Btrfs-progs: check out if the swap device

Currently, the following commands succeed.

 # cat /proc/swaps
 Filename                                Type            Size    Used    Priority
 /dev/sda3                               partition       8388604 0       -1
 /dev/sdc8                               partition       9765884 0       -2
 # mkfs.btrfs /dev/sdc8

 WARNING! - Btrfs v0.20-rc1-165-g82ac345 IS EXPERIMENTAL
 WARNING! - see http://btrfs.wiki.kernel.org before using

 fs created label (null) on /dev/sdc8
         nodesize 4096 leafsize 4096 sectorsize 4096 size 9.31GB
 Btrfs v0.20-rc1-165-g82ac345
 # btrfs fi sh /dev/sdc8
 Label: none  uuid: fc0bdbd0-7eed-460f-b4e9-131273b66df2
         Total devices 1 FS bytes used 28.00KB
         devid    1 size 9.31GB used 989.62MB path /dev/sdc8

 Btrfs v0.20-rc1-165-g82ac345
 #

But we should check out the swap device. Fixed it.

Signed-off-by: Tsutomu Itoh <t-itoh@jp.fujitsu.com>
Tested-by: David Sterba <dsterba@suse.cz>

diff --git a/mkfs.c b/mkfs.c
index 2d3c2af..2210312 100644 (file)
--- a/mkfs.c
+++ b/mkfs.c
@@ -1366,6 +1366,16 @@ int main(int ac, char **av)
 
        if (source_dir == 0) {
                file = av[optind++];
+               ret = is_swap_device(file);
+               if (ret < 0) {
+                       fprintf(stderr, "error checking %s status: %s\n", file,
+                               strerror(-ret));
+                       exit(1);
+               }
+               if (ret == 1) {
+                       fprintf(stderr, "%s is a swap device\n", file);
+                       exit(1);
+               }
                ret = check_mounted(file);
                if (ret < 0) {
                        fprintf(stderr, "error checking %s mount status\n", file);
@@ -1376,9 +1386,23 @@ int main(int ac, char **av)
                        exit(1);
                }
                ac--;
+               /* check if the device is busy */
+               fd = open(file, O_RDWR|O_EXCL);
+               if (fd < 0) {
+                       fprintf(stderr, "unable to open %s: %s\n", file,
+                               strerror(errno));
+                       exit(1);
+               }
+               close(fd);
+               /*
+                * open again without O_EXCL so that the problem should not
+                * occur by the following processing.
+                * (btrfs_register_one_device() fails if O_EXCL is on)
+                */
                fd = open(file, O_RDWR);
                if (fd < 0) {
-                       fprintf(stderr, "unable to open %s\n", file);
+                       fprintf(stderr, "unable to open %s: %s\n", file,
+                               strerror(errno));
                        exit(1);
                }
                first_file = file;
@@ -1461,6 +1485,16 @@ int main(int ac, char **av)
                int old_mixed = mixed;
 
                file = av[optind++];
+               ret = is_swap_device(file);
+               if (ret < 0) {
+                       fprintf(stderr, "error checking %s status: %s\n", file,
+                               strerror(-ret));
+                       exit(1);
+               }
+               if (ret == 1) {
+                       fprintf(stderr, "%s is a swap device\n", file);
+                       exit(1);
+               }
                ret = check_mounted(file);
                if (ret < 0) {
                        fprintf(stderr, "error checking %s mount status\n",
@@ -1471,9 +1505,23 @@ int main(int ac, char **av)
                        fprintf(stderr, "%s is mounted\n", file);
                        exit(1);
                }
+               /* check if the device is busy */
+               fd = open(file, O_RDWR|O_EXCL);
+               if (fd < 0) {
+                       fprintf(stderr, "unable to open %s: %s\n", file,
+                               strerror(errno));
+                       exit(1);
+               }
+               close(fd);
+               /*
+                * open again without O_EXCL so that the problem should not
+                * occur by the following processing.
+                * (btrfs_register_one_device() fails if O_EXCL is on)
+                */
                fd = open(file, O_RDWR);
                if (fd < 0) {
-                       fprintf(stderr, "unable to open %s\n", file);
+                       fprintf(stderr, "unable to open %s: %s\n", file,
+                               strerror(errno));
                        exit(1);
                }
                ret = btrfs_device_already_in_root(root, fd,

diff --git a/utils.c b/utils.c
index 01780ff..d660507 100644 (file)
--- a/utils.c
+++ b/utils.c
@@ -1387,3 +1387,78 @@ int get_fs_info(int fd, char *path, struct btrfs_ioctl_fs_info_args *fi_args,
 
        return 0;
 }
+
+#define isoctal(c)     (((c) & ~7) == '0')
+
+static inline void translate(char *f, char *t)
+{
+       while (*f != '\0') {
+               if (*f == '\\' &&
+                   isoctal(f[1]) && isoctal(f[2]) && isoctal(f[3])) {
+                       *t++ = 64*(f[1] & 7) + 8*(f[2] & 7) + (f[3] & 7);
+                       f += 4;
+               } else
+                       *t++ = *f++;
+       }
+       *t = '\0';
+       return;
+}
+
+/*
+ * Checks if the swap device.
+ * Returns 1 if swap device, < 0 on error or 0 if not swap device.
+ */
+int is_swap_device(const char *file)
+{
+       FILE    *f;
+       struct stat     st_buf;
+       dev_t   dev;
+       ino_t   ino = 0;
+       char    tmp[PATH_MAX];
+       char    buf[PATH_MAX];
+       char    *cp;
+       int     ret = 0;
+
+       if (stat(file, &st_buf) < 0)
+               return -errno;
+       if (S_ISBLK(st_buf.st_mode))
+               dev = st_buf.st_rdev;
+       else if (S_ISREG(st_buf.st_mode)) {
+               dev = st_buf.st_dev;
+               ino = st_buf.st_ino;
+       } else
+               return 0;
+
+       if ((f = fopen("/proc/swaps", "r")) == NULL)
+               return 0;
+
+       /* skip the first line */
+       if (fgets(tmp, sizeof(tmp), f) == NULL)
+               goto out;
+
+       while (fgets(tmp, sizeof(tmp), f) != NULL) {
+               if ((cp = strchr(tmp, ' ')) != NULL)
+                       *cp = '\0';
+               if ((cp = strchr(tmp, '\t')) != NULL)
+                       *cp = '\0';
+               translate(tmp, buf);
+               if (stat(buf, &st_buf) != 0)
+                       continue;
+               if (S_ISBLK(st_buf.st_mode)) {
+                       if (dev == st_buf.st_rdev) {
+                               ret = 1;
+                               break;
+                       }
+               } else if (S_ISREG(st_buf.st_mode)) {
+                       if (dev == st_buf.st_dev && ino == st_buf.st_ino) {
+                               ret = 1;
+                               break;
+                       }
+               }
+       }
+
+out:
+       fclose(f);
+
+       return ret;
+}

diff --git a/utils.h b/utils.h
index bbcaf6a..60a0fea 100644 (file)
--- a/utils.h
+++ b/utils.h
@@ -55,6 +55,7 @@ int get_fs_info(int fd, char *path, struct btrfs_ioctl_fs_info_args *fi_args,
                struct btrfs_ioctl_dev_info_args **di_ret);
 
 char *__strncpy__null(char *dest, const char *src, size_t n);
+int is_swap_device(const char *file);
 /* Helper to always get proper size of the destination string */
 #define strncpy_null(dest, src) __strncpy__null(dest, src, sizeof(dest))