btrfs: handle errors properly in update_inline_extent_backref()
[PROBLEM]
Inside function update_inline_extent_backref(), we have several
BUG_ON()s along with some ASSERT()s which can be triggered by corrupted
filesystem.
[ANAYLYSE]
Most of those BUG_ON()s and ASSERT()s are just a way of handling
unexpected on-disk data.
Although we have tree-checker to rule out obviously incorrect extent
tree blocks, it's not enough for these ones. Thus we need proper error
handling for them.
[FIX]
Thankfully all the callers of update_inline_extent_backref() would
eventually handle the errror by aborting the current transaction.
So this patch would do the proper error handling by:
- Make update_inline_extent_backref() to return int
The return value would be either 0 or -EUCLEAN.
- Replace BUG_ON()s and ASSERT()s with proper error handling
This includes:
* Dump the bad extent tree leaf
* Output an error message for the cause
This would include the extent bytenr, num_bytes (if needed), the bad
values and expected good values.
* Return -EUCLEAN
Note here we remove all the WARN_ON()s, as eventually the transaction
would be aborted, thus a backtrace would be triggered anyway.
- Better comments on why we expect refs == 1 and refs_to_mode == -1 for
tree blocks
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>