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.c | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-) (limited to 'fs/ocfs2/alloc.c') diff --git a/fs/ocfs2/alloc.c b/fs/ocfs2/alloc.c index 38a42f5d59ff..5661db139ca0 100644 --- a/fs/ocfs2/alloc.c +++ b/fs/ocfs2/alloc.c @@ -1765,9 +1765,9 @@ set_and_inc: * * The array index of the subtree root is passed back. */ -static int ocfs2_find_subtree_root(struct ocfs2_extent_tree *et, - struct ocfs2_path *left, - struct ocfs2_path *right) +int ocfs2_find_subtree_root(struct ocfs2_extent_tree *et, + struct ocfs2_path *left, + struct ocfs2_path *right) { int i = 0; @@ -2872,8 +2872,8 @@ out: * This looks similar, but is subtly different to * ocfs2_find_cpos_for_left_leaf(). */ -static int ocfs2_find_cpos_for_right_leaf(struct super_block *sb, - struct ocfs2_path *path, u32 *cpos) +int ocfs2_find_cpos_for_right_leaf(struct super_block *sb, + struct ocfs2_path *path, u32 *cpos) { int i, j, ret = 0; u64 blkno; -- cgit v1.2.3