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Date: Fri, 18 Nov 2016 09:47:08 +0100
From: Jan Kara <jack@...e.cz>
To: Ted Tso <tytso@....edu>
Cc: <linux-ext4@...r.kernel.org>,
Ross Zwisler <ross.zwisler@...ux.intel.com>,
Jan Kara <jack@...e.cz>
Subject: [PATCH 08/10] ext4: Rip out DAX handling from direct IO path
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@...ux.intel.com>
Signed-off-by: Jan Kara <jack@...e.cz>
---
fs/ext4/ext4.h | 2 --
fs/ext4/inode.c | 97 +++++++++------------------------------------------------
2 files changed, 15 insertions(+), 84 deletions(-)
diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
index 098b39910001..8b763113a1b8 100644
--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h
@@ -2457,8 +2457,6 @@ 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,
diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index 4d71c7bc3524..d13f7cb6b1d5 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -3272,46 +3272,6 @@ 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)
{
@@ -3465,14 +3425,6 @@ 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,
@@ -3594,19 +3546,7 @@ 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;
@@ -3620,14 +3560,9 @@ 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)) {
@@ -3696,6 +3631,7 @@ 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;
/*
@@ -3704,19 +3640,12 @@ 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;
@@ -3745,6 +3674,10 @@ 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);
--
2.6.6
--
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