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: 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/dax.c | 34 ++++++++++++++++++++++++++++++++--
fs/ext2/inode.c | 5 +++--
fs/ext4/indirect.c | 11 +++++++----
fs/ext4/inode.c | 5 +++--
fs/xfs/xfs_aops.c | 7 ++++---
include/linux/dax.h | 6 +++++-
7 files changed, 57 insertions(+), 16 deletions(-)
diff --git a/fs/block_dev.c b/fs/block_dev.c
index 9c0765b..f3873ab 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_do_io(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/dax.c b/fs/dax.c
index a30481e..b90c8e9 100644
--- a/fs/dax.c
+++ b/fs/dax.c
@@ -208,7 +208,7 @@ static ssize_t dax_io(struct inode *inode, struct iov_iter *iter,
}
/**
- * dax_do_io - Perform I/O to a DAX file
+ * __dax_do_io - Perform I/O to a DAX file
* @iocb: The control block for this I/O
* @inode: The file which the I/O is directed at
* @iter: The addresses to do I/O from or to
@@ -224,7 +224,7 @@ static ssize_t dax_io(struct inode *inode, struct iov_iter *iter,
* As with do_blockdev_direct_IO(), we increment i_dio_count while the I/O
* is in progress.
*/
-ssize_t dax_do_io(struct kiocb *iocb, struct inode *inode,
+ssize_t __dax_do_io(struct kiocb *iocb, struct inode *inode,
struct iov_iter *iter, loff_t pos, get_block_t get_block,
dio_iodone_t end_io, int flags)
{
@@ -262,8 +262,38 @@ ssize_t dax_do_io(struct kiocb *iocb, struct inode *inode,
out:
return retval;
}
+EXPORT_SYMBOL_GPL(__dax_do_io);
+
+/*
+ * This is a library function for use by file systems. It will perform a
+ * fallback to direct_io semantics if the dax_io fails due to a media error.
+ */
+ssize_t dax_do_io(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,
+ * 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)
+ return -EIO;
+ }
+ return retval;
+}
EXPORT_SYMBOL_GPL(dax_do_io);
+
/*
* The user has performed a load from a hole in the file. Allocating
* a new page in the file would cause excessive storage usage for
diff --git a/fs/ext2/inode.c b/fs/ext2/inode.c
index 824f249..8a307cf 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_do_io(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/indirect.c b/fs/ext4/indirect.c
index 355ef9c..4b087b7 100644
--- a/fs/ext4/indirect.c
+++ b/fs/ext4/indirect.c
@@ -692,8 +692,9 @@ retry:
goto locked;
}
if (IS_DAX(inode))
- ret = dax_do_io(iocb, inode, iter, offset,
- ext4_get_block, NULL, 0);
+ ret = dax_do_io(iocb, inode, inode->i_sb->s_bdev, iter,
+ offset, ext4_get_block, ext4_get_block,
+ NULL, NULL, 0);
else
ret = __blockdev_direct_IO(iocb, inode,
inode->i_sb->s_bdev, iter,
@@ -703,8 +704,10 @@ retry:
} else {
locked:
if (IS_DAX(inode))
- ret = dax_do_io(iocb, inode, iter, offset,
- ext4_get_block, NULL, DIO_LOCKING);
+ ret = dax_do_io(iocb, inode, inode->i_sb->s_bdev, iter,
+ offset, ext4_get_block, ext4_get_block,
+ NULL, NULL, DIO_LOCKING |
+ DIO_SKIP_HOLES);
else
ret = blockdev_direct_IO(iocb, inode, iter, offset,
ext4_get_block);
diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index aee960b..4220dac 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -3315,8 +3315,9 @@ static ssize_t ext4_ext_direct_IO(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_do_io(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 a9ebabfe..dc4e088 100644
--- a/fs/xfs/xfs_aops.c
+++ b/fs/xfs/xfs_aops.c
@@ -1682,11 +1682,12 @@ xfs_vm_do_dio(
void *private),
int flags)
{
- struct block_device *bdev;
+ struct block_device *bdev = xfs_find_bdev_for_inode(inode);
if (IS_DAX(inode))
- return dax_do_io(iocb, inode, iter, offset,
- xfs_get_blocks_direct, endio, 0);
+ return dax_do_io(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,
diff --git a/include/linux/dax.h b/include/linux/dax.h
index 933198a..6981076 100644
--- a/include/linux/dax.h
+++ b/include/linux/dax.h
@@ -5,8 +5,12 @@
#include <linux/mm.h>
#include <asm/pgtable.h>
-ssize_t dax_do_io(struct kiocb *, struct inode *, struct iov_iter *, loff_t,
+ssize_t __dax_do_io(struct kiocb *, struct inode *, struct iov_iter *, loff_t,
get_block_t, dio_iodone_t, int flags);
+ssize_t dax_do_io(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);
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,
--
2.5.5
--
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