MD: hold mddev lock to change bitmap location

Changing the location changes a lot of things. Holding the lock to avoid race.
This makes the .quiesce called with mddev lock hold too.

Acked-by: NeilBrown <neilb@suse.com>
Signed-off-by: Shaohua Li <shli@fb.com>

diff --git a/drivers/md/bitmap.c b/drivers/md/bitmap.c
index 6fff794e0c723c0d8e11d1f1899ba109c0bcef29..13041ee37ad6b504a4e1c1182a10cce9d77d0f9d 100644 (file)
--- a/drivers/md/bitmap.c
+++ b/drivers/md/bitmap.c
@@ -2183,19 +2183,29 @@ location_show(struct mddev *mddev, char *page)
 static ssize_t
 location_store(struct mddev *mddev, const char *buf, size_t len)
 {
+       int rv;
 
+       rv = mddev_lock(mddev);
+       if (rv)
+               return rv;
        if (mddev->pers) {
-               if (!mddev->pers->quiesce)
-                       return -EBUSY;
-               if (mddev->recovery || mddev->sync_thread)
-                       return -EBUSY;
+               if (!mddev->pers->quiesce) {
+                       rv = -EBUSY;
+                       goto out;
+               }
+               if (mddev->recovery || mddev->sync_thread) {
+                       rv = -EBUSY;
+                       goto out;
+               }
        }
 
        if (mddev->bitmap || mddev->bitmap_info.file ||
            mddev->bitmap_info.offset) {
                /* bitmap already configured.  Only option is to clear it */
-               if (strncmp(buf, "none", 4) != 0)
-                       return -EBUSY;
+               if (strncmp(buf, "none", 4) != 0) {
+                       rv = -EBUSY;
+                       goto out;
+               }
                if (mddev->pers) {
                        mddev->pers->quiesce(mddev, 1);
                        bitmap_destroy(mddev);
@@ -2214,21 +2224,25 @@ location_store(struct mddev *mddev, const char *buf, size_t len)
                        /* nothing to be done */;
                else if (strncmp(buf, "file:", 5) == 0) {
                        /* Not supported yet */
-                       return -EINVAL;
+                       rv = -EINVAL;
+                       goto out;
                } else {
-                       int rv;
                        if (buf[0] == '+')
                                rv = kstrtoll(buf+1, 10, &offset);
                        else
                                rv = kstrtoll(buf, 10, &offset);
                        if (rv)
-                               return rv;
-                       if (offset == 0)
-                               return -EINVAL;
+                               goto out;
+                       if (offset == 0) {
+                               rv = -EINVAL;
+                               goto out;
+                       }
                        if (mddev->bitmap_info.external == 0 &&
                            mddev->major_version == 0 &&
-                           offset != mddev->bitmap_info.default_offset)
-                               return -EINVAL;
+                           offset != mddev->bitmap_info.default_offset) {
+                               rv = -EINVAL;
+                               goto out;
+                       }
                        mddev->bitmap_info.offset = offset;
                        if (mddev->pers) {
                                struct bitmap *bitmap;
@@ -2245,7 +2259,7 @@ location_store(struct mddev *mddev, const char *buf, size_t len)
                                mddev->pers->quiesce(mddev, 0);
                                if (rv) {
                                        bitmap_destroy(mddev);
-                                       return rv;
+                                       goto out;
                                }
                        }
                }
@@ -2257,6 +2271,11 @@ location_store(struct mddev *mddev, const char *buf, size_t len)
                set_bit(MD_CHANGE_DEVS, &mddev->flags);
                md_wakeup_thread(mddev->thread);
        }
+       rv = 0;
+out:
+       mddev_unlock(mddev);
+       if (rv)
+               return rv;
        return len;
 }