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/ext4/ext4.h | 1 +
fs/ext4/inode.c | 11 +++--------
fs/ext4/super.c | 5 +++++
3 files changed, 9 insertions(+), 8 deletions(-)
diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
index a2bb7d2870e4..194e622dc3dd 100644
--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h
@@ -1528,6 +1528,7 @@ struct ext4_sb_info {
/* Barrier between changing inodes' journal flags and writepages ops. */
struct percpu_rw_semaphore s_journal_flag_rwsem;
+ struct dax_device *s_daxdev;
};
static inline struct ext4_sb_info *EXT4_SB(struct super_block *sb)
diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index c774bdc22759..16424b5c4e88 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -3404,7 +3404,7 @@ static int ext4_releasepage(struct page *page, gfp_t wait)
static int ext4_iomap_begin(struct inode *inode, loff_t offset, loff_t length,
unsigned flags, struct iomap *iomap)
{
- struct block_device *bdev;
+ struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
unsigned int blkbits = inode->i_blkbits;
unsigned long first_block = offset >> blkbits;
unsigned long last_block = (offset + length - 1) >> blkbits;
@@ -3473,12 +3473,8 @@ static int ext4_iomap_begin(struct inode *inode, loff_t offset, loff_t length,
}
iomap->flags = 0;
- bdev = inode->i_sb->s_bdev;
- iomap->bdev = bdev;
- 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->bdev = inode->i_sb->s_bdev;
+ iomap->dax_dev = sbi->s_daxdev;
iomap->offset = first_block << blkbits;
if (ret == 0) {
@@ -3511,7 +3507,6 @@ static int ext4_iomap_end(struct inode *inode, loff_t offset, loff_t length,
int blkbits = inode->i_blkbits;
bool truncate = false;
- fs_put_dax(iomap->dax_dev);
if (!(flags & IOMAP_WRITE) || (flags & IOMAP_FAULT))
return 0;
diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index d61a70e2193a..0b3d94e25efb 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -864,6 +864,7 @@ static inline void ext4_quota_off_umount(struct super_block *sb)
static void ext4_put_super(struct super_block *sb)
{
struct ext4_sb_info *sbi = EXT4_SB(sb);
+ struct dax_device *dax_dev = sbi->s_daxdev;
struct ext4_super_block *es = sbi->s_es;
int aborted = 0;
int i, err;
@@ -952,6 +953,7 @@ static void ext4_put_super(struct super_block *sb)
crypto_free_shash(sbi->s_chksum_driver);
kfree(sbi->s_blockgroup_lock);
kfree(sbi);
+ fs_put_dax(dax_dev);
}
static struct kmem_cache *ext4_inode_cachep;
@@ -3377,6 +3379,7 @@ static void ext4_set_resv_clusters(struct super_block *sb)
static int ext4_fill_super(struct super_block *sb, void *data, int silent)
{
+ struct dax_device *dax_dev = fs_dax_get_by_bdev(sb->s_bdev);
char *orig_data = kstrdup(data, GFP_KERNEL);
struct buffer_head *bh;
struct ext4_super_block *es = NULL;
@@ -3399,6 +3402,7 @@ static int ext4_fill_super(struct super_block *sb, void *data, int silent)
unsigned int journal_ioprio = DEFAULT_JOURNAL_IOPRIO;
ext4_group_t first_not_zeroed;
+ sbi->s_daxdev = dax_dev;
if ((data && !orig_data) || !sbi)
goto out_free_base;
@@ -4378,6 +4382,7 @@ static int ext4_fill_super(struct super_block *sb, void *data, int silent)
out_free_base:
kfree(sbi);
kfree(orig_data);
+ fs_put_dax(dax_dev);
return err ? err : ret;
}
--
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