Messages in this thread Patch in this message | ![/](/images/icornerl.gif) | | From | Bo Ye <> | Subject | [PATCH 2/2] f2fs: add __pack attribute for extent_info | Date | Fri, 31 Mar 2023 17:26:57 +0800 |
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From: Qilin Tan <qilin.tan@mediatek.com>
Need add __pack for struct extent_info to align to memory layout of struct rb_entry.
struct rb_entry { struct rb_node rb_node; /* rb node located in rb-tree */ union { struct { unsigned int ofs; /* start offset of the entry */ unsigned int len; /* length of the entry */ }; unsigned long long key; /* 64-bits key */ } __packed; };
struct extent_info { unsigned int fofs; /* start offset in a file */ unsigned int len; /* length of the extent */ union { ... /* block age extent_cache */ struct { /* block age of the extent */ unsigned long long age; /* last total blocks allocated */ unsigned long long last_blocks; }; };
The new fields(age, last_blocks) are u64 in change 71644dff4811, it cause the memory alignment based on 8 bytes in some complier. So the field fofs and len are alloced with 8 bytes and using the last 4 byts. Its memory is not aligned with struct rb_entry. the ofs of rb_entry pointer to a invalid value and cause writing file failed.
struct extent_info's offset should be 12 rather than 16 from the beginning of struct rb_entry.
The offset dump for the bad case as: kworker/u16:6: [name:f2fs&]f2fs_lookup_rb_tree_for_insert:MTK_DEBUG: ino=1629 re=0xc675dc08 ofs=0 re->ofs=0, re->len=68 ei=0xc675dc18 ei.fofs=68 ei.len=277
Fixes: 71644dff4811 ("f2fs: add block_age-based extent cache") Signed-off-by: Bo Ye <bo.ye@mediatek.com> Signed-off-by: Qilin Tan <qilin.tan@mediatek.com> --- fs/f2fs/f2fs.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h index b0ab2062038a..7c690667a42f 100644 --- a/fs/f2fs/f2fs.h +++ b/fs/f2fs/f2fs.h @@ -660,7 +660,7 @@ struct extent_info { unsigned long long last_blocks; }; }; -}; +} __packed; struct extent_node { struct rb_node rb_node; /* rb node located in rb-tree */ -- 2.17.0
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