Btrfs: check_int: use the known block location

The xfstest btrfs/014 which tests the balance operation caused issues with
the check_int module. The attempt was made to use btrfs_map_block() to
find the physical location for a written block. However, this was not
at all needed since the location of the written block was known since
a hook to submit_bio() was the reason for entering the check_int module.
Additionally, after a block relocation it happened that btrfs_map_block()
failed causing misleading error messages afterwards.

This patch changes the check_int module to use the known information of
the physical location from the bio.

Reported-by: Wang Shilong <wangshilong1991@gmail.com>
Signed-off-by: Stefan Behrens <sbehrens@giantdisaster.de>
Tested-by: Wang Shilong <wangshilong1991@gmail.com>
Signed-off-by: Chris Mason <clm@fb.com>

diff --git a/fs/btrfs/check-integrity.c b/fs/btrfs/check-integrity.c
index 66e820f..b5aa812 100644 (file)
--- a/fs/btrfs/check-integrity.c
+++ b/fs/btrfs/check-integrity.c
@@ -326,9 +326,6 @@ static int btrfsic_handle_extent_data(struct btrfsic_state *state,
 static int btrfsic_map_block(struct btrfsic_state *state, u64 bytenr, u32 len,
                             struct btrfsic_block_data_ctx *block_ctx_out,
                             int mirror_num);
-static int btrfsic_map_superblock(struct btrfsic_state *state, u64 bytenr,
-                                 u32 len, struct block_device *bdev,
-                                 struct btrfsic_block_data_ctx *block_ctx_out);
 static void btrfsic_release_block_ctx(struct btrfsic_block_data_ctx *block_ctx);
 static int btrfsic_read_block(struct btrfsic_state *state,
                              struct btrfsic_block_data_ctx *block_ctx);
@@ -1607,25 +1604,6 @@ static int btrfsic_map_block(struct btrfsic_state *state, u64 bytenr, u32 len,
        return ret;
 }
 
-static int btrfsic_map_superblock(struct btrfsic_state *state, u64 bytenr,
-                                 u32 len, struct block_device *bdev,
-                                 struct btrfsic_block_data_ctx *block_ctx_out)
-{
-       block_ctx_out->dev = btrfsic_dev_state_lookup(bdev);
-       block_ctx_out->dev_bytenr = bytenr;
-       block_ctx_out->start = bytenr;
-       block_ctx_out->len = len;
-       block_ctx_out->datav = NULL;
-       block_ctx_out->pagev = NULL;
-       block_ctx_out->mem_to_free = NULL;
-       if (NULL != block_ctx_out->dev) {
-               return 0;
-       } else {
-               printk(KERN_INFO "btrfsic: error, cannot lookup dev (#2)!\n");
-               return -ENXIO;
-       }
-}
-
 static void btrfsic_release_block_ctx(struct btrfsic_block_data_ctx *block_ctx)
 {
        if (block_ctx->mem_to_free) {
@@ -2002,24 +1980,13 @@ again:
                        }
                }
 
-               if (block->is_superblock)
-                       ret = btrfsic_map_superblock(state, bytenr,
-                                                    processed_len,
-                                                    bdev, &block_ctx);
-               else
-                       ret = btrfsic_map_block(state, bytenr, processed_len,
-                                               &block_ctx, 0);
-               if (ret) {
-                       printk(KERN_INFO
-                              "btrfsic: btrfsic_map_block(root @%llu)"
-                              " failed!\n", bytenr);
-                       goto continue_loop;
-               }
-               block_ctx.datav = mapped_datav;
-               /* the following is required in case of writes to mirrors,
-                * use the same that was used for the lookup */
                block_ctx.dev = dev_state;
                block_ctx.dev_bytenr = dev_bytenr;
+               block_ctx.start = bytenr;
+               block_ctx.len = processed_len;
+               block_ctx.pagev = NULL;
+               block_ctx.mem_to_free = NULL;
+               block_ctx.datav = mapped_datav;
 
                if (is_metadata || state->include_extent_data) {
                        block->never_written = 0;
@@ -2133,10 +2100,6 @@ again:
                        /* this is getting ugly for the
                         * include_extent_data case... */
                        bytenr = 0;     /* unknown */
-                       block_ctx.start = bytenr;
-                       block_ctx.len = processed_len;
-                       block_ctx.mem_to_free = NULL;
-                       block_ctx.pagev = NULL;
                } else {
                        processed_len = state->metablock_size;
                        bytenr = btrfs_stack_header_bytenr(
@@ -2149,22 +2112,15 @@ again:
                                       "Written block @%llu (%s/%llu/?)"
                                       " !found in hash table, M.\n",
                                       bytenr, dev_state->name, dev_bytenr);
-
-                       ret = btrfsic_map_block(state, bytenr, processed_len,
-                                               &block_ctx, 0);
-                       if (ret) {
-                               printk(KERN_INFO
-                                      "btrfsic: btrfsic_map_block(root @%llu)"
-                                      " failed!\n",
-                                      dev_bytenr);
-                               goto continue_loop;
-                       }
                }
-               block_ctx.datav = mapped_datav;
-               /* the following is required in case of writes to mirrors,
-                * use the same that was used for the lookup */
+
                block_ctx.dev = dev_state;
                block_ctx.dev_bytenr = dev_bytenr;
+               block_ctx.start = bytenr;
+               block_ctx.len = processed_len;
+               block_ctx.pagev = NULL;
+               block_ctx.mem_to_free = NULL;
+               block_ctx.datav = mapped_datav;
 
                block = btrfsic_block_alloc();
                if (NULL == block) {