[PATCH v2 1/2] dax: supply DAX clearing code with correct bdev

Ross Zwisler
2016-02-10T20:49:55Z

dax_clear_blocks() needs a valid struct block_device and previously it was
using inode->i_sb->s_bdev in all cases. This is correct for normal inodes
on mounted ext2, ext4 and XFS filesystems, but is incorrect for DAX raw
block devices and for XFS real-time devices.

Instead, rename dax_clear_blocks() to dax_clear_sectors(), and change its
arguments to take a bdev and a sector instead of an inode and a block.
This better reflects what the function does, and it allows the filesystem
and raw block device code to pass in an appropriate struct block_device.

Signed-off-by: Ross Zwisler <ross.zwisler@linux.intel.com>
Suggested-by: Dan Williams <dan.j.williams@intel.com>
---
fs/dax.c | 9 ++++-----
fs/ext2/inode.c | 6 ++++--
fs/xfs/xfs_aops.c | 2 +-
fs/xfs/xfs_aops.h | 1 +
fs/xfs/xfs_bmap_util.c | 3 ++-
include/linux/dax.h | 2 +-
6 files changed, 13 insertions(+), 10 deletions(-)

diff --git a/fs/dax.c b/fs/dax.c
index fc2e314..9a173dd 100644
--- a/fs/dax.c
+++ b/fs/dax.c
@@ -79,15 +79,14 @@ struct page *read_dax_sector(struct block_device *bdev, sector_t n)
}

/*
- * dax_clear_blocks() is called from within transaction context from XFS,
+ * dax_clear_sectors() is called from within transaction context from XFS,
* and hence this means the stack from this point must follow GFP_NOFS
* semantics for all operations.
*/
-int dax_clear_blocks(struct inode *inode, sector_t block, long _size)
+int dax_clear_sectors(struct block_device *bdev, sector_t _sector, long _size)
{
- struct block_device *bdev = inode->i_sb->s_bdev;
struct blk_dax_ctl dax = {
- .sector = block << (inode->i_blkbits - 9),
+ .sector = _sector,
.size = _size,
};

@@ -109,7 +108,7 @@ int dax_clear_blocks(struct inode *inode, sector_t block, long _size)
wmb_pmem();
return 0;
}
-EXPORT_SYMBOL_GPL(dax_clear_blocks);
+EXPORT_SYMBOL_GPL(dax_clear_sectors);

/* the clear_pmem() calls are ordered by a wmb_pmem() in the caller */
static void dax_new_buf(void __pmem *addr, unsigned size, unsigned first,
diff --git a/fs/ext2/inode.c b/fs/ext2/inode.c
index 338eefd..b6b965b 100644
--- a/fs/ext2/inode.c
+++ b/fs/ext2/inode.c
@@ -737,8 +737,10 @@ static int ext2_get_blocks(struct inode *inode,
* so that it's not found by another thread before it's
* initialised
*/
- err = dax_clear_blocks(inode, le32_to_cpu(chain[depth-1].key),
- 1 << inode->i_blkbits);
+ err = dax_clear_sectors(inode->i_sb->s_bdev,
+ le32_to_cpu(chain[depth-1].key) <<
+ (inode->i_blkbits - 9),
+ 1 << inode->i_blkbits);
if (err) {
mutex_unlock(&ei->truncate_mutex);
goto cleanup;
diff --git a/fs/xfs/xfs_aops.c b/fs/xfs/xfs_aops.c
index 379c089..fc20518 100644
--- a/fs/xfs/xfs_aops.c
+++ b/fs/xfs/xfs_aops.c
@@ -55,7 +55,7 @@ xfs_count_page_state(
} while ((bh = bh->b_this_page) != head);
}

-STATIC struct block_device *
+struct block_device *
xfs_find_bdev_for_inode(
struct inode *inode)
{
diff --git a/fs/xfs/xfs_aops.h b/fs/xfs/xfs_aops.h
index f6ffc9a..a4343c6 100644
--- a/fs/xfs/xfs_aops.h
+++ b/fs/xfs/xfs_aops.h
@@ -62,5 +62,6 @@ int xfs_get_blocks_dax_fault(struct inode *inode, sector_t offset,
struct buffer_head *map_bh, int create);

extern void xfs_count_page_state(struct page *, int *, int *);
+extern struct block_device *xfs_find_bdev_for_inode(struct inode *);

#endif /* __XFS_AOPS_H__ */
diff --git a/fs/xfs/xfs_bmap_util.c b/fs/xfs/xfs_bmap_util.c
index 07ef29b..ae9d755 100644
--- a/fs/xfs/xfs_bmap_util.c
+++ b/fs/xfs/xfs_bmap_util.c
@@ -75,7 +75,8 @@ xfs_zero_extent(
ssize_t size = XFS_FSB_TO_B(mp, count_fsb);

if (IS_DAX(VFS_I(ip)))
- return dax_clear_blocks(VFS_I(ip), block, size);
+ return dax_clear_sectors(xfs_find_bdev_for_inode(VFS_I(ip)),
+ sector, size);

/*
* let the block layer decide on the fastest method of
diff --git a/include/linux/dax.h b/include/linux/dax.h
index 818e450..7b6bced 100644
--- a/include/linux/dax.h
+++ b/include/linux/dax.h
@@ -7,7 +7,7 @@

ssize_t dax_do_io(struct kiocb *, struct inode *, struct iov_iter *, loff_t,
get_block_t, dio_iodone_t, int flags);
-int dax_clear_blocks(struct inode *, sector_t block, long size);
+int dax_clear_sectors(struct block_device *bdev, sector_t _sector, long _size);
int dax_zero_page_range(struct inode *, loff_t from, unsigned len, get_block_t);
int dax_truncate_page(struct inode *, loff_t from, get_block_t);
int dax_fault(struct vm_area_struct *, struct vm_fault *, get_block_t,
--
2.5.0