From: Gao Xiang <gaoxiang25@huawei.com>
To: Christoph Hellwig <hch@infradead.org>
Cc: devel@driverdev.osuosl.org,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
linux-fsdevel@vger.kernel.org, linux-erofs@lists.ozlabs.org
Subject: Re: [PATCH 00/21] erofs: patchset addressing Christoph's comments
Date: Tue, 3 Sep 2019 16:17:49 +0800 [thread overview]
Message-ID: <20190903081749.GA89379@architecture4> (raw)
In-Reply-To: <20190903065803.GA11205@infradead.org>
Hi Christoph,
On Mon, Sep 02, 2019 at 11:58:03PM -0700, Christoph Hellwig wrote:
> On Mon, Sep 02, 2019 at 11:50:38PM +0800, Gao Xiang wrote:
> > > > You means killing erofs_get_meta_page or avoid erofs_read_raw_page?
> > > >
> > > > - For killing erofs_get_meta_page, here is the current erofs_get_meta_page:
> > >
> > > > I think it is simple enough. read_cache_page need write a similar
> > > > filler, or read_cache_page_gfp will call .readpage, and then
> > > > introduce buffer_heads, that is what I'd like to avoid now (no need these
> > > > bd_inode buffer_heads in memory...)
> > >
> > > If using read_cache_page_gfp and ->readpage works, please do. The
> > > fact that the block device inode uses buffer heads is an implementation
> > > detail that might not last very long and should be invisible to you.
> > > It also means you can get rid of a lot of code that you don't have
> > > to maintain and others don't have to update for global API changes.
> >
> > I care about those useless buffer_heads in memory for our products...
> >
> > Since we are nobh filesystem (a little request, could I use it
> > after buffer_heads are fully avoided, I have no idea why I need
> > those buffer_heads in memory.... But I think bd_inode is good
> > for caching metadata...)
>
> Then please use read_cache_page with iomap_readpage(s), and write
> comment explaining why your are not using read_cache_page_gfp.
I implement a prelimitary version, but I have no idea it is a really
cleanup for now.
From 001e3e64c81e4ced0d22b147e6abf90060e704b5 Mon Sep 17 00:00:00 2001
From: Gao Xiang <gaoxiang25@huawei.com>
Date: Tue, 3 Sep 2019 16:13:00 +0800
Subject: [PATCH] erofs: use iomap_readpage for erofs_get_meta_page
Signed-off-by: Gao Xiang <gaoxiang25@huawei.com>
---
fs/erofs/Kconfig | 1 +
fs/erofs/data.c | 91 ++++++++++++++++++++++++++----------------------
2 files changed, 51 insertions(+), 41 deletions(-)
diff --git a/fs/erofs/Kconfig b/fs/erofs/Kconfig
index 9d634d3a1845..c9eeb0bf4737 100644
--- a/fs/erofs/Kconfig
+++ b/fs/erofs/Kconfig
@@ -3,6 +3,7 @@
config EROFS_FS
tristate "EROFS filesystem support"
depends on BLOCK
+ select FS_IOMAP
help
EROFS (Enhanced Read-Only File System) is a lightweight
read-only file system with modern designs (eg. page-sized
diff --git a/fs/erofs/data.c b/fs/erofs/data.c
index 3881c0689134..34c6e05fab71 100644
--- a/fs/erofs/data.c
+++ b/fs/erofs/data.c
@@ -5,6 +5,9 @@
* Created by Gao Xiang <gaoxiang25@huawei.com>
*/
#include "internal.h"
+#include <linux/iomap.h>
+#include <linux/mpage.h>
+#include <linux/sched/mm.h>
#include <linux/prefetch.h>
#include <trace/events/erofs.h>
@@ -51,54 +54,60 @@ static struct bio *erofs_grab_raw_bio(struct super_block *sb,
return bio;
}
-struct page *erofs_get_meta_page(struct super_block *sb, erofs_blk_t blkaddr)
+static int erofs_meta_iomap_begin(struct inode *inode, loff_t pos,
+ loff_t length, unsigned int flags,
+ struct iomap *iomap)
{
- struct inode *const bd_inode = sb->s_bdev->bd_inode;
- struct address_space *const mapping = bd_inode->i_mapping;
- /* prefer retrying in the allocator to blindly looping below */
- const gfp_t gfp = mapping_gfp_constraint(mapping, ~__GFP_FS);
- struct page *page;
- int err;
-
-repeat:
- page = find_or_create_page(mapping, blkaddr, gfp);
- if (!page)
- return ERR_PTR(-ENOMEM);
-
- DBG_BUGON(!PageLocked(page));
-
- if (!PageUptodate(page)) {
- struct bio *bio;
+ const unsigned int blkbits = inode->i_blkbits;
+
+ iomap->flags = 0;
+ iomap->bdev = I_BDEV(inode);
+ iomap->offset = round_down(pos, 1 << blkbits);
+ iomap->addr = iomap->offset;
+ iomap->length = round_up(length, 1 << blkbits);
+ iomap->type = IOMAP_MAPPED;
+ return 0;
+}
- bio = erofs_grab_raw_bio(sb, blkaddr, 1, true);
+static const struct iomap_ops erofs_meta_iomap_ops = {
+ .iomap_begin = erofs_meta_iomap_begin,
+};
- if (bio_add_page(bio, page, PAGE_SIZE, 0) != PAGE_SIZE) {
- err = -EFAULT;
- goto err_out;
- }
+static int
+erofs_meta_get_block(struct inode *inode, sector_t iblock,
+ struct buffer_head *bh, int create)
+{
+ bh->b_bdev = I_BDEV(inode);
+ bh->b_blocknr = iblock;
+ set_buffer_mapped(bh);
+ return 0;
+}
- submit_bio(bio);
- lock_page(page);
+static int erofs_read_meta_page(void *file, struct page *page)
+{
+ /* in case of getting some pages with buffer_heads */
+ if (i_blocksize(page->mapping->host) == PAGE_SIZE &&
+ !page_has_buffers(page))
+ return iomap_readpage(page, &erofs_meta_iomap_ops);
+
+ /*
+ * cannot use blkdev_readpage or blkdev_get_block directly
+ * since static in block_dev.c
+ */
+ return mpage_readpage(page, erofs_meta_get_block);
+}
- /* this page has been truncated by others */
- if (page->mapping != mapping) {
- unlock_page(page);
- put_page(page);
- goto repeat;
- }
+struct page *erofs_get_meta_page(struct super_block *sb, erofs_blk_t blkaddr)
+{
+ struct inode *const bd_inode = sb->s_bdev->bd_inode;
+ struct address_space *const mapping = bd_inode->i_mapping;
+ unsigned int nofs_flag;
+ struct page *page;
- /* more likely a read error */
- if (!PageUptodate(page)) {
- err = -EIO;
- goto err_out;
- }
- }
+ nofs_flag = memalloc_nofs_save();
+ page = read_cache_page(mapping, blkaddr, erofs_read_meta_page, NULL);
+ memalloc_nofs_restore(nofs_flag);
return page;
-
-err_out:
- unlock_page(page);
- put_page(page);
- return ERR_PTR(err);
}
static int erofs_map_blocks_flatmode(struct inode *inode,
--
2.17.1
next prev parent reply other threads:[~2019-09-03 8:18 UTC|newest]
Thread overview: 159+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-08-02 12:53 [PATCH v6 00/24] erofs: promote erofs from staging Gao Xiang
2019-08-02 12:53 ` [PATCH v6 01/24] erofs: add on-disk layout Gao Xiang
2019-08-29 9:59 ` Christoph Hellwig
2019-08-29 10:32 ` Gao Xiang
2019-08-29 10:36 ` Christoph Hellwig
2019-08-29 10:58 ` Gao Xiang
2019-08-29 15:58 ` Joe Perches
2019-08-29 17:26 ` Gao Xiang
2019-08-30 12:07 ` David Sterba
2019-08-30 12:18 ` Gao Xiang via Linux-erofs
2019-09-02 8:43 ` Pavel Machek
2019-09-02 14:07 ` David Sterba
2019-09-03 11:27 ` Pavel Machek
2019-08-29 15:41 ` Gao Xiang
2019-09-01 7:54 ` Gao Xiang via Linux-erofs
2019-09-02 12:45 ` Christoph Hellwig
2019-09-02 13:02 ` Gao Xiang
2019-09-02 8:40 ` Pavel Machek
2019-09-02 10:35 ` Gao Xiang
2019-08-02 12:53 ` [PATCH v6 02/24] erofs: add erofs in-memory stuffs Gao Xiang
2019-08-02 12:53 ` [PATCH v6 03/24] erofs: add super block operations Gao Xiang
2019-08-29 10:15 ` Christoph Hellwig
2019-08-29 10:50 ` Gao Xiang
2019-08-30 16:39 ` Christoph Hellwig
2019-08-30 17:15 ` Gao Xiang
2019-08-31 0:54 ` Gao Xiang
2019-08-31 6:34 ` Amir Goldstein
2019-08-31 6:48 ` Gao Xiang
2019-09-01 8:54 ` Gao Xiang via Linux-erofs
2019-09-02 12:51 ` Christoph Hellwig
2019-09-02 14:43 ` Gao Xiang
2019-09-02 15:19 ` Christoph Hellwig
2019-09-02 15:24 ` Gao Xiang
2019-08-02 12:53 ` [PATCH v6 04/24] erofs: add raw address_space operations Gao Xiang
2019-08-29 10:17 ` Christoph Hellwig
2019-08-29 11:46 ` Gao Xiang
2019-08-30 16:40 ` Christoph Hellwig
2019-08-30 17:23 ` Gao Xiang
2019-08-02 12:53 ` [PATCH v6 05/24] erofs: add inode operations Gao Xiang
2019-08-29 10:24 ` Christoph Hellwig
2019-08-29 11:59 ` Gao Xiang
2019-08-30 16:42 ` Christoph Hellwig
2019-08-30 18:46 ` Gao Xiang
2019-09-01 9:34 ` Gao Xiang via Linux-erofs
2019-09-02 12:53 ` Christoph Hellwig
2019-09-02 13:43 ` David Sterba
2019-09-02 13:55 ` Gao Xiang
2019-08-02 12:53 ` [PATCH v6 06/24] erofs: support special inode Gao Xiang
2019-08-29 10:25 ` Christoph Hellwig
2019-09-01 9:39 ` Gao Xiang via Linux-erofs
2019-08-02 12:53 ` [PATCH v6 07/24] erofs: add directory operations Gao Xiang
2019-08-02 12:53 ` [PATCH v6 08/24] erofs: add namei functions Gao Xiang
2019-08-29 10:28 ` Christoph Hellwig
2019-08-29 11:28 ` Gao Xiang
2019-08-02 12:53 ` [PATCH v6 09/24] erofs: support tracepoint Gao Xiang
2019-08-02 12:53 ` [PATCH v6 10/24] erofs: update Kconfig and Makefile Gao Xiang
2019-08-02 12:53 ` [PATCH v6 11/24] erofs: introduce xattr & posixacl support Gao Xiang
2019-08-02 12:53 ` [PATCH v6 12/24] erofs: introduce tagged pointer Gao Xiang
2019-08-02 12:53 ` [PATCH v6 13/24] erofs: add compression indexes support Gao Xiang
2019-08-02 12:53 ` [PATCH v6 14/24] erofs: introduce superblock registration Gao Xiang
2019-08-02 12:53 ` [PATCH v6 15/24] erofs: introduce erofs shrinker Gao Xiang
2019-08-02 12:53 ` [PATCH v6 16/24] erofs: introduce workstation for decompression Gao Xiang
2019-08-02 12:53 ` [PATCH v6 17/24] erofs: introduce per-CPU buffers implementation Gao Xiang
2019-08-02 12:53 ` [PATCH v6 18/24] erofs: introduce pagevec for decompression subsystem Gao Xiang
2019-08-02 12:53 ` [PATCH v6 19/24] erofs: add erofs_allocpage() Gao Xiang
2019-08-02 12:53 ` [PATCH v6 20/24] erofs: introduce generic decompression backend Gao Xiang
2019-08-02 12:53 ` [PATCH v6 21/24] erofs: introduce LZ4 decompression inplace Gao Xiang
2019-08-02 12:53 ` [PATCH v6 22/24] erofs: introduce the decompression frontend Gao Xiang
2019-08-02 12:53 ` [PATCH v6 23/24] erofs: introduce cached decompression Gao Xiang
2019-08-02 12:53 ` [PATCH v6 24/24] erofs: add document Gao Xiang
2019-09-01 5:51 ` [PATCH 00/21] erofs: patchset addressing Christoph's comments Gao Xiang via Linux-erofs
2019-09-01 5:51 ` [PATCH 01/21] erofs: remove all the byte offset comments Gao Xiang via Linux-erofs
2019-09-02 12:05 ` Christoph Hellwig
2019-09-01 5:51 ` [PATCH 02/21] erofs: on-disk format should have explicitly assigned numbers Gao Xiang via Linux-erofs
2019-09-02 12:05 ` Christoph Hellwig
2019-09-01 5:51 ` [PATCH 03/21] erofs: some macros are much more readable as a function Gao Xiang via Linux-erofs
2019-09-02 12:06 ` Christoph Hellwig
2019-09-01 5:51 ` [PATCH 04/21] erofs: kill __packed for on-disk structures Gao Xiang via Linux-erofs
2019-09-02 12:06 ` Christoph Hellwig
2019-09-01 5:51 ` [PATCH 05/21] erofs: update erofs_inode_is_data_compressed helper Gao Xiang via Linux-erofs
2019-09-02 12:07 ` Christoph Hellwig
2019-09-01 5:51 ` [PATCH 06/21] erofs: kill erofs_{init,exit}_inode_cache Gao Xiang via Linux-erofs
2019-09-02 12:09 ` Christoph Hellwig
2019-09-01 5:51 ` [PATCH 07/21] erofs: use erofs_inode naming Gao Xiang via Linux-erofs
2019-09-02 12:10 ` Christoph Hellwig
2019-09-02 12:13 ` Gao Xiang
2019-09-02 12:47 ` Christoph Hellwig
2019-09-02 13:33 ` Gao Xiang
2019-09-01 5:51 ` [PATCH 08/21] erofs: update comments in inode.c Gao Xiang via Linux-erofs
2019-09-01 5:51 ` [PATCH 09/21] erofs: update erofs symlink stuffs Gao Xiang via Linux-erofs
2019-09-02 12:11 ` Christoph Hellwig
2019-09-01 5:51 ` [PATCH 10/21] erofs: kill is_inode_layout_compression() Gao Xiang via Linux-erofs
2019-09-02 12:11 ` Christoph Hellwig
2019-09-01 5:51 ` [PATCH 11/21] erofs: use dsb instead of layout for ondisk super_block Gao Xiang via Linux-erofs
2019-09-02 12:12 ` Christoph Hellwig
2019-09-02 12:15 ` Gao Xiang
2019-09-01 5:51 ` [PATCH 12/21] erofs: kill verbose debug info in erofs_fill_super Gao Xiang via Linux-erofs
2019-09-02 12:14 ` Christoph Hellwig
2019-09-02 12:18 ` Gao Xiang
2019-09-01 5:51 ` [PATCH 13/21] erofs: simplify erofs_grab_bio() since bio_alloc() never fail Gao Xiang via Linux-erofs
2019-09-02 12:20 ` Christoph Hellwig
2019-09-01 5:51 ` [PATCH 14/21] erofs: kill prio and nofail of erofs_get_meta_page() Gao Xiang via Linux-erofs
2019-09-02 12:21 ` Christoph Hellwig
2019-09-01 5:51 ` [PATCH 15/21] erofs: kill __submit_bio() Gao Xiang via Linux-erofs
2019-09-01 5:51 ` [PATCH 16/21] erofs: kill magic underscores Gao Xiang via Linux-erofs
2019-09-02 12:26 ` Christoph Hellwig
2019-09-02 12:39 ` Gao Xiang
2019-09-02 12:54 ` Christoph Hellwig
2019-09-02 13:38 ` Gao Xiang
2019-09-01 5:51 ` [PATCH 17/21] erofs: use a switch statement when dealing with the file modes Gao Xiang via Linux-erofs
2019-09-02 12:27 ` Christoph Hellwig
2019-09-01 5:51 ` [PATCH 18/21] erofs: add "erofs_" prefix for common and short functions Gao Xiang via Linux-erofs
2019-09-02 12:28 ` Christoph Hellwig
2019-09-01 5:51 ` [PATCH 19/21] erofs: kill all erofs specific fault injection Gao Xiang via Linux-erofs
2019-09-02 12:28 ` Christoph Hellwig
2019-09-01 5:51 ` [PATCH 20/21] erofs: kill use_vmap module parameter Gao Xiang via Linux-erofs
2019-09-02 12:31 ` Christoph Hellwig
2019-09-02 12:43 ` Gao Xiang
2019-09-01 5:51 ` [PATCH 21/21] erofs: save one level of indentation Gao Xiang via Linux-erofs
2019-09-02 12:31 ` Christoph Hellwig
2019-09-02 12:46 ` [PATCH 00/21] erofs: patchset addressing Christoph's comments Christoph Hellwig
2019-09-02 14:24 ` Gao Xiang
2019-09-02 15:23 ` Christoph Hellwig
2019-09-02 15:50 ` Gao Xiang
2019-09-03 6:58 ` Christoph Hellwig
2019-09-03 8:17 ` Gao Xiang [this message]
2019-09-03 15:37 ` Christoph Hellwig
2019-09-03 15:43 ` Gao Xiang via Linux-erofs
2019-09-04 2:08 ` [PATCH v2 00/25] " Gao Xiang
2019-09-04 2:08 ` [PATCH v2 01/25] erofs: remove all the byte offset comments Gao Xiang
2019-09-04 2:08 ` [PATCH v2 02/25] erofs: on-disk format should have explicitly assigned numbers Gao Xiang
2019-09-04 2:08 ` [PATCH v2 03/25] erofs: some macros are much more readable as a function Gao Xiang
2019-09-04 2:08 ` [PATCH v2 04/25] erofs: kill __packed for on-disk structures Gao Xiang
2019-09-04 2:08 ` [PATCH v2 05/25] erofs: update erofs_inode_is_data_compressed helper Gao Xiang
2019-09-04 2:08 ` [PATCH v2 06/25] erofs: use feature_incompat rather than requirements Gao Xiang
2019-09-04 2:08 ` [PATCH v2 07/25] erofs: better naming for erofs inode related stuffs Gao Xiang
2019-09-04 2:08 ` [PATCH v2 08/25] erofs: kill erofs_{init,exit}_inode_cache Gao Xiang
2019-09-04 2:08 ` [PATCH v2 09/25] erofs: use erofs_inode naming Gao Xiang
2019-09-04 2:08 ` [PATCH v2 10/25] erofs: update erofs_fs.h comments Gao Xiang
2019-09-04 2:08 ` [PATCH v2 11/25] erofs: update comments in inode.c Gao Xiang
2019-09-04 2:08 ` [PATCH v2 12/25] erofs: better erofs symlink stuffs Gao Xiang
2019-09-04 2:09 ` [PATCH v2 13/25] erofs: use dsb instead of layout for ondisk super_block Gao Xiang
2019-09-04 2:09 ` [PATCH v2 14/25] erofs: kill verbose debug info in erofs_fill_super Gao Xiang
2019-09-04 2:09 ` [PATCH v2 15/25] erofs: localize erofs_grab_bio() Gao Xiang
2019-09-04 2:09 ` [PATCH v2 16/25] erofs: kill prio and nofail of erofs_get_meta_page() Gao Xiang
2019-09-04 2:09 ` [PATCH v2 17/25] erofs: kill __submit_bio() Gao Xiang
2019-09-04 2:09 ` [PATCH v2 18/25] erofs: add "erofs_" prefix for common and short functions Gao Xiang
2019-09-04 2:09 ` [PATCH v2 19/25] erofs: kill all erofs specific fault injection Gao Xiang
2019-09-04 2:09 ` [PATCH v2 20/25] erofs: kill use_vmap module parameter Gao Xiang
2019-09-04 2:09 ` [PATCH v2 21/25] erofs: save one level of indentation Gao Xiang
2019-09-04 2:09 ` [PATCH v2 22/25] erofs: rename errln/infoln/debugln to erofs_{err, info, dbg} Gao Xiang
2019-09-04 2:09 ` [PATCH v2 23/25] erofs: use read_mapping_page instead of sb_bread Gao Xiang
2019-09-04 2:09 ` [PATCH v2 24/25] erofs: always use iget5_locked Gao Xiang
2019-09-04 2:09 ` [PATCH v2 25/25] erofs: use read_cache_page_gfp for erofs_get_meta_page Gao Xiang
2019-09-04 3:27 ` [PATCH v2 00/25] erofs: patchset addressing Christoph's comments Chao Yu
2019-09-05 1:03 ` Gao Xiang via Linux-erofs
2019-09-05 11:30 ` Christoph Hellwig
2019-09-04 5:16 ` Christoph Hellwig
2019-09-04 6:08 ` Gao Xiang via Linux-erofs
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