[PATCH v2 1/2] btrfs: Don't search devid for every verify_one_dev_extent() call

[Qu Wenruo]

verify_one_dev_extent() will call btrfs_find_device() for each dev
extent, this waste some CPU time just searching the devices list.

Move the search one level up, into the btrfs_verify_dev_extents(), so
for each device we only call btrfs_find_device() once.

Signed-off-by: Qu Wenruo <w...@suse.com>
Reviewed-by: Nikolay Borisov <nbori...@suse.com>
Reviewed-by: Anand Jain <anand.j...@oracle.com>
---
 fs/btrfs/volumes.c | 30 ++++++++++++++++++------------
 1 file changed, 18 insertions(+), 12 deletions(-)

diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index 03f223aa7194..bae03111273e 100644
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -7772,13 +7772,14 @@ static u64 calc_stripe_length(u64 type, u64 chunk_len, 
int num_stripes)
 }
 
 static int verify_one_dev_extent(struct btrfs_fs_info *fs_info,
-                                u64 chunk_offset, u64 devid,
-                                u64 physical_offset, u64 physical_len)
+                                struct btrfs_device *dev,
+                                u64 chunk_offset, u64 physical_offset,
+                                u64 physical_len)
 {
        struct extent_map_tree *em_tree = &fs_info->mapping_tree.map_tree;
        struct extent_map *em;
        struct map_lookup *map;
-       struct btrfs_device *dev;
+       u64 devid = dev->devid;
        u64 stripe_len;
        bool found = false;
        int ret = 0;
@@ -7830,15 +7831,8 @@ 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, true);
-       if (!dev) {
-               btrfs_err(fs_info, "failed to find devid %llu", devid);
-               ret = -EUCLEAN;
-               goto out;
-       }
-
-       /* It's possible this device is a dummy for seed device */
        if (dev->disk_total_bytes == 0) {
+               /* This device is a dummy for seed device */
                dev = btrfs_find_device(fs_info->fs_devices->seed, devid, NULL,
                                        NULL, false);
                if (!dev) {
@@ -7898,6 +7892,7 @@ int btrfs_verify_dev_extents(struct btrfs_fs_info 
*fs_info)
 {
        struct btrfs_path *path;
        struct btrfs_root *root = fs_info->dev_root;
+       struct btrfs_device *device = NULL;
        struct btrfs_key key;
        u64 prev_devid = 0;
        u64 prev_dev_ext_end = 0;
@@ -7941,6 +7936,17 @@ int btrfs_verify_dev_extents(struct btrfs_fs_info 
*fs_info)
                devid = key.objectid;
                physical_offset = key.offset;
 
+               if (!device || devid != device->devid) {
+                       device = btrfs_find_device(fs_info->fs_devices, devid,
+                                                  NULL, NULL, true);
+                       if (!device) {
+                               btrfs_err(fs_info, "failed to find devid %llu",
+                                         devid);
+                               ret = -EUCLEAN;
+                               goto out;
+                       }
+               }
+
                dext = btrfs_item_ptr(leaf, slot, struct btrfs_dev_extent);
                chunk_offset = btrfs_dev_extent_chunk_offset(leaf, dext);
                physical_len = btrfs_dev_extent_length(leaf, dext);
@@ -7954,7 +7960,7 @@ int btrfs_verify_dev_extents(struct btrfs_fs_info 
*fs_info)
                        goto out;
                }
 
-               ret = verify_one_dev_extent(fs_info, chunk_offset, devid,
+               ret = verify_one_dev_extent(fs_info, device, chunk_offset,
                                            physical_offset, physical_len);
                if (ret < 0)
                        goto out;
-- 
2.20.1