From: NeilBrown <neilb@suse.de>
Date: Thu, 5 May 2011 06:14:53 +0000 (+1000)
Subject: lafs: allow some commands to open busy devices with --force
X-Git-Url: http://git.neil.brown.name/?a=commitdiff_plain;p=lafs-utils.git

lafs: allow some commands to open busy devices with --force

Useful for looking at the filesystem while the kernel is stuck.

Signed-off-by: NeilBrown <neilb@suse.de>
---

diff --git a/tools/internal.h b/tools/internal.h
index de9a4bd..50b5d80 100644
--- a/tools/internal.h
+++ b/tools/internal.h
@@ -1,4 +1,4 @@
 
 int open_device(char *devname, long long *device_bytes, int regular_file,
-		char **error);
+		int force, char **error);
 long long parse_size(char *arg, char **error);
diff --git a/tools/lafs.c b/tools/lafs.c
index c6d1409..3ac7578 100644
--- a/tools/lafs.c
+++ b/tools/lafs.c
@@ -948,6 +948,7 @@ static struct args args_add_device[] = {
 /*5*/	{ "-stride", opaque, -1, {NULL}, "Stride (from one member device to next)"},
 /*6*/	{ "-width",  opaque, -1, {NULL}, "Width of array in data-devices"},
 /*7*/	{ "-usage_inum", opaque, -1, {NULL}, "Inode number for segment-usage file"},
+/*8*/	{ "-force",  flag, -1, {NULL}, "Open device even if in-use"},
 	TERMINAL_ARG
 };
 static void c_add_device(struct state *st, void **args)
@@ -1018,7 +1019,8 @@ static void c_add_device(struct state *st, void **args)
 			return;
 	}
 
-	fd = open_device(devname, &device_bytes, args[2] != NULL, &err);
+	fd = open_device(devname, &device_bytes, args[2] != NULL,
+			 args[8] != NULL, &err);
 
 	if (fd < 0) {
 		printf("add_device: %s\n", err);
@@ -1178,6 +1180,7 @@ static char help_load_dev[] = "Allow access to LaFS filesystem stored on given d
 static struct args args_load_dev[] = {
 	{ "DEVNAME", external, -1, {NULL}, "Device to load filesystem info from"},
 	{ "-file",   external,  0, {NULL}, "Regular file to load filesystem info from"},
+	{ "-force",  flag,  -1, {NULL}, "Open device even if currently in use"},
 	TERMINAL_ARG
 };
 static void c_load_dev(struct state *st, void **args)
@@ -1193,7 +1196,8 @@ static void c_load_dev(struct state *st, void **args)
 		return;
 	}
 
-	fd = open_device(devname, &device_bytes, args[2] != NULL, &err);
+	fd = open_device(devname, &device_bytes, args[2] != NULL,
+			 args[3] != NULL, &err);
 
 	if (fd < 0) {
 		printf("load_dev: %s\n", err);
@@ -1246,7 +1250,8 @@ static void c_mount(struct state *st, void **args)
 			       devname);
 			return;
 		}
-		fd = open_device(devname, &device_bytes, args[2] != NULL, &err);
+		fd = open_device(devname, &device_bytes, args[2] != NULL,
+				 args[3] != NULL, &err);
 		if (fd < 0) {
 			printf("mount: %s\n", err);
 			free(err);
@@ -1354,7 +1359,7 @@ static void c_show_device(struct state *st, void **args)
 			       addrstr);
 			return;
 		}
-		fd = open_device(devname, &device_bytes, args[3] != NULL, &err);
+		fd = open_device(devname, &device_bytes, args[3] != NULL, 1, &err);
 		if (fd < 0) {
 			printf("show device: %s\n", err);	
 			free(err);
@@ -1382,7 +1387,7 @@ static void c_show_device(struct state *st, void **args)
 	if (!devname)
 		return;
 	/* Not already loaded, try to load-and-print */
-	fd = open_device(devname, &device_bytes, args[3] != NULL, &err);
+	fd = open_device(devname, &device_bytes, args[3] != NULL, 1, &err);
 	if (fd < 0) {
 		printf("show device: %s\n", err);
 		free(err);
@@ -1448,7 +1453,7 @@ static void c_show_state(struct state *st, void **args)
 			return;
 		}
 		dv = NULL;
-		fd = open_device(devname, &device_bytes, args[3] != NULL, &err);
+		fd = open_device(devname, &device_bytes, args[3] != NULL, 1, &err);
 		if (fd < 0) {
 			printf("show state: %s\n", err);
 			free(err);
diff --git a/tools/mkfs.lafs.c b/tools/mkfs.lafs.c
index 20a210d..e91e2db 100644
--- a/tools/mkfs.lafs.c
+++ b/tools/mkfs.lafs.c
@@ -214,7 +214,7 @@ int main(int argc, char *argv[])
 	}
 
 	/* Validate device */
-	dev_fd = open_device(devname, &device_bytes, regular_file, &error);
+	dev_fd = open_device(devname, &device_bytes, regular_file, 0, &error);
 	if (dev_fd < 0) {
 		fprintf(stderr, "mkfs.lafs: %s\n", error);
 		free(error);
diff --git a/tools/open_device.c b/tools/open_device.c
index bbdb8c6..b2d715b 100644
--- a/tools/open_device.c
+++ b/tools/open_device.c
@@ -14,7 +14,7 @@
 #include "internal.h"
 
 int open_device(char *devname, long long *device_bytes, int regular_file,
-		char **error)
+		int force, char **error)
 {
 	/* must be able to get an exclusive open on the device and its size
 	 * must be non-trivial
@@ -29,7 +29,7 @@ int open_device(char *devname, long long *device_bytes, int regular_file,
 	*error = NULL;
 
 	if (!regular_file)
-		fd = open(devname, O_RDWR|O_EXCL);
+		fd = open(devname, O_RDWR|(force?0:O_EXCL));
 	else if (*device_bytes)
 		fd = open(devname, O_RDWR|O_CREAT, 0666);
 	else