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authorJeff Moyer <jmoyer@redhat.com>2015-08-14 16:15:31 -0400
committerDan Williams <dan.j.williams@intel.com>2015-09-15 20:07:35 -0400
commite94f5a2285fc94202a9efb2c687481f29b64132c (patch)
tree2cb07ecaaaf15389bad53415ecf7c6143f07a9fa /fs
parent6ff33f3902c3b1c5d0db6b1e2c70b6d76fba357f (diff)
downloadlinux-e94f5a2285fc94202a9efb2c687481f29b64132c.tar.bz2
dax: fix O_DIRECT I/O to the last block of a blockdev
commit bbab37ddc20b (block: Add support for DAX reads/writes to block devices) caused a regression in mkfs.xfs. That utility sets the block size of the device to the logical block size using the BLKBSZSET ioctl, and then issues a single sector read from the last sector of the device. This results in the dax_io code trying to do a page-sized read from 512 bytes from the end of the device. The result is -ERANGE being returned to userspace. The fix is to align the block to the page size before calling get_block. Thanks to willy for simplifying my original patch. Cc: <stable@vger.kernel.org> Signed-off-by: Jeff Moyer <jmoyer@redhat.com> Tested-by: Linda Knippers <linda.knippers@hp.com> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Diffstat (limited to 'fs')
-rw-r--r--fs/dax.c3
1 files changed, 2 insertions, 1 deletions
diff --git a/fs/dax.c b/fs/dax.c
index 93bf2f990ace..7ae6df7ea1d2 100644
--- a/fs/dax.c
+++ b/fs/dax.c
@@ -119,7 +119,8 @@ static ssize_t dax_io(struct inode *inode, struct iov_iter *iter,
size_t len;
if (pos == max) {
unsigned blkbits = inode->i_blkbits;
- sector_t block = pos >> blkbits;
+ long page = pos >> PAGE_SHIFT;
+ sector_t block = page << (PAGE_SHIFT - blkbits);
unsigned first = pos - (block << blkbits);
long size;