[RFC,ONLY,04/23] btrfs: explicitly keep track of file extent item size.

Commit Message

Sweet Tea Dorminy July 13, 2022, 10:29 a.m. UTC

From: Omar Sandoval <[e-mail]>

Previously, file extents were always of constant size. However, for
fscrypt, they will need to store an IV, and this IV varies in length
according to the encryption algorithm, making the file extent items also
of variable length. Therefore, this begins passing around the actual
file extent item size instead of assuming it is merely the size of the
item in memory.

Signed-off-by: Sweet Tea Dorminy <[e-mail]>
---
 fs/btrfs/ctree.h   | 1 +
 fs/btrfs/file.c    | 4 ++--
 fs/btrfs/inode.c   | 1 +
 fs/btrfs/reflink.c | 1 +
 4 files changed, 5 insertions(+), 2 deletions(-)

Patch

diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index 538a1f357e59..ddff384604ee 100644
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -1355,6 +1355,7 @@  struct btrfs_replace_extent_info {
 	u64 file_offset;
 	/* Pointer to a file extent item of type regular or prealloc. */
 	char *extent_buf;
+	u32 extent_buf_size;
 	/*
 	 * Set to true when attempting to replace a file range with a new extent
 	 * described by this structure, set to false when attempting to clone an
diff --git a/fs/btrfs/file.c b/fs/btrfs/file.c
index d0172cb54d9f..a93b205c663b 100644
--- a/fs/btrfs/file.c
+++ b/fs/btrfs/file.c
@@ -2687,14 +2687,14 @@  static int btrfs_insert_replace_extent(struct btrfs_trans_handle *trans,
 	key.type = BTRFS_EXTENT_DATA_KEY;
 	key.offset = extent_info->file_offset;
 	ret = btrfs_insert_empty_item(trans, root, path, &key,
-				      sizeof(struct btrfs_file_extent_item));
+				      extent_info->extent_buf_size);
 	if (ret)
 		return ret;
 	leaf = path->nodes[0];
 	slot = path->slots[0];
 	write_extent_buffer(leaf, extent_info->extent_buf,
 			    btrfs_item_ptr_offset(leaf, slot),
-			    sizeof(struct btrfs_file_extent_item));
+			    extent_info->extent_buf_size);
 	extent = btrfs_item_ptr(leaf, slot, struct btrfs_file_extent_item);
 	ASSERT(btrfs_file_extent_type(leaf, extent) != BTRFS_FILE_EXTENT_INLINE);
 	btrfs_set_file_extent_offset(leaf, extent, extent_info->data_offset);
diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index 057744b8815c..43ebf37a156e 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -9966,6 +9966,7 @@  static struct btrfs_trans_handle *insert_prealloc_file_extent(
 	extent_info.data_len = len;
 	extent_info.file_offset = file_offset;
 	extent_info.extent_buf = (char *)&stack_fi;
+	extent_info.extent_buf_size = sizeof(stack_fi);
 	extent_info.is_new_extent = true;
 	extent_info.update_times = true;
 	extent_info.qgroup_reserved = qgroup_released;
diff --git a/fs/btrfs/reflink.c b/fs/btrfs/reflink.c
index 9acf47b11fe6..e5c2616a486e 100644
--- a/fs/btrfs/reflink.c
+++ b/fs/btrfs/reflink.c
@@ -495,6 +495,7 @@  static int btrfs_clone(struct inode *src, struct inode *inode,
 			clone_info.data_len = datal;
 			clone_info.file_offset = new_key.offset;
 			clone_info.extent_buf = buf;
+			clone_info.extent_buf_size = size;
 			clone_info.is_new_extent = false;
 			clone_info.update_times = !no_time_update;
 			ret = btrfs_replace_file_extents(BTRFS_I(inode), path,