[PATCH 3.2 14/52] Btrfs: don't use ram_bytes for uncompressed inline items

[Ben Hutchings]

3.2.74-rc1 review patch.  If anyone has any objections, please let me know.

------------------

From: Chris Mason <clm@xxxxxx>

commit 514ac8ad8793a097c0c9d89202c642479d6dfa34 upstream.

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@xxxxxx>
Signed-off-by: Chris Mason <clm@xxxxxx>
[bwh: Backported to 3.2:
 - Don't use btrfs_map_token API
 - There are fewer callers of btrfs_file_extent_inline_len() to change
 - Adjust context]
Signed-off-by: Ben Hutchings <ben@xxxxxxxxxxxxxxx>
---
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -2174,15 +2174,6 @@ BTRFS_SETGET_FUNCS(file_extent_encryptio
 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
@@ -2196,6 +2187,29 @@ static inline u32 btrfs_file_extent_inli
 	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)
+{
+	/*
+	 * return the space used on disk if this item isn't
+	 * compressed or encoded
+	 */
+	if (btrfs_file_extent_compression(eb, fi) == 0 &&
+	    btrfs_file_extent_encryption(eb, fi) == 0 &&
+	    btrfs_file_extent_other_encoding(eb, fi) == 0) {
+		return btrfs_file_extent_inline_item_len(eb,
+							 btrfs_item_nr(eb, slot));
+	}
+
+	/* otherwise use the ram bytes field */
+	return btrfs_file_extent_ram_bytes(eb, fi);
+}
+
+
 static inline struct btrfs_root *btrfs_sb(struct super_block *sb)
 {
 	return sb->s_fs_info;
--- a/fs/btrfs/file.c
+++ b/fs/btrfs/file.c
@@ -622,7 +622,8 @@ next_slot:
 				btrfs_file_extent_num_bytes(leaf, fi);
 		} else if (extent_type == BTRFS_FILE_EXTENT_INLINE) {
 			extent_end = key.offset +
-				btrfs_file_extent_inline_len(leaf, fi);
+				btrfs_file_extent_inline_len(leaf,
+						     path->slots[0], fi);
 		} else {
 			WARN_ON(1);
 			extent_end = search_start;
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -1178,7 +1178,8 @@ next_slot:
 			nocow = 1;
 		} else if (extent_type == BTRFS_FILE_EXTENT_INLINE) {
 			extent_end = found_key.offset +
-				btrfs_file_extent_inline_len(leaf, fi);
+				btrfs_file_extent_inline_len(leaf,
+						     path->slots[0], fi);
 			extent_end = ALIGN(extent_end, root->sectorsize);
 		} else {
 			BUG_ON(1);
@@ -3095,7 +3096,7 @@ search_again:
 				    btrfs_file_extent_num_bytes(leaf, fi);
 			} else if (extent_type == BTRFS_FILE_EXTENT_INLINE) {
 				item_end += btrfs_file_extent_inline_len(leaf,
-									 fi);
+							 path->slots[0], fi);
 			}
 			item_end--;
 		}
@@ -3161,6 +3162,12 @@ search_again:
 					inode_sub_bytes(inode, item_end + 1 -
 							new_size);
 				}
+
+				/*
+				 * update the ram bytes to properly reflect
+				 * the new size of our item
+				 */
+				btrfs_set_file_extent_ram_bytes(leaf, fi, size);
 				size =
 				    btrfs_file_extent_calc_inline_size(size);
 				ret = btrfs_truncate_item(trans, root, path,
@@ -5036,7 +5043,7 @@ again:
 		       btrfs_file_extent_num_bytes(leaf, item);
 	} else if (found_type == BTRFS_FILE_EXTENT_INLINE) {
 		size_t size;
-		size = btrfs_file_extent_inline_len(leaf, item);
+		size = btrfs_file_extent_inline_len(leaf, path->slots[0], item);
 		extent_end = (extent_start + size + root->sectorsize - 1) &
 			~((u64)root->sectorsize - 1);
 	}
@@ -5103,7 +5110,7 @@ again:
 			goto out;
 		}
 
-		size = btrfs_file_extent_inline_len(leaf, item);
+		size = btrfs_file_extent_inline_len(leaf, path->slots[0], item);
 		extent_offset = page_offset(page) + pg_offset - extent_start;
 		copy_size = min_t(u64, PAGE_CACHE_SIZE - pg_offset,
 				size - extent_offset);
--- a/fs/btrfs/print-tree.c
+++ b/fs/btrfs/print-tree.c
@@ -240,7 +240,7 @@ void btrfs_print_leaf(struct btrfs_root
 			    BTRFS_FILE_EXTENT_INLINE) {
 				printk(KERN_INFO "\t\tinline extent data "
 				       "size %u\n",
-				       btrfs_file_extent_inline_len(l, fi));
+				       btrfs_file_extent_inline_len(l, i, fi));
 				break;
 			}
 			printk(KERN_INFO "\t\textent data disk bytenr %llu "
--- a/fs/btrfs/tree-log.c
+++ b/fs/btrfs/tree-log.c
@@ -537,7 +537,7 @@ static noinline int replay_one_extent(st
 		if (btrfs_file_extent_disk_bytenr(eb, item) == 0)
 			nbytes = 0;
 	} else if (found_type == BTRFS_FILE_EXTENT_INLINE) {
-		size = btrfs_file_extent_inline_len(eb, item);
+		size = btrfs_file_extent_inline_len(eb, slot, item);
 		nbytes = btrfs_file_extent_ram_bytes(eb, item);
 		extent_end = (start + size + mask) & ~mask;
 	} else {

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