From 38a04e432768ec0b016f3c687b4de31ac111ae59 Mon Sep 17 00:00:00 2001 From: Tao Ma Date: Mon, 30 Nov 2009 14:32:19 +0800 Subject: ocfs2: Find proper end cpos for a leaf refcount block. ocfs2 refcount tree is stored as an extent tree while the leaf ocfs2_refcount_rec points to a refcount block. The following step can trip a kernel panic. mkfs.ocfs2 -b 512 -C 1M --fs-features=refcount $DEVICE mount -t ocfs2 $DEVICE $MNT_DIR FILE_NAME=$RANDOM FILE_NAME_1=$RANDOM FILE_REF="${FILE_NAME}_ref" FILE_REF_1="${FILE_NAME}_ref_1" for((i=0;i<305;i++)) do # /mnt/1048576 is a file with 1048576 sizes. cat /mnt/1048576 >> $MNT_DIR/$FILE_NAME cat /mnt/1048576 >> $MNT_DIR/$FILE_NAME_1 done for((i=0;i<3;i++)) do cat /mnt/1048576 >> $MNT_DIR/$FILE_NAME done for((i=0;i<2;i++)) do cat /mnt/1048576 >> $MNT_DIR/$FILE_NAME cat /mnt/1048576 >> $MNT_DIR/$FILE_NAME_1 done cat /mnt/1048576 >> $MNT_DIR/$FILE_NAME for((i=0;i<11;i++)) do cat /mnt/1048576 >> $MNT_DIR/$FILE_NAME cat /mnt/1048576 >> $MNT_DIR/$FILE_NAME_1 done reflink $MNT_DIR/$FILE_NAME $MNT_DIR/$FILE_REF # write_f is a program which will write some bytes to a file at offset. # write_f -f file_name -l offset -w write_bytes. ./write_f -f $MNT_DIR/$FILE_REF -l $[310*1048576] -w 4096 ./write_f -f $MNT_DIR/$FILE_REF -l $[306*1048576] -w 4096 ./write_f -f $MNT_DIR/$FILE_REF -l $[311*1048576] -w 4096 ./write_f -f $MNT_DIR/$FILE_NAME -l $[310*1048576] -w 4096 ./write_f -f $MNT_DIR/$FILE_NAME -l $[311*1048576] -w 4096 reflink $MNT_DIR/$FILE_NAME $MNT_DIR/$FILE_REF_1 ./write_f -f $MNT_DIR/$FILE_NAME -l $[311*1048576] -w 4096 #kernel panic here. The reason is that if the ocfs2_extent_rec is the last record in a leaf extent block, the old solution fails to find the suitable end cpos. So this patch try to walk through the b-tree, find the next sub root and get the c_pos the next sub-tree starts from. btw, I have runned tristan's test case against the patched kernel for several days and this type of kernel panic never happens again. Signed-off-by: Tao Ma Signed-off-by: Joel Becker --- fs/ocfs2/alloc.h | 5 +++++ 1 file changed, 5 insertions(+) (limited to 'fs/ocfs2/alloc.h') diff --git a/fs/ocfs2/alloc.h b/fs/ocfs2/alloc.h index 9c122d574464..1db4359ccb90 100644 --- a/fs/ocfs2/alloc.h +++ b/fs/ocfs2/alloc.h @@ -317,4 +317,9 @@ int ocfs2_path_bh_journal_access(handle_t *handle, int ocfs2_journal_access_path(struct ocfs2_caching_info *ci, handle_t *handle, struct ocfs2_path *path); +int ocfs2_find_cpos_for_right_leaf(struct super_block *sb, + struct ocfs2_path *path, u32 *cpos); +int ocfs2_find_subtree_root(struct ocfs2_extent_tree *et, + struct ocfs2_path *left, + struct ocfs2_path *right); #endif /* OCFS2_ALLOC_H */ -- cgit v1.2.3