From: Yu Kuai <yukuai1@huaweicloud.com>
To: axboe@kernel.dk, roger.pau@citrix.com, colyli@suse.de,
kent.overstreet@gmail.com, joern@lazybastard.org,
miquel.raynal@bootlin.com, richard@nod.at, vigneshr@ti.com,
sth@linux.ibm.com, hoeppner@linux.ibm.com, hca@linux.ibm.com,
gor@linux.ibm.com, agordeev@linux.ibm.com, jejb@linux.ibm.com,
martin.petersen@oracle.com, clm@fb.com, josef@toxicpanda.com,
dsterba@suse.com, viro@zeniv.linux.org.uk, brauner@kernel.org,
nico@fluxnic.net, xiang@kernel.org, chao@kernel.org,
tytso@mit.edu, adilger.kernel@dilger.ca, jack@suse.com,
konishi.ryusuke@gmail.com, willy@infradead.org,
akpm@linux-foundation.org, hare@suse.de, p.raghav@samsung.com
Cc: linux-block@vger.kernel.org, linux-kernel@vger.kernel.org,
xen-devel@lists.xenproject.org, linux-bcache@vger.kernel.org,
linux-mtd@lists.infradead.org, linux-s390@vger.kernel.org,
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linux-btrfs@vger.kernel.org, linux-fsdevel@vger.kernel.org,
linux-erofs@lists.ozlabs.org, linux-ext4@vger.kernel.org,
linux-nilfs@vger.kernel.org, yukuai3@huawei.com,
yukuai1@huaweicloud.com, yi.zhang@huawei.com,
yangerkun@huawei.com
Subject: [PATCH RFC v3 for-6.8/block 14/17] buffer: add a new helper to read sb block
Date: Thu, 21 Dec 2023 16:58:53 +0800 [thread overview]
Message-ID: <20231221085853.1770062-1-yukuai1@huaweicloud.com> (raw)
In-Reply-To: <20231221085712.1766333-1-yukuai1@huaweicloud.com>
From: Yu Kuai <yukuai3@huawei.com>
Unlike __bread_gfp(), ext4 has special handing while reading sb block:
1) __GFP_NOFAIL is not set, and memory allocation can fail;
2) If buffer write failed before, set buffer uptodate and don't read
block from disk;
3) REQ_META is set for all IO, and REQ_PRIO is set for reading xattr;
4) If failed, return error ptr instead of NULL;
This patch add a new helper __bread_gfp2() that will match above 2 and 3(
1 will be used, and 4 will still be encapsulated by ext4), and prepare to
prevent calling mapping_gfp_constraint() directly on bd_inode->i_mapping
in ext4.
Signed-off-by: Yu Kuai <yukuai3@huawei.com>
---
fs/buffer.c | 68 ++++++++++++++++++++++++++-----------
include/linux/buffer_head.h | 18 +++++++++-
2 files changed, 65 insertions(+), 21 deletions(-)
diff --git a/fs/buffer.c b/fs/buffer.c
index 967f34b70aa8..188bd36c9fea 100644
--- a/fs/buffer.c
+++ b/fs/buffer.c
@@ -1255,16 +1255,19 @@ void __bforget(struct buffer_head *bh)
}
EXPORT_SYMBOL(__bforget);
-static struct buffer_head *__bread_slow(struct buffer_head *bh)
+static struct buffer_head *__bread_slow(struct buffer_head *bh,
+ blk_opf_t op_flags,
+ bool check_write_error)
{
lock_buffer(bh);
- if (buffer_uptodate(bh)) {
+ if (buffer_uptodate(bh) ||
+ (check_write_error && buffer_uptodate_or_error(bh))) {
unlock_buffer(bh);
return bh;
} else {
get_bh(bh);
bh->b_end_io = end_buffer_read_sync;
- submit_bh(REQ_OP_READ, bh);
+ submit_bh(REQ_OP_READ | op_flags, bh);
wait_on_buffer(bh);
if (buffer_uptodate(bh))
return bh;
@@ -1445,6 +1448,31 @@ void __breadahead(struct block_device *bdev, sector_t block, unsigned size)
}
EXPORT_SYMBOL(__breadahead);
+static struct buffer_head *
+bread_gfp(struct block_device *bdev, sector_t block, unsigned int size,
+ blk_opf_t op_flags, gfp_t gfp, bool check_write_error)
+{
+ struct buffer_head *bh;
+
+ gfp |= mapping_gfp_constraint(bdev->bd_inode->i_mapping, ~__GFP_FS);
+
+ /*
+ * Prefer looping in the allocator rather than here, at least that
+ * code knows what it's doing.
+ */
+ gfp |= __GFP_NOFAIL;
+
+ bh = bdev_getblk(bdev, block, size, gfp);
+ if (unlikely(!bh))
+ return NULL;
+
+ if (buffer_uptodate(bh) ||
+ (check_write_error && buffer_uptodate_or_error(bh)))
+ return bh;
+
+ return __bread_slow(bh, op_flags, check_write_error);
+}
+
/**
* __bread_gfp() - reads a specified block and returns the bh
* @bdev: the block_device to read from
@@ -1458,27 +1486,27 @@ EXPORT_SYMBOL(__breadahead);
* It returns NULL if the block was unreadable.
*/
struct buffer_head *
-__bread_gfp(struct block_device *bdev, sector_t block,
- unsigned size, gfp_t gfp)
+__bread_gfp(struct block_device *bdev, sector_t block, unsigned int size,
+ gfp_t gfp)
{
- struct buffer_head *bh;
-
- gfp |= mapping_gfp_constraint(bdev->bd_inode->i_mapping, ~__GFP_FS);
-
- /*
- * Prefer looping in the allocator rather than here, at least that
- * code knows what it's doing.
- */
- gfp |= __GFP_NOFAIL;
-
- bh = bdev_getblk(bdev, block, size, gfp);
-
- if (likely(bh) && !buffer_uptodate(bh))
- bh = __bread_slow(bh);
- return bh;
+ return bread_gfp(bdev, block, size, 0, gfp, false);
}
EXPORT_SYMBOL(__bread_gfp);
+/*
+ * This works like __bread_gfp() except:
+ * 1) If buffer write failed before, set buffer uptodate and don't read
+ * block from disk;
+ * 2) Caller can pass in additional op_flags like REQ_META;
+ */
+struct buffer_head *
+__bread_gfp2(struct block_device *bdev, sector_t block, unsigned int size,
+ blk_opf_t op_flags, gfp_t gfp)
+{
+ return bread_gfp(bdev, block, size, op_flags, gfp, true);
+}
+EXPORT_SYMBOL(__bread_gfp2);
+
static void __invalidate_bh_lrus(struct bh_lru *b)
{
int i;
diff --git a/include/linux/buffer_head.h b/include/linux/buffer_head.h
index 5f23ee599889..751b2744b4ae 100644
--- a/include/linux/buffer_head.h
+++ b/include/linux/buffer_head.h
@@ -171,6 +171,18 @@ static __always_inline int buffer_uptodate(const struct buffer_head *bh)
return test_bit_acquire(BH_Uptodate, &bh->b_state);
}
+static __always_inline int buffer_uptodate_or_error(struct buffer_head *bh)
+{
+ /*
+ * If the buffer has the write error flag, data was failed to write
+ * out in the block. In this case, set buffer uptodate to prevent
+ * reading old data.
+ */
+ if (buffer_write_io_error(bh))
+ set_buffer_uptodate(bh);
+ return buffer_uptodate(bh);
+}
+
static inline unsigned long bh_offset(const struct buffer_head *bh)
{
return (unsigned long)(bh)->b_data & (page_size(bh->b_page) - 1);
@@ -231,7 +243,11 @@ void __brelse(struct buffer_head *);
void __bforget(struct buffer_head *);
void __breadahead(struct block_device *, sector_t block, unsigned int size);
struct buffer_head *__bread_gfp(struct block_device *,
- sector_t block, unsigned size, gfp_t gfp);
+ sector_t block, unsigned int size, gfp_t gfp);
+struct buffer_head *__bread_gfp2(struct block_device *bdev, sector_t block,
+ unsigned int size, blk_opf_t op_flags,
+ gfp_t gfp);
+
struct buffer_head *alloc_buffer_head(gfp_t gfp_flags);
void free_buffer_head(struct buffer_head * bh);
void unlock_buffer(struct buffer_head *bh);
--
2.39.2
next prev parent reply other threads:[~2023-12-21 9:00 UTC|newest]
Thread overview: 37+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-12-21 8:56 [PATCH RFC v3 for-6.8/block 00/17] block: don't access bd_inode directly from other modules Yu Kuai
2023-12-21 8:56 ` [PATCH RFC v3 for-6.8/block 01/17] block: add some bdev apis Yu Kuai
2023-12-21 8:56 ` [PATCH RFC v3 for-6.8/block 02/17] xen/blkback: use bdev api in xen_update_blkif_status() Yu Kuai
2024-01-04 11:06 ` Jan Kara
2024-01-04 12:19 ` Yu Kuai
2024-01-04 15:16 ` Jan Kara
2024-01-05 6:08 ` Christoph Hellwig
2023-12-21 8:56 ` [PATCH RFC v3 for-6.8/block 03/17] bcache: use bdev api in read_super() Yu Kuai
2023-12-21 8:56 ` [PATCH RFC v3 for-6.8/block 04/17] mtd: block2mtd: use bdev apis Yu Kuai
2024-01-04 11:28 ` Jan Kara
2024-01-04 12:22 ` Yu Kuai
2024-01-05 6:10 ` Christoph Hellwig
2024-01-05 10:31 ` Yu Kuai
2023-12-21 8:57 ` [PATCH RFC v3 for-6.8/block 05/17] s390/dasd: use bdev api in dasd_format() Yu Kuai
2023-12-21 8:57 ` [PATCH RFC v3 for-6.8/block 06/17] scsicam: use bdev api in scsi_bios_ptable() Yu Kuai
2023-12-21 8:57 ` [PATCH RFC v3 for-6.8/block 07/17] bcachefs: remove dead function bdev_sectors() Yu Kuai
2024-04-11 17:49 ` Kent Overstreet
2023-12-21 8:57 ` [PATCH RFC v3 for-6.8/block 08/17] bio: export bio_add_folio_nofail() Yu Kuai
2023-12-21 8:57 ` [PATCH RFC v3 for-6.8/block 09/17] btrfs: use bdev apis Yu Kuai
2023-12-23 17:31 ` Matthew Wilcox
2023-12-23 18:39 ` Kent Overstreet
2024-01-04 11:49 ` Jan Kara
2024-04-10 17:28 ` David Sterba
2023-12-21 8:57 ` [PATCH RFC v3 for-6.8/block 10/17] cramfs: use bdev apis in cramfs_blkdev_read() Yu Kuai
2023-12-21 8:58 ` [PATCH RFC v3 for-6.8/block 11/17] erofs: use bdev api Yu Kuai
2024-01-04 12:02 ` Jan Kara
2024-01-04 12:32 ` Yu Kuai
2024-01-05 4:43 ` Gao Xiang
2023-12-21 8:58 ` [PATCH RFC v3 for-6.8/block 12/17] nilfs2: use bdev api in nilfs_attach_log_writer() Yu Kuai
2023-12-21 14:54 ` Ryusuke Konishi
2023-12-21 8:58 ` [PATCH RFC v3 for-6.8/block 13/17] jbd2: use bdev apis Yu Kuai
2024-01-04 12:11 ` Jan Kara
2023-12-21 8:58 ` Yu Kuai [this message]
2024-01-04 12:22 ` [PATCH RFC v3 for-6.8/block 14/17] buffer: add a new helper to read sb block Jan Kara
2023-12-21 8:58 ` [PATCH RFC v3 for-6.8/block 15/17] ext4: use " Yu Kuai
2023-12-21 8:59 ` [PATCH RFC v3 for-6.8/block 16/17] ext4: remove block_device_ejected() Yu Kuai
2023-12-21 8:59 ` [PATCH RFC v3 for-6.8/block 17/17] ext4: use bdev apis Yu Kuai
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