by Robin Dong

[permalink] [raw]

Subject: [PATCH 9/9 bigalloc] ext4: make cluster works for mmap

From: Robin Dong <[email protected]>

When users write a page in mmap regioin, it need to zero out other
pages around it.

Signed-off-by: Robin Dong <[email protected]>
---
fs/ext4/inode.c | 69 ++++++++++++++++++++++++++++++++++++++++++++++++++++++-
1 files changed, 68 insertions(+), 1 deletions(-)

diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index 69d0031..4a25767 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -4649,13 +4649,17 @@ int ext4_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf)
struct page *page = vmf->page;
loff_t size;
unsigned long len;
- int ret;
+ int ret, i, uninit = 0;
struct file *file = vma->vm_file;
struct inode *inode = file->f_path.dentry->d_inode;
+ struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
struct address_space *mapping = inode->i_mapping;
+ struct ext4_write_cluster_ctxt *ewcc = NULL;
handle_t *handle;
get_block_t *get_block;
int retries = 0;
+ unsigned int flags = AOP_FLAG_NOFS;
+ unsigned long from, to;

/*
* This check is racy but catches the common case. We rely on
@@ -4712,7 +4716,47 @@ retry_alloc:
ret = VM_FAULT_SIGBUS;
goto out;
}
+
+ ewcc = ext4_alloc_write_cluster_ctxt();
+ if (!ewcc) {
+ ret = -ENOMEM;
+ goto out;
+ }
+
+ if (sbi->s_cluster_ratio > 1) {
+ /* We need to know whether the block is allocated already
+ */
+ struct ext4_map_blocks map;
+ map.m_lblk = page->index;
+ map.m_len = 1;
+ ret = ext4_map_blocks(handle, inode, &map, 0);
+ uninit = map.m_flags & EXT4_MAP_UNWRITTEN;
+ if (ret <= 0 || uninit) {
+ ret = ext4_prepare_cluster_left_pages(inode,
+ page->index, ewcc, flags);
+ if (ret)
+ goto err_out;
+ }
+ }
+
ret = __block_page_mkwrite(vma, vmf, get_block);
+ if (ret)
+ goto err_out;
+
+ if (sbi->s_cluster_ratio > 1 && uninit) {
+ ret = ext4_prepare_cluster_right_pages(inode, page->index,
+ ewcc, flags);
+ if (ret)
+ goto err_out;
+ for (i = 0; i < ewcc->w_num_pages; i++) {
+ if (!ewcc->w_pages[i] ||
+ !page_buffers(ewcc->w_pages[i]))
+ break;
+ block_commit_write(ewcc->w_pages[i],
+ 0, PAGE_CACHE_SIZE);
+ }
+ }
+
if (!ret && ext4_should_journal_data(inode)) {
if (walk_page_buffers(handle, page_buffers(page), 0,
PAGE_CACHE_SIZE, NULL, do_journal_get_write_access)) {
@@ -4720,13 +4764,36 @@ retry_alloc:
ret = VM_FAULT_SIGBUS;
goto out;
}
+
+ for (i = 0; i < ewcc->w_num_pages; i++) {
+ page = ewcc->w_pages[i];
+ if (!page || !page_buffers(page))
+ continue;
+ from = page->index << PAGE_CACHE_SHIFT;
+ to = from + PAGE_CACHE_SIZE;
+ ret = walk_page_buffers(handle, page_buffers(page),
+ from, to, NULL, do_journal_get_write_access);
+ if (ret) {
+ ret = VM_FAULT_SIGBUS;
+ goto out;
+ }
+ }
ext4_set_inode_state(inode, EXT4_STATE_JDATA);
}
+
+err_out:
+ if (ewcc) {
+ ext4_free_write_cluster_ctxt(ewcc);
+ ewcc = NULL;
+ }
ext4_journal_stop(handle);
if (ret == -ENOSPC && ext4_should_retry_alloc(inode->i_sb, &retries))
goto retry_alloc;
out_ret:
ret = block_page_mkwrite_return(ret);
+
out:
+ if (ewcc)
+ ext4_free_write_cluster_ctxt(ewcc);
return ret;
}
--
1.7.3.2