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btrfs: remove btrfs_inode::dio_sem 

The inode dio_sem can be eliminated because all DIO synchronization is
now performed through inode->i_rwsem that provides the same guarantees.

This reduces btrfs_inode size by 40 bytes.

Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Goldwyn Rodrigues <rgoldwyn@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
This commit is contained in:
Goldwyn Rodrigues 2020-09-24 11:39:19 -05:00 committed by David Sterba
parent e9adabb971
commit 502756b380
3 changed files with 0 additions and 24 deletions
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10
fs/btrfs/btrfs_inode.h
View File

@ -203,16 +203,6 @@ struct btrfs_inode {
/* Hook into fs_info->delayed_iputs */
struct list_head delayed_iput;
/*
* To avoid races between lockless (i_mutex not held) direct IO writes
* and concurrent fsync requests. Direct IO writes must acquire read
* access on this semaphore for creating an extent map and its
* corresponding ordered extent. The fast fsync path must acquire write
* access on this semaphore before it collects ordered extents and
* extent maps.
*/
struct rw_semaphore dio_sem;
struct inode vfs_inode;
};

13
fs/btrfs/file.c
View File

@ -1948,8 +1948,6 @@ static ssize_t btrfs_direct_write(struct kiocb *iocb, struct iov_iter *from)
goto buffered;
}
down_read(&BTRFS_I(inode)->dio_sem);
/*
* This is actually a sync iocb, so we need our fancy endio to know if
* we need to sync.
@ -1964,7 +1962,6 @@ static ssize_t btrfs_direct_write(struct kiocb *iocb, struct iov_iter *from)
if (written == -ENOTBLK)
written = 0;
up_read(&BTRFS_I(inode)->dio_sem);
btrfs_inode_unlock(inode, ilock_flags);
if (written < 0 || !iov_iter_count(from)) {
@ -2172,13 +2169,6 @@ int btrfs_sync_file(struct file *file, loff_t start, loff_t end, int datasync)
inode_lock(inode);
/*
* We take the dio_sem here because the tree log stuff can race with
* lockless dio writes and get an extent map logged for an extent we
* never waited on. We need it this high up for lockdep reasons.
*/
down_write(&BTRFS_I(inode)->dio_sem);
atomic_inc(&root->log_batch);
/*
@ -2209,7 +2199,6 @@ int btrfs_sync_file(struct file *file, loff_t start, loff_t end, int datasync)
*/
ret = start_ordered_ops(inode, start, end);
if (ret) {
up_write(&BTRFS_I(inode)->dio_sem);
inode_unlock(inode);
goto out;
}
@ -2306,7 +2295,6 @@ int btrfs_sync_file(struct file *file, loff_t start, loff_t end, int datasync)
* file again, but that will end up using the synchronization
* inside btrfs_sync_log to keep things safe.
*/
up_write(&BTRFS_I(inode)->dio_sem);
inode_unlock(inode);
if (ret != BTRFS_NO_LOG_SYNC) {
@ -2337,7 +2325,6 @@ int btrfs_sync_file(struct file *file, loff_t start, loff_t end, int datasync)
out_release_extents:
btrfs_release_log_ctx_extents(&ctx);
up_write(&BTRFS_I(inode)->dio_sem);
inode_unlock(inode);
goto out;
}

1
fs/btrfs/inode.c
View File

@ -8650,7 +8650,6 @@ struct inode *btrfs_alloc_inode(struct super_block *sb)
INIT_LIST_HEAD(&ei->delalloc_inodes);
INIT_LIST_HEAD(&ei->delayed_iput);
RB_CLEAR_NODE(&ei->rb_node);
init_rwsem(&ei->dio_sem);
return inode;
}