btrfs-progs: lowmem check: Output more detailed information about file extent interrupt

[platform/upstream/btrfs-progs.git] / cmds-fi-usage.c

diff --git a/cmds-fi-usage.c b/cmds-fi-usage.c
index 101a0c4..0b0e47f 100644 (file)
--- a/cmds-fi-usage.c
+++ b/cmds-fi-usage.c
@@ -22,6 +22,7 @@
 #include <errno.h>
 #include <stdarg.h>
 #include <getopt.h>
+#include <fcntl.h>
 
 #include "utils.h"
 #include "kerncompat.h"
@@ -29,6 +30,7 @@
 #include "string-table.h"
 #include "cmds-fi-usage.h"
 #include "commands.h"
+#include "disk-io.h"
 
 #include "version.h"
 #include "help.h"
@@ -506,6 +508,33 @@ static int cmp_device_info(const void *a, const void *b)
                        ((struct device_info *)b)->path);
 }
 
+int dev_to_fsid(const char *dev, u8 *fsid)
+{
+       struct btrfs_super_block *disk_super;
+       char buf[BTRFS_SUPER_INFO_SIZE];
+       int ret;
+       int fd;
+
+       fd = open(dev, O_RDONLY);
+       if (fd < 0) {
+               ret = -errno;
+               return ret;
+       }
+
+       disk_super = (struct btrfs_super_block *)buf;
+       ret = btrfs_read_dev_super(fd, disk_super,
+                                  BTRFS_SUPER_INFO_OFFSET, SBREAD_DEFAULT);
+       if (ret)
+               goto out;
+
+       memcpy(fsid, disk_super->fsid, BTRFS_FSID_SIZE);
+       ret = 0;
+
+out:
+       close(fd);
+       return ret;
+}
+
 /*
  *  This function loads the device_info structure and put them in an array
  */
@@ -516,6 +545,7 @@ static int load_device_info(int fd, struct device_info **device_info_ptr,
        struct btrfs_ioctl_fs_info_args fi_args;
        struct btrfs_ioctl_dev_info_args dev_info;
        struct device_info *info;
+       u8 fsid[BTRFS_UUID_SIZE];
 
        *device_info_count = 0;
        *device_info_ptr = NULL;
@@ -539,6 +569,8 @@ static int load_device_info(int fd, struct device_info **device_info_ptr,
                if (ndevs >= fi_args.num_devices) {
                        error("unexpected number of devices: %d >= %llu", ndevs,
                                (unsigned long long)fi_args.num_devices);
+                       error(
+               "if seed device is used, try running this command as root");
                        goto out;
                }
                memset(&dev_info, 0, sizeof(dev_info));
@@ -551,6 +583,17 @@ static int load_device_info(int fd, struct device_info **device_info_ptr,
                        goto out;
                }
 
+               /*
+                * Skip seed device by checking device's fsid (requires root).
+                * And we will skip only if dev_to_fsid is successful and dev
+                * is a seed device.
+                * Ignore any other error including -EACCES, which is seen when
+                * a non-root process calls dev_to_fsid(path)->open(path).
+                */
+               ret = dev_to_fsid((const char *)dev_info.path, fsid);
+               if (!ret && memcmp(fi_args.fsid, fsid, BTRFS_FSID_SIZE) != 0)
+                       continue;
+
                info[ndevs].devid = dev_info.devid;
                if (!dev_info.path[0]) {
                        strcpy(info[ndevs].path, "missing");
@@ -1040,6 +1083,7 @@ void print_device_sizes(struct device_info *devinfo, unsigned unit_mode)
                pretty_size_mode(devinfo->device_size, unit_mode));
        printf("   Device slack: %*s%10s\n",
                (int)(20 - strlen("Device slack")), "",
-               pretty_size_mode(devinfo->device_size - devinfo->size,
+               pretty_size_mode(devinfo->device_size > 0 ?
+                       devinfo->device_size - devinfo->size : 0,
                        unit_mode));
 }