dax_do_io (called for read() or write() for a dax file system) may fail
in the presence of bad blocks or media errors. Since we expect that a
write should clear media errors on nvdimms, make dax_do_io fall back to
the direct_IO path, which will send down a bio to the driver, which can
then attempt to clear the error.
Cc: Matthew Wilcox <matthew.r.wilcox@xxxxxxxxx>
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>
Cc: Jens Axboe <axboe@xxxxxx>
Cc: Al Viro <viro@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Vishal Verma <vishal.l.verma@xxxxxxxxx>
---
fs/block_dev.c | 5 +++--
fs/ext2/inode.c | 5 +++--
fs/ext4/inode.c | 5 +++--
fs/xfs/xfs_aops.c | 8 ++++----
include/linux/dax.h | 30 ++++++++++++++++++++++++++++++
5 files changed, 43 insertions(+), 10 deletions(-)
diff --git a/fs/block_dev.c b/fs/block_dev.c
index 79defba..7c90516 100644
--- a/fs/block_dev.c
+++ b/fs/block_dev.c
@@ -168,8 +168,9 @@ blkdev_direct_IO(struct kiocb *iocb, struct iov_iter *iter, loff_t offset)
struct inode *inode = bdev_file_inode(file);
if (IS_DAX(inode))
- return dax_do_io(iocb, inode, iter, offset, blkdev_get_block,
- NULL, DIO_SKIP_DIO_COUNT);
+ return dax_io_fallback(iocb, inode, I_BDEV(inode), iter, offset,
+ blkdev_get_block, blkdev_get_block,
+ NULL, NULL, DIO_SKIP_DIO_COUNT);
return __blockdev_direct_IO(iocb, inode, I_BDEV(inode), iter, offset,
blkdev_get_block, NULL, NULL,
DIO_SKIP_DIO_COUNT);
diff --git a/fs/ext2/inode.c b/fs/ext2/inode.c
index 35f2b0bf..1cec54b 100644
--- a/fs/ext2/inode.c
+++ b/fs/ext2/inode.c
@@ -862,8 +862,9 @@ ext2_direct_IO(struct kiocb *iocb, struct iov_iter *iter, loff_t offset)
ssize_t ret;
if (IS_DAX(inode))
- ret = dax_do_io(iocb, inode, iter, offset, ext2_get_block, NULL,
- DIO_LOCKING);
+ ret = dax_io_fallback(iocb, inode, inode->i_sb->s_bdev, iter,
+ offset, ext2_get_block, ext2_get_block,
+ NULL, NULL, DIO_LOCKING | DIO_SKIP_HOLES);
else
ret = blockdev_direct_IO(iocb, inode, iter, offset,
ext2_get_block);
diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index 6d5d5c1..d29848b 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -3411,8 +3411,9 @@ static ssize_t ext4_direct_IO_write(struct kiocb *iocb, struct iov_iter *iter,
BUG_ON(ext4_encrypted_inode(inode) && S_ISREG(inode->i_mode));
#endif
if (IS_DAX(inode)) {
- ret = dax_do_io(iocb, inode, iter, offset, get_block_func,
- ext4_end_io_dio, dio_flags);
+ ret = dax_io_fallback(iocb, inode, inode->i_sb->s_bdev, iter,
+ offset, get_block_func, get_block_func,
+ ext4_end_io_dio, NULL, dio_flags);
} else
ret = __blockdev_direct_IO(iocb, inode,
inode->i_sb->s_bdev, iter, offset,
diff --git a/fs/xfs/xfs_aops.c b/fs/xfs/xfs_aops.c
index e49b240..48fe10a 100644
--- a/fs/xfs/xfs_aops.c
+++ b/fs/xfs/xfs_aops.c
@@ -1412,7 +1412,7 @@ xfs_vm_direct_IO(
struct inode *inode = iocb->ki_filp->f_mapping->host;
dio_iodone_t *endio = NULL;
int flags = 0;
- struct block_device *bdev;
+ struct block_device *bdev = xfs_find_bdev_for_inode(inode);
if (iov_iter_rw(iter) == WRITE) {
endio = xfs_end_io_direct_write;
@@ -1420,11 +1420,11 @@ xfs_vm_direct_IO(
}
if (IS_DAX(inode)) {
- return dax_do_io(iocb, inode, iter, offset,
- xfs_get_blocks_direct, endio, 0);
+ return dax_io_fallback(iocb, inode, bdev, iter, offset,
+ xfs_get_blocks_direct, xfs_get_blocks_direct,
+ endio, NULL, flags);
}
- bdev = xfs_find_bdev_for_inode(inode);
return __blockdev_direct_IO(iocb, inode, bdev, iter, offset,
xfs_get_blocks_direct, endio, NULL, flags);
}
diff --git a/include/linux/dax.h b/include/linux/dax.h
index 426841a..7200e6f 100644
--- a/include/linux/dax.h
+++ b/include/linux/dax.h
@@ -3,6 +3,7 @@
#include <linux/fs.h>
#include <linux/mm.h>
+#include <linux/uio.h>
#include <linux/radix-tree.h>
#include <asm/pgtable.h>
@@ -64,4 +65,33 @@ static inline bool dax_mapping(struct address_space *mapping)
struct writeback_control;
int dax_writeback_mapping_range(struct address_space *mapping,
struct block_device *bdev, struct writeback_control *wbc);
+/*
+ * This is a wrapper for dax_do_io which may be used for writes, and will
+ * perform a fallback to direct_io semantics if the dax_io fails due to a
+ * media error.
+ */
+static inline ssize_t dax_io_fallback(struct kiocb *iocb, struct inode *inode,
+ struct block_device *bdev, struct iov_iter *iter, loff_t pos,
+ get_block_t dax_get_block, get_block_t dio_get_block,
+ dio_iodone_t end_io, dio_submit_t submit_io, int flags)
+{
+ ssize_t retval;
+
+ retval = dax_do_io(iocb, inode, iter, pos, dax_get_block, end_io,
+ flags);
+ if (iov_iter_rw(iter) == WRITE && retval == -EIO) {
+ /*
+ * __dax_do_io may have failed a write due to a bad block.
+ * Retry with direct_io, and if the direct_IO also fails
+ * (with the exception of -EIOCBQUEUED), return -EIO as
+ * that was the original error that led us down the
+ * direct_IO path.
+ */
+ retval = __blockdev_direct_IO(iocb, inode, bdev, iter, pos,
+ dio_get_block, end_io, submit_io, flags);
+ if (retval < 0 && retval != -EIOCBQUEUED)
+ return -EIO;
+ }
+ return retval;
+}
#endif
--
2.5.5
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