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Revert "btrfs: remove BTRFS_INODE_READDIO_NEED_LOCK"

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This reverts commit 5f008163a5.

The patch is a simplification after direct IO port to iomap
infrastructure, which gets reverted.

Signed-off-by: David Sterba <dsterba@suse.com>
This commit is contained in:
David Sterba 2020-06-09 19:21:48 +02:00
parent f4c48b4408
commit 8e0fa5d7b3
2 changed files with 21 additions and 0 deletions
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18
fs/btrfs/btrfs_inode.h
View file

@ -28,6 +28,7 @@ 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,
};
@ -312,6 +313,23 @@ 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

@ -4811,7 +4811,10 @@ 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) {