Btrfs-progs: don't close the file descriptor 0 when closing a device

As we know, the file descriptor 0 is a special number, so we shouldn't
use it to initialize the file descriptor of the devices, or we might
close this special file descriptor by mistake when we close the devices.
"-1" is a better choice.

Signed-off-by: Miao Xie <miaox@cn.fujitsu.com>
Signed-off-by: Chris Mason <chris.mason@fusionio.com>

diff --git a/btrfs-find-root.c b/btrfs-find-root.c
index 810d835..3e1396d 100644 (file)
--- a/btrfs-find-root.c
+++ b/btrfs-find-root.c
@@ -76,7 +76,10 @@ static int close_all_devices(struct btrfs_fs_info *fs_info)
        list = &fs_info->fs_devices->devices;
        list_for_each(next, list) {
                device = list_entry(next, struct btrfs_device, dev_list);
-               close(device->fd);
+               if (device->fd != -1) {
+                       close(device->fd);
+                       device->fd = -1;
+               }
        }
        return 0;
 }

diff --git a/disk-io.c b/disk-io.c
index 9ffe6e4..4003636 100644 (file)
--- a/disk-io.c
+++ b/disk-io.c
@@ -1270,12 +1270,13 @@ static int close_all_devices(struct btrfs_fs_info *fs_info)
        while (!list_empty(list)) {
                device = list_entry(list->next, struct btrfs_device, dev_list);
                list_del_init(&device->dev_list);
-               if (device->fd) {
+               if (device->fd != -1) {
                        fsync(device->fd);
                        if (posix_fadvise(device->fd, 0, 0, POSIX_FADV_DONTNEED))
                                fprintf(stderr, "Warning, could not drop caches\n");
+                       close(device->fd);
+                       device->fd = -1;
                }
-               close(device->fd);
                kfree(device->name);
                kfree(device->label);
                kfree(device);

diff --git a/volumes.c b/volumes.c
index d6f81f8..b88385b 100644 (file)
--- a/volumes.c
+++ b/volumes.c
@@ -116,6 +116,7 @@ static int device_list_add(const char *path,
                        /* we can safely leave the fs_devices entry around */
                        return -ENOMEM;
                }
+               device->fd = -1;
                device->devid = devid;
                memcpy(device->uuid, disk_super->dev_item.uuid,
                       BTRFS_UUID_SIZE);
@@ -161,8 +162,10 @@ int btrfs_close_devices(struct btrfs_fs_devices *fs_devices)
 again:
        list_for_each(cur, &fs_devices->devices) {
                device = list_entry(cur, struct btrfs_device, dev_list);
-               close(device->fd);
-               device->fd = -1;
+               if (device->fd != -1) {
+                       close(device->fd);
+                       device->fd = -1;
+               }
                device->writeable = 0;
        }