In the truncate or hole-punch path in dax, we clear out sub-page ranges.
If these sub-page ranges are sector aligned and sized, we can do the
zeroing through the driver instead so that error-clearing is handled
automatically.
For sub-sector ranges, we still have to rely on clear_pmem and have the
possibility of tripping over errors.
Cc: Matthew Wilcox <matthew@xxxxxx>
Cc: Dan Williams <dan.j.williams@xxxxxxxxx>
Cc: Ross Zwisler <ross.zwisler@xxxxxxxxxxxxxxx>
Cc: Jeff Moyer <jmoyer@xxxxxxxxxx>
Cc: Christoph Hellwig <hch@xxxxxxxxxxxxx>
Cc: Dave Chinner <david@xxxxxxxxxxxxx>
Cc: Jan Kara <jack@xxxxxxx>
Signed-off-by: Vishal Verma <vishal.l.verma@xxxxxxxxx>
---
fs/dax.c | 30 +++++++++++++++++++++++++-----
1 file changed, 25 insertions(+), 5 deletions(-)
diff --git a/fs/dax.c b/fs/dax.c
index 5948d9b..d8c974e 100644
--- a/fs/dax.c
+++ b/fs/dax.c
@@ -1196,6 +1196,20 @@ out:
}
EXPORT_SYMBOL_GPL(dax_pfn_mkwrite);
+static bool dax_range_is_aligned(struct block_device *bdev,
+ struct blk_dax_ctl *dax, unsigned int offset,
+ unsigned int length)
+{
+ unsigned short sector_size = bdev_logical_block_size(bdev);
+
+ if (((u64)dax->addr + offset) % sector_size)
+ return false;
+ if (length % sector_size)
+ return false;
+
+ return true;
+}
+
/**
* dax_zero_page_range - zero a range within a page of a DAX file
* @inode: The file being truncated
@@ -1240,11 +1254,17 @@ int dax_zero_page_range(struct inode *inode, loff_t from, unsigned length,
.size = PAGE_SIZE,
};
- if (dax_map_atomic(bdev, &dax) < 0)
- return PTR_ERR(dax.addr);
- clear_pmem(dax.addr + offset, length);
- wmb_pmem();
- dax_unmap_atomic(bdev, &dax);
+ if (dax_range_is_aligned(bdev, &dax, offset, length))
+ return blkdev_issue_zeroout(bdev, dax.sector,
+ length / bdev_logical_block_size(bdev),
+ GFP_NOFS, true);
+ else {
+ if (dax_map_atomic(bdev, &dax) < 0)
+ return PTR_ERR(dax.addr);
+ clear_pmem(dax.addr + offset, length);
+ wmb_pmem();
+ dax_unmap_atomic(bdev, &dax);
+ }
}
return 0;
--
2.5.5
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