Root-CEPH: Root device: %s\n", ceph_root_device);
+ pr_debug("Root-CEPH: Root options: %s\n", ceph_root_options);
+ *root_device = ceph_root_device;
+ *root_data = ceph_root_options;
+
+ res = 0;
+
+out:
+ kfree(tmp_root_path);
+ return res;
+}
diff --git a/include/linux/ceph/ceph_root.h b/include/linux/ceph/ceph_root.h
new file mode 100644
index 0000000..e6bae63
--- /dev/null
+++ b/include/linux/ceph/ceph_root.h
@@ -0,0 +1,10 @@
+/*
+ * Copyright (C) 2012 Codethink Ltd. <mark.doffman@xxxxxxxxxxxxxxx>
+ *
+ * This file is released under the GPL v2
+ *
+ * ceph_root.h
+ */
+
+/* linux/fs/ceph/root.c */
+extern int ceph_root_data(char **root_device, char **root_data); /*__init*/
diff --git a/include/linux/root_dev.h b/include/linux/root_dev.h
index ed241aa..af6b182 100644
--- a/include/linux/root_dev.h
+++ b/include/linux/root_dev.h
@@ -16,6 +16,7 @@ enum {
Root_SDA2 = MKDEV(SCSI_DISK0_MAJOR, 2),
Root_HDC1 = MKDEV(IDE1_MAJOR, 1),
Root_SR0 = MKDEV(SCSI_CDROM_MAJOR, 0),
+ Root_CEPH = MKDEV(UNNAMED_MAJOR, 254),
};
extern dev_t ROOT_DEV;
diff --git a/init/do_mounts.c b/init/do_mounts.c
index 8e5addc..d075020 100644
--- a/init/do_mounts.c
+++ b/init/do_mounts.c
@@ -33,6 +33,8 @@
#include <linux/nfs_fs_sb.h>
#include <linux/nfs_mount.h>
+#include <linux/ceph/ceph_root.h>
+
#include "do_mounts.h"
int __initdata rd_doload; /* 1 = load RAM disk, 0 = don't load */
@@ -199,6 +201,7 @@ done:
* a partition with a known unique id.
* 8) <major>:<minor> major and minor number of the device separated by
* a colon.
+ * 9) /dev/ceph represents Root_CEPH
*
* If name doesn't have fall into the categories above, we return (0,0).
* block_class is used to check if something is a disk name. If the disk
@@ -245,7 +248,9 @@ dev_t name_to_dev_t(char *name)
res = Root_RAM0;
if (strcmp(name, "ram") == 0)
goto done;
-
+ res = Root_CEPH;
+ if (strcmp(name, "ceph") == 0)
+ goto done;
if (strlen(name) > 31)
goto fail;
strcpy(s, name);
@@ -473,6 +478,22 @@ static int __init mount_nfs_root(void)
}
#endif
+#ifdef CONFIG_ROOT_CEPH
+static int __init mount_ceph_root(void)
+{
+ char *root_dev, *root_data;
+
+ if (ceph_root_data(&root_dev, &root_data))
+ return 0;
+
+ if (do_mount_root(root_dev, "ceph",
+ root_mountflags, root_data))
+ return 0;
+
+ return 1;
+}
+#endif
+
#if defined(CONFIG_BLK_DEV_RAM) || defined(CONFIG_BLK_DEV_FD)
void __init change_floppy(char *fmt, ...)
{
@@ -514,6 +535,15 @@ void __init mount_root(void)
ROOT_DEV = Root_FD0;
}
#endif
+#ifdef CONFIG_ROOT_CEPH
+ if (ROOT_DEV == Root_CEPH) {
+ if (mount_ceph_root())
+ return;
+
+ printk(KERN_ERR "VFS: Unable to mount root fs via CephFS, trying floppy.\n");
+ ROOT_DEV = Root_FD0;
+ }
+#endif
#ifdef CONFIG_BLK_DEV_FD
if (MAJOR(ROOT_DEV) == FLOPPY_MAJOR) {
/* rd_doload is 2 for a dual initrd/ramload setup */
diff --git a/net/ipv4/ipconfig.c b/net/ipv4/ipconfig.c
index efa1138..765eea4 100644
--- a/net/ipv4/ipconfig.c
+++ b/net/ipv4/ipconfig.c
@@ -1435,10 +1435,10 @@ static int __init ip_auto_config(void)
* missing values.
*/
if (ic_myaddr == NONE ||
-#ifdef CONFIG_ROOT_NFS
+#if defined(CONFIG_ROOT_NFS) || defined(CONFIG_ROOT_CEPH)
(root_server_addr == NONE &&
ic_servaddr == NONE &&
- ROOT_DEV == Root_NFS) ||
+ (ROOT_DEV == Root_NFS || ROOT_DEV == Root_CEPH)) ||
#endif
ic_first_dev->next) {
#ifdef IPCONFIG_DYNAMIC
@@ -1465,6 +1465,12 @@ static int __init ip_auto_config(void)
goto try_try_again;
}
#endif
+#ifdef CONFIG_ROOT_CEPH
+ if (ROOT_DEV == Root_CEPH) {
+ pr_err("IP-Config: Retrying forever (CEPH root)...\n");
+ goto try_try_again;
+ }
+#endif
if (--retries) {
pr_err("IP-Config: Reopening network devices...\n");
--
1.8.4
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