From 8cf037a8b22f71c6659bd0246bfaba9e79766f64 Mon Sep 17 00:00:00 2001
From: Dan Williams <dan.j.williams@intel.com>
Date: Wed, 30 Aug 2017 09:43:34 -0700
Subject: [PATCH 3/4] ext2: perform dax_device lookup at mount
Git-commit: 8cf037a8b22f71c6659bd0246bfaba9e79766f64
Patch-mainline: v4.14-rc1
References: fate#322879
The ->iomap_begin() operation is a hot path, so cache the
fs_dax_get_by_host() result at mount time to avoid the incurring the
hash lookup overhead on a per-i/o basis.
Cc: "Theodore Ts'o" <tytso@mit.edu>
Cc: Andreas Dilger <adilger.kernel@dilger.ca>
Reviewed-by: Jan Kara <jack@suse.cz>
Reported-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Acked-by: Jan Kara <jack@suse.cz>
---
fs/ext2/ext2.h | 1 +
fs/ext2/inode.c | 11 +++--------
fs/ext2/super.c | 4 ++++
3 files changed, 8 insertions(+), 8 deletions(-)
--- a/fs/ext2/ext2.h
+++ b/fs/ext2/ext2.h
@@ -114,6 +114,7 @@ struct ext2_sb_info {
*/
spinlock_t s_lock;
struct mb_cache *s_mb_cache;
+ struct dax_device *s_daxdev;
};
static inline spinlock_t *
--- a/fs/ext2/inode.c
+++ b/fs/ext2/inode.c
@@ -799,10 +799,10 @@ int ext2_get_block(struct inode *inode,
static int ext2_iomap_begin(struct inode *inode, loff_t offset, loff_t length,
unsigned flags, struct iomap *iomap)
{
- struct block_device *bdev;
unsigned int blkbits = inode->i_blkbits;
unsigned long first_block = offset >> blkbits;
unsigned long max_blocks = (length + (1 << blkbits) - 1) >> blkbits;
+ struct ext2_sb_info *sbi = EXT2_SB(inode->i_sb);
bool new = false, boundary = false;
u32 bno;
int ret;
@@ -813,13 +813,9 @@ static int ext2_iomap_begin(struct inode
return ret;
iomap->flags = 0;
- bdev = inode->i_sb->s_bdev;
- iomap->bdev = bdev;
+ iomap->bdev = inode->i_sb->s_bdev;
iomap->offset = (u64)first_block << blkbits;
- if (blk_queue_dax(bdev->bd_queue))
- iomap->dax_dev = fs_dax_get_by_host(bdev->bd_disk->disk_name);
- else
- iomap->dax_dev = NULL;
+ iomap->dax_dev = sbi->s_daxdev;
if (ret == 0) {
iomap->type = IOMAP_HOLE;
@@ -841,7 +837,6 @@ static int
ext2_iomap_end(struct inode *inode, loff_t offset, loff_t length,
ssize_t written, unsigned flags, struct iomap *iomap)
{
- fs_put_dax(iomap->dax_dev);
if (iomap->type == IOMAP_MAPPED &&
written < length &&
(flags & IOMAP_WRITE))
--- a/fs/ext2/super.c
+++ b/fs/ext2/super.c
@@ -171,6 +171,7 @@ static void ext2_put_super (struct super
brelse (sbi->s_sbh);
sb->s_fs_info = NULL;
kfree(sbi->s_blockgroup_lock);
+ fs_put_dax(sbi->s_daxdev);
kfree(sbi);
}
@@ -813,6 +814,7 @@ static unsigned long descriptor_loc(stru
static int ext2_fill_super(struct super_block *sb, void *data, int silent)
{
+ struct dax_device *dax_dev = fs_dax_get_by_bdev(sb->s_bdev);
struct buffer_head * bh;
struct ext2_sb_info * sbi;
struct ext2_super_block * es;
@@ -842,6 +844,7 @@ static int ext2_fill_super(struct super_
}
sb->s_fs_info = sbi;
sbi->s_sb_block = sb_block;
+ sbi->s_daxdev = dax_dev;
spin_lock_init(&sbi->s_lock);
@@ -1200,6 +1203,7 @@ failed_sbi:
kfree(sbi->s_blockgroup_lock);
kfree(sbi);
failed:
+ fs_put_dax(dax_dev);
return ret;
}