Fix btrfs_get_extent and get_block corner cases, and disable O_DIRECT reads

The generic O_DIRECT code assumes all the bios have the same bdev,
which isn't true for multi-device btrfs.

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

3 files changed, 23 insertions, 12 deletions

diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c
index 81f8b4fd069b..6e4bf029c6d4 100644
--- a/fs/btrfs/extent_io.c
+++ b/fs/btrfs/extent_io.c
@@ -1694,6 +1694,7 @@ extent_bio_alloc(struct block_device *bdev, u64 first_sector, int nr_vecs,
         }
 
         if (bio) {
+                bio->bi_size = 0;
                 bio->bi_bdev = bdev;
                 bio->bi_sector = first_sector;
         }
diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index e875c7c8a647..abfe86df02d2 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -494,6 +494,7 @@ int btrfs_readpage_io_failed_hook(struct bio *failed_bio,
         bio->bi_end_io = failed_bio->bi_end_io;
         bio->bi_sector = failrec->logical >> 9;
         bio->bi_bdev = failed_bio->bi_bdev;
+        bio->bi_size = 0;
         bio_add_page(bio, page, failrec->len, start - page_offset(page));
         btrfs_submit_bio_hook(inode, READ, bio, failrec->last_mirror);
         return 0;
@@ -2187,12 +2188,9 @@ again:
         spin_unlock(&em_tree->lock);
 
         if (em) {
-                if (em->start > start) {
-                        printk("get_extent lookup [%Lu %Lu] em [%Lu %Lu]\n",
-                               start, len, em->start, em->len);
-                        WARN_ON(1);
-                }
-                if (em->block_start == EXTENT_MAP_INLINE && page)
+                if (em->start > start || em->start + em->len <= start)
+                        free_extent_map(em);
+                else if (em->block_start == EXTENT_MAP_INLINE && page)
                         free_extent_map(em);
                 else
                         goto out;
@@ -2340,7 +2338,6 @@ insert:
         err = 0;
         spin_lock(&em_tree->lock);
         ret = add_extent_mapping(em_tree, em);
-
         /* it is possible that someone inserted the extent into the tree
          * while we had the lock dropped.  It is also possible that
          * an overlapping map exists in the tree
@@ -2348,6 +2345,11 @@ insert:
         if (ret == -EEXIST) {
                 struct extent_map *existing;
                 existing = lookup_extent_mapping(em_tree, start, len);
+                if (existing && (existing->start > start ||
+                    existing->start + existing->len <= start)) {
+                        free_extent_map(existing);
+                        existing = NULL;
+                }
                 if (!existing) {
                         existing = lookup_extent_mapping(em_tree, em->start,
                                                          em->len);
@@ -2388,6 +2390,7 @@ out:
         return em;
 }
 
+#if 0 /* waiting for O_DIRECT reads */
 static int btrfs_get_block(struct inode *inode, sector_t iblock,
                         struct buffer_head *bh_result, int create)
 {
@@ -2405,22 +2408,24 @@ static int btrfs_get_block(struct inode *inode, sector_t iblock,
         if (!em || IS_ERR(em))
                 goto out;
 
-        if (em->start > start || em->start + em->len <= start)
+        if (em->start > start || em->start + em->len <= start) {
             goto out;
+        }
 
         if (em->block_start == EXTENT_MAP_INLINE) {
                 ret = -EINVAL;
                 goto out;
         }
 
+        len = em->start + em->len - start;
+        len = min_t(u64, len, INT_LIMIT(typeof(bh_result->b_size)));
+
         if (em->block_start == EXTENT_MAP_HOLE ||
             em->block_start == EXTENT_MAP_DELALLOC) {
+                bh_result->b_size = len;
                 goto out;
         }
 
-        len = em->start + em->len - start;
-        len = min_t(u64, len, INT_LIMIT(typeof(bh_result->b_size)));
-
         logical = start - em->start;
         logical = em->block_start + logical;
 
@@ -2430,6 +2435,7 @@ static int btrfs_get_block(struct inode *inode, sector_t iblock,
         BUG_ON(ret);
         bh_result->b_blocknr = multi->stripes[0].physical >> inode->i_blkbits;
         bh_result->b_size = min(map_length, len);
+
         bh_result->b_bdev = multi->stripes[0].dev->bdev;
         set_buffer_mapped(bh_result);
         kfree(multi);
@@ -2437,11 +2443,14 @@ out:
         free_extent_map(em);
         return ret;
 }
+#endif
 
 static ssize_t btrfs_direct_IO(int rw, struct kiocb *iocb,
                         const struct iovec *iov, loff_t offset,
                         unsigned long nr_segs)
 {
+        return -EINVAL;
+#if 0
         struct file *file = iocb->ki_filp;
         struct inode *inode = file->f_mapping->host;
 
@@ -2450,6 +2459,7 @@ static ssize_t btrfs_direct_IO(int rw, struct kiocb *iocb,
 
         return blockdev_direct_IO(rw, iocb, inode, inode->i_sb->s_bdev, iov,
                                   offset, nr_segs, btrfs_get_block, NULL);
+#endif
 }
 
 static sector_t btrfs_bmap(struct address_space *mapping, sector_t iblock)
diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index 5619e50583e3..bccb5566fd84 100644
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -1161,7 +1161,6 @@ int btrfs_map_bio(struct btrfs_root *root, int rw, struct bio *bio,
         int total_devs = 1;
 
         length = bio->bi_size;
-
         map_tree = &root->fs_info->mapping_tree;
         map_length = length;
 
@@ -1192,6 +1191,7 @@ int btrfs_map_bio(struct btrfs_root *root, int rw, struct bio *bio,
                 }
                 bio->bi_sector = multi->stripes[dev_nr].physical >> 9;
                 dev = multi->stripes[dev_nr].dev;
+
                 bio->bi_bdev = dev->bdev;
                 spin_lock(&dev->io_lock);
                 dev->total_ios++;