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btrfs: replace readpage_end_io_hook with direct calls

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Don't call readpage_end_io_hook for the btree inode.  Instead of relying
on indirect calls to implement metadata buffer validation simply check
if the inode whose page we are processing equals the btree inode. If it
does call the necessary function.

This is an improvement in 2 directions:

1. We aren't paying the penalty of indirect calls in a post-speculation
   attacks world.

2. The function is now named more explicitly so it's obvious what's
   going on

This is in preparation to removing struct extent_io_ops altogether.

Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
This commit is contained in:
Nikolay Borisov
2020-09-18 16:34:33 +03:00
committed by David Sterba
parent 9c2b4e0347
commit 9a446d6a9f
5 changed files with 18 additions and 12 deletions
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7
fs/btrfs/inode.c
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@@ -2832,9 +2832,8 @@ zeroit:
* if there's a match, we allow the bio to finish. If not, the code in
* extent_io.c will try to find good copies for us.
*/
static int btrfs_readpage_end_io_hook(struct btrfs_io_bio *io_bio,
u64 phy_offset, struct page *page,
u64 start, u64 end, int mirror)
int btrfs_verify_data_csum(struct btrfs_io_bio *io_bio, u64 phy_offset,
struct page *page, u64 start, u64 end, int mirror)
{
size_t offset = start - page_offset(page);
struct inode *inode = page->mapping->host;
@@ -10261,7 +10260,7 @@ static const struct file_operations btrfs_dir_file_operations = {
static const struct extent_io_ops btrfs_extent_io_ops = {
/* mandatory callbacks */
.submit_bio_hook = btrfs_submit_bio_hook,
.readpage_end_io_hook = btrfs_readpage_end_io_hook,
.readpage_end_io_hook = NULL
};
/*