btrfs: fix integer overflow in calc_reclaim_items_nr

Dave Jones hit a WARN_ON(nr < 0) in btrfs_wait_ordered_roots() with
v4.12-rc6.  This was because commit 70e7af244 made it possible for
calc_reclaim_items_nr() to return a negative number.  It's not really a
bug in that commit, it just didn't go far enough down the stack to find
all the possible 64->32 bit overflows.

This switches calc_reclaim_items_nr() to return a u64 and changes everyone
that uses the results of that math to u64 as well.

Reported-by: Dave Jones <davej@codemonkey.org.uk>
Fixes: 70e7af2 ("Btrfs: fix delalloc accounting leak caused by u32 overflow")
Signed-off-by: Chris Mason <clm@fb.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

10 files changed, 24 insertions, 25 deletions

diff --git a/fs/btrfs/dev-replace.c b/fs/btrfs/dev-replace.c
index 5fe1ca8abc70..bee3edeea7a3 100644
--- a/fs/btrfs/dev-replace.c
+++ b/fs/btrfs/dev-replace.c
@@ -388,7 +388,7 @@ int btrfs_dev_replace_start(struct btrfs_fs_info *fs_info,
         if (ret)
                 btrfs_err(fs_info, "kobj add dev failed %d", ret);
 
-        btrfs_wait_ordered_roots(fs_info, -1, 0, (u64)-1);
+        btrfs_wait_ordered_roots(fs_info, U64_MAX, 0, (u64)-1);
 
         /* force writing the updated state information to disk */
         trans = btrfs_start_transaction(root, 0);
@@ -507,7 +507,7 @@ static int btrfs_dev_replace_finishing(struct btrfs_fs_info *fs_info,
                 mutex_unlock(&dev_replace->lock_finishing_cancel_unmount);
                 return ret;
         }
-        btrfs_wait_ordered_roots(fs_info, -1, 0, (u64)-1);
+        btrfs_wait_ordered_roots(fs_info, U64_MAX, 0, (u64)-1);
 
         trans = btrfs_start_transaction(root, 0);
         if (IS_ERR(trans)) {
diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index a3339acec28c..375f8c728d91 100644
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -4288,7 +4288,7 @@ commit_trans:
 
                         if (need_commit > 0) {
                                 btrfs_start_delalloc_roots(fs_info, 0, -1);
-                                btrfs_wait_ordered_roots(fs_info, -1, 0,
+                                btrfs_wait_ordered_roots(fs_info, U64_MAX, 0,
                                                          (u64)-1);
                         }
 
@@ -4748,14 +4748,14 @@ static void btrfs_writeback_inodes_sb_nr(struct btrfs_fs_info *fs_info,
         }
 }
 
-static inline int calc_reclaim_items_nr(struct btrfs_fs_info *fs_info,
+static inline u64 calc_reclaim_items_nr(struct btrfs_fs_info *fs_info,
                                         u64 to_reclaim)
 {
         u64 bytes;
-        int nr;
+        u64 nr;
 
         bytes = btrfs_calc_trans_metadata_size(fs_info, 1);
-        nr = (int)div64_u64(to_reclaim, bytes);
+        nr = div64_u64(to_reclaim, bytes);
         if (!nr)
                 nr = 1;
         return nr;
@@ -4774,15 +4774,15 @@ static void shrink_delalloc(struct btrfs_fs_info *fs_info, u64 to_reclaim,
         struct btrfs_trans_handle *trans;
         u64 delalloc_bytes;
         u64 max_reclaim;
+        u64 items;
         long time_left;
         unsigned long nr_pages;
         int loops;
-        int items;
         enum btrfs_reserve_flush_enum flush;
 
         /* Calc the number of the pages we need flush for space reservation */
         items = calc_reclaim_items_nr(fs_info, to_reclaim);
-        to_reclaim = (u64)items * EXTENT_SIZE_PER_ITEM;
+        to_reclaim = items * EXTENT_SIZE_PER_ITEM;
 
         trans = (struct btrfs_trans_handle *)current->journal_info;
         block_rsv = &fs_info->delalloc_block_rsv;
diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
index b4e9941efb60..fa1b78cf25f6 100644
--- a/fs/btrfs/ioctl.c
+++ b/fs/btrfs/ioctl.c
@@ -689,7 +689,7 @@ static int create_snapshot(struct btrfs_root *root, struct inode *dir,
         if (ret)
                 goto dec_and_free;
 
-        btrfs_wait_ordered_extents(root, -1, 0, (u64)-1);
+        btrfs_wait_ordered_extents(root, U64_MAX, 0, (u64)-1);
 
         btrfs_init_block_rsv(&pending_snapshot->block_rsv,
                              BTRFS_BLOCK_RSV_TEMP);
diff --git a/fs/btrfs/ordered-data.c b/fs/btrfs/ordered-data.c
index 7b40e2e7292a..a3aca495e33e 100644
--- a/fs/btrfs/ordered-data.c
+++ b/fs/btrfs/ordered-data.c
@@ -663,7 +663,7 @@ static void btrfs_run_ordered_extent_work(struct btrfs_work *work)
  * wait for all the ordered extents in a root.  This is done when balancing
  * space between drives.
  */
-int btrfs_wait_ordered_extents(struct btrfs_root *root, int nr,
+u64 btrfs_wait_ordered_extents(struct btrfs_root *root, u64 nr,
                                const u64 range_start, const u64 range_len)
 {
         struct btrfs_fs_info *fs_info = root->fs_info;
@@ -671,7 +671,7 @@ int btrfs_wait_ordered_extents(struct btrfs_root *root, int nr,
         LIST_HEAD(skipped);
         LIST_HEAD(works);
         struct btrfs_ordered_extent *ordered, *next;
-        int count = 0;
+        u64 count = 0;
         const u64 range_end = range_start + range_len;
 
         mutex_lock(&root->ordered_extent_mutex);
@@ -701,7 +701,7 @@ int btrfs_wait_ordered_extents(struct btrfs_root *root, int nr,
 
                 cond_resched();
                 spin_lock(&root->ordered_extent_lock);
-                if (nr != -1)
+                if (nr != U64_MAX)
                         nr--;
                 count++;
         }
@@ -720,13 +720,13 @@ int btrfs_wait_ordered_extents(struct btrfs_root *root, int nr,
         return count;
 }
 
-int btrfs_wait_ordered_roots(struct btrfs_fs_info *fs_info, int nr,
-                              const u64 range_start, const u64 range_len)
+u64 btrfs_wait_ordered_roots(struct btrfs_fs_info *fs_info, u64 nr,
+                             const u64 range_start, const u64 range_len)
 {
         struct btrfs_root *root;
         struct list_head splice;
-        int done;
-        int total_done = 0;
+        u64 total_done = 0;
+        u64 done;
 
         INIT_LIST_HEAD(&splice);
 
@@ -748,9 +748,8 @@ int btrfs_wait_ordered_roots(struct btrfs_fs_info *fs_info, int nr,
                 total_done += done;
 
                 spin_lock(&fs_info->ordered_root_lock);
-                if (nr != -1) {
+                if (nr != U64_MAX) {
                         nr -= done;
-                        WARN_ON(nr < 0);
                 }
         }
         list_splice_tail(&splice, &fs_info->ordered_roots);
diff --git a/fs/btrfs/ordered-data.h b/fs/btrfs/ordered-data.h
index e0c1d5b8d859..56c4c0ee6381 100644
--- a/fs/btrfs/ordered-data.h
+++ b/fs/btrfs/ordered-data.h
@@ -200,9 +200,9 @@ int btrfs_ordered_update_i_size(struct inode *inode, u64 offset,
                                 struct btrfs_ordered_extent *ordered);
 int btrfs_find_ordered_sum(struct inode *inode, u64 offset, u64 disk_bytenr,
                            u32 *sum, int len);
-int btrfs_wait_ordered_extents(struct btrfs_root *root, int nr,
+u64 btrfs_wait_ordered_extents(struct btrfs_root *root, u64 nr,
                                const u64 range_start, const u64 range_len);
-int btrfs_wait_ordered_roots(struct btrfs_fs_info *fs_info, int nr,
+u64 btrfs_wait_ordered_roots(struct btrfs_fs_info *fs_info, u64 nr,
                               const u64 range_start, const u64 range_len);
 void btrfs_get_logged_extents(struct btrfs_inode *inode,
                               struct list_head *logged_list,
diff --git a/fs/btrfs/qgroup.c b/fs/btrfs/qgroup.c
index fc9dffaa9524..4ce351efe281 100644
--- a/fs/btrfs/qgroup.c
+++ b/fs/btrfs/qgroup.c
@@ -2405,7 +2405,7 @@ retry:
                                 ret = btrfs_start_delalloc_inodes(root, 0);
                                 if (ret)
                                         return ret;
-                                btrfs_wait_ordered_extents(root, -1, 0, (u64)-1);
+                                btrfs_wait_ordered_extents(root, U64_MAX, 0, (u64)-1);
                                 trans = btrfs_join_transaction(root);
                                 if (IS_ERR(trans))
                                         return PTR_ERR(trans);
diff --git a/fs/btrfs/relocation.c b/fs/btrfs/relocation.c
index dc69b6ba29af..65661d1aae4e 100644
--- a/fs/btrfs/relocation.c
+++ b/fs/btrfs/relocation.c
@@ -4373,7 +4373,7 @@ int btrfs_relocate_block_group(struct btrfs_fs_info *fs_info, u64 group_start)
 
         btrfs_wait_block_group_reservations(rc->block_group);
         btrfs_wait_nocow_writers(rc->block_group);
-        btrfs_wait_ordered_roots(fs_info, -1,
+        btrfs_wait_ordered_roots(fs_info, U64_MAX,
                                  rc->block_group->key.objectid,
                                  rc->block_group->key.offset);
 
diff --git a/fs/btrfs/scrub.c b/fs/btrfs/scrub.c
index 738e784ba20d..0cebeb5eb5d0 100644
--- a/fs/btrfs/scrub.c
+++ b/fs/btrfs/scrub.c
@@ -3836,7 +3836,7 @@ int scrub_enumerate_chunks(struct scrub_ctx *sctx,
                          */
                         btrfs_wait_block_group_reservations(cache);
                         btrfs_wait_nocow_writers(cache);
-                        ret = btrfs_wait_ordered_roots(fs_info, -1,
+                        ret = btrfs_wait_ordered_roots(fs_info, U64_MAX,
                                                        cache->key.objectid,
                                                        cache->key.offset);
                         if (ret > 0) {
diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c
index ba2cb7f96986..74e47794e63f 100644
--- a/fs/btrfs/super.c
+++ b/fs/btrfs/super.c
@@ -1177,7 +1177,7 @@ int btrfs_sync_fs(struct super_block *sb, int wait)
                 return 0;
         }
 
-        btrfs_wait_ordered_roots(fs_info, -1, 0, (u64)-1);
+        btrfs_wait_ordered_roots(fs_info, U64_MAX, 0, (u64)-1);
 
         trans = btrfs_attach_transaction_barrier(root);
         if (IS_ERR(trans)) {
diff --git a/fs/btrfs/transaction.c b/fs/btrfs/transaction.c
index 309b73da756b..f615d59b0489 100644
--- a/fs/btrfs/transaction.c
+++ b/fs/btrfs/transaction.c
@@ -1923,7 +1923,7 @@ static inline int btrfs_start_delalloc_flush(struct btrfs_fs_info *fs_info)
 static inline void btrfs_wait_delalloc_flush(struct btrfs_fs_info *fs_info)
 {
         if (btrfs_test_opt(fs_info, FLUSHONCOMMIT))
-                btrfs_wait_ordered_roots(fs_info, -1, 0, (u64)-1);
+                btrfs_wait_ordered_roots(fs_info, U64_MAX, 0, (u64)-1);
 }
 
 static inline void