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ocfs2: Integrate CoW in file write.

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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: Tao Ma <tao.ma@oracle.com>
This commit is contained in:
Tao Ma
2009-08-25 08:02:48 +08:00
committed by Joel Becker
parent 6ae23c5555
commit 293b2f70b4
3 changed files with 104 additions and 1 deletions
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84
fs/ocfs2/file.c
View File

@ -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.
@ -1758,7 +1839,8 @@ static int ocfs2_prepare_inode_for_write(struct dentry *dentry,
*ppos = saved_pos;
out_unlock:
ocfs2_inode_unlock(inode, meta_level);
if (meta_level >= 0)
ocfs2_inode_unlock(inode, meta_level);
out:
return ret;