Commit 5f008163 authored by Goldwyn Rodrigues's avatar Goldwyn Rodrigues Committed by David Sterba
Browse files

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: default avatarNikolay Borisov <nborisov@suse.com>
Reviewed-by: default avatarJohannes Thumshirn <jth@kernel.org>
Signed-off-by: default avatarGoldwyn Rodrigues <rgoldwyn@suse.com>
Signed-off-by: default avatarDavid Sterba <dsterba@suse.com>
parent b75b7ca7

fs/btrfs/btrfs_inode.h

+0 −18
Original line number Diff line number Diff line
@@ -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

fs/btrfs/inode.c

+0 −3
Original line number Diff line number Diff line
@@ -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) {

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