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btrfs: remove BTRFS_INODE_READDIO_NEED_LOCK 

Since we now perform direct reads using i_rwsem, we can remove this
inode flag used to co-ordinate unlocked reads.

The truncate call takes i_rwsem. This means it is correctly synchronized
with concurrent direct reads.

Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: Johannes Thumshirn <jth@kernel.org>
Signed-off-by: Goldwyn Rodrigues <rgoldwyn@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
This commit is contained in:
Goldwyn Rodrigues 2019-12-04 05:58:53 -06:00 committed by David Sterba
parent b75b7ca7c2
commit 5f008163a5
2 changed files with 0 additions and 21 deletions
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18
fs/btrfs/btrfs_inode.h
View File

@ -28,7 +28,6 @@ enum {
BTRFS_INODE_NEEDS_FULL_SYNC,
BTRFS_INODE_COPY_EVERYTHING,
BTRFS_INODE_IN_DELALLOC_LIST,
BTRFS_INODE_READDIO_NEED_LOCK,
BTRFS_INODE_HAS_PROPS,
BTRFS_INODE_SNAPSHOT_FLUSH,
};
@ -313,23 +312,6 @@ struct btrfs_dio_private {
u8 csums[];
};
/*
* Disable DIO read nolock optimization, so new dio readers will be forced
* to grab i_mutex. It is used to avoid the endless truncate due to
* nonlocked dio read.
*/
static inline void btrfs_inode_block_unlocked_dio(struct btrfs_inode *inode)
{
set_bit(BTRFS_INODE_READDIO_NEED_LOCK, &inode->runtime_flags);
smp_mb();
}
static inline void btrfs_inode_resume_unlocked_dio(struct btrfs_inode *inode)
{
smp_mb__before_atomic();
clear_bit(BTRFS_INODE_READDIO_NEED_LOCK, &inode->runtime_flags);
}
/* Array of bytes with variable length, hexadecimal format 0x1234 */
#define CSUM_FMT "0x%*phN"
#define CSUM_FMT_VALUE(size, bytes) size, bytes

3
fs/btrfs/inode.c
View File

@ -4750,10 +4750,7 @@ static int btrfs_setsize(struct inode *inode, struct iattr *attr)
truncate_setsize(inode, newsize);
/* Disable nonlocked read DIO to avoid the endless truncate */
btrfs_inode_block_unlocked_dio(BTRFS_I(inode));
inode_dio_wait(inode);
btrfs_inode_resume_unlocked_dio(BTRFS_I(inode));
ret = btrfs_truncate(inode, newsize == oldsize);
if (ret && inode->i_nlink) {