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 <[email protected]> Cc: Dan Williams <[email protected]> Cc: Ross Zwisler <[email protected]> Cc: Jeff Moyer <[email protected]> Cc: Christoph Hellwig <[email protected]> Cc: Dave Chinner <[email protected]> Cc: Jan Kara <[email protected]> Cc: Jens Axboe <[email protected]> Cc: Al Viro <[email protected]> Signed-off-by: Vishal Verma <[email protected]> --- 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
