From: Robin Dong <sanbai@xxxxxxxxxx>
When users write one page which in the middle of a cluster, we need to zero the
anthor pages around it.
Signed-off-by: Robin Dong <sanbai@xxxxxxxxxx>
---
fs/ext4/ext4.h | 18 ++++
fs/ext4/inode.c | 293 ++++++++++++++++++++++++++++++++++++++++++++++++++++---
2 files changed, 295 insertions(+), 16 deletions(-)
diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
index 1dea3e8..90ae8a2 100644
--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h
@@ -675,6 +675,15 @@ struct move_extent {
#define EXT4_EPOCH_MASK ((1 << EXT4_EPOCH_BITS) - 1)
#define EXT4_NSEC_MASK (~0UL << EXT4_EPOCH_BITS)
+#define EXT4_MAX_CLUSTERSIZE 1048576
+#define EXT4_MAX_CTXT_PAGES (EXT4_MAX_CLUSTERSIZE / PAGE_CACHE_SIZE)
+
+/* tracking cluster write pages */
+struct ext4_write_cluster_ctxt {
+ unsigned long w_num_pages;
+ struct page *w_pages[EXT4_MAX_CTXT_PAGES];
+};
+
/*
* Extended fields will fit into an inode if the filesystem was formatted
* with large inodes (-I 256 or larger) and there are not currently any EAs
@@ -1849,6 +1858,15 @@ extern int ext4_group_add_blocks(handle_t *handle, struct super_block *sb,
extern int ext4_trim_fs(struct super_block *, struct fstrim_range *);
/* inode.c */
+int walk_page_buffers(handle_t *handle, struct buffer_head *head,
+ unsigned from, unsigned to, int *partial,
+ int (*fn)(handle_t *handle, struct buffer_head *bh));
+int do_journal_get_write_access(handle_t *handle, struct buffer_head *bh);
+struct ext4_write_cluster_ctxt *ext4_alloc_write_cluster_ctxt(void);
+void ext4_free_write_cluster_ctxt(struct ext4_write_cluster_ctxt *ewcc);
+int ext4_zero_cluster_page(struct inode *inode, int index,
+ struct ext4_write_cluster_ctxt *ewcc, unsigned flags);
+
struct buffer_head *ext4_getblk(handle_t *, struct inode *,
ext4_lblk_t, int, int *);
struct buffer_head *ext4_bread(handle_t *, struct inode *,
diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index 9b83c3c..0ae546d 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -38,6 +38,7 @@
#include <linux/printk.h>
#include <linux/slab.h>
#include <linux/ratelimit.h>
+#include <linux/swap.h>
#include "ext4_jbd2.h"
#include "xattr.h"
@@ -49,6 +50,31 @@
#define MPAGE_DA_EXTENT_TAIL 0x01
+static void ext4_write_cluster_add_page(struct ext4_write_cluster_ctxt *ewcc,
+ struct page *page)
+{
+ ewcc->w_pages[ewcc->w_num_pages] = page;
+ ewcc->w_num_pages++;
+}
+
+struct ext4_write_cluster_ctxt *ext4_alloc_write_cluster_ctxt(void)
+{
+ return kzalloc(sizeof(struct ext4_write_cluster_ctxt), GFP_NOFS);
+}
+
+void ext4_free_write_cluster_ctxt(struct ext4_write_cluster_ctxt *ewcc)
+{
+ int i;
+ for (i = 0; i < ewcc->w_num_pages; i++) {
+ if (ewcc->w_pages[i]) {
+ unlock_page(ewcc->w_pages[i]);
+ mark_page_accessed(ewcc->w_pages[i]);
+ page_cache_release(ewcc->w_pages[i]);
+ }
+ }
+ kfree(ewcc);
+}
+
static inline int ext4_begin_ordered_truncate(struct inode *inode,
loff_t new_size)
{
@@ -656,7 +682,7 @@ struct buffer_head *ext4_bread(handle_t *handle, struct inode *inode,
return NULL;
}
-static int walk_page_buffers(handle_t *handle,
+int walk_page_buffers(handle_t *handle,
struct buffer_head *head,
unsigned from,
unsigned to,
@@ -712,7 +738,7 @@ static int walk_page_buffers(handle_t *handle,
* is elevated. We'll still have enough credits for the tiny quotafile
* write.
*/
-static int do_journal_get_write_access(handle_t *handle,
+int do_journal_get_write_access(handle_t *handle,
struct buffer_head *bh)
{
int dirty = buffer_dirty(bh);
@@ -738,15 +764,176 @@ static int do_journal_get_write_access(handle_t *handle,
static int ext4_get_block_write(struct inode *inode, sector_t iblock,
struct buffer_head *bh_result, int create);
+
+int ext4_cluster_write_begin(struct page *page, loff_t pos, unsigned len,
+ get_block_t *get_block)
+{
+ unsigned from = pos & (PAGE_CACHE_SIZE - 1);
+ unsigned to = from + len;
+ struct inode *inode = page->mapping->host;
+ unsigned block_start, block_end;
+ sector_t block;
+ int err = 0;
+ unsigned blocksize, bbits;
+ struct buffer_head *bh, *head, *wait[2], **wait_bh = wait;
+
+ BUG_ON(!PageLocked(page));
+ BUG_ON(from > PAGE_CACHE_SIZE);
+ BUG_ON(to > PAGE_CACHE_SIZE);
+ BUG_ON(from > to);
+
+ blocksize = 1 << inode->i_blkbits;
+ if (!page_has_buffers(page))
+ create_empty_buffers(page, blocksize, 0);
+ head = page_buffers(page);
+
+ bbits = inode->i_blkbits;
+ block = (sector_t)page->index << (PAGE_CACHE_SHIFT - bbits);
+
+ for (bh = head, block_start = 0; bh != head || !block_start;
+ block++, block_start = block_end, bh = bh->b_this_page) {
+ block_end = block_start + blocksize;
+ if (block_end <= from || block_start >= to) {
+ if (PageUptodate(page)) {
+ if (!buffer_uptodate(bh))
+ set_buffer_uptodate(bh);
+ }
+ continue;
+ }
+ if (buffer_new(bh))
+ clear_buffer_new(bh);
+ if (!buffer_mapped(bh)) {
+ WARN_ON(bh->b_size != blocksize);
+ err = get_block(inode, block, bh, 1);
+ if (err)
+ break;
+ unmap_underlying_metadata(bh->b_bdev,
+ bh->b_blocknr);
+ if (PageUptodate(page)) {
+ clear_buffer_new(bh);
+ set_buffer_uptodate(bh);
+ mark_buffer_dirty(bh);
+ continue;
+ }
+ if (block_end > to || block_start < from)
+ zero_user_segments(page,
+ to, block_end,
+ block_start, from);
+ continue;
+ }
+ if (PageUptodate(page)) {
+ if (!buffer_uptodate(bh))
+ set_buffer_uptodate(bh);
+ continue;
+ }
+ if (!buffer_uptodate(bh) && !buffer_delay(bh) &&
+ !buffer_unwritten(bh) &&
+ (block_start < from || block_end > to)) {
+ ll_rw_block(READ, 1, &bh);
+ *wait_bh++ = bh;
+ }
+ }
+ /*
+ * If we issued read requests - let them complete.
+ */
+ while (wait_bh > wait) {
+ wait_on_buffer(*--wait_bh);
+ if (!buffer_uptodate(*wait_bh))
+ err = -EIO;
+ }
+ if (unlikely(err))
+ page_zero_new_buffers(page, from, to);
+ return err;
+}
+
+int ext4_zero_cluster_page(struct inode *inode, int index,
+ struct ext4_write_cluster_ctxt *ewcc, unsigned flags)
+{
+ int ret = 0;
+ struct page *page;
+
+ page = grab_cache_page_write_begin(inode->i_mapping, index, flags);
+ if (!page) {
+ ret = -ENOMEM;
+ goto out;
+ }
+
+ ext4_write_cluster_add_page(ewcc, page);
+
+ /* if page is already uptodate and has buffers, don't get_block again
+ */
+ if (PageUptodate(page) && PagePrivate(page))
+ goto out;
+
+ zero_user_segment(page, 0, PAGE_CACHE_SIZE);
+ SetPageUptodate(page);
+ if (ext4_should_dioread_nolock(inode))
+ ret = ext4_cluster_write_begin(page, index << PAGE_CACHE_SHIFT,
+ PAGE_CACHE_SIZE, ext4_get_block_write);
+ else
+ ret = ext4_cluster_write_begin(page, index << PAGE_CACHE_SHIFT,
+ PAGE_CACHE_SIZE, ext4_get_block);
+
+out:
+ return ret;
+}
+
+int ext4_prepare_cluster_left_pages(struct inode *inode, int index,
+ struct ext4_write_cluster_ctxt *ewcc, unsigned flags)
+{
+ struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
+ int ret = 0;
+ int block;
+ sector_t left_offset = index & (sbi->s_cluster_ratio - 1);
+ sector_t begin;
+
+ if (left_offset) {
+ begin = index - left_offset;
+ for (block = begin; block < index; block++) {
+ ret = ext4_zero_cluster_page(inode, block, ewcc, flags);
+ if (ret)
+ goto out;
+ }
+ }
+
+out:
+ return ret;
+}
+
+int ext4_prepare_cluster_right_pages(struct inode *inode, int index,
+ struct ext4_write_cluster_ctxt *ewcc, unsigned flags)
+{
+ struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
+ int ret = 0;
+ int block;
+ sector_t left_offset = index & (sbi->s_cluster_ratio - 1);
+ sector_t right_offset = sbi->s_cluster_ratio - left_offset - 1;
+ sector_t begin;
+
+ if (right_offset) {
+ begin = index + 1;
+ for (block = begin; block < index + right_offset + 1; block++) {
+ ret = ext4_zero_cluster_page(inode, block, ewcc, flags);
+ if (ret)
+ goto out;
+ }
+ }
+
+out:
+ return ret;
+}
+
static int ext4_write_begin(struct file *file, struct address_space *mapping,
loff_t pos, unsigned len, unsigned flags,
struct page **pagep, void **fsdata)
{
struct inode *inode = mapping->host;
+ struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
int ret, needed_blocks;
handle_t *handle;
- int retries = 0;
- struct page *page;
+ int retries = 0, uninit = 0;
+ struct page *page = NULL;
+ struct ext4_write_cluster_ctxt *ewcc;
pgoff_t index;
unsigned from, to;
@@ -761,6 +948,12 @@ static int ext4_write_begin(struct file *file, struct address_space *mapping,
to = from + len;
retry:
+ ewcc = ext4_alloc_write_cluster_ctxt();
+ if (!ewcc) {
+ ret = -ENOMEM;
+ goto out;
+ }
+
handle = ext4_journal_start(inode, needed_blocks);
if (IS_ERR(handle)) {
ret = PTR_ERR(handle);
@@ -771,27 +964,76 @@ retry:
* started */
flags |= AOP_FLAG_NOFS;
+ if (sbi->s_cluster_ratio > 1) {
+ /* We need to know whether the block is allocated already
+ */
+ struct ext4_map_blocks map;
+ map.m_lblk = 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, index,
+ ewcc, flags);
+ if (ret)
+ goto err_out;
+ }
+ }
+
page = grab_cache_page_write_begin(mapping, index, flags);
if (!page) {
- ext4_journal_stop(handle);
ret = -ENOMEM;
- goto out;
+ goto err_out;
}
+
*pagep = page;
- if (ext4_should_dioread_nolock(inode))
- ret = __block_write_begin(page, pos, len, ext4_get_block_write);
- else
- ret = __block_write_begin(page, pos, len, ext4_get_block);
+ ext4_write_cluster_add_page(ewcc, page);
+
+ /* if the block is already allocated by cluster, we should use
+ * ext4_cluster_write_begin (it will not read buffer again)
+ */
+ if (sbi->s_cluster_ratio > 1 && pos + len > inode->i_size) {
+ if (ext4_should_dioread_nolock(inode))
+ ret = ext4_cluster_write_begin(page, pos, len,
+ ext4_get_block_write);
+ else
+ ret = ext4_cluster_write_begin(page, pos, len,
+ ext4_get_block);
+ } else {
+ if (ext4_should_dioread_nolock(inode))
+ ret = __block_write_begin(page, pos, len,
+ ext4_get_block_write);
+ else
+ ret = __block_write_begin(page, pos, len,
+ ext4_get_block);
+ }
+
+ if (sbi->s_cluster_ratio > 1 && uninit) {
+ ret = ext4_prepare_cluster_right_pages(inode, index,
+ ewcc, flags);
+ if (ret)
+ goto err_out;
+ }
if (!ret && ext4_should_journal_data(inode)) {
- ret = walk_page_buffers(handle, page_buffers(page),
+ int i;
+ unsigned long from, to;
+ 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)
+ break;
+ }
}
if (ret) {
- unlock_page(page);
- page_cache_release(page);
+ ext4_free_write_cluster_ctxt(ewcc);
/*
* __block_write_begin may have instantiated a few blocks
* outside i_size. Trim these off again. Don't need
@@ -819,8 +1061,15 @@ retry:
if (ret == -ENOSPC && ext4_should_retry_alloc(inode->i_sb, &retries))
goto retry;
+
+ *fsdata = ewcc;
out:
return ret;
+
+err_out:
+ ext4_free_write_cluster_ctxt(ewcc);
+ ext4_journal_stop(handle);
+ return ret;
}
/* For write_end() in data=journal mode */
@@ -837,11 +1086,24 @@ static int ext4_generic_write_end(struct file *file,
loff_t pos, unsigned len, unsigned copied,
struct page *page, void *fsdata)
{
- int i_size_changed = 0;
+ int i_size_changed = 0, i;
struct inode *inode = mapping->host;
+ struct ext4_write_cluster_ctxt *ewcc = fsdata;
handle_t *handle = ext4_journal_current_handle();
copied = block_write_end(file, mapping, pos, len, copied, page, fsdata);
+ for (i = 0; i < ewcc->w_num_pages; i++) {
+ unsigned long pos;
+ struct page *cluster_page;
+ cluster_page = ewcc->w_pages[i];
+ if (!cluster_page)
+ break;
+ if (cluster_page == page)
+ continue;
+ pos = cluster_page->index << PAGE_CACHE_SHIFT;
+ block_write_end(file, mapping, pos, PAGE_CACHE_SIZE,
+ PAGE_CACHE_SIZE, cluster_page, fsdata);
+ }
/*
* No need to use i_size_read() here, the i_size
@@ -863,8 +1125,7 @@ static int ext4_generic_write_end(struct file *file,
ext4_update_i_disksize(inode, (pos + copied));
i_size_changed = 1;
}
- unlock_page(page);
- page_cache_release(page);
+ ext4_free_write_cluster_ctxt(ewcc);
/*
* Don't mark the inode dirty under page lock. First, it unnecessarily
--
1.7.3.2
--
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