From: Christoph Hellwig Date: Wed, 24 May 2023 15:03:14 +0000 (+0200) Subject: btrfs: atomically insert the new extent in btrfs_split_ordered_extent X-Git-Tag: v6.6.7~2168^2~107 X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=816f589b8d43f7c258b0c10a5ce29daf01614651;p=platform%2Fkernel%2Flinux-starfive.git btrfs: atomically insert the new extent in btrfs_split_ordered_extent Currently there is a small race window in btrfs_split_ordered_extent, where the reduced old extent can be looked up on the per-inode rbtree or the per-root list while the newly split out one isn't visible yet. Fix this by open coding btrfs_alloc_ordered_extent in btrfs_split_ordered_extent, and holding the tree lock and root->ordered_extent_lock over the entire tree and extent manipulation. Note that this introduces new lock ordering because previously ordered_extent_lock was never held over the tree lock. Reviewed-by: Johannes Thumshirn Signed-off-by: Christoph Hellwig Reviewed-by: David Sterba Signed-off-by: David Sterba --- diff --git a/fs/btrfs/ordered-data.c b/fs/btrfs/ordered-data.c index ea1c2ec..0dc2bd0 100644 --- a/fs/btrfs/ordered-data.c +++ b/fs/btrfs/ordered-data.c @@ -1135,15 +1135,17 @@ bool btrfs_try_lock_ordered_range(struct btrfs_inode *inode, u64 start, u64 end, struct btrfs_ordered_extent *btrfs_split_ordered_extent( struct btrfs_ordered_extent *ordered, u64 len) { - struct inode *inode = ordered->inode; - struct btrfs_ordered_inode_tree *tree = &BTRFS_I(inode)->ordered_tree; - struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb); + struct btrfs_inode *inode = BTRFS_I(ordered->inode); + struct btrfs_ordered_inode_tree *tree = &inode->ordered_tree; + struct btrfs_root *root = inode->root; + struct btrfs_fs_info *fs_info = root->fs_info; u64 file_offset = ordered->file_offset; u64 disk_bytenr = ordered->disk_bytenr; unsigned long flags = ordered->flags & BTRFS_ORDERED_TYPE_FLAGS; + struct btrfs_ordered_extent *new; struct rb_node *node; - trace_btrfs_ordered_extent_split(BTRFS_I(inode), ordered); + trace_btrfs_ordered_extent_split(inode, ordered); ASSERT(!(flags & (1U << BTRFS_ORDERED_COMPRESSED))); @@ -1163,7 +1165,16 @@ struct btrfs_ordered_extent *btrfs_split_ordered_extent( if (WARN_ON_ONCE(!list_empty(&ordered->list))) return ERR_PTR(-EINVAL); - spin_lock_irq(&tree->lock); + new = alloc_ordered_extent(inode, file_offset, len, len, disk_bytenr, + len, 0, flags, ordered->compress_type); + if (IS_ERR(new)) + return new; + + /* One ref for the tree. */ + refcount_inc(&new->refs); + + spin_lock_irq(&root->ordered_extent_lock); + spin_lock(&tree->lock); /* Remove from tree once */ node = &ordered->rb_node; rb_erase(node, &tree->tree); @@ -1182,19 +1193,19 @@ struct btrfs_ordered_extent *btrfs_split_ordered_extent( if (node) btrfs_panic(fs_info, -EEXIST, "zoned: inconsistency in ordered tree at offset %llu", - ordered->file_offset); + ordered->file_offset); - spin_unlock_irq(&tree->lock); - - /* - * The splitting extent is already counted and will be added again in - * btrfs_alloc_ordered_extent(). Subtract len to avoid double counting. - */ - percpu_counter_add_batch(&fs_info->ordered_bytes, -len, fs_info->delalloc_batch); + node = tree_insert(&tree->tree, new->file_offset, &new->rb_node); + if (node) + btrfs_panic(fs_info, -EEXIST, + "zoned: inconsistency in ordered tree at offset %llu", + new->file_offset); + spin_unlock(&tree->lock); - return btrfs_alloc_ordered_extent(BTRFS_I(inode), file_offset, len, len, - disk_bytenr, len, 0, flags, - ordered->compress_type); + list_add_tail(&new->root_extent_list, &root->ordered_extents); + root->nr_ordered_extents++; + spin_unlock_irq(&root->ordered_extent_lock); + return new; } int __init ordered_data_init(void)