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Commit 37f8a2bf authored by Tao Ma's avatar Tao Ma Committed by Joel Becker
Browse files

ocfs2: CoW a reflinked cluster when it is truncated. 



When we truncate a file to a specific size which resides in a reflinked
cluster, we need to CoW it since ocfs2_zero_range_for_truncate will
zero the space after the size(just another type of write).

So we add a "max_cpos" in ocfs2_refcount_cow so that it will stop when
it hit the max cluster offset.

Signed-off-by: default avatarTao Ma <tao.ma@oracle.com>
parent 293b2f70

fs/ocfs2/aops.c

+1 −1
Original line number Diff line number Diff line
@@ -1712,7 +1712,7 @@ int ocfs2_write_begin_nolock(struct address_space *mapping, 
		goto out;

	} else if (ret == 1) {

		ret = ocfs2_refcount_cow(inode, di_bh,

					 wc->w_cpos, wc->w_clen);

					 wc->w_cpos, wc->w_clen, UINT_MAX);

		if (ret) {

			mlog_errno(ret);

			goto out;

fs/ocfs2/file.c

+45 −1
Original line number Diff line number Diff line
@@ -335,6 +335,39 @@ out: 
	return ret;

}



static int ocfs2_cow_file_pos(struct inode *inode,

			      struct buffer_head *fe_bh,

			      u64 offset)

{

	int status;

	u32 phys, cpos = offset >> OCFS2_SB(inode->i_sb)->s_clustersize_bits;

	unsigned int num_clusters = 0;

	unsigned int ext_flags = 0;



	/*

	 * If the new offset is aligned to the range of the cluster, there is

	 * no space for ocfs2_zero_range_for_truncate to fill, so no need to

	 * CoW either.

	 */

	if ((offset & (OCFS2_SB(inode->i_sb)->s_clustersize - 1)) == 0)

		return 0;



	status = ocfs2_get_clusters(inode, cpos, &phys,

				    &num_clusters, &ext_flags);

	if (status) {

		mlog_errno(status);

		goto out;

	}



	if (!(ext_flags & OCFS2_EXT_REFCOUNTED))

		goto out;



	return ocfs2_refcount_cow(inode, fe_bh, cpos, 1, cpos+1);



out:

	return status;

}



static int ocfs2_orphan_for_truncate(struct ocfs2_super *osb,

				     struct inode *inode,

				     struct buffer_head *fe_bh,
@@ -347,6 +380,17 @@ static int ocfs2_orphan_for_truncate(struct ocfs2_super *osb, 


	mlog_entry_void();



	/*

	 * We need to CoW the cluster contains the offset if it is reflinked

	 * since we will call ocfs2_zero_range_for_truncate later which will

	 * write "0" from offset to the end of the cluster.

	 */

	status = ocfs2_cow_file_pos(inode, fe_bh, new_i_size);

	if (status) {

		mlog_errno(status);

		return status;

	}



	/* TODO: This needs to actually orphan the inode in this

	 * transaction. */
@@ -1713,7 +1757,7 @@ static int ocfs2_prepare_inode_for_refcount(struct inode *inode, 


	*meta_level = 1;



	ret = ocfs2_refcount_cow(inode, di_bh, cpos, clusters);

	ret = ocfs2_refcount_cow(inode, di_bh, cpos, clusters, UINT_MAX);

	if (ret)

		mlog_errno(ret);

out:

fs/ocfs2/refcounttree.c

+23 −11
Original line number Diff line number Diff line
@@ -2482,6 +2482,7 @@ static inline unsigned int ocfs2_cow_align_length(struct super_block *sb, 
 *

 * cpos is vitual start cluster position we want to do CoW in a

 * file and write_len is the cluster length.

 * max_cpos is the place where we want to stop CoW intentionally.

 *

 * Normal we will start CoW from the beginning of extent record cotaining cpos.

 * We try to break up extents on boundaries of MAX_CONTIG_BYTES so that we
@@ -2491,6 +2492,7 @@ static int ocfs2_refcount_cal_cow_clusters(struct inode *inode, 
					   struct buffer_head *di_bh,

					   u32 cpos,

					   u32 write_len,

					   u32 max_cpos,

					   u32 *cow_start,

					   u32 *cow_len)

{
@@ -2505,6 +2507,8 @@ static int ocfs2_refcount_cal_cow_clusters(struct inode *inode, 
	int contig_clusters = ocfs2_cow_contig_clusters(inode->i_sb);

	int leaf_clusters;



	BUG_ON(cpos + write_len > max_cpos);



	if (tree_height > 0) {

		ret = ocfs2_find_leaf(INODE_CACHE(inode), el, cpos, &eb_bh);

		if (ret) {
@@ -2549,15 +2553,20 @@ static int ocfs2_refcount_cal_cow_clusters(struct inode *inode, 
		}



		/*

		 * If we encounter a hole or a non-refcounted record,

		 * stop the search.

		 * If we encounter a hole, a non-refcounted record or

		 * pass the max_cpos, stop the search.

		 */

		if ((!(rec->e_flags & OCFS2_EXT_REFCOUNTED)) ||

		    (*cow_len && rec_end != le32_to_cpu(rec->e_cpos)))

		    (*cow_len && rec_end != le32_to_cpu(rec->e_cpos)) ||

		    (max_cpos <= le32_to_cpu(rec->e_cpos)))

			break;



		leaf_clusters = le16_to_cpu(rec->e_leaf_clusters);

		rec_end = le32_to_cpu(rec->e_cpos) + leaf_clusters;

		if (rec_end > max_cpos) {

			rec_end = max_cpos;

			leaf_clusters = rec_end - le32_to_cpu(rec->e_cpos);

		}



		/*

		 * How many clusters do we actually need from
@@ -3184,12 +3193,13 @@ static int ocfs2_replace_cow(struct inode *inode, 
}



/*

 * Starting at cpos, try to CoW write_len clusters.

 * This will stop when it runs into a hole or an unrefcounted extent.

 * Starting at cpos, try to CoW write_len clusters.  Don't CoW

 * past max_cpos.  This will stop when it runs into a hole or an

 * unrefcounted extent.

 */

static int ocfs2_refcount_cow_hunk(struct inode *inode,

				   struct buffer_head *di_bh,

				   u32 cpos, u32 write_len)

				   u32 cpos, u32 write_len, u32 max_cpos)

{

	int ret;

	u32 cow_start = 0, cow_len = 0;
@@ -3201,12 +3211,14 @@ static int ocfs2_refcount_cow_hunk(struct inode *inode, 


	BUG_ON(!(oi->ip_dyn_features & OCFS2_HAS_REFCOUNT_FL));



	ret = ocfs2_refcount_cal_cow_clusters(inode, di_bh, cpos, write_len,

	ret = ocfs2_refcount_cal_cow_clusters(inode, di_bh,

					      cpos, write_len, max_cpos,

					      &cow_start, &cow_len);

	if (ret) {

		mlog_errno(ret);

		goto out;

	}



	mlog(0, "CoW inode %lu, cpos %u, write_len %u, cow_start %u, "

	     "cow_len %u\n", inode->i_ino,

	     cpos, write_len, cow_start, cow_len);
@@ -3233,12 +3245,12 @@ out: 


/*

 * CoW any and all clusters between cpos and cpos+write_len.

 * If this returns successfully, all clusters between cpos and

 * cpos+write_len are safe to modify.

 * Don't CoW past max_cpos.  If this returns successfully, all

 * clusters between cpos and cpos+write_len are safe to modify.

 */

int ocfs2_refcount_cow(struct inode *inode,

		       struct buffer_head *di_bh,

		       u32 cpos, u32 write_len)

		       u32 cpos, u32 write_len, u32 max_cpos)

{

	int ret = 0;

	u32 p_cluster, num_clusters;
@@ -3257,7 +3269,7 @@ int ocfs2_refcount_cow(struct inode *inode, 


		if (ext_flags & OCFS2_EXT_REFCOUNTED) {

			ret = ocfs2_refcount_cow_hunk(inode, di_bh, cpos,

						      num_clusters);

						      num_clusters, max_cpos);

			if (ret) {

				mlog_errno(ret);

				break;

fs/ocfs2/refcounttree.h

+1 −1
Original line number Diff line number Diff line
@@ -53,5 +53,5 @@ int ocfs2_prepare_refcount_change_for_del(struct inode *inode, 
					  int *credits,

					  struct ocfs2_alloc_context **meta_ac);

int ocfs2_refcount_cow(struct inode *inode, struct buffer_head *di_bh,

		       u32 cpos, u32 write_len);

		       u32 cpos, u32 write_len, u32 max_cpos);

#endif /* OCFS2_REFCOUNTTREE_H */