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btrfs: qgroup: Introduce extent changeset for qgroup reserve functions

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Introduce a new parameter, struct extent_changeset for
btrfs_qgroup_reserved_data() and its callers.

Such extent_changeset was used in btrfs_qgroup_reserve_data() to record
which range it reserved in current reserve, so it can free it in error
paths.

The reason we need to export it to callers is, at buffered write error
path, without knowing what exactly which range we reserved in current
allocation, we can free space which is not reserved by us.

This will lead to qgroup reserved space underflow.

Reviewed-by: Chandan Rajendra <chandan@linux.vnet.ibm.com>
Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com>
Signed-off-by: David Sterba <dsterba@suse.com>
This commit is contained in:
Qu Wenruo
2017-02-27 15:10:38 +08:00
committed by David Sterba
parent a12b877b55
commit 364ecf3651
10 changed files with 119 additions and 41 deletions
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5
fs/btrfs/ioctl.c
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@@ -1127,6 +1127,7 @@ static int cluster_pages_for_defrag(struct inode *inode,
struct btrfs_ordered_extent *ordered;
struct extent_state *cached_state = NULL;
struct extent_io_tree *tree;
struct extent_changeset *data_reserved = NULL;
gfp_t mask = btrfs_alloc_write_mask(inode->i_mapping);
file_end = (isize - 1) >> PAGE_SHIFT;
@@ -1135,7 +1136,7 @@ static int cluster_pages_for_defrag(struct inode *inode,
page_cnt = min_t(u64, (u64)num_pages, (u64)file_end - start_index + 1);
ret = btrfs_delalloc_reserve_space(inode,
ret = btrfs_delalloc_reserve_space(inode, &data_reserved,
start_index << PAGE_SHIFT,
page_cnt << PAGE_SHIFT);
if (ret)
@@ -1247,6 +1248,7 @@ again:
unlock_page(pages[i]);
put_page(pages[i]);
}
extent_changeset_free(data_reserved);
return i_done;
out:
for (i = 0; i < i_done; i++) {
@@ -1256,6 +1258,7 @@ out:
btrfs_delalloc_release_space(inode,
start_index << PAGE_SHIFT,
page_cnt << PAGE_SHIFT);
extent_changeset_free(data_reserved);
return ret;
}