[PATCH v3 2/3] fsdax: pass blocksize to dax_truncate_page()

From: Zhang Yi
Date: Fri May 17 2024 - 07:25:13 EST


From: Zhang Yi <yi.zhang@xxxxxxxxxx>

dax_truncate_page() always assumes the block size of the truncating
inode is i_blocksize(), this is not always true for some filesystems,
e.g. XFS does extent size alignment for realtime inodes. Drop this
assumption and pass the block size for zeroing into dax_truncate_page(),
allow filesystems to indicate the correct block size.

Suggested-by: Dave Chinner <david@xxxxxxxxxxxxx>
Signed-off-by: Zhang Yi <yi.zhang@xxxxxxxxxx>
---
fs/dax.c | 13 +++++++++----
fs/ext2/inode.c | 4 ++--
fs/xfs/xfs_iomap.c | 2 +-
include/linux/dax.h | 4 ++--
4 files changed, 14 insertions(+), 9 deletions(-)

diff --git a/fs/dax.c b/fs/dax.c
index 423fc1607dfa..98419280d9ae 100644
--- a/fs/dax.c
+++ b/fs/dax.c
@@ -25,6 +25,7 @@
#include <linux/mmu_notifier.h>
#include <linux/iomap.h>
#include <linux/rmap.h>
+#include <linux/math64.h>
#include <asm/pgalloc.h>

#define CREATE_TRACE_POINTS
@@ -1403,11 +1404,15 @@ int dax_zero_range(struct inode *inode, loff_t pos, loff_t len, bool *did_zero,
}
EXPORT_SYMBOL_GPL(dax_zero_range);

-int dax_truncate_page(struct inode *inode, loff_t pos, bool *did_zero,
- const struct iomap_ops *ops)
+int dax_truncate_page(struct inode *inode, loff_t pos, unsigned int blocksize,
+ bool *did_zero, const struct iomap_ops *ops)
{
- unsigned int blocksize = i_blocksize(inode);
- unsigned int off = pos & (blocksize - 1);
+ unsigned int off;
+
+ if (is_power_of_2(blocksize))
+ off = pos & (blocksize - 1);
+ else
+ div_u64_rem(pos, blocksize, &off);

/* Block boundary? Nothing to do */
if (!off)
diff --git a/fs/ext2/inode.c b/fs/ext2/inode.c
index f3d570a9302b..fbbd479f3c4e 100644
--- a/fs/ext2/inode.c
+++ b/fs/ext2/inode.c
@@ -1278,8 +1278,8 @@ static int ext2_setsize(struct inode *inode, loff_t newsize)
inode_dio_wait(inode);

if (IS_DAX(inode))
- error = dax_truncate_page(inode, newsize, NULL,
- &ext2_iomap_ops);
+ error = dax_truncate_page(inode, newsize, i_blocksize(inode),
+ NULL, &ext2_iomap_ops);
else
error = block_truncate_page(inode->i_mapping,
newsize, ext2_get_block);
diff --git a/fs/xfs/xfs_iomap.c b/fs/xfs/xfs_iomap.c
index 31ac07bb8425..4958cc3337bc 100644
--- a/fs/xfs/xfs_iomap.c
+++ b/fs/xfs/xfs_iomap.c
@@ -1470,7 +1470,7 @@ xfs_truncate_page(
unsigned int blocksize = i_blocksize(inode);

if (IS_DAX(inode))
- return dax_truncate_page(inode, pos, did_zero,
+ return dax_truncate_page(inode, pos, blocksize, did_zero,
&xfs_dax_write_iomap_ops);
return iomap_truncate_page(inode, pos, blocksize, did_zero,
&xfs_buffered_write_iomap_ops);
diff --git a/include/linux/dax.h b/include/linux/dax.h
index 9d3e3327af4c..4aa8ef7c8fd4 100644
--- a/include/linux/dax.h
+++ b/include/linux/dax.h
@@ -210,8 +210,8 @@ int dax_file_unshare(struct inode *inode, loff_t pos, loff_t len,
const struct iomap_ops *ops);
int dax_zero_range(struct inode *inode, loff_t pos, loff_t len, bool *did_zero,
const struct iomap_ops *ops);
-int dax_truncate_page(struct inode *inode, loff_t pos, bool *did_zero,
- const struct iomap_ops *ops);
+int dax_truncate_page(struct inode *inode, loff_t pos, unsigned int blocksize,
+ bool *did_zero, const struct iomap_ops *ops);

#if IS_ENABLED(CONFIG_DAX)
int dax_read_lock(void);
--
2.39.2