mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2024-09-29 22:02:02 +00:00
btrfs: fix the error handling for submit_extent_page() for btrfs_do_readpage()
commit 10f7f6f879
upstream.
[BUG]
Test case generic/475 have a very high chance (almost 100%) to hit a fs
hang, where a data page will never be unlocked and hang all later
operations.
[CAUSE]
In btrfs_do_readpage(), if we hit an error from submit_extent_page() we
will try to do the cleanup for our current io range, and exit.
This works fine for PAGE_SIZE == sectorsize cases, but not for subpage.
For subpage btrfs_do_readpage() will lock the full page first, which can
contain several different sectors and extents:
btrfs_do_readpage()
|- begin_page_read()
| |- btrfs_subpage_start_reader();
| Now the page will have PAGE_SIZE / sectorsize reader pending,
| and the page is locked.
|
|- end_page_read() for different branches
| This function will reduce subpage readers, and when readers
| reach 0, it will unlock the page.
But when submit_extent_page() failed, we only cleanup the current
io range, while the remaining io range will never be cleaned up, and the
page remains locked forever.
[FIX]
Update the error handling of submit_extent_page() to cleanup all the
remaining subpage range before exiting the loop.
Please note that, now submit_extent_page() can only fail due to
sanity check in alloc_new_bio().
Thus regular IO errors are impossible to trigger the error path.
CC: stable@vger.kernel.org # 5.15+
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
parent
80e2340d1f
commit
08128d6cac
1 changed files with 6 additions and 2 deletions
|
@ -3727,8 +3727,12 @@ int btrfs_do_readpage(struct page *page, struct extent_map **em_cached,
|
|||
this_bio_flag,
|
||||
force_bio_submit);
|
||||
if (ret) {
|
||||
unlock_extent(tree, cur, cur + iosize - 1);
|
||||
end_page_read(page, false, cur, iosize);
|
||||
/*
|
||||
* We have to unlock the remaining range, or the page
|
||||
* will never be unlocked.
|
||||
*/
|
||||
unlock_extent(tree, cur, end);
|
||||
end_page_read(page, false, cur, end + 1 - cur);
|
||||
goto out;
|
||||
}
|
||||
cur = cur + iosize;
|
||||
|
|
Loading…
Reference in a new issue