On 2018年04月07日 01:07, David Sterba wrote: > On Mon, Apr 02, 2018 at 06:47:32PM +0800, Qu Wenruo wrote: >> On 2018年03月28日 23:49, David Sterba wrote: >>> On Tue, Mar 27, 2018 at 08:44:19PM +0800, Qu Wenruo wrote: >>>> We have several reports about node pointer points to incorrect child >>>> tree blocks, which could have even wrong owner and level but still with >>>> valid generation and checksum. >>>> >>>> Although btrfs check could handle it and print error message like: >>>> leaf parent key incorrect 60670574592 >>>> >>>> Kernel doesn't have enough check on this type of corruption correctly. >>>> At least add such check to read_tree_block() and btrfs_read_buffer(), >>>> where we need two new parameters @level and @first_key to verify the >>>> child tree block. >>>> >>>> The new @level check is mandatory and all call sites are already >>>> modified to extract expected level from its call chain. >>>> >>>> While @first_key is optional, the following call sites are skipping such >>>> check: >>>> 1) Root node/leaf >>>> As ROOT_ITEM doesn't contain the first key, skip @first_key check. >>>> 2) Direct backref >>>> Only parent bytenr and level is known and we need to resolve the key >>>> all by ourselves, skip @first_key check. >>>> >>>> Another note of this verification is, it needs extra info from nodeptr >>>> or ROOT_ITEM, so it can't fit into current tree-checker framework, which >>>> is limited to node/leaf boundary. >>>> >>>> Signed-off-by: Qu Wenruo <[email protected]> >>>> --- >>>> changelog: >>>> v2: >>>> Make @level check mandatory, suggesed by Jeff and Nikolay. >>>> Change parameter order as @level is now mandatory, put it in front of >>>> @first_key. >>>> Change verify_parent_level() to verify_key_level() to avoid confusion >>>> on the @level parameter. >>>> Add btrfs_error() output for CONFIG_BTRFS_DEBUG to help debugging. >>> >>> That's much better overall, thanks. Adding it to next. >> >> Nikolay reported a case where @first_key check seems to cause false alert. >> (Although my xfstests check hasn't exposed it yet) >> >> Please discard this patch since it has the possibility to cause false >> alert for btrfs core functionality. > > Too late, the patch is in master now, so we need to fix it.
Seems to be a very rare race in tree operations, still under investigation. Thanks, Qu > -- > To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in > the body of a message to [email protected] > More majordomo info at http://vger.kernel.org/majordomo-info.html > -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
