From: colyli@suse.de
To: axboe@kernel.dk
Cc: linux-bcache@vger.kernel.org, linux-block@vger.kernel.org,
Christoph Hellwig <hch@lst.de>, Coly Li <colyli@suse.de>
Subject: [PATCH 09/17] bcache: use read_cache_page_gfp to read the superblock
Date: Fri, 24 Jan 2020 01:01:34 +0800 [thread overview]
Message-ID: <20200123170142.98974-10-colyli@suse.de> (raw)
In-Reply-To: <20200123170142.98974-1-colyli@suse.de>
From: Christoph Hellwig <hch@lst.de>
Avoid a pointless dependency on buffer heads in bcache by simply open
coding reading a single page. Also add a SB_OFFSET define for the
byte offset of the superblock instead of using magic numbers.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Coly Li <colyli@suse.de>
---
drivers/md/bcache/super.c | 16 +++++++---------
include/uapi/linux/bcache.h | 1 +
2 files changed, 8 insertions(+), 9 deletions(-)
diff --git a/drivers/md/bcache/super.c b/drivers/md/bcache/super.c
index 5797c03f993e..3dea1d5acd5c 100644
--- a/drivers/md/bcache/super.c
+++ b/drivers/md/bcache/super.c
@@ -15,7 +15,6 @@
#include "writeback.h"
#include <linux/blkdev.h>
-#include <linux/buffer_head.h>
#include <linux/debugfs.h>
#include <linux/genhd.h>
#include <linux/idr.h>
@@ -64,13 +63,14 @@ static const char *read_super(struct cache_sb *sb, struct block_device *bdev,
{
const char *err;
struct cache_sb_disk *s;
- struct buffer_head *bh = __bread(bdev, 1, SB_SIZE);
+ struct page *page;
unsigned int i;
- if (!bh)
+ page = read_cache_page_gfp(bdev->bd_inode->i_mapping,
+ SB_OFFSET >> PAGE_SHIFT, GFP_KERNEL);
+ if (IS_ERR(page))
return "IO error";
-
- s = (struct cache_sb_disk *)bh->b_data;
+ s = page_address(page) + offset_in_page(SB_OFFSET);
sb->offset = le64_to_cpu(s->offset);
sb->version = le64_to_cpu(s->version);
@@ -188,12 +188,10 @@ static const char *read_super(struct cache_sb *sb, struct block_device *bdev,
}
sb->last_mount = (u32)ktime_get_real_seconds();
- err = NULL;
-
- get_page(bh->b_page);
*res = s;
+ return NULL;
err:
- put_bh(bh);
+ put_page(page);
return err;
}
diff --git a/include/uapi/linux/bcache.h b/include/uapi/linux/bcache.h
index 1d8b3a9fc080..9a1965c6c3d0 100644
--- a/include/uapi/linux/bcache.h
+++ b/include/uapi/linux/bcache.h
@@ -148,6 +148,7 @@ static inline struct bkey *bkey_idx(const struct bkey *k, unsigned int nr_keys)
#define BCACHE_SB_MAX_VERSION 4
#define SB_SECTOR 8
+#define SB_OFFSET (SB_SECTOR << SECTOR_SHIFT)
#define SB_SIZE 4096
#define SB_LABEL_SIZE 32
#define SB_JOURNAL_BUCKETS 256U
--
2.16.4
next prev parent reply other threads:[~2020-01-23 17:01 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-01-23 17:01 [PATCH 00/17] bcache patches for Linux v5.6 colyli
2020-01-23 17:01 ` [PATCH 01/17] bcache: cached_dev_free needs to put the sb page colyli
2020-01-23 17:01 ` [PATCH 02/17] bcache: use a separate data structure for the on-disk super block colyli
2020-01-23 17:01 ` [PATCH 03/17] bcache: rework error unwinding in register_bcache colyli
2020-01-23 17:01 ` [PATCH 04/17] bcache: properly initialize 'path' and 'err' in register_bcache() colyli
2020-01-23 17:01 ` [PATCH 05/17] bcache: fix use-after-free " colyli
2020-01-23 17:01 ` [PATCH 06/17] bcache: transfer the sb_page reference to register_{bdev,cache} colyli
2020-01-23 17:01 ` [PATCH 07/17] bcache: return a pointer to the on-disk sb from read_super colyli
2020-01-23 17:01 ` [PATCH 08/17] bcache: store a pointer to the on-disk sb in the cache and cached_dev structures colyli
2020-01-23 17:01 ` colyli [this message]
2020-01-23 17:01 ` [PATCH 10/17] lib: crc64: include <linux/crc64.h> for 'crc64_be' colyli
2020-01-23 17:01 ` [PATCH 11/17] bcache: add code comments for state->pool in __btree_sort() colyli
2020-01-23 17:01 ` [PATCH 12/17] bcache: avoid unnecessary btree nodes flushing in btree_flush_write() colyli
2020-01-23 17:01 ` [PATCH 13/17] bcache: print written and keys in trace_bcache_btree_write colyli
2020-01-23 17:01 ` [PATCH 14/17] bcache: back to cache all readahead I/Os colyli
2020-01-23 17:19 ` Michael Lyle
2020-01-23 17:27 ` Coly Li
2020-01-23 18:31 ` Jens Axboe
2020-01-24 0:49 ` Coly Li
2020-01-24 1:14 ` Jens Axboe
2020-01-24 16:48 ` Michael Lyle
2020-01-23 17:01 ` [PATCH 15/17] bcache: remove member accessed from struct btree colyli
2020-01-23 17:01 ` [PATCH 16/17] bcache: reap c->btree_cache_freeable from the tail in bch_mca_scan() colyli
2020-01-23 17:01 ` [PATCH 17/17] bcache: reap from tail of c->btree_cache " colyli
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