Commit 2ae99a60 authored by Mark Fasheh's avatar Mark Fasheh
Browse files

ocfs2: Support creation of unwritten extents 



This can now be trivially supported with re-use of our existing extend code.

ocfs2_allocate_unwritten_extents() takes a start offset and a byte length
and iterates over the inode, adding extents (marked as unwritten) until len
is reached. Existing extents are skipped over.

Signed-off-by: default avatarMark Fasheh <mark.fasheh@oracle.com>
parent b27b7cbc

fs/ocfs2/alloc.c

+2 −0
Original line number Diff line number Diff line
@@ -3726,6 +3726,7 @@ int ocfs2_insert_extent(struct ocfs2_super *osb, 
			u32 cpos,

			u64 start_blk,

			u32 new_clusters,

			u8 flags,

			struct ocfs2_alloc_context *meta_ac)

{

	int status;
@@ -3749,6 +3750,7 @@ int ocfs2_insert_extent(struct ocfs2_super *osb, 
	rec.e_cpos = cpu_to_le32(cpos);

	rec.e_blkno = cpu_to_le64(start_blk);

	rec.e_leaf_clusters = cpu_to_le16(new_clusters);

	rec.e_flags = flags;



	status = ocfs2_figure_insert_type(inode, fe_bh, &last_eb_bh, &rec,

					  &insert);

fs/ocfs2/alloc.h

+1 −0
Original line number Diff line number Diff line
@@ -34,6 +34,7 @@ int ocfs2_insert_extent(struct ocfs2_super *osb, 
			u32 cpos,

			u64 start_blk,

			u32 new_clusters,

			u8 flags,

			struct ocfs2_alloc_context *meta_ac);

struct ocfs2_cached_dealloc_ctxt;

int ocfs2_mark_extent_written(struct inode *inode, struct buffer_head *di_bh,

fs/ocfs2/aops.c

+1 −1
Original line number Diff line number Diff line
@@ -1136,7 +1136,7 @@ static int ocfs2_write_cluster(struct address_space *mapping, 
		 */

		tmp_pos = cpos;

		ret = ocfs2_do_extend_allocation(OCFS2_SB(inode->i_sb), inode,

						 &tmp_pos, 1, wc->w_di_bh,

						 &tmp_pos, 1, 0, wc->w_di_bh,

						 wc->w_handle, data_ac,

						 meta_ac, NULL);

		/*

fs/ocfs2/dir.c

+1 −1
Original line number Diff line number Diff line
@@ -368,7 +368,7 @@ int ocfs2_do_extend_dir(struct super_block *sb, 
		u32 offset = OCFS2_I(dir)->ip_clusters;



		status = ocfs2_do_extend_allocation(OCFS2_SB(sb), dir, &offset,

						    1, parent_fe_bh, handle,

						    1, 0, parent_fe_bh, handle,

						    data_ac, meta_ac, NULL);

		BUG_ON(status == -EAGAIN);

		if (status < 0) {

fs/ocfs2/file.c

+96 −23
Original line number Diff line number Diff line
@@ -425,6 +425,7 @@ int ocfs2_do_extend_allocation(struct ocfs2_super *osb, 
			       struct inode *inode,

			       u32 *logical_offset,

			       u32 clusters_to_add,

			       int mark_unwritten,

			       struct buffer_head *fe_bh,

			       handle_t *handle,

			       struct ocfs2_alloc_context *data_ac,
@@ -437,9 +438,13 @@ int ocfs2_do_extend_allocation(struct ocfs2_super *osb, 
	enum ocfs2_alloc_restarted reason = RESTART_NONE;

	u32 bit_off, num_bits;

	u64 block;

	u8 flags = 0;



	BUG_ON(!clusters_to_add);



	if (mark_unwritten)

		flags = OCFS2_EXT_UNWRITTEN;



	free_extents = ocfs2_num_free_extents(osb, inode, fe);

	if (free_extents < 0) {

		status = free_extents;
@@ -489,7 +494,7 @@ int ocfs2_do_extend_allocation(struct ocfs2_super *osb, 
	     num_bits, bit_off, (unsigned long long)OCFS2_I(inode)->ip_blkno);

	status = ocfs2_insert_extent(osb, handle, inode, fe_bh,

				     *logical_offset, block, num_bits,

				     meta_ac);

				     flags, meta_ac);

	if (status < 0) {

		mlog_errno(status);

		goto leave;
@@ -522,9 +527,11 @@ leave: 
 * For a given allocation, determine which allocators will need to be

 * accessed, and lock them, reserving the appropriate number of bits.

 *

 * Called from ocfs2_extend_allocation() for file systems which don't

 * support holes, and from ocfs2_write() for file systems which

 * understand sparse inodes.

 * Sparse file systems call this from ocfs2_write_begin_nolock()

 * and ocfs2_allocate_unwritten_extents().

 *

 * File systems which don't support holes call this from

 * ocfs2_extend_allocation().

 */

int ocfs2_lock_allocators(struct inode *inode, struct ocfs2_dinode *di,

			  u32 clusters_to_add, u32 extents_to_split,
@@ -595,14 +602,13 @@ out: 
	return ret;

}



static int ocfs2_extend_allocation(struct inode *inode,

				   u32 clusters_to_add)

static int __ocfs2_extend_allocation(struct inode *inode, u32 logical_start,

				     u32 clusters_to_add, int mark_unwritten)

{

	int status = 0;

	int restart_func = 0;

	int drop_alloc_sem = 0;

	int credits;

	u32 prev_clusters, logical_start;

	u32 prev_clusters;

	struct buffer_head *bh = NULL;

	struct ocfs2_dinode *fe = NULL;

	handle_t *handle = NULL;
@@ -617,7 +623,7 @@ static int ocfs2_extend_allocation(struct inode *inode, 
	 * This function only exists for file systems which don't

	 * support holes.

	 */

	BUG_ON(ocfs2_sparse_alloc(osb));

	BUG_ON(mark_unwritten && !ocfs2_sparse_alloc(osb));



	status = ocfs2_read_block(osb, OCFS2_I(inode)->ip_blkno, &bh,

				  OCFS2_BH_CACHED, inode);
@@ -633,18 +639,9 @@ static int ocfs2_extend_allocation(struct inode *inode, 
		goto leave;

	}



	logical_start = OCFS2_I(inode)->ip_clusters;



restart_all:

	BUG_ON(le32_to_cpu(fe->i_clusters) != OCFS2_I(inode)->ip_clusters);



	/* blocks peope in read/write from reading our allocation

	 * until we're done changing it. We depend on i_mutex to block

	 * other extend/truncate calls while we're here. Ordering wrt

	 * start_trans is important here -- always do it before! */

	down_write(&OCFS2_I(inode)->ip_alloc_sem);

	drop_alloc_sem = 1;



	status = ocfs2_lock_allocators(inode, fe, clusters_to_add, 0, &data_ac,

				       &meta_ac);

	if (status) {
@@ -678,6 +675,7 @@ restarted_transaction: 
					    inode,

					    &logical_start,

					    clusters_to_add,

					    mark_unwritten,

					    bh,

					    handle,

					    data_ac,
@@ -730,10 +728,6 @@ restarted_transaction: 
	     OCFS2_I(inode)->ip_clusters, i_size_read(inode));



leave:

	if (drop_alloc_sem) {

		up_write(&OCFS2_I(inode)->ip_alloc_sem);

		drop_alloc_sem = 0;

	}

	if (handle) {

		ocfs2_commit_trans(osb, handle);

		handle = NULL;
@@ -759,6 +753,25 @@ leave: 
	return status;

}



static int ocfs2_extend_allocation(struct inode *inode, u32 logical_start,

				   u32 clusters_to_add, int mark_unwritten)

{

	int ret;



	/*

	 * The alloc sem blocks peope in read/write from reading our

	 * allocation until we're done changing it. We depend on

	 * i_mutex to block other extend/truncate calls while we're

	 * here.

	 */

	down_write(&OCFS2_I(inode)->ip_alloc_sem);

	ret = __ocfs2_extend_allocation(inode, logical_start, clusters_to_add,

					mark_unwritten);

	up_write(&OCFS2_I(inode)->ip_alloc_sem);



	return ret;

}



/* Some parts of this taken from generic_cont_expand, which turned out

 * to be too fragile to do exactly what we need without us having to

 * worry about recursive locking in ->prepare_write() and
@@ -900,7 +913,9 @@ static int ocfs2_extend_file(struct inode *inode, 
	}



	if (clusters_to_add) {

		ret = ocfs2_extend_allocation(inode, clusters_to_add);

		ret = ocfs2_extend_allocation(inode,

					      OCFS2_I(inode)->ip_clusters,

					      clusters_to_add, 0);

		if (ret < 0) {

			mlog_errno(ret);

			goto out_unlock;
@@ -1176,6 +1191,64 @@ out: 
	return ret;

}



/*

 * Allocate enough extents to cover the region starting at byte offset

 * start for len bytes. Existing extents are skipped, any extents

 * added are marked as "unwritten".

 */

static int ocfs2_allocate_unwritten_extents(struct inode *inode,

					    u64 start, u64 len)

{

	int ret;

	u32 cpos, phys_cpos, clusters, alloc_size;



	/*

	 * We consider both start and len to be inclusive.

	 */

	cpos = start >> OCFS2_SB(inode->i_sb)->s_clustersize_bits;

	clusters = ocfs2_clusters_for_bytes(inode->i_sb, start + len);

	clusters -= cpos;



	while (clusters) {

		ret = ocfs2_get_clusters(inode, cpos, &phys_cpos,

					 &alloc_size, NULL);

		if (ret) {

			mlog_errno(ret);

			goto out;

		}



		/*

		 * Hole or existing extent len can be arbitrary, so

		 * cap it to our own allocation request.

		 */

		if (alloc_size > clusters)

			alloc_size = clusters;



		if (phys_cpos) {

			/*

			 * We already have an allocation at this

			 * region so we can safely skip it.

			 */

			goto next;

		}



		ret = __ocfs2_extend_allocation(inode, cpos, alloc_size, 1);

		if (ret) {

			if (ret != -ENOSPC)

				mlog_errno(ret);

			goto out;

		}



next:

		cpos += alloc_size;

		clusters -= alloc_size;

	}



	ret = 0;

out:

	return ret;

}



static int ocfs2_prepare_inode_for_write(struct dentry *dentry,

					 loff_t *ppos,

					 size_t count,

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