From 5e405595e5bf4c09fab9ca1e7dbe5b62872757b5 Mon Sep 17 00:00:00 2001 From: Dan Williams Date: Thu, 24 Aug 2017 16:42:48 -0700 Subject: [PATCH] ext4: perform dax_device lookup at mount 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" Cc: Andreas Dilger Reviewed-by: Jan Kara Reported-by: Christoph Hellwig Signed-off-by: Dan Williams --- fs/ext4/ext4.h | 1 + fs/ext4/inode.c | 11 +++-------- fs/ext4/super.c | 4 ++++ 3 files changed, 8 insertions(+), 8 deletions(-) diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h index a2bb7d2..194e622 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 c774bdc..16424b5 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 @@ retry: } 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 d61a70e2..3e58f95 100644 --- a/fs/ext4/super.c +++ b/fs/ext4/super.c @@ -951,6 +951,7 @@ static void ext4_put_super(struct super_block *sb) if (sbi->s_chksum_driver) crypto_free_shash(sbi->s_chksum_driver); kfree(sbi->s_blockgroup_lock); + fs_put_dax(sbi->s_daxdev); kfree(sbi); } @@ -3377,6 +3378,7 @@ 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 +3401,7 @@ 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 +4381,7 @@ out_fail: out_free_base: kfree(sbi); kfree(orig_data); + fs_put_dax(dax_dev); return err ? err : ret; } -- 2.7.4