btrfs: merge btrfs_find_device and find_device

mainline inclusion
from mainline-v5.1-rc7
commit 09ba3bc9
category: bugfix
bugzilla: 13690
CVE: CVE-2019-18885

-------------------------------------------------

Both btrfs_find_device() and find_device() does the same thing except
that the latter does not take the seed device onto account in the device
scanning context. We can merge them.
Signed-off-by: NAnand Jain <anand.jain@oracle.com>
Reviewed-by: NDavid Sterba <dsterba@suse.com>
Signed-off-by: NDavid Sterba <dsterba@suse.com>
Conflicts:
  fs/btrfs/volumes.c
[yyl adjust context]
Signed-off-by: NYang Yingliang <yangyingliang@huawei.com>
Reviewed-by: NYi Zhang <yi.zhang@huawei.com>
Signed-off-by: NYang Yingliang <yangyingliang@huawei.com>

fs/btrfs/dev-replace.c

@@ -113,10 +113,10 @@ int btrfs_init_dev_replace(struct btrfs_fs_info *fs_info)
 	case BTRFS_IOCTL_DEV_REPLACE_STATE_STARTED:
 	case BTRFS_IOCTL_DEV_REPLACE_STATE_SUSPENDED:
 		dev_replace->srcdev = btrfs_find_device(fs_info->fs_devices,
-							src_devid, NULL, NULL);
+						src_devid, NULL, NULL, true);
 		dev_replace->tgtdev = btrfs_find_device(fs_info->fs_devices,
 							BTRFS_DEV_REPLACE_DEVID,
-							NULL, NULL);
+							NULL, NULL, true);
 		/*
 		 * allow 'btrfs dev replace_cancel' if src/tgt device is
 		 * missing

fs/btrfs/ioctl.c

@@ -1636,7 +1636,7 @@ static noinline int btrfs_ioctl_resize(struct file *file,
 		btrfs_info(fs_info, "resizing devid %llu", devid);
 	}
 
-	device = btrfs_find_device(fs_info->fs_devices, devid, NULL, NULL);
+	device = btrfs_find_device(fs_info->fs_devices, devid, NULL, NULL, true);
 	if (!device) {
 		btrfs_info(fs_info, "resizer unable to find device %llu",
 			   devid);
@@ -3173,7 +3173,7 @@ static long btrfs_ioctl_dev_info(struct btrfs_fs_info *fs_info,
 
 	rcu_read_lock();
 	dev = btrfs_find_device(fs_info->fs_devices, di_args->devid, s_uuid,
-				NULL);
+				NULL, true);
 
 	if (!dev) {
 		ret = -ENODEV;

fs/btrfs/scrub.c

@@ -3836,7 +3836,7 @@ int btrfs_scrub_dev(struct btrfs_fs_info *fs_info, u64 devid, u64 start,
 		return PTR_ERR(sctx);
 
 	mutex_lock(&fs_info->fs_devices->device_list_mutex);
-	dev = btrfs_find_device(fs_info->fs_devices, devid, NULL, NULL);
+	dev = btrfs_find_device(fs_info->fs_devices, devid, NULL, NULL, true);
 	if (!dev || (test_bit(BTRFS_DEV_STATE_MISSING, &dev->dev_state) &&
 		     !is_dev_replace)) {
 		mutex_unlock(&fs_info->fs_devices->device_list_mutex);
@@ -4020,7 +4020,7 @@ int btrfs_scrub_progress(struct btrfs_fs_info *fs_info, u64 devid,
 	struct scrub_ctx *sctx = NULL;
 
 	mutex_lock(&fs_info->fs_devices->device_list_mutex);
-	dev = btrfs_find_device(fs_info->fs_devices, devid, NULL, NULL);
+	dev = btrfs_find_device(fs_info->fs_devices, devid, NULL, NULL, true);
 	if (dev)
 		sctx = dev->scrub_ctx;
 	if (sctx)

fs/btrfs/volumes.c

@@ -347,27 +347,6 @@ static struct btrfs_device *__alloc_device(void)
 	return dev;
 }
 
-/*
- * Find a device specified by @devid or @uuid in the list of @fs_devices, or
- * return NULL.
- *
- * If devid and uuid are both specified, the match must be exact, otherwise
- * only devid is used.
- */
-static struct btrfs_device *find_device(struct btrfs_fs_devices *fs_devices,
-		u64 devid, const u8 *uuid)
-{
-	struct btrfs_device *dev;
-
-	list_for_each_entry(dev, &fs_devices->devices, dev_list) {
-		if (dev->devid == devid &&
-		    (!uuid || !memcmp(dev->uuid, uuid, BTRFS_UUID_SIZE))) {
-			return dev;
-		}
-	}
-	return NULL;
-}
-
 static noinline struct btrfs_fs_devices *find_fsid(u8 *fsid)
 {
 	struct btrfs_fs_devices *fs_devices;
@@ -772,8 +751,8 @@ static noinline struct btrfs_device *device_list_add(const char *path,
 		device = NULL;
 	} else {
 		mutex_lock(&fs_devices->device_list_mutex);
-		device = find_device(fs_devices, devid,
-				disk_super->dev_item.uuid);
+		device = btrfs_find_device(fs_devices, devid,
+				disk_super->dev_item.uuid, NULL, false);
 	}
 
 	if (!device) {
@@ -2145,7 +2124,7 @@ static int btrfs_find_device_by_path(struct btrfs_fs_info *fs_info,
 	devid = btrfs_stack_device_id(&disk_super->dev_item);
 	dev_uuid = disk_super->dev_item.uuid;
 	*device = btrfs_find_device(fs_info->fs_devices, devid, dev_uuid,
-				    disk_super->fsid);
+				    disk_super->fsid, true);
 	brelse(bh);
 	if (!*device)
 		ret = -ENOENT;
@@ -2192,7 +2171,7 @@ int btrfs_find_device_by_devspec(struct btrfs_fs_info *fs_info, u64 devid,
 	if (devid) {
 		ret = 0;
 		*device = btrfs_find_device(fs_info->fs_devices, devid, NULL,
-					    NULL);
+					    NULL, true);
 		if (!*device)
 			ret = -ENOENT;
 	} else {
@@ -2325,7 +2304,7 @@ static int btrfs_finish_sprout(struct btrfs_trans_handle *trans,
 		read_extent_buffer(leaf, fs_uuid, btrfs_device_fsid(dev_item),
 				   BTRFS_FSID_SIZE);
 		device = btrfs_find_device(fs_info->fs_devices, devid, dev_uuid,
-					   fs_uuid);
+					   fs_uuid, true);
 		BUG_ON(!device); /* Logic error */
 
 		if (device->fs_devices->seeding) {
@@ -6262,19 +6241,36 @@ blk_status_t btrfs_map_bio(struct btrfs_fs_info *fs_info, struct bio *bio,
 	return BLK_STS_OK;
 }
 
+/*
+ * Find a device specified by @devid or @uuid in the list of @fs_devices, or
+ * return NULL.
+ *
+ * If devid and uuid are both specified, the match must be exact, otherwise
+ * only devid is used.
+ *
+ * If @seed is true, traverse through the seed devices.
+ */
 struct btrfs_device *btrfs_find_device(struct btrfs_fs_devices *fs_devices,
-				       u64 devid, u8 *uuid, u8 *fsid)
+				       u64 devid, u8 *uuid, u8 *fsid,
+				       bool seed)
 {
 	struct btrfs_device *device;
 
 	while (fs_devices) {
 		if (!fsid ||
 		    !memcmp(fs_devices->fsid, fsid, BTRFS_FSID_SIZE)) {
-			device = find_device(fs_devices, devid, uuid);
-			if (device)
-				return device;
+			list_for_each_entry(device, &fs_devices->devices,
+					    dev_list) {
+				if (device->devid == devid &&
+				    (!uuid || memcmp(device->uuid, uuid,
+						     BTRFS_UUID_SIZE) == 0))
+					return device;
+			}
 		}
-		fs_devices = fs_devices->seed;
+		if (seed)
+			fs_devices = fs_devices->seed;
+		else
+			return NULL;
 	}
 	return NULL;
 }
@@ -6520,7 +6516,7 @@ static int read_one_chunk(struct btrfs_fs_info *fs_info, struct btrfs_key *key,
 				   btrfs_stripe_dev_uuid_nr(chunk, i),
 				   BTRFS_UUID_SIZE);
 		map->stripes[i].dev = btrfs_find_device(fs_info->fs_devices,
-							devid, uuid, NULL);
+							devid, uuid, NULL, true);
 		if (!map->stripes[i].dev &&
 		    !btrfs_test_opt(fs_info, DEGRADED)) {
 			free_extent_map(em);
@@ -6660,7 +6656,7 @@ static int read_one_dev(struct btrfs_fs_info *fs_info,
 	}
 
 	device = btrfs_find_device(fs_info->fs_devices, devid, dev_uuid,
-				   fs_uuid);
+				   fs_uuid, true);
 	if (!device) {
 		if (!btrfs_test_opt(fs_info, DEGRADED)) {
 			btrfs_report_missing_device(fs_info, devid,
@@ -7250,7 +7246,8 @@ int btrfs_get_dev_stats(struct btrfs_fs_info *fs_info,
 	int i;
 
 	mutex_lock(&fs_devices->device_list_mutex);
-	dev = btrfs_find_device(fs_info->fs_devices, stats->devid, NULL, NULL);
+	dev = btrfs_find_device(fs_info->fs_devices, stats->devid, NULL, NULL,
+				true);
 	mutex_unlock(&fs_devices->device_list_mutex);
 
 	if (!dev) {
@@ -7465,7 +7462,7 @@ static int verify_one_dev_extent(struct btrfs_fs_info *fs_info,
 	}
 
 	/* Make sure no dev extent is beyond device bondary */
-	dev = btrfs_find_device(fs_info->fs_devices, devid, NULL, NULL);
+	dev = btrfs_find_device(fs_info->fs_devices, devid, NULL, NULL, true);
 	if (!dev) {
 		btrfs_err(fs_info, "failed to find devid %llu", devid);
 		ret = -EUCLEAN;
@@ -7474,7 +7471,8 @@ static int verify_one_dev_extent(struct btrfs_fs_info *fs_info,
 
 	/* It's possible this device is a dummy for seed device */
 	if (dev->disk_total_bytes == 0) {
-		dev = find_device(fs_info->fs_devices->seed, devid, NULL);
+		dev = btrfs_find_device(fs_info->fs_devices->seed, devid, NULL,
+					NULL, false);
 		if (!dev) {
 			btrfs_err(fs_info, "failed to find seed devid %llu",
 				  devid);

fs/btrfs/volumes.h

@@ -432,7 +432,7 @@ int btrfs_num_copies(struct btrfs_fs_info *fs_info, u64 logical, u64 len);
 int btrfs_grow_device(struct btrfs_trans_handle *trans,
 		      struct btrfs_device *device, u64 new_size);
 struct btrfs_device *btrfs_find_device(struct btrfs_fs_devices *fs_devices,
-				       u64 devid, u8 *uuid, u8 *fsid);
+				       u64 devid, u8 *uuid, u8 *fsid, bool seed);
 int btrfs_shrink_device(struct btrfs_device *device, u64 new_size);
 int btrfs_init_new_device(struct btrfs_fs_info *fs_info, const char *path);
 int btrfs_balance(struct btrfs_fs_info *fs_info,