From: "Paulo Alcantara (SUSE)" <pc@cjr.nz>
To: linux-kernel@vger.kernel.org, netdev@vger.kernel.org,
linux-cifs@vger.kernel.org, samba-technical@lists.samba.org
Cc: "Paulo Alcantara (SUSE)" <pc@cjr.nz>,
Andrew Morton <akpm@linux-foundation.org>
Subject: [PATCH v2 2/3] init: Support mounting root file systems over SMB
Date: Thu, 19 Sep 2019 12:21:15 -0300 [thread overview]
Message-ID: <20190919152116.27076-2-pc@cjr.nz> (raw)
In-Reply-To: <20190919152116.27076-1-pc@cjr.nz>
Add a new virtual device named /dev/cifs (0xfe) to tell the kernel to
mount the root file system over the network by using SMB protocol.
cifs_root_data() will be responsible to retrieve the parsed
information of the new command-line option (cifsroot=) and then call
do_mount_root() with the appropriate mount options for cifs.ko.
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Paulo Alcantara (SUSE) <pc@cjr.nz>
---
init/do_mounts.c | 49 ++++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 49 insertions(+)
diff --git a/init/do_mounts.c b/init/do_mounts.c
index 53cb37b66227..cffef647a95b 100644
--- a/init/do_mounts.c
+++ b/init/do_mounts.c
@@ -212,6 +212,7 @@ static int match_dev_by_label(struct device *dev, const void *data)
* a colon.
* 9) PARTLABEL=<name> with name being the GPT partition label.
* MSDOS partitions do not support labels!
+ * 10) /dev/cifs represents Root_CIFS (0xfe)
*
* 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
@@ -268,6 +269,9 @@ dev_t name_to_dev_t(const char *name)
res = Root_NFS;
if (strcmp(name, "nfs") == 0)
goto done;
+ res = Root_CIFS;
+ if (strcmp(name, "cifs") == 0)
+ goto done;
res = Root_RAM0;
if (strcmp(name, "ram") == 0)
goto done;
@@ -501,6 +505,42 @@ static int __init mount_nfs_root(void)
}
#endif
+#ifdef CONFIG_CIFS_ROOT
+
+extern int cifs_root_data(char **dev, char **opts);
+
+#define CIFSROOT_TIMEOUT_MIN 5
+#define CIFSROOT_TIMEOUT_MAX 30
+#define CIFSROOT_RETRY_MAX 5
+
+static int __init mount_cifs_root(void)
+{
+ char *root_dev, *root_data;
+ unsigned int timeout;
+ int try, err;
+
+ err = cifs_root_data(&root_dev, &root_data);
+ if (err != 0)
+ return 0;
+
+ timeout = CIFSROOT_TIMEOUT_MIN;
+ for (try = 1; ; try++) {
+ err = do_mount_root(root_dev, "cifs", root_mountflags,
+ root_data);
+ if (err == 0)
+ return 1;
+ if (try > CIFSROOT_RETRY_MAX)
+ break;
+
+ ssleep(timeout);
+ timeout <<= 1;
+ if (timeout > CIFSROOT_TIMEOUT_MAX)
+ timeout = CIFSROOT_TIMEOUT_MAX;
+ }
+ return 0;
+}
+#endif
+
#if defined(CONFIG_BLK_DEV_RAM) || defined(CONFIG_BLK_DEV_FD)
void __init change_floppy(char *fmt, ...)
{
@@ -542,6 +582,15 @@ void __init mount_root(void)
ROOT_DEV = Root_FD0;
}
#endif
+#ifdef CONFIG_CIFS_ROOT
+ if (ROOT_DEV == Root_CIFS) {
+ if (mount_cifs_root())
+ return;
+
+ printk(KERN_ERR "VFS: Unable to mount root fs via SMB, 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 */
--
2.23.0
next prev parent reply other threads:[~2019-09-19 15:21 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-07-16 22:04 [PATCH 1/3] cifs: Add support for root file systems Paulo Alcantara (SUSE)
2019-07-16 22:04 ` [PATCH 2/3] init: Support mounting root file systems over SMB Paulo Alcantara (SUSE)
2019-07-16 22:04 ` [PATCH 3/3] ipconfig: Handle CONFIG_CIFS_ROOT option Paulo Alcantara (SUSE)
2019-09-19 15:21 ` [PATCH v2 1/3] cifs: Add support for root file systems Paulo Alcantara (SUSE)
2019-09-19 15:21 ` Paulo Alcantara (SUSE) [this message]
2019-09-19 15:21 ` [PATCH v2 3/3] ipconfig: Handle CONFIG_CIFS_ROOT option Paulo Alcantara (SUSE)
2019-09-20 10:04 ` [PATCH v2 1/3] cifs: Add support for root file systems Paulo Alcantara
2019-09-23 8:53 ` David Miller
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