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btrfs: autodefrag: only scan one inode once

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Although we have btrfs_requeue_inode_defrag(), for autodefrag we are
still just exhausting all inode_defrag items in the tree.

This means, it doesn't make much difference to requeue an inode_defrag,
other than scan the inode from the beginning till its end.

Change the behaviour to always scan from offset 0 of an inode, and till
the end.

By this we get the following benefit:

- Straight-forward code

- No more re-queue related check

- Fewer members in inode_defrag

We still keep the same btrfs_get_fs_root() and btrfs_iget() check for
each loop, and added extra should_auto_defrag() check per-loop.

Note: the patch needs to be backported and is intentionally written
to minimize the diff size, code will be cleaned up later.

CC: stable@vger.kernel.org # 5.16
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
This commit is contained in:
Qu Wenruo 2022-02-22 18:20:59 +01:00 committed by David Sterba
parent 199257a78b
commit 26fbac2517
1 changed files with 22 additions and 62 deletions
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84
fs/btrfs/file.c
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@ -49,12 +49,6 @@ struct inode_defrag {
/* root objectid */
u64 root;
/* last offset we were able to defrag */
u64 last_offset;
/* if we've wrapped around back to zero once already */
int cycled;
};
static int __compare_inode_defrag(struct inode_defrag *defrag1,
@ -107,8 +101,6 @@ static int __btrfs_add_inode_defrag(struct btrfs_inode *inode,
*/
if (defrag->transid < entry->transid)
entry->transid = defrag->transid;
if (defrag->last_offset > entry->last_offset)
entry->last_offset = defrag->last_offset;
return -EEXIST;
}
}
@ -178,34 +170,6 @@ int btrfs_add_inode_defrag(struct btrfs_trans_handle *trans,
return 0;
}
/*
* Requeue the defrag object. If there is a defrag object that points to
* the same inode in the tree, we will merge them together (by
* __btrfs_add_inode_defrag()) and free the one that we want to requeue.
*/
static void btrfs_requeue_inode_defrag(struct btrfs_inode *inode,
struct inode_defrag *defrag)
{
struct btrfs_fs_info *fs_info = inode->root->fs_info;
int ret;
if (!__need_auto_defrag(fs_info))
goto out;
/*
* Here we don't check the IN_DEFRAG flag, because we need merge
* them together.
*/
spin_lock(&fs_info->defrag_inodes_lock);
ret = __btrfs_add_inode_defrag(inode, defrag);
spin_unlock(&fs_info->defrag_inodes_lock);
if (ret)
goto out;
return;
out:
kmem_cache_free(btrfs_inode_defrag_cachep, defrag);
}
/*
* pick the defragable inode that we want, if it doesn't exist, we will get
* the next one.
@ -278,8 +242,14 @@ static int __btrfs_run_defrag_inode(struct btrfs_fs_info *fs_info,
struct btrfs_root *inode_root;
struct inode *inode;
struct btrfs_ioctl_defrag_range_args range;
int num_defrag;
int ret;
int ret = 0;
u64 cur = 0;
again:
if (test_bit(BTRFS_FS_STATE_REMOUNTING, &fs_info->fs_state))
goto cleanup;
if (!__need_auto_defrag(fs_info))
goto cleanup;
/* get the inode */
inode_root = btrfs_get_fs_root(fs_info, defrag->root, true);
@ -295,39 +265,29 @@ static int __btrfs_run_defrag_inode(struct btrfs_fs_info *fs_info,
goto cleanup;
}
if (cur >= i_size_read(inode)) {
iput(inode);
goto cleanup;
}
/* do a chunk of defrag */
clear_bit(BTRFS_INODE_IN_DEFRAG, &BTRFS_I(inode)->runtime_flags);
memset(&range, 0, sizeof(range));
range.len = (u64)-1;
range.start = defrag->last_offset;
range.start = cur;
sb_start_write(fs_info->sb);
num_defrag = btrfs_defrag_file(inode, NULL, &range, defrag->transid,
ret = btrfs_defrag_file(inode, NULL, &range, defrag->transid,
BTRFS_DEFRAG_BATCH);
sb_end_write(fs_info->sb);
/*
* if we filled the whole defrag batch, there
* must be more work to do. Queue this defrag
* again
*/
if (num_defrag == BTRFS_DEFRAG_BATCH) {
defrag->last_offset = range.start;
btrfs_requeue_inode_defrag(BTRFS_I(inode), defrag);
} else if (defrag->last_offset && !defrag->cycled) {
/*
* we didn't fill our defrag batch, but
* we didn't start at zero. Make sure we loop
* around to the start of the file.
*/
defrag->last_offset = 0;
defrag->cycled = 1;
btrfs_requeue_inode_defrag(BTRFS_I(inode), defrag);
} else {
kmem_cache_free(btrfs_inode_defrag_cachep, defrag);
}
iput(inode);
return 0;
if (ret < 0)
goto cleanup;
cur = max(cur + fs_info->sectorsize, range.start);
goto again;
cleanup:
kmem_cache_free(btrfs_inode_defrag_cachep, defrag);
return ret;