btrfs: move can_cow_file_range_inline() outside of the extent lock

These checks aren't reliant on the extent lock.  Move this up into
cow_file_range_inline(), and then update encoded writes to call this
check before calling __cow_file_range_inline().  This will allow us to
skip the extent lock if we're not able to inline the given extent.
Reviewed-by: Goldwyn Rodrigues <rgoldwyn@suse.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: David Sterba <dsterba@suse.com>

fs/btrfs/inode.c

@@ -661,6 +661,9 @@ static bool can_cow_file_range_inline(struct btrfs_inode *inode,
  * conditionally insert an inline extent into the file.  This
  * does the checks required to make sure the data is small enough
  * to fit as an inline extent.
+ *
+ * If being used directly, you must have already checked we're allowed to cow
+ * the range by getting true from can_cow_file_range_inline().
  */
 static noinline int __cow_file_range_inline(struct btrfs_inode *inode, u64 offset,
 					    u64 size, size_t compressed_size,
@@ -676,9 +679,6 @@ static noinline int __cow_file_range_inline(struct btrfs_inode *inode, u64 offse
 	int ret;
 	struct btrfs_path *path;
 
-	if (!can_cow_file_range_inline(inode, offset, size, compressed_size))
-		return 1;
-
 	path = btrfs_alloc_path();
 	if (!path)
 		return -ENOMEM;
@@ -750,6 +750,9 @@ static noinline int cow_file_range_inline(struct btrfs_inode *inode, u64 offset,
 	u64 size = min_t(u64, i_size_read(&inode->vfs_inode), end + 1);
 	int ret;
 
+	if (!can_cow_file_range_inline(inode, offset, size, compressed_size))
+		return 1;
+
 	lock_extent(&inode->io_tree, offset, end, &cached);
 	ret = __cow_file_range_inline(inode, offset, size, compressed_size,
 				      compress_type, compressed_folio,
@@ -10287,7 +10290,8 @@ ssize_t btrfs_do_encoded_write(struct kiocb *iocb, struct iov_iter *from,
 
 	/* Try an inline extent first. */
 	if (encoded->unencoded_len == encoded->len &&
-	    encoded->unencoded_offset == 0) {
+	    encoded->unencoded_offset == 0 &&
+	    can_cow_file_range_inline(inode, start, encoded->len, orig_count)) {
 		ret = __cow_file_range_inline(inode, start, encoded->len,
 					      orig_count, compression, folios[0],
 					      true);