From 293b2f70b4a16a1ca91efd28ef3d6634262c6887 Mon Sep 17 00:00:00 2001 From: Tao Ma Date: Tue, 25 Aug 2009 08:02:48 +0800 Subject: 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: Tao Ma --- fs/ocfs2/file.c | 84 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++- 1 file changed, 83 insertions(+), 1 deletion(-) (limited to 'fs/ocfs2/file.c') diff --git a/fs/ocfs2/file.c b/fs/ocfs2/file.c index 4921b4ee943..6ee20e82bcc 100644 --- a/fs/ocfs2/file.c +++ b/fs/ocfs2/file.c @@ -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; -- cgit v1.2.3