From 14a5275d8c31ba24832f45eeb2469e835ded660d Mon Sep 17 00:00:00 2001 From: Joseph Qi Date: Tue, 14 Apr 2015 15:43:13 -0700 Subject: [PATCH] ocfs2: do not use ocfs2_zero_extend during direct IO In ocfs2_direct_IO_write, we use ocfs2_zero_extend to zero allocated clusters in case of cluster not aligned. But ocfs2_zero_extend uses page cache, this may happen that it clears the data which blockdev_direct_IO has already written. We should use blkdev_issue_zeroout instead of ocfs2_zero_extend during direct IO. So fix this issue by introducing ocfs2_direct_IO_zero_extend and ocfs2_direct_IO_extend_no_holes. Reported-by: Yiwen Jiang Signed-off-by: Joseph Qi Tested-by: Yiwen Jiang Cc: Mark Fasheh Cc: Joel Becker Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- fs/ocfs2/aops.c | 138 +++++++++++++++++++++++++++++++++++++++++++++--- 1 file changed, 130 insertions(+), 8 deletions(-) diff --git a/fs/ocfs2/aops.c b/fs/ocfs2/aops.c index 973a636285d1..1b0463a92b17 100644 --- a/fs/ocfs2/aops.c +++ b/fs/ocfs2/aops.c @@ -663,6 +663,117 @@ static int ocfs2_is_overwrite(struct ocfs2_super *osb, return 0; } +static int ocfs2_direct_IO_zero_extend(struct ocfs2_super *osb, + struct inode *inode, loff_t offset, + u64 zero_len, int cluster_align) +{ + u32 p_cpos = 0; + u32 v_cpos = ocfs2_bytes_to_clusters(osb->sb, i_size_read(inode)); + unsigned int num_clusters = 0; + unsigned int ext_flags = 0; + int ret = 0; + + if (offset <= i_size_read(inode) || cluster_align) + return 0; + + ret = ocfs2_get_clusters(inode, v_cpos, &p_cpos, &num_clusters, + &ext_flags); + if (ret < 0) { + mlog_errno(ret); + return ret; + } + + if (p_cpos && !(ext_flags & OCFS2_EXT_UNWRITTEN)) { + u64 s = i_size_read(inode); + sector_t sector = (p_cpos << (osb->s_clustersize_bits - 9)) + + (do_div(s, osb->s_clustersize) >> 9); + + ret = blkdev_issue_zeroout(osb->sb->s_bdev, sector, + zero_len >> 9, GFP_NOFS, false); + if (ret < 0) + mlog_errno(ret); + } + + return ret; +} + +static int ocfs2_direct_IO_extend_no_holes(struct ocfs2_super *osb, + struct inode *inode, loff_t offset) +{ + u64 zero_start, zero_len, total_zero_len; + u32 p_cpos = 0, clusters_to_add; + u32 v_cpos = ocfs2_bytes_to_clusters(osb->sb, i_size_read(inode)); + unsigned int num_clusters = 0; + unsigned int ext_flags = 0; + u32 size_div, offset_div; + int ret = 0; + + { + u64 o = offset; + u64 s = i_size_read(inode); + + offset_div = do_div(o, osb->s_clustersize); + size_div = do_div(s, osb->s_clustersize); + } + + if (offset <= i_size_read(inode)) + return 0; + + clusters_to_add = ocfs2_bytes_to_clusters(inode->i_sb, offset) - + ocfs2_bytes_to_clusters(inode->i_sb, i_size_read(inode)); + total_zero_len = offset - i_size_read(inode); + if (clusters_to_add) + total_zero_len -= offset_div; + + /* Allocate clusters to fill out holes, and this is only needed + * when we add more than one clusters. Otherwise the cluster will + * be allocated during direct IO */ + if (clusters_to_add > 1) { + ret = ocfs2_extend_allocation(inode, + OCFS2_I(inode)->ip_clusters, + clusters_to_add - 1, 0); + if (ret) { + mlog_errno(ret); + goto out; + } + } + + while (total_zero_len) { + ret = ocfs2_get_clusters(inode, v_cpos, &p_cpos, &num_clusters, + &ext_flags); + if (ret < 0) { + mlog_errno(ret); + goto out; + } + + zero_start = ocfs2_clusters_to_bytes(osb->sb, p_cpos) + + size_div; + zero_len = ocfs2_clusters_to_bytes(osb->sb, num_clusters) - + size_div; + zero_len = min(total_zero_len, zero_len); + + if (p_cpos && !(ext_flags & OCFS2_EXT_UNWRITTEN)) { + ret = blkdev_issue_zeroout(osb->sb->s_bdev, + zero_start >> 9, zero_len >> 9, + GFP_NOFS, false); + if (ret < 0) { + mlog_errno(ret); + goto out; + } + } + + total_zero_len -= zero_len; + v_cpos += ocfs2_bytes_to_clusters(osb->sb, zero_len + size_div); + + /* Only at first iteration can be cluster not aligned. + * So set size_div to 0 for the rest */ + size_div = 0; + } + +out: + return ret; +} + static ssize_t ocfs2_direct_IO_write(struct kiocb *iocb, struct iov_iter *iter, loff_t offset) @@ -677,8 +788,8 @@ static ssize_t ocfs2_direct_IO_write(struct kiocb *iocb, struct buffer_head *di_bh = NULL; size_t count = iter->count; journal_t *journal = osb->journal->j_journal; - u32 zero_len; - int cluster_align; + u64 zero_len_head, zero_len_tail; + int cluster_align_head, cluster_align_tail; loff_t final_size = offset + count; int append_write = offset >= i_size_read(inode) ? 1 : 0; unsigned int num_clusters = 0; @@ -686,9 +797,16 @@ static ssize_t ocfs2_direct_IO_write(struct kiocb *iocb, { u64 o = offset; + u64 s = i_size_read(inode); + + zero_len_head = do_div(o, 1 << osb->s_clustersize_bits); + cluster_align_head = !zero_len_head; - zero_len = do_div(o, 1 << osb->s_clustersize_bits); - cluster_align = !zero_len; + zero_len_tail = osb->s_clustersize - + do_div(s, osb->s_clustersize); + if ((offset - i_size_read(inode)) < zero_len_tail) + zero_len_tail = offset - i_size_read(inode); + cluster_align_tail = !zero_len_tail; } /* @@ -712,10 +830,13 @@ static ssize_t ocfs2_direct_IO_write(struct kiocb *iocb, goto clean_orphan; } + /* zeroing out the previously allocated cluster tail + * that but not zeroed */ if (ocfs2_sparse_alloc(OCFS2_SB(inode->i_sb))) - ret = ocfs2_zero_extend(inode, di_bh, offset); + ret = ocfs2_direct_IO_zero_extend(osb, inode, offset, + zero_len_tail, cluster_align_tail); else - ret = ocfs2_extend_no_holes(inode, di_bh, offset, + ret = ocfs2_direct_IO_extend_no_holes(osb, inode, offset); if (ret < 0) { mlog_errno(ret); @@ -768,7 +889,8 @@ static ssize_t ocfs2_direct_IO_write(struct kiocb *iocb, mlog_errno(ret); } } else if (written > 0 && append_write && !is_overwrite && - !cluster_align) { + !cluster_align_head) { + /* zeroing out the allocated cluster head */ u32 p_cpos = 0; u32 v_cpos = ocfs2_bytes_to_clusters(osb->sb, offset); @@ -790,7 +912,7 @@ static ssize_t ocfs2_direct_IO_write(struct kiocb *iocb, ret = blkdev_issue_zeroout(osb->sb->s_bdev, p_cpos << (osb->s_clustersize_bits - 9), - zero_len >> 9, GFP_NOFS, false); + zero_len_head >> 9, GFP_NOFS, false); if (ret < 0) mlog_errno(ret); -- GitLab