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Commit 293b2f70 authored by Tao Ma's avatar Tao Ma Committed by Joel Becker
Browse files

ocfs2: Integrate CoW in file write. 



When we use mmap, we CoW the refcountd clusters in
ocfs2_write_begin_nolock. While for normal file
io(including directio), we do CoW in
ocfs2_prepare_inode_for_write.

Signed-off-by: default avatarTao Ma <tao.ma@oracle.com>
parent 6ae23c55

fs/ocfs2/aops.c

+19 −0
Original line number Diff line number Diff line
@@ -44,6 +44,7 @@ 
#include "suballoc.h"

#include "super.h"

#include "symlink.h"

#include "refcounttree.h"



#include "buffer_head_io.h"
@@ -590,6 +591,8 @@ static int ocfs2_direct_IO_get_blocks(struct inode *inode, sector_t iblock, 
		goto bail;

	}



	/* We should already CoW the refcounted extent. */

	BUG_ON(ext_flags & OCFS2_EXT_REFCOUNTED);

	/*

	 * get_more_blocks() expects us to describe a hole by clearing

	 * the mapped bit on bh_result().
@@ -1449,6 +1452,9 @@ static int ocfs2_populate_write_desc(struct inode *inode, 
				goto out;

			}



			/* We should already CoW the refcountd extent. */

			BUG_ON(ext_flags & OCFS2_EXT_REFCOUNTED);



			/*

			 * Assume worst case - that we're writing in

			 * the middle of the extent.
@@ -1700,6 +1706,19 @@ int ocfs2_write_begin_nolock(struct address_space *mapping, 
		goto out;

	}



	ret = ocfs2_check_range_for_refcount(inode, pos, len);

	if (ret < 0) {

		mlog_errno(ret);

		goto out;

	} else if (ret == 1) {

		ret = ocfs2_refcount_cow(inode, di_bh,

					 wc->w_cpos, wc->w_clen);

		if (ret) {

			mlog_errno(ret);

			goto out;

		}

	}



	ret = ocfs2_populate_write_desc(inode, wc, &clusters_to_alloc,

					&extents_to_split);

	if (ret) {

fs/ocfs2/file.c

+83 −1
Original line number Diff line number Diff line
@@ -59,6 +59,7 @@ 
#include "xattr.h"

#include "acl.h"

#include "quota.h"

#include "refcounttree.h"



#include "buffer_head_io.h"
@@ -1656,6 +1657,70 @@ static long ocfs2_fallocate(struct inode *inode, int mode, loff_t offset, 
					 OCFS2_IOC_RESVSP64, &sr, change_size);

}



int ocfs2_check_range_for_refcount(struct inode *inode, loff_t pos,

				   size_t count)

{

	int ret = 0;

	unsigned int extent_flags;

	u32 cpos, clusters, extent_len, phys_cpos;

	struct super_block *sb = inode->i_sb;



	if (!ocfs2_refcount_tree(OCFS2_SB(inode->i_sb)) ||

	    !(OCFS2_I(inode)->ip_dyn_features & OCFS2_HAS_REFCOUNT_FL))

		return 0;



	cpos = pos >> OCFS2_SB(sb)->s_clustersize_bits;

	clusters = ocfs2_clusters_for_bytes(sb, pos + count) - cpos;



	while (clusters) {

		ret = ocfs2_get_clusters(inode, cpos, &phys_cpos, &extent_len,

					 &extent_flags);

		if (ret < 0) {

			mlog_errno(ret);

			goto out;

		}



		if (phys_cpos && (extent_flags & OCFS2_EXT_REFCOUNTED)) {

			ret = 1;

			break;

		}



		if (extent_len > clusters)

			extent_len = clusters;



		clusters -= extent_len;

		cpos += extent_len;

	}

out:

	return ret;

}



static int ocfs2_prepare_inode_for_refcount(struct inode *inode,

					    loff_t pos, size_t count,

					    int *meta_level)

{

	int ret;

	struct buffer_head *di_bh = NULL;

	u32 cpos = pos >> OCFS2_SB(inode->i_sb)->s_clustersize_bits;

	u32 clusters =

		ocfs2_clusters_for_bytes(inode->i_sb, pos + count) - cpos;



	ret = ocfs2_inode_lock(inode, &di_bh, 1);

	if (ret) {

		mlog_errno(ret);

		goto out;

	}



	*meta_level = 1;



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

	if (ret)

		mlog_errno(ret);

out:

	brelse(di_bh);

	return ret;

}



static int ocfs2_prepare_inode_for_write(struct dentry *dentry,

					 loff_t *ppos,

					 size_t count,
@@ -1712,6 +1777,22 @@ static int ocfs2_prepare_inode_for_write(struct dentry *dentry, 


		end = saved_pos + count;



		ret = ocfs2_check_range_for_refcount(inode, saved_pos, count);

		if (ret == 1) {

			ocfs2_inode_unlock(inode, meta_level);

			meta_level = -1;



			ret = ocfs2_prepare_inode_for_refcount(inode,

							       saved_pos,

							       count,

							       &meta_level);

		}



		if (ret < 0) {

			mlog_errno(ret);

			goto out_unlock;

		}



		/*

		 * Skip the O_DIRECT checks if we don't need

		 * them.
@@ -1758,6 +1839,7 @@ static int ocfs2_prepare_inode_for_write(struct dentry *dentry, 
		*ppos = saved_pos;



out_unlock:

	if (meta_level >= 0)

		ocfs2_inode_unlock(inode, meta_level);



out:

fs/ocfs2/file.h

+2 −0
Original line number Diff line number Diff line
@@ -69,4 +69,6 @@ int ocfs2_update_inode_atime(struct inode *inode, 
int ocfs2_change_file_space(struct file *file, unsigned int cmd,

			    struct ocfs2_space_resv *sr);



int ocfs2_check_range_for_refcount(struct inode *inode, loff_t pos,

				   size_t count);

#endif /* OCFS2_FILE_H */