Btrfs: Handle data checksumming on bios that span multiple ordered extents

Data checksumming is done right before the bio is sent down the IO stack,
which means a single bio might span more than one ordered extent.  In
this case, the checksumming data is split between two ordered extents.

Signed-off-by: Chris Mason <chris.mason@oracle.com>

5 files changed, 69 insertions, 31 deletions

diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index acbce542d291..96ab2797c09a 100644
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -1579,8 +1579,8 @@ int btrfs_lookup_file_extent(struct btrfs_trans_handle *trans,
 int btrfs_csum_file_blocks(struct btrfs_trans_handle *trans,
                            struct btrfs_root *root, struct inode *inode,
                            struct btrfs_ordered_sum *sums);
-int btrfs_csum_one_bio(struct btrfs_root *root,
-                       struct bio *bio, struct btrfs_ordered_sum **sums_ret);
+int btrfs_csum_one_bio(struct btrfs_root *root, struct inode *inode,
+                       struct bio *bio);
 struct btrfs_csum_item *btrfs_lookup_csum(struct btrfs_trans_handle *trans,
                                           struct btrfs_root *root,
                                           struct btrfs_path *path,
diff --git a/fs/btrfs/file-item.c b/fs/btrfs/file-item.c
index 345caf8ff516..e02f1e5acb0a 100644
--- a/fs/btrfs/file-item.c
+++ b/fs/btrfs/file-item.c
@@ -134,26 +134,53 @@ int btrfs_lookup_file_extent(struct btrfs_trans_handle *trans,
         return ret;
 }
 
-int btrfs_csum_one_bio(struct btrfs_root *root,
-                       struct bio *bio, struct btrfs_ordered_sum **sums_ret)
+int btrfs_csum_one_bio(struct btrfs_root *root, struct inode *inode,
+                       struct bio *bio)
 {
         struct btrfs_ordered_sum *sums;
         struct btrfs_sector_sum *sector_sum;
+        struct btrfs_ordered_extent *ordered;
         char *data;
         struct bio_vec *bvec = bio->bi_io_vec;
         int bio_index = 0;
+        unsigned long total_bytes = 0;
+        unsigned long this_sum_bytes = 0;
+        u64 offset;
 
         WARN_ON(bio->bi_vcnt <= 0);
         sums = kzalloc(btrfs_ordered_sum_size(root, bio->bi_size), GFP_NOFS);
         if (!sums)
                 return -ENOMEM;
-        *sums_ret = sums;
+
         sector_sum = &sums->sums;
-        sums->file_offset = page_offset(bvec->bv_page);
+        sums->file_offset = page_offset(bvec->bv_page) + bvec->bv_offset;
         sums->len = bio->bi_size;
         INIT_LIST_HEAD(&sums->list);
+        ordered = btrfs_lookup_ordered_extent(inode, sums->file_offset);
+        BUG_ON(!ordered);
 
         while(bio_index < bio->bi_vcnt) {
+                offset = page_offset(bvec->bv_page) + bvec->bv_offset;
+                if (offset >= ordered->file_offset + ordered->len) {
+                        unsigned long bytes_left;
+                        sums->len = this_sum_bytes;
+                        this_sum_bytes = 0;
+                        btrfs_add_ordered_sum(inode, ordered, sums);
+                        btrfs_put_ordered_extent(ordered);
+
+                        bytes_left = bio->bi_size - total_bytes;
+
+                        sums = kzalloc(btrfs_ordered_sum_size(root, bytes_left),
+                                       GFP_NOFS);
+                        BUG_ON(!sums);
+                        sector_sum = &sums->sums;
+                        sums->len = bytes_left;
+                        sums->file_offset = offset;
+                        ordered = btrfs_lookup_ordered_extent(inode,
+                                                      sums->file_offset);
+                        BUG_ON(!ordered);
+                }
+
                 data = kmap_atomic(bvec->bv_page, KM_USER0);
                 sector_sum->sum = ~(u32)0;
                 sector_sum->sum = btrfs_csum_data(root,
@@ -165,10 +192,18 @@ int btrfs_csum_one_bio(struct btrfs_root *root,
                                  (char *)&sector_sum->sum);
                 sector_sum->offset = page_offset(bvec->bv_page) +
                         bvec->bv_offset;
+
                 sector_sum++;
                 bio_index++;
+                total_bytes += bvec->bv_len;
+                this_sum_bytes += bvec->bv_len;
                 bvec++;
         }
+        btrfs_add_ordered_sum(inode, ordered, sums);
+        btrfs_put_ordered_extent(ordered);
+        if (total_bytes != bio->bi_size) {
+printk("warning, total bytes %lu bio size %u\n", total_bytes, bio->bi_size);
+        }
         return 0;
 }
 
diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index f37e09e724f7..4d729d90d2b8 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -351,12 +351,8 @@ int __btrfs_submit_bio_hook(struct inode *inode, int rw, struct bio *bio,
 {
         struct btrfs_root *root = BTRFS_I(inode)->root;
         int ret = 0;
-        struct btrfs_ordered_sum *sums;
 
-        ret = btrfs_csum_one_bio(root, bio, &sums);
-        BUG_ON(ret);
-
-        ret = btrfs_add_ordered_sum(inode, sums);
+        ret = btrfs_csum_one_bio(root, inode, bio);
         BUG_ON(ret);
 
         return btrfs_map_bio(root, rw, bio, mirror_num, 1);
diff --git a/fs/btrfs/ordered-data.c b/fs/btrfs/ordered-data.c
index 230fd3ca6b2c..1ddb7bceea99 100644
--- a/fs/btrfs/ordered-data.c
+++ b/fs/btrfs/ordered-data.c
@@ -186,22 +186,17 @@ int btrfs_add_ordered_extent(struct inode *inode, u64 file_offset,
 
 /*
  * Add a struct btrfs_ordered_sum into the list of checksums to be inserted
- * when an ordered extent is finished.
+ * when an ordered extent is finished.  If the list covers more than one
+ * ordered extent, it is split across multiples.
  */
-int btrfs_add_ordered_sum(struct inode *inode, struct btrfs_ordered_sum *sum)
+int btrfs_add_ordered_sum(struct inode *inode,
+                          struct btrfs_ordered_extent *entry,
+                          struct btrfs_ordered_sum *sum)
 {
         struct btrfs_ordered_inode_tree *tree;
-        struct rb_node *node;
-        struct btrfs_ordered_extent *entry;
 
         tree = &BTRFS_I(inode)->ordered_tree;
         mutex_lock(&tree->mutex);
-        node = tree_search(tree, sum->file_offset);
-        BUG_ON(!node);
-
-        entry = rb_entry(node, struct btrfs_ordered_extent, rb_node);
-        BUG_ON(!offset_in_entry(entry, sum->file_offset));
-
         list_add_tail(&sum->list, &entry->list);
         mutex_unlock(&tree->mutex);
         return 0;
@@ -524,8 +519,10 @@ int btrfs_find_ordered_sum(struct inode *inode, u64 offset, u32 *sum)
         struct btrfs_ordered_extent *ordered;
         struct btrfs_ordered_inode_tree *tree = &BTRFS_I(inode)->ordered_tree;
         struct list_head *cur;
+        unsigned long num_sectors;
+        unsigned long i;
+        u32 sectorsize = BTRFS_I(inode)->root->sectorsize;
         int ret = 1;
-        int index;
 
         ordered = btrfs_lookup_ordered_extent(inode, offset);
         if (!ordered)
@@ -534,14 +531,17 @@ int btrfs_find_ordered_sum(struct inode *inode, u64 offset, u32 *sum)
         mutex_lock(&tree->mutex);
         list_for_each_prev(cur, &ordered->list) {
                 ordered_sum = list_entry(cur, struct btrfs_ordered_sum, list);
-                if (offset >= ordered_sum->file_offset &&
-                    offset < ordered_sum->file_offset + ordered_sum->len) {
-                        index = (offset - ordered_sum->file_offset) /
-                                BTRFS_I(inode)->root->sectorsize;;
+                if (offset >= ordered_sum->file_offset) {
+                        num_sectors = ordered_sum->len / sectorsize;
                         sector_sums = &ordered_sum->sums;
-                        *sum = sector_sums[index].sum;
-                        ret = 0;
-                        goto out;
+                        for (i = 0; i < num_sectors; i++) {
+                                if (sector_sums[i].offset == offset) {
+printk("find ordered sum inode %lu offset %Lu\n", inode->i_ino, offset);
+                                        *sum = sector_sums[i].sum;
+                                        ret = 0;
+                                        goto out;
+                                }
+                        }
                 }
         }
 out:
diff --git a/fs/btrfs/ordered-data.h b/fs/btrfs/ordered-data.h
index 98f491d1022b..1794efd13ca3 100644
--- a/fs/btrfs/ordered-data.h
+++ b/fs/btrfs/ordered-data.h
@@ -39,7 +39,11 @@ struct btrfs_sector_sum {
 
 struct btrfs_ordered_sum {
         u64 file_offset;
-        u64 len;
+        /*
+         * this is the length in bytes covered by the sums array below.
+         * But, the sums array may not be contiguous in the file.
+         */
+        unsigned long len;
         struct list_head list;
         /* last field is a variable length array of btrfs_sector_sums */
         struct btrfs_sector_sum sums;
@@ -95,6 +99,7 @@ static inline int btrfs_ordered_sum_size(struct btrfs_root *root, u64 bytes)
 {
         unsigned long num_sectors = (bytes + root->sectorsize - 1) /
                 root->sectorsize;
+        num_sectors++;
         return sizeof(struct btrfs_ordered_sum) +
                 num_sectors * sizeof(struct btrfs_sector_sum);
 }
@@ -114,7 +119,9 @@ int btrfs_dec_test_ordered_pending(struct inode *inode,
                                        u64 file_offset, u64 io_size);
 int btrfs_add_ordered_extent(struct inode *inode, u64 file_offset,
                              u64 start, u64 len);
-int btrfs_add_ordered_sum(struct inode *inode, struct btrfs_ordered_sum *sum);
+int btrfs_add_ordered_sum(struct inode *inode,
+                          struct btrfs_ordered_extent *entry,
+                          struct btrfs_ordered_sum *sum);
 struct btrfs_ordered_extent *btrfs_lookup_ordered_extent(struct inode *inode,
                                                          u64 file_offset);
 void btrfs_start_ordered_extent(struct inode *inode,