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@xxxxxxx>
Cc: Andreas Dilger <adilger.kernel@xxxxxxxxx>
Cc: Jan Kara <jack@xxxxxxx>
Reported-by: Christoph Hellwig <hch@xxxxxx>
Signed-off-by: Dan Williams <dan.j.williams@xxxxxxxxx>
---
fs/ext2/ext2.h | 1 +
fs/ext2/inode.c | 11 +++--------
fs/ext2/super.c | 5 +++++
3 files changed, 9 insertions(+), 8 deletions(-)
diff --git a/fs/ext2/ext2.h b/fs/ext2/ext2.h
index 23ebb92484c6..28de3edd4f4d 100644
--- 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_ea_block_cache;
+ struct dax_device *s_daxdev;
};
static inline spinlock_t *
diff --git a/fs/ext2/inode.c b/fs/ext2/inode.c
index 30163d007b2f..4dca6f348714 100644
--- a/fs/ext2/inode.c
+++ b/fs/ext2/inode.c
@@ -800,10 +800,10 @@ int ext2_get_block(struct inode *inode, sector_t iblock,
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;
@@ -814,13 +814,9 @@ static int ext2_iomap_begin(struct inode *inode, loff_t offset, loff_t length,
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;
@@ -842,7 +838,6 @@ 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))
diff --git a/fs/ext2/super.c b/fs/ext2/super.c
index 7b1bc9059863..d9dd999568c2 100644
--- a/fs/ext2/super.c
+++ b/fs/ext2/super.c
@@ -144,6 +144,7 @@ static void ext2_put_super (struct super_block * sb)
int db_count;
int i;
struct ext2_sb_info *sbi = EXT2_SB(sb);
+ struct dax_device *dax_dev = sbi->s_daxdev;
ext2_quota_off_umount(sb);
@@ -172,6 +173,7 @@ static void ext2_put_super (struct super_block * sb)
sb->s_fs_info = NULL;
kfree(sbi->s_blockgroup_lock);
kfree(sbi);
+ fs_put_dax(dax_dev);
}
static struct kmem_cache * ext2_inode_cachep;
@@ -813,6 +815,7 @@ static unsigned long descriptor_loc(struct super_block *sb,
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 +845,7 @@ static int ext2_fill_super(struct super_block *sb, void *data, int silent)
}
sb->s_fs_info = sbi;
sbi->s_sb_block = sb_block;
+ sbi->s_daxdev = dax_dev;
spin_lock_init(&sbi->s_lock);
@@ -1200,6 +1204,7 @@ static int ext2_fill_super(struct super_block *sb, void *data, int silent)
kfree(sbi->s_blockgroup_lock);
kfree(sbi);
failed:
+ fs_put_dax(dax_dev);
return ret;
}
--
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