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Message-Id: <20190823132542.13434-6-chandan@linux.ibm.com>
Date: Fri, 23 Aug 2019 18:55:40 +0530
From: Chandan Rajendra <chandan@...ux.ibm.com>
To: linux-fsdevel@...r.kernel.org, linux-ext4@...r.kernel.org,
linux-fscrypt@...r.kernel.org
Cc: Chandan Rajendra <chandan@...ux.ibm.com>, tytso@....edu,
adilger.kernel@...ger.ca, ebiggers@...nel.org, hch@...radead.org,
chandanrlinux@...il.com
Subject: [PATCH V5 5/7] ext4: Wire up ext4_readpage[s] to use mpage_readpage[s]
Now that do_mpage_readpage() is "post read process" aware, this commit
gets ext4_readpage[s] to use mpage_readpage[s] and deletes ext4's
readpage.c since the associated functionality is not required anymore.
---
fs/ext4/Makefile | 2 +-
fs/ext4/inode.c | 5 +-
fs/ext4/readpage.c | 295 ---------------------------------------------
3 files changed, 3 insertions(+), 299 deletions(-)
delete mode 100644 fs/ext4/readpage.c
diff --git a/fs/ext4/Makefile b/fs/ext4/Makefile
index 8fdfcd3c3e04..7c38803a808d 100644
--- a/fs/ext4/Makefile
+++ b/fs/ext4/Makefile
@@ -8,7 +8,7 @@ obj-$(CONFIG_EXT4_FS) += ext4.o
ext4-y := balloc.o bitmap.o block_validity.o dir.o ext4_jbd2.o extents.o \
extents_status.o file.o fsmap.o fsync.o hash.o ialloc.o \
indirect.o inline.o inode.o ioctl.o mballoc.o migrate.o \
- mmp.o move_extent.o namei.o page-io.o readpage.o resize.o \
+ mmp.o move_extent.o namei.o page-io.o resize.o \
super.o symlink.o sysfs.o xattr.o xattr_trusted.o xattr_user.o
ext4-$(CONFIG_EXT4_FS_POSIX_ACL) += acl.o
diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index 58597db621e1..a1136faed9d3 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -3361,8 +3361,7 @@ static int ext4_readpage(struct file *file, struct page *page)
ret = ext4_readpage_inline(inode, page);
if (ret == -EAGAIN)
- return ext4_mpage_readpages(page->mapping, NULL, page, 1,
- false);
+ return mpage_readpage(page, ext4_get_block);
return ret;
}
@@ -3377,7 +3376,7 @@ ext4_readpages(struct file *file, struct address_space *mapping,
if (ext4_has_inline_data(inode))
return 0;
- return ext4_mpage_readpages(mapping, pages, NULL, nr_pages, true);
+ return mpage_readpages(mapping, pages, nr_pages, ext4_get_block);
}
static void ext4_invalidatepage(struct page *page, unsigned int offset,
diff --git a/fs/ext4/readpage.c b/fs/ext4/readpage.c
deleted file mode 100644
index 75cef6af6080..000000000000
--- a/fs/ext4/readpage.c
+++ /dev/null
@@ -1,295 +0,0 @@
-// SPDX-License-Identifier: GPL-2.0
-/*
- * linux/fs/ext4/readpage.c
- *
- * Copyright (C) 2002, Linus Torvalds.
- * Copyright (C) 2015, Google, Inc.
- *
- * This was originally taken from fs/mpage.c
- *
- * The intent is the ext4_mpage_readpages() function here is intended
- * to replace mpage_readpages() in the general case, not just for
- * encrypted files. It has some limitations (see below), where it
- * will fall back to read_block_full_page(), but these limitations
- * should only be hit when page_size != block_size.
- *
- * This will allow us to attach a callback function to support ext4
- * encryption.
- *
- * If anything unusual happens, such as:
- *
- * - encountering a page which has buffers
- * - encountering a page which has a non-hole after a hole
- * - encountering a page with non-contiguous blocks
- *
- * then this code just gives up and calls the buffer_head-based read function.
- * It does handle a page which has holes at the end - that is a common case:
- * the end-of-file on blocksize < PAGE_SIZE setups.
- *
- */
-
-#include <linux/kernel.h>
-#include <linux/export.h>
-#include <linux/mm.h>
-#include <linux/kdev_t.h>
-#include <linux/gfp.h>
-#include <linux/bio.h>
-#include <linux/fs.h>
-#include <linux/buffer_head.h>
-#include <linux/blkdev.h>
-#include <linux/highmem.h>
-#include <linux/prefetch.h>
-#include <linux/mpage.h>
-#include <linux/writeback.h>
-#include <linux/backing-dev.h>
-#include <linux/pagevec.h>
-#include <linux/cleancache.h>
-
-#include "ext4.h"
-
-static inline bool ext4_bio_encrypted(struct bio *bio)
-{
-#ifdef CONFIG_FS_ENCRYPTION
- return unlikely(bio->bi_private != NULL);
-#else
- return false;
-#endif
-}
-
-/*
- * I/O completion handler for multipage BIOs.
- *
- * The mpage code never puts partial pages into a BIO (except for end-of-file).
- * If a page does not map to a contiguous run of blocks then it simply falls
- * back to block_read_full_page().
- *
- * Why is this? If a page's completion depends on a number of different BIOs
- * which can complete in any order (or at the same time) then determining the
- * status of that page is hard. See end_buffer_async_read() for the details.
- * There is no point in duplicating all that complexity.
- */
-static void mpage_end_io(struct bio *bio)
-{
- struct bio_vec *bv;
- int i;
- struct bvec_iter_all iter_all;
-
- if (ext4_bio_encrypted(bio)) {
- if (bio->bi_status) {
- fscrypt_release_ctx(bio->bi_private);
- } else {
- fscrypt_enqueue_decrypt_bio(bio->bi_private, bio);
- return;
- }
- }
- bio_for_each_segment_all(bv, bio, i, iter_all) {
- struct page *page = bv->bv_page;
-
- if (!bio->bi_status) {
- SetPageUptodate(page);
- } else {
- ClearPageUptodate(page);
- SetPageError(page);
- }
- unlock_page(page);
- }
-
- bio_put(bio);
-}
-
-int ext4_mpage_readpages(struct address_space *mapping,
- struct list_head *pages, struct page *page,
- unsigned nr_pages, bool is_readahead)
-{
- struct bio *bio = NULL;
- sector_t last_block_in_bio = 0;
-
- struct inode *inode = mapping->host;
- const unsigned blkbits = inode->i_blkbits;
- const unsigned blocks_per_page = PAGE_SIZE >> blkbits;
- const unsigned blocksize = 1 << blkbits;
- sector_t block_in_file;
- sector_t last_block;
- sector_t last_block_in_file;
- sector_t blocks[MAX_BUF_PER_PAGE];
- unsigned page_block;
- struct block_device *bdev = inode->i_sb->s_bdev;
- int length;
- unsigned relative_block = 0;
- struct ext4_map_blocks map;
-
- map.m_pblk = 0;
- map.m_lblk = 0;
- map.m_len = 0;
- map.m_flags = 0;
-
- for (; nr_pages; nr_pages--) {
- int fully_mapped = 1;
- unsigned first_hole = blocks_per_page;
-
- prefetchw(&page->flags);
- if (pages) {
- page = lru_to_page(pages);
- list_del(&page->lru);
- if (add_to_page_cache_lru(page, mapping, page->index,
- readahead_gfp_mask(mapping)))
- goto next_page;
- }
-
- if (page_has_buffers(page))
- goto confused;
-
- block_in_file = (sector_t)page->index << (PAGE_SHIFT - blkbits);
- last_block = block_in_file + nr_pages * blocks_per_page;
- last_block_in_file = (i_size_read(inode) + blocksize - 1) >> blkbits;
- if (last_block > last_block_in_file)
- last_block = last_block_in_file;
- page_block = 0;
-
- /*
- * Map blocks using the previous result first.
- */
- if ((map.m_flags & EXT4_MAP_MAPPED) &&
- block_in_file > map.m_lblk &&
- block_in_file < (map.m_lblk + map.m_len)) {
- unsigned map_offset = block_in_file - map.m_lblk;
- unsigned last = map.m_len - map_offset;
-
- for (relative_block = 0; ; relative_block++) {
- if (relative_block == last) {
- /* needed? */
- map.m_flags &= ~EXT4_MAP_MAPPED;
- break;
- }
- if (page_block == blocks_per_page)
- break;
- blocks[page_block] = map.m_pblk + map_offset +
- relative_block;
- page_block++;
- block_in_file++;
- }
- }
-
- /*
- * Then do more ext4_map_blocks() calls until we are
- * done with this page.
- */
- while (page_block < blocks_per_page) {
- if (block_in_file < last_block) {
- map.m_lblk = block_in_file;
- map.m_len = last_block - block_in_file;
-
- if (ext4_map_blocks(NULL, inode, &map, 0) < 0) {
- set_error_page:
- SetPageError(page);
- zero_user_segment(page, 0,
- PAGE_SIZE);
- unlock_page(page);
- goto next_page;
- }
- }
- if ((map.m_flags & EXT4_MAP_MAPPED) == 0) {
- fully_mapped = 0;
- if (first_hole == blocks_per_page)
- first_hole = page_block;
- page_block++;
- block_in_file++;
- continue;
- }
- if (first_hole != blocks_per_page)
- goto confused; /* hole -> non-hole */
-
- /* Contiguous blocks? */
- if (page_block && blocks[page_block-1] != map.m_pblk-1)
- goto confused;
- for (relative_block = 0; ; relative_block++) {
- if (relative_block == map.m_len) {
- /* needed? */
- map.m_flags &= ~EXT4_MAP_MAPPED;
- break;
- } else if (page_block == blocks_per_page)
- break;
- blocks[page_block] = map.m_pblk+relative_block;
- page_block++;
- block_in_file++;
- }
- }
- if (first_hole != blocks_per_page) {
- zero_user_segment(page, first_hole << blkbits,
- PAGE_SIZE);
- if (first_hole == 0) {
- SetPageUptodate(page);
- unlock_page(page);
- goto next_page;
- }
- } else if (fully_mapped) {
- SetPageMappedToDisk(page);
- }
- if (fully_mapped && blocks_per_page == 1 &&
- !PageUptodate(page) && cleancache_get_page(page) == 0) {
- SetPageUptodate(page);
- goto confused;
- }
-
- /*
- * This page will go to BIO. Do we need to send this
- * BIO off first?
- */
- if (bio && (last_block_in_bio != blocks[0] - 1)) {
- submit_and_realloc:
- submit_bio(bio);
- bio = NULL;
- }
- if (bio == NULL) {
- struct fscrypt_ctx *ctx = NULL;
-
- if (IS_ENCRYPTED(inode) && S_ISREG(inode->i_mode)) {
- ctx = fscrypt_get_ctx(GFP_NOFS);
- if (IS_ERR(ctx))
- goto set_error_page;
- }
- bio = bio_alloc(GFP_KERNEL,
- min_t(int, nr_pages, BIO_MAX_PAGES));
- if (!bio) {
- if (ctx)
- fscrypt_release_ctx(ctx);
- goto set_error_page;
- }
- bio_set_dev(bio, bdev);
- bio->bi_iter.bi_sector = blocks[0] << (blkbits - 9);
- bio->bi_end_io = mpage_end_io;
- bio->bi_private = ctx;
- bio_set_op_attrs(bio, REQ_OP_READ,
- is_readahead ? REQ_RAHEAD : 0);
- }
-
- length = first_hole << blkbits;
- if (bio_add_page(bio, page, length, 0) < length)
- goto submit_and_realloc;
-
- if (((map.m_flags & EXT4_MAP_BOUNDARY) &&
- (relative_block == map.m_len)) ||
- (first_hole != blocks_per_page)) {
- submit_bio(bio);
- bio = NULL;
- } else
- last_block_in_bio = blocks[blocks_per_page - 1];
- goto next_page;
- confused:
- if (bio) {
- submit_bio(bio);
- bio = NULL;
- }
- if (!PageUptodate(page))
- block_read_full_page(page, ext4_get_block);
- else
- unlock_page(page);
- next_page:
- if (pages)
- put_page(page);
- }
- BUG_ON(pages && !list_empty(pages));
- if (bio)
- submit_bio(bio);
- return 0;
-}
--
2.19.1
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