On 08/07/2009 03:19 PM, Jens Axboe wrote: > On Fri, Aug 07 2009, Yan Zheng wrote: >> On 08/07/2009 02:50 PM, Jens Axboe wrote: >>> On Fri, Aug 07 2009, Yan Zheng wrote: >>>> invalidate_inode_pages2_range may return -EBUSY occasionally >>>> which results Oops. This patch fixes the issue by moving >>>> invalidate_inode_pages2_range into a loop and keeping calling >>>> it until the return value is not -EBUSY. >>>> >>>> Signed-off-by: Yan Zheng <[email protected]> >>>> >>>> --- >>>> diff -urp 1/fs/btrfs/relocation.c 2/fs/btrfs/relocation.c >>>> --- 1/fs/btrfs/relocation.c 2009-07-29 10:03:04.367858774 +0800 >>>> +++ 2/fs/btrfs/relocation.c 2009-08-07 13:26:43.882147138 +0800 >>>> @@ -2553,8 +2553,13 @@ int relocate_inode_pages(struct inode *i >>>> last_index = (start + len - 1) >> PAGE_CACHE_SHIFT; >>>> >>>> /* make sure the dirty trick played by the caller work */ >>>> - ret = invalidate_inode_pages2_range(inode->i_mapping, >>>> - first_index, last_index); >>>> + while (1) { >>>> + ret = invalidate_inode_pages2_range(inode->i_mapping, >>>> + first_index, last_index); >>>> + if (ret != -EBUSY) >>>> + break; >>>> + cond_resched(); >>>> + } >>> If it returns EBUSY, would it not make more sense to call >>> filemap_write_and_wait_range() instead of hammering on invalidate? >>> >> The pages to invalidate are not dirty, they are from page read-ahead. >> Actually I have no idea how invalidate_inode_pages2_range can return >> -EBUSY here. (the only user of the inode is the balancer, and it does >> not hold references to the pages) > > Weird, I looked it up, and it already does a writeback wait. But I guess > that's not your issue. Patch still looks like a hack though, it would be > far better to figure out why it returns EBUSY and fix/wait appropriately > for that to pass. >
EBUSY is from the EXTENT_LOCK test in try_release_extent_state. The test can be true is because some codes call lock_extent while corresponding pages are not all locked. (one example is btrfs_finish_ordered_io) Yan, Zheng -- 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
