diff --git a/fs/btrfs/btrfs_inode.h b/fs/btrfs/btrfs_inode.h
index e9a979d0a958..ec6679a538c1 100644
--- a/fs/btrfs/btrfs_inode.h
+++ b/fs/btrfs/btrfs_inode.h
@@ -85,6 +85,7 @@ struct btrfs_inode {
 	 * logged_trans), to access/update delalloc_bytes, new_delalloc_bytes,
 	 * defrag_bytes, disk_i_size, outstanding_extents, csum_bytes and to
 	 * update the VFS' inode number of bytes used.
+	 * Also protects setting struct file::private_data.
 	 */
 	spinlock_t lock;
 
diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index 06333a74d6c4..f7bb4c34b984 100644
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -445,6 +445,8 @@ struct btrfs_file_private {
 	void *filldir_buf;
 	u64 last_index;
 	struct extent_state *llseek_cached_state;
+	/* Task that allocated this structure. */
+	struct task_struct *owner_task;
 };
 
 static inline u32 BTRFS_LEAF_DATA_SIZE(const struct btrfs_fs_info *info)
diff --git a/fs/btrfs/file.c b/fs/btrfs/file.c
index 15fd8c00f4c0..fc6c91773bc8 100644
--- a/fs/btrfs/file.c
+++ b/fs/btrfs/file.c
@@ -3481,7 +3481,7 @@ static bool find_desired_extent_in_hole(struct btrfs_inode *inode, int whence,
 static loff_t find_desired_extent(struct file *file, loff_t offset, int whence)
 {
 	struct btrfs_inode *inode = BTRFS_I(file->f_mapping->host);
-	struct btrfs_file_private *private = file->private_data;
+	struct btrfs_file_private *private;
 	struct btrfs_fs_info *fs_info = inode->root->fs_info;
 	struct extent_state *cached_state = NULL;
 	struct extent_state **delalloc_cached_state;
@@ -3509,7 +3509,19 @@ static loff_t find_desired_extent(struct file *file, loff_t offset, int whence)
 	    inode_get_bytes(&inode->vfs_inode) == i_size)
 		return i_size;
 
-	if (!private) {
+	spin_lock(&inode->lock);
+	private = file->private_data;
+	spin_unlock(&inode->lock);
+
+	if (private && private->owner_task != current) {
+		/*
+		 * Not allocated by us, don't use it as its cached state is used
+		 * by the task that allocated it and we don't want neither to
+		 * mess with it nor get incorrect results because it reflects an
+		 * invalid state for the current task.
+		 */
+		private = NULL;
+	} else if (!private) {
 		private = kzalloc(sizeof(*private), GFP_KERNEL);
 		/*
 		 * No worries if memory allocation failed.
@@ -3517,7 +3529,23 @@ static loff_t find_desired_extent(struct file *file, loff_t offset, int whence)
 		 * lseek SEEK_HOLE/DATA calls to a file when there's delalloc,
 		 * so everything will still be correct.
 		 */
-		file->private_data = private;
+		if (private) {
+			bool free = false;
+
+			private->owner_task = current;
+
+			spin_lock(&inode->lock);
+			if (file->private_data)
+				free = true;
+			else
+				file->private_data = private;
+			spin_unlock(&inode->lock);
+
+			if (free) {
+				kfree(private);
+				private = NULL;
+			}
+		}
 	}
 
 	if (private)