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Commit 555936bf authored by Tao Ma's avatar Tao Ma Committed by Joel Becker
Browse files

ocfs2: Abstract extent split process. 



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: default avatarTao Ma <tao.ma@oracle.com>
parent 853a3a14

fs/ocfs2/alloc.c

+100 −50
Original line number Diff line number Diff line
@@ -5032,9 +5032,8 @@ out: 
}



/*

 * Mark part or all of the extent record at split_index in the leaf

 * pointed to by path as written. This removes the unwritten

 * extent flag.

 * Split part or all of the extent record at split_index in the leaf

 * pointed to by path. Merge with the contiguous extent record if needed.

 *

 * Care is taken to handle contiguousness so as to not grow the tree.

 *
@@ -5051,7 +5050,7 @@ out: 
 * have been brought into cache (and pinned via the journal), so the

 * extra overhead is not expressed in terms of disk reads.

 */

static int __ocfs2_mark_extent_written(handle_t *handle,

static int __ocfs2_split_extent(handle_t *handle,

				struct ocfs2_extent_tree *et,

				struct ocfs2_path *path,

				int split_index,
@@ -5066,12 +5065,6 @@ static int __ocfs2_mark_extent_written(handle_t *handle, 
	struct ocfs2_merge_ctxt ctxt;

	struct ocfs2_extent_list *rightmost_el;



	if (!(rec->e_flags & OCFS2_EXT_UNWRITTEN)) {

		ret = -EIO;

		mlog_errno(ret);

		goto out;

	}



	if (le32_to_cpu(rec->e_cpos) > le32_to_cpu(split_rec->e_cpos) ||

	    ((le32_to_cpu(rec->e_cpos) + le16_to_cpu(rec->e_leaf_clusters)) <

	     (le32_to_cpu(split_rec->e_cpos) + le16_to_cpu(split_rec->e_leaf_clusters)))) {
@@ -5141,42 +5134,31 @@ out: 
}



/*

 * Mark the already-existing extent at cpos as written for len clusters.

 * Change the flags of the already-existing extent at cpos for len clusters.

 *

 * new_flags: the flags we want to set.

 * clear_flags: the flags we want to clear.

 * phys: the new physical offset we want this new extent starts from.

 *

 * If the existing extent is larger than the request, initiate a

 * split. An attempt will be made at merging with adjacent extents.

 *

 * The caller is responsible for passing down meta_ac if we'll need it.

 */

int ocfs2_mark_extent_written(struct inode *inode,

static int ocfs2_change_extent_flag(handle_t *handle,

				    struct ocfs2_extent_tree *et,

			      handle_t *handle, u32 cpos, u32 len, u32 phys,

				    u32 cpos, u32 len, u32 phys,

				    struct ocfs2_alloc_context *meta_ac,

			      struct ocfs2_cached_dealloc_ctxt *dealloc)

				    struct ocfs2_cached_dealloc_ctxt *dealloc,

				    int new_flags, int clear_flags)

{

	int ret, index;

	u64 start_blkno = ocfs2_clusters_to_blocks(inode->i_sb, phys);

	struct super_block *sb = ocfs2_metadata_cache_get_super(et->et_ci);

	u64 start_blkno = ocfs2_clusters_to_blocks(sb, phys);

	struct ocfs2_extent_rec split_rec;

	struct ocfs2_path *left_path = NULL;

	struct ocfs2_extent_list *el;



	mlog(0, "Inode %lu cpos %u, len %u, phys %u (%llu)\n",

	     inode->i_ino, cpos, len, phys, (unsigned long long)start_blkno);



	if (!ocfs2_writes_unwritten_extents(OCFS2_SB(inode->i_sb))) {

		ocfs2_error(inode->i_sb, "Inode %llu has unwritten extents "

			    "that are being written to, but the feature bit "

			    "is not set in the super block.",

			    (unsigned long long)OCFS2_I(inode)->ip_blkno);

		ret = -EROFS;

		goto out;

	}



	/*

	 * XXX: This should be fixed up so that we just re-insert the

	 * next extent records.

	 */

	ocfs2_et_extent_map_truncate(et, 0);

	struct ocfs2_extent_rec *rec;



	left_path = ocfs2_new_path_from_et(et);

	if (!left_path) {
@@ -5194,22 +5176,44 @@ int ocfs2_mark_extent_written(struct inode *inode, 


	index = ocfs2_search_extent_list(el, cpos);

	if (index == -1 || index >= le16_to_cpu(el->l_next_free_rec)) {

		ocfs2_error(inode->i_sb,

			    "Inode %llu has an extent at cpos %u which can no "

		ocfs2_error(sb,

			    "Owner %llu has an extent at cpos %u which can no "

			    "longer be found.\n",

			    (unsigned long long)OCFS2_I(inode)->ip_blkno, cpos);

			     (unsigned long long)

			     ocfs2_metadata_cache_owner(et->et_ci), cpos);

		ret = -EROFS;

		goto out;

	}



	ret = -EIO;

	rec = &el->l_recs[index];

	if (new_flags && (rec->e_flags & new_flags)) {

		mlog(ML_ERROR, "Owner %llu tried to set %d flags on an "

		     "extent that already had them",

		     (unsigned long long)ocfs2_metadata_cache_owner(et->et_ci),

		     new_flags);

		goto out;

	}



	if (clear_flags && !(rec->e_flags & clear_flags)) {

		mlog(ML_ERROR, "Owner %llu tried to clear %d flags on an "

		     "extent that didn't have them",

		     (unsigned long long)ocfs2_metadata_cache_owner(et->et_ci),

		     clear_flags);

		goto out;

	}



	memset(&split_rec, 0, sizeof(struct ocfs2_extent_rec));

	split_rec.e_cpos = cpu_to_le32(cpos);

	split_rec.e_leaf_clusters = cpu_to_le16(len);

	split_rec.e_blkno = cpu_to_le64(start_blkno);

	split_rec.e_flags = path_leaf_el(left_path)->l_recs[index].e_flags;

	split_rec.e_flags &= ~OCFS2_EXT_UNWRITTEN;

	split_rec.e_flags = rec->e_flags;

	if (new_flags)

		split_rec.e_flags |= new_flags;

	if (clear_flags)

		split_rec.e_flags &= ~clear_flags;



	ret = __ocfs2_mark_extent_written(handle, et, left_path,

	ret = __ocfs2_split_extent(handle, et, left_path,

				  index, &split_rec, meta_ac,

				  dealloc);

	if (ret)
@@ -5218,6 +5222,52 @@ int ocfs2_mark_extent_written(struct inode *inode, 
out:

	ocfs2_free_path(left_path);

	return ret;



}



/*

 * Mark the already-existing extent at cpos as written for len clusters.

 * This removes the unwritten extent flag.

 *

 * If the existing extent is larger than the request, initiate a

 * split. An attempt will be made at merging with adjacent extents.

 *

 * The caller is responsible for passing down meta_ac if we'll need it.

 */

int ocfs2_mark_extent_written(struct inode *inode,

			      struct ocfs2_extent_tree *et,

			      handle_t *handle, u32 cpos, u32 len, u32 phys,

			      struct ocfs2_alloc_context *meta_ac,

			      struct ocfs2_cached_dealloc_ctxt *dealloc)

{

	int ret;



	mlog(0, "Inode %lu cpos %u, len %u, phys clusters %u\n",

	     inode->i_ino, cpos, len, phys);



	if (!ocfs2_writes_unwritten_extents(OCFS2_SB(inode->i_sb))) {

		ocfs2_error(inode->i_sb, "Inode %llu has unwritten extents "

			    "that are being written to, but the feature bit "

			    "is not set in the super block.",

			    (unsigned long long)OCFS2_I(inode)->ip_blkno);

		ret = -EROFS;

		goto out;

	}



	/*

	 * XXX: This should be fixed up so that we just re-insert the

	 * next extent records.

	 */

	ocfs2_et_extent_map_truncate(et, 0);



	ret = ocfs2_change_extent_flag(handle, et, cpos,

				       len, phys, meta_ac, dealloc,

				       0, OCFS2_EXT_UNWRITTEN);

	if (ret)

		mlog_errno(ret);



out:

	return ret;

}



static int ocfs2_split_tree(handle_t *handle, struct ocfs2_extent_tree *et,