Btrfs: don't use ram_bytes for uncompressed inline items

If we truncate an uncompressed inline item, ram_bytes isn't updated to reflect
the new size.  The fixe uses the size directly from the item header when
reading uncompressed inlines, and also fixes truncate to update the
size as it goes.

Reported-by: Jens Axboe <axboe@fb.com>
Signed-off-by: Chris Mason <clm@fb.com>
CC: stable@vger.kernel.org

1 files changed, 26 insertions, 9 deletions

diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index 84d4c052fcd..fceddbdfdd3 100644
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -2990,15 +2990,6 @@ BTRFS_SETGET_FUNCS(file_extent_encryption, struct btrfs_file_extent_item,
 BTRFS_SETGET_FUNCS(file_extent_other_encoding, struct btrfs_file_extent_item,
 		   other_encoding, 16);
 
-/* this returns the number of file bytes represented by the inline item.
- * If an item is compressed, this is the uncompressed size
- */
-static inline u32 btrfs_file_extent_inline_len(struct extent_buffer *eb,
-					       struct btrfs_file_extent_item *e)
-{
-	return btrfs_file_extent_ram_bytes(eb, e);
-}
-
 /*
  * this returns the number of bytes used by the item on disk, minus the
  * size of any extent headers.  If a file is compressed on disk, this is
@@ -3012,6 +3003,32 @@ static inline u32 btrfs_file_extent_inline_item_len(struct extent_buffer *eb,
 	return btrfs_item_size(eb, e) - offset;
 }
 
+/* this returns the number of file bytes represented by the inline item.
+ * If an item is compressed, this is the uncompressed size
+ */
+static inline u32 btrfs_file_extent_inline_len(struct extent_buffer *eb,
+					       int slot,
+					       struct btrfs_file_extent_item *fi)
+{
+	struct btrfs_map_token token;
+
+	btrfs_init_map_token(&token);
+	/*
+	 * return the space used on disk if this item isn't
+	 * compressed or encoded
+	 */
+	if (btrfs_token_file_extent_compression(eb, fi, &token) == 0 &&
+	    btrfs_token_file_extent_encryption(eb, fi, &token) == 0 &&
+	    btrfs_token_file_extent_other_encoding(eb, fi, &token) == 0) {
+		return btrfs_file_extent_inline_item_len(eb,
+							 btrfs_item_nr(slot));
+	}
+
+	/* otherwise use the ram bytes field */
+	return btrfs_token_file_extent_ram_bytes(eb, fi, &token);
+}
+
+
 /* btrfs_dev_stats_item */
 static inline u64 btrfs_dev_stats_value(struct extent_buffer *eb,
 					struct btrfs_dev_stats_item *ptr,