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ext4: rip out DAX handling from direct IO path

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Reads and writes for DAX inodes should no longer end up in direct IO
code. Rip out the support and add a warning.

Reviewed-by: Ross Zwisler <ross.zwisler@linux.intel.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
This commit is contained in:
Jan Kara 2016-11-20 18:53:30 -05:00 committed by Theodore Ts'o
parent e2ae766c1b
commit 0bd2d5ec3d
2 changed files with 15 additions and 84 deletions
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2
fs/ext4/ext4.h
View File

@ -2452,8 +2452,6 @@ struct buffer_head *ext4_getblk(handle_t *, struct inode *, ext4_lblk_t, int);
struct buffer_head *ext4_bread(handle_t *, struct inode *, ext4_lblk_t, int);
int ext4_get_block_unwritten(struct inode *inode, sector_t iblock,
struct buffer_head *bh_result, int create);
int ext4_dax_get_block(struct inode *inode, sector_t iblock,
struct buffer_head *bh_result, int create);
int ext4_get_block(struct inode *inode, sector_t iblock,
struct buffer_head *bh_result, int create);
int ext4_dio_get_block(struct inode *inode, sector_t iblock,

97
fs/ext4/inode.c
View File

@ -3280,46 +3280,6 @@ static int ext4_releasepage(struct page *page, gfp_t wait)
}
#ifdef CONFIG_FS_DAX
/*
* Get block function for DAX IO and mmap faults. It takes care of converting
* unwritten extents to written ones and initializes new / converted blocks
* to zeros.
*/
int ext4_dax_get_block(struct inode *inode, sector_t iblock,
struct buffer_head *bh_result, int create)
{
int ret;
ext4_debug("inode %lu, create flag %d\n", inode->i_ino, create);
if (!create)
return _ext4_get_block(inode, iblock, bh_result, 0);
ret = ext4_get_block_trans(inode, iblock, bh_result,
EXT4_GET_BLOCKS_PRE_IO |
EXT4_GET_BLOCKS_CREATE_ZERO);
if (ret < 0)
return ret;
if (buffer_unwritten(bh_result)) {
/*
* We are protected by i_mmap_sem or i_mutex so we know block
* cannot go away from under us even though we dropped
* i_data_sem. Convert extent to written and write zeros there.
*/
ret = ext4_get_block_trans(inode, iblock, bh_result,
EXT4_GET_BLOCKS_CONVERT |
EXT4_GET_BLOCKS_CREATE_ZERO);
if (ret < 0)
return ret;
}
/*
* At least for now we have to clear BH_New so that DAX code
* doesn't attempt to zero blocks again in a racy way.
*/
clear_buffer_new(bh_result);
return 0;
}
static int ext4_iomap_begin(struct inode *inode, loff_t offset, loff_t length,
unsigned flags, struct iomap *iomap)
{
@ -3473,14 +3433,6 @@ struct iomap_ops ext4_iomap_ops = {
.iomap_end = ext4_iomap_end,
};
#else
/* Just define empty function, it will never get called. */
int ext4_dax_get_block(struct inode *inode, sector_t iblock,
struct buffer_head *bh_result, int create)
{
BUG();
return 0;
}
#endif
static int ext4_end_io_dio(struct kiocb *iocb, loff_t offset,
@ -3602,19 +3554,7 @@ static ssize_t ext4_direct_IO_write(struct kiocb *iocb, struct iov_iter *iter)
iocb->private = NULL;
if (overwrite)
get_block_func = ext4_dio_get_block_overwrite;
else if (IS_DAX(inode)) {
/*
* We can avoid zeroing for aligned DAX writes beyond EOF. Other
* writes need zeroing either because they can race with page
* faults or because they use partial blocks.
*/
if (round_down(offset, 1<<inode->i_blkbits) >= inode->i_size &&
ext4_aligned_io(inode, offset, count))
get_block_func = ext4_dio_get_block;
else
get_block_func = ext4_dax_get_block;
dio_flags = DIO_LOCKING;
} else if (!ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS) ||
else if (!ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS) ||
round_down(offset, 1 << inode->i_blkbits) >= inode->i_size) {
get_block_func = ext4_dio_get_block;
dio_flags = DIO_LOCKING | DIO_SKIP_HOLES;
@ -3628,14 +3568,9 @@ static ssize_t ext4_direct_IO_write(struct kiocb *iocb, struct iov_iter *iter)
#ifdef CONFIG_EXT4_FS_ENCRYPTION
BUG_ON(ext4_encrypted_inode(inode) && S_ISREG(inode->i_mode));
#endif
if (IS_DAX(inode)) {
ret = dax_do_io(iocb, inode, iter, get_block_func,
ext4_end_io_dio, dio_flags);
} else
ret = __blockdev_direct_IO(iocb, inode,
inode->i_sb->s_bdev, iter,
get_block_func,
ext4_end_io_dio, NULL, dio_flags);
ret = __blockdev_direct_IO(iocb, inode, inode->i_sb->s_bdev, iter,
get_block_func, ext4_end_io_dio, NULL,
dio_flags);
if (ret > 0 && !overwrite && ext4_test_inode_state(inode,
EXT4_STATE_DIO_UNWRITTEN)) {
@ -3704,6 +3639,7 @@ static ssize_t ext4_direct_IO_read(struct kiocb *iocb, struct iov_iter *iter)
{
struct address_space *mapping = iocb->ki_filp->f_mapping;
struct inode *inode = mapping->host;
size_t count = iov_iter_count(iter);
ssize_t ret;
/*
@ -3712,19 +3648,12 @@ static ssize_t ext4_direct_IO_read(struct kiocb *iocb, struct iov_iter *iter)
* we are protected against page writeback as well.
*/
inode_lock_shared(inode);
if (IS_DAX(inode)) {
ret = dax_do_io(iocb, inode, iter, ext4_dio_get_block, NULL, 0);
} else {
size_t count = iov_iter_count(iter);
ret = filemap_write_and_wait_range(mapping, iocb->ki_pos,
iocb->ki_pos + count);
if (ret)
goto out_unlock;
ret = __blockdev_direct_IO(iocb, inode, inode->i_sb->s_bdev,
iter, ext4_dio_get_block,
NULL, NULL, 0);
}
ret = filemap_write_and_wait_range(mapping, iocb->ki_pos,
iocb->ki_pos + count);
if (ret)
goto out_unlock;
ret = __blockdev_direct_IO(iocb, inode, inode->i_sb->s_bdev,
iter, ext4_dio_get_block, NULL, NULL, 0);
out_unlock:
inode_unlock_shared(inode);
return ret;
@ -3753,6 +3682,10 @@ static ssize_t ext4_direct_IO(struct kiocb *iocb, struct iov_iter *iter)
if (ext4_has_inline_data(inode))
return 0;
/* DAX uses iomap path now */
if (WARN_ON_ONCE(IS_DAX(inode)))
return 0;
trace_ext4_direct_IO_enter(inode, offset, count, iov_iter_rw(iter));
if (iov_iter_rw(iter) == READ)
ret = ext4_direct_IO_read(iocb, iter);