From 88e2e6d72423912f62b3e44aeeb967d798a2c2f5 Mon Sep 17 00:00:00 2001
From: Qu Wenruo <wqu@suse.com>
Date: Wed, 26 Jun 2024 09:34:40 +0930
Subject: [PATCH] btrfs: ignore incorrect btrfs_file_extent_item::ram_bytes
[HICCUP]
Kernels can create file extent items with incorrect ram_bytes like this:
item 6 key (257 EXTENT_DATA 0) itemoff 15816 itemsize 53
generation 7 type 1 (regular)
extent data disk byte 13631488 nr 32768
extent data offset 0 nr 4096 ram 4096
extent compression 0 (none)
Thankfully kernel can handle them properly, as in that case ram_bytes is
not utilized at all.
[ENHANCEMENT]
Since the hiccup is not going to cause any data-loss and is only a minor
violation of on-disk format, here we only need to ignore the incorrect
ram_bytes value, and use the correct one from
btrfs_file_extent_item::disk_num_bytes.
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
---
fs/btrfs/file-item.c | 7 +++++++
1 file changed, 7 insertions(+)
diff --git a/fs/btrfs/file-item.c b/fs/btrfs/file-item.c
index 2cc61c792ee68..e815fefaffe17 100644
--- a/fs/btrfs/file-item.c
+++ b/fs/btrfs/file-item.c
@@ -1306,6 +1306,13 @@ void btrfs_extent_item_to_extent_map(struct btrfs_inode *inode,
if (compress_type != BTRFS_COMPRESS_NONE) {
extent_map_set_compression(em, compress_type);
} else {
+ /*
+ * Older kernels can create regular non-hole data
+ * extents with ram_bytes smaller than disk_num_bytes.
+ * Not a big deal, just always use disk_num_bytes
+ * for ram_bytes.
+ */
+ em->ram_bytes = em->disk_num_bytes;
if (type == BTRFS_FILE_EXTENT_PREALLOC)
em->flags |= EXTENT_FLAG_PREALLOC;
}
--
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