| Summary: | When moving imported maildir folders, before they are completely written to disk, they arrive empty, losing all the mails. | ||
|---|---|---|---|
| Product: | [Applications] kmail2 | Reporter: | quazgar <quazgar> |
| Component: | commands and actions | Assignee: | kdepim bugs <kdepim-bugs> |
| Status: | CONFIRMED --- | ||
| Severity: | major | CC: | Martin |
| Priority: | NOR | ||
| Version: | 5.6.3 | ||
| Target Milestone: | --- | ||
| Platform: | Other | ||
| OS: | Linux | ||
| Latest Commit: | Version Fixed In: | ||
| Sentry Crash Report: | |||
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Description
quazgar
2018-01-30 11:03:59 UTC
A small addition: I was able to reproduce this by moving a single folder (which contains subfolders) to a different location in the same maildir structure:
-+-A
|
+-B
+-C
+-D
Here I was trying to move C into A so that the structure would look like this:
-+-A
| +-C
| +-D
|
+-B
In the folder overview D looked as if it had still a large number of unread mails, but when I entered the folder, the number of unread mails was reset to zero and the folder was empty.
OK, I think I can fully reproduce the problem now and have found its reason:
Steps to reproduce
------------------
1) Create a KMail archive, it should contain a folder ("somedir") and some subfolders and sufficiently many emails (in my case, a total of 700 emails was enough).
2) Create a target maildir directory, e.g. "target"
3) Import the archive into a folder, e.g. "imported"
4) Shortly after the import has finished, move the imported folders, e.g. "imported/somedir" to "target".
Expected result
---------------
1) The moved folders should have an identical content compared to the archive's source.
Actual result
-------------
1) Some, or all, of the emails are missing.
Workaround
----------
1) Wait until the folder structure on the file system exists and has been populated. This can be checked e.g. by watching the output of:
find ~/.local/share/akonadi_maildir_resource_0/.imported.directory/ -type f | wc -l
2) Only when the number looks reasonable and does not change any more, start moving the folder.
Notes
-----
Since in this case, the bug only happens after importing mails, maybe the severity can be downgraded, because no data is lost as long as the archive is still available and the problem has been noticed soon enough.
I think that may be related to [Akonadi] [Bug 364114] New: moving a folder within one maildir resource is extremely slow and inefficient and thus [Akonadi] Foreign payload https://phabricator.kde.org/T630 Ah, I missed to mention my current work around: I move the folder in the filesystem and let Akonadi update the database. That still takes some time, but on my system it is much, much faster than doing it within KMail and thus Akonadi itself. More detail about this in the other bug report I mentioned. Hmmm, okay, here it is about moving the folder before the import in the background has finished. But yet also there, as a work-around, just moving it in the filesystem should be faster. And it should safe, as it circumvents that Akonadi first stuffes mail into the database and then puts them into the destination location. It may confuse Akonadi at first, but I bet it will pick up the move in the filesystem as it uses inotify to watch the maildir folders. |