Btrfs: kill max_extent mount option

As Yan pointed out, theres not much reason for all this complicated math to
account for file extents being split up into max_extent chunks, since they are
likely to all end up in the same leaf anyway.  Since there isn't much reason to
use max_extent, just remove the option altogether so we have one less thing we
need to test.

Signed-off-by: Josef Bacik <josef@redhat.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>

6 files changed, 13 insertions, 81 deletions

diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index 11115847d875..ae8c40922c54 100644
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -834,7 +834,6 @@ struct btrfs_fs_info {
         u64 last_trans_log_full_commit;
         u64 open_ioctl_trans;
         unsigned long mount_opt;
-        u64 max_extent;
         u64 max_inline;
         u64 alloc_start;
         struct btrfs_transaction *running_transaction;
diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index 5ae1c0fcfce0..6632e5c4c8bb 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -1634,7 +1634,6 @@ struct btrfs_root *open_ctree(struct super_block *sb,
         atomic_set(&fs_info->async_submit_draining, 0);
         atomic_set(&fs_info->nr_async_bios, 0);
         fs_info->sb = sb;
-        fs_info->max_extent = (u64)-1;
         fs_info->max_inline = 8192 * 1024;
         fs_info->metadata_ratio = 0;
 
diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index 4c910359c807..5f6bc283c0c8 100644
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -2846,7 +2846,7 @@ int btrfs_unreserve_metadata_for_delalloc(struct btrfs_root *root,
         }
         spin_unlock(&BTRFS_I(inode)->accounting_lock);
 
-        BTRFS_I(inode)->reserved_extents--;
+        BTRFS_I(inode)->reserved_extents -= num_items;
         BUG_ON(BTRFS_I(inode)->reserved_extents < 0);
 
         if (meta_sinfo->bytes_delalloc < num_bytes) {
@@ -3111,7 +3111,7 @@ again:
                 return -ENOSPC;
         }
 
-        BTRFS_I(inode)->reserved_extents++;
+        BTRFS_I(inode)->reserved_extents += num_items;
         check_force_delalloc(meta_sinfo);
         spin_unlock(&meta_sinfo->lock);
 
diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index 2a337a09c650..a85b90c86cb0 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -796,7 +796,7 @@ static noinline int cow_file_range(struct inode *inode,
         while (disk_num_bytes > 0) {
                 unsigned long op;
 
-                cur_alloc_size = min(disk_num_bytes, root->fs_info->max_extent);
+                cur_alloc_size = disk_num_bytes;
                 ret = btrfs_reserve_extent(trans, root, cur_alloc_size,
                                            root->sectorsize, 0, alloc_hint,
                                            (u64)-1, &ins, 1);
@@ -1227,30 +1227,9 @@ static int run_delalloc_range(struct inode *inode, struct page *locked_page,
 static int btrfs_split_extent_hook(struct inode *inode,
                                     struct extent_state *orig, u64 split)
 {
-        struct btrfs_root *root = BTRFS_I(inode)->root;
-        u64 size;
-
         if (!(orig->state & EXTENT_DELALLOC))
                 return 0;
 
-        size = orig->end - orig->start + 1;
-        if (size > root->fs_info->max_extent) {
-                u64 num_extents;
-                u64 new_size;
-
-                new_size = orig->end - split + 1;
-                num_extents = div64_u64(size + root->fs_info->max_extent - 1,
-                                        root->fs_info->max_extent);
-
-                /*
-                 * if we break a large extent up then leave oustanding_extents
-                 * be, since we've already accounted for the large extent.
-                 */
-                if (div64_u64(new_size + root->fs_info->max_extent - 1,
-                              root->fs_info->max_extent) < num_extents)
-                        return 0;
-        }
-
         spin_lock(&BTRFS_I(inode)->accounting_lock);
         BTRFS_I(inode)->outstanding_extents++;
         spin_unlock(&BTRFS_I(inode)->accounting_lock);
@@ -1268,38 +1247,10 @@ static int btrfs_merge_extent_hook(struct inode *inode,
                                    struct extent_state *new,
                                    struct extent_state *other)
 {
-        struct btrfs_root *root = BTRFS_I(inode)->root;
-        u64 new_size, old_size;
-        u64 num_extents;
-
         /* not delalloc, ignore it */
         if (!(other->state & EXTENT_DELALLOC))
                 return 0;
 
-        old_size = other->end - other->start + 1;
-        if (new->start < other->start)
-                new_size = other->end - new->start + 1;
-        else
-                new_size = new->end - other->start + 1;
-
-        /* we're not bigger than the max, unreserve the space and go */
-        if (new_size <= root->fs_info->max_extent) {
-                spin_lock(&BTRFS_I(inode)->accounting_lock);
-                BTRFS_I(inode)->outstanding_extents--;
-                spin_unlock(&BTRFS_I(inode)->accounting_lock);
-                return 0;
-        }
-
-        /*
-         * If we grew by another max_extent, just return, we want to keep that
-         * reserved amount.
-         */
-        num_extents = div64_u64(old_size + root->fs_info->max_extent - 1,
-                                root->fs_info->max_extent);
-        if (div64_u64(new_size + root->fs_info->max_extent - 1,
-                      root->fs_info->max_extent) > num_extents)
-                return 0;
-
         spin_lock(&BTRFS_I(inode)->accounting_lock);
         BTRFS_I(inode)->outstanding_extents--;
         spin_unlock(&BTRFS_I(inode)->accounting_lock);
@@ -1328,6 +1279,7 @@ static int btrfs_set_bit_hook(struct inode *inode, u64 start, u64 end,
                 BTRFS_I(inode)->outstanding_extents++;
                 spin_unlock(&BTRFS_I(inode)->accounting_lock);
                 btrfs_delalloc_reserve_space(root, inode, end - start + 1);
+
                 spin_lock(&root->fs_info->delalloc_lock);
                 BTRFS_I(inode)->delalloc_bytes += end - start + 1;
                 root->fs_info->delalloc_bytes += end - start + 1;
@@ -1356,6 +1308,7 @@ static int btrfs_clear_bit_hook(struct inode *inode,
 
                 if (bits & EXTENT_DO_ACCOUNTING) {
                         spin_lock(&BTRFS_I(inode)->accounting_lock);
+                        WARN_ON(!BTRFS_I(inode)->outstanding_extents);
                         BTRFS_I(inode)->outstanding_extents--;
                         spin_unlock(&BTRFS_I(inode)->accounting_lock);
                         btrfs_unreserve_metadata_for_delalloc(root, inode, 1);
@@ -5384,7 +5337,6 @@ free:
 void btrfs_drop_inode(struct inode *inode)
 {
         struct btrfs_root *root = BTRFS_I(inode)->root;
-
         if (inode->i_nlink > 0 && btrfs_root_refs(&root->root_item) == 0)
                 generic_delete_inode(inode);
         else
@@ -5788,18 +5740,15 @@ static int prealloc_file_range(struct inode *inode, u64 start, u64 end,
         struct btrfs_trans_handle *trans;
         struct btrfs_root *root = BTRFS_I(inode)->root;
         struct btrfs_key ins;
-        u64 alloc_size;
         u64 cur_offset = start;
         u64 num_bytes = end - start;
         int ret = 0;
         u64 i_size;
 
         while (num_bytes > 0) {
-                alloc_size = min(num_bytes, root->fs_info->max_extent);
-
                 trans = btrfs_start_transaction(root, 1);
 
-                ret = btrfs_reserve_extent(trans, root, alloc_size,
+                ret = btrfs_reserve_extent(trans, root, num_bytes,
                                            root->sectorsize, 0, alloc_hint,
                                            (u64)-1, &ins, 1);
                 if (ret) {
diff --git a/fs/btrfs/ordered-data.c b/fs/btrfs/ordered-data.c
index a8ffecd0b491..5c99882b9763 100644
--- a/fs/btrfs/ordered-data.c
+++ b/fs/btrfs/ordered-data.c
@@ -303,6 +303,7 @@ static int __btrfs_remove_ordered_extent(struct inode *inode,
                                 struct btrfs_ordered_extent *entry)
 {
         struct btrfs_ordered_inode_tree *tree;
+        struct btrfs_root *root = BTRFS_I(inode)->root;
         struct rb_node *node;
 
         tree = &BTRFS_I(inode)->ordered_tree;
@@ -312,12 +313,13 @@ static int __btrfs_remove_ordered_extent(struct inode *inode,
         set_bit(BTRFS_ORDERED_COMPLETE, &entry->flags);
 
         spin_lock(&BTRFS_I(inode)->accounting_lock);
+        WARN_ON(!BTRFS_I(inode)->outstanding_extents);
         BTRFS_I(inode)->outstanding_extents--;
         spin_unlock(&BTRFS_I(inode)->accounting_lock);
         btrfs_unreserve_metadata_for_delalloc(BTRFS_I(inode)->root,
                                               inode, 1);
 
-        spin_lock(&BTRFS_I(inode)->root->fs_info->ordered_extent_lock);
+        spin_lock(&root->fs_info->ordered_extent_lock);
         list_del_init(&entry->root_extent_list);
 
         /*
@@ -329,7 +331,7 @@ static int __btrfs_remove_ordered_extent(struct inode *inode,
             !mapping_tagged(inode->i_mapping, PAGECACHE_TAG_DIRTY)) {
                 list_del_init(&BTRFS_I(inode)->ordered_operations);
         }
-        spin_unlock(&BTRFS_I(inode)->root->fs_info->ordered_extent_lock);
+        spin_unlock(&root->fs_info->ordered_extent_lock);
 
         return 0;
 }
diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c
index 9ac612e6ca60..d11b12fc086b 100644
--- a/fs/btrfs/super.c
+++ b/fs/btrfs/super.c
@@ -64,10 +64,9 @@ static void btrfs_put_super(struct super_block *sb)
 
 enum {
         Opt_degraded, Opt_subvol, Opt_subvolid, Opt_device, Opt_nodatasum,
-        Opt_nodatacow, Opt_max_extent, Opt_max_inline, Opt_alloc_start,
-        Opt_nobarrier, Opt_ssd, Opt_nossd, Opt_ssd_spread, Opt_thread_pool,
-        Opt_noacl, Opt_compress, Opt_compress_force, Opt_notreelog, Opt_ratio,
-        Opt_flushoncommit,
+        Opt_nodatacow, Opt_max_inline, Opt_alloc_start, Opt_nobarrier, Opt_ssd,
+        Opt_nossd, Opt_ssd_spread, Opt_thread_pool, Opt_noacl, Opt_compress,
+        Opt_compress_force, Opt_notreelog, Opt_ratio, Opt_flushoncommit,
         Opt_discard, Opt_err,
 };
 
@@ -79,7 +78,6 @@ static match_table_t tokens = {
         {Opt_nodatasum, "nodatasum"},
         {Opt_nodatacow, "nodatacow"},
         {Opt_nobarrier, "nobarrier"},
-        {Opt_max_extent, "max_extent=%s"},
         {Opt_max_inline, "max_inline=%s"},
         {Opt_alloc_start, "alloc_start=%s"},
         {Opt_thread_pool, "thread_pool=%d"},
@@ -188,18 +186,6 @@ int btrfs_parse_options(struct btrfs_root *root, char *options)
                                        info->thread_pool_size);
                         }
                         break;
-                case Opt_max_extent:
-                        num = match_strdup(&args[0]);
-                        if (num) {
-                                info->max_extent = memparse(num, NULL);
-                                kfree(num);
-
-                                info->max_extent = max_t(u64,
-                                        info->max_extent, root->sectorsize);
-                                printk(KERN_INFO "btrfs: max_extent at %llu\n",
-                                       (unsigned long long)info->max_extent);
-                        }
-                        break;
                 case Opt_max_inline:
                         num = match_strdup(&args[0]);
                         if (num) {
@@ -529,9 +515,6 @@ static int btrfs_show_options(struct seq_file *seq, struct vfsmount *vfs)
                 seq_puts(seq, ",nodatacow");
         if (btrfs_test_opt(root, NOBARRIER))
                 seq_puts(seq, ",nobarrier");
-        if (info->max_extent != (u64)-1)
-                seq_printf(seq, ",max_extent=%llu",
-                           (unsigned long long)info->max_extent);
         if (info->max_inline != 8192 * 1024)
                 seq_printf(seq, ",max_inline=%llu",
                            (unsigned long long)info->max_inline);