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authorDan Williams <dan.j.williams@intel.com>2017-08-25 02:42:48 +0300
committerDan Williams <dan.j.williams@intel.com>2017-08-31 21:12:13 +0300
commit5e405595e5bf4c09fab9ca1e7dbe5b62872757b5 (patch)
treed26852e38cf6c07551d0f42f1e03435e75067583
parent8cf037a8b22f71c6659bd0246bfaba9e79766f64 (diff)
downloadlinux-5e405595e5bf4c09fab9ca1e7dbe5b62872757b5.tar.xz
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" <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>
-rw-r--r--fs/ext4/ext4.h1
-rw-r--r--fs/ext4/inode.c11
-rw-r--r--fs/ext4/super.c4
3 files changed, 8 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 @@ 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 d61a70e2193a..3e58f952eddc 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;
}