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 <tao.ma@oracle.com>
Signed-off-by: Joel Becker <joel.becker@oracle.com>
In ocfs2_extend_rotate_transaction, op_credits is the orignal
credits in the handle and we only want to extend the credits
for the rotation, but the old solution always double it. It
is harmless for some minor operations, but for actions like
reflink we may rotate tree many times and cause the credits
increase dramatically. So this patch try to only increase
the desired credits.
Signed-off-by: Tao Ma <tao.ma@oracle.com>
During CoW, if the old extent record is refcounted, we allocate
som new clusters and do CoW. Actually we can have some improvement
here. If the old extent has refcount=1, that means now it is only
used by this file. So we don't need to allocate new clusters, just
remove the refcounted flag and it is OK. We also have to remove
it from the refcount tree while not deleting it.
Signed-off-by: Tao Ma <tao.ma@oracle.com>
This patch try CoW support for a refcounted record.
the whole process will be:
1. Calculate how many clusters we need to CoW and where we start.
Extents that are not completely encompassed by the write will
be broken on 1MB boundaries.
2. Do CoW for the clusters with the help of page cache.
3. Change the b-tree structure with the new allocated clusters.
Signed-off-by: Tao Ma <tao.ma@oracle.com>
Add 'Decrement refcount for delete' in to the normal truncate
process. So for a refcounted extent record, call refcount rec
decrementation instead of cluster free.
Signed-off-by: Tao Ma <tao.ma@oracle.com>
Given a physical cpos and length, decrement the refcount
in the tree. If the refcount for any portion of the extent goes
to zero, that portion is queued for freeing.
Signed-off-by: Tao Ma <tao.ma@oracle.com>
Now fs/ocfs2/alloc.c has more than 7000 lines. It contains our
basic b-tree operation. Although we have already make our b-tree
operation generic, the basic structrue ocfs2_path which is used
to iterate one b-tree branch is still static and limited to only
used in alloc.c. As refcount tree need them and I don't want to
add any more b-tree unrelated code to alloc.c, export them out.
Signed-off-by: Tao Ma <tao.ma@oracle.com>
Add refcount b-tree as a new extent tree so that it can
use the b-tree to store and maniuplate ocfs2_refcount_rec.
Signed-off-by: Tao Ma <tao.ma@oracle.com>
ocfs2_mark_extent_written actually does the following things:
1. check the parameters.
2. initialize the left_path and split_rec.
3. call __ocfs2_mark_extent_written. it will do:
1) check the flags of unwritten
2) do the real split work.
The whole process is packed tightly somehow. So this patch
will abstract 2 different functions so that future b-tree
operation can work with it.
1. __ocfs2_split_extent will accept path and split_rec and do
the real split work.
2. ocfs2_change_extent_flag will accept a new flag and initialize
path and split_rec.
So now ocfs2_mark_extent_written will do:
1. check the parameters.
2. call ocfs2_change_extent_flag.
1) initalize the left_path and split_rec.
2) check whether the new flags conflict with the old one.
3) call __ocfs2_split_extent to do the split.
Signed-off-by: Tao Ma <tao.ma@oracle.com>
Add a new operation eo_ocfs2_extent_contig int the extent tree's
operations vector. So that with the new refcount tree, We want
this so that refcount trees can always return CONTIG_NONE and
prevent extent merging.
Signed-off-by: Tao Ma <tao.ma@oracle.com>
With this commit, extent tree operations are divorced from inodes and
rely on ocfs2_caching_info. Phew!
Signed-off-by: Joel Becker <joel.becker@oracle.com>
We only allow unwritten extents on data, so the toplevel
ocfs2_mark_extent_written() can use an inode all it wants. But the
subfunction isn't even using the inode argument.
Signed-off-by: Joel Becker <joel.becker@oracle.com>
ocfs2_insert_extent() wants to insert a record into the extent map if
it's an inode data extent. But since many btrees can call that
function, let's make it an op on ocfs2_extent_tree. Other tree types
can leave it empty.
Signed-off-by: Joel Becker <joel.becker@oracle.com>
ocfs2_remove_extent() wants to truncate the extent map if it's
truncating an inode data extent. But since many btrees can call that
function, let's make it an op on ocfs2_extent_tree. Other tree types
can leave it empty.
Signed-off-by: Joel Becker <joel.becker@oracle.com>
ocfs2_grow_branch() not really using it other than to pass it to the
subfunctions ocfs2_shift_tree_depth(), ocfs2_find_branch_target(), and
ocfs2_add_branch(). The first two weren't it either, so they drop the
argument. ocfs2_add_branch() only passed it to
ocfs2_adjust_rightmost_branch(), which drops the inode argument and uses
the ocfs2_extent_tree as well.
ocfs2_append_rec_to_path() can be take an ocfs2_extent_tree instead of
the inode. The function ocfs2_adjust_rightmost_records() goes along for
the ride.
Signed-off-by: Joel Becker <joel.becker@oracle.com>
It already gets ocfs2_extent_tree, so we can just use that. This chains
to the same modification for ocfs2_remove_rightmost_path() and
ocfs2_rotate_rightmost_leaf_left().
Signed-off-by: Joel Becker <joel.becker@oracle.com>
It already has struct ocfs2_extent_tree, which has the caching info. So
we don't need to pass it struct inode.
Signed-off-by: Joel Becker <joel.becker@oracle.com>
It already has struct ocfs2_extent_tree, which has the caching info. So
we don't need to pass it struct inode.
Signed-off-by: Joel Becker <joel.becker@oracle.com>
Get rid of the inode argument. Use extent_tree instead. This means a
few more functions have to pass an extent_tree around.
Signed-off-by: Joel Becker <joel.becker@oracle.com>
Pass the ocfs2_extent_list down through ocfs2_rotate_tree_right() and
get rid of struct inode in ocfs2_rotate_subtree_root_right().
Signed-off-by: Joel Becker <joel.becker@oracle.com>
Pass struct ocfs2_extent_tree into ocfs2_create_new_meta_bhs(). It no
longer needs struct inode or ocfs2_super.
Signed-off-by: Joel Becker <joel.becker@oracle.com>
ocfs2_find_path and ocfs2_find_leaf() walk our btrees, reading extent
blocks. They need struct ocfs2_caching_info for that, but not struct
inode.
Signed-off-by: Joel Becker <joel.becker@oracle.com>
extent blocks belong to btrees on more than just inodes, so we want to
pass the ocfs2_caching_info structure directly to
ocfs2_read_extent_block(). A number of places in alloc.c can now drop
struct inode from their argument list.
Signed-off-by: Joel Becker <joel.becker@oracle.com>
What do we cache? Metadata blocks. What are most of our non-inode metadata
blocks? Extent blocks for our btrees. struct ocfs2_extent_tree is the
main structure for managing those. So let's store the associated
ocfs2_caching_info there.
This means that ocfs2_et_root_journal_access() doesn't need struct inode
anymore, and any place that has an et can refer to et->et_ci instead of
INODE_CACHE(inode).
Signed-off-by: Joel Becker <joel.becker@oracle.com>
The next step in divorcing metadata I/O management from struct inode is
to pass struct ocfs2_caching_info to the journal functions. Thus the
journal locks a metadata cache with the cache io_lock function. It also
can compare ci_last_trans and ci_created_trans directly.
This is a large patch because of all the places we change
ocfs2_journal_access..(handle, inode, ...) to
ocfs2_journal_access..(handle, INODE_CACHE(inode), ...).
Signed-off-by: Joel Becker <joel.becker@oracle.com>
We are really passing the inode into the ocfs2_read/write_blocks()
functions to get at the metadata cache. This commit passes the cache
directly into the metadata block functions, divorcing them from the
inode.
Signed-off-by: Joel Becker <joel.becker@oracle.com>
In ocfs2_do_truncate, we forget to release last_eb_bh which
will cause memleak. So call brelse in the end.
Signed-off-by: Tao Ma <tao.ma@oracle.com>
Signed-off-by: Joel Becker <joel.becker@oracle.com>
In ocfs2_adjust_adjacent_records, we will adjust adjacent records
according to the extent_list in the lower level. But actually
the lower level tree will either be a leaf or a branch. If we only
use ocfs2_is_empty_extent we will meet with some problem if the lower
tree is a branch (tree_depth > 1). So use !ocfs2_rec_clusters instead.
And actually only the leaf record can have holes. So add a BUG_ON
for non-leaf branch.
Signed-off-by: Tao Ma <tao.ma@oracle.com>
Signed-off-by: Joel Becker <joel.becker@oracle.com>
In normal tree rotation left process, we will never touch the tree
branch above subtree_index and ocfs2_extend_rotate_transaction doesn't
reserve the credits for them either.
But when we want to delete the rightmost extent block, we have to update
the rightmost records for all the rightmost branch(See
ocfs2_update_edge_lengths), so we have to allocate extra credits for them.
What's more, we have to access them also.
Signed-off-by: Tao Ma <tao.ma@oracle.com>
Signed-off-by: Joel Becker <joel.becker@oracle.com>
