immutable: storage servers accept any size shares now
Nathan Wilcox observed that the storage server can rely on the size of the share file combined with the count of leases to unambiguously identify the location of the leases. This means that it can hold any size share data, even though the field nominally used to hold the size of the share data is only 32 bits wide.
With this patch, the storage server still writes the "size of the share data" field (just in case the server gets downgraded to an earlier version which requires that field, or the share file gets moved to another server which is of an earlier vintage), but it doesn't use it. Also, with this patch, the server no longer rejects requests to write shares which are >= 2^32 bytes in size, and it no longer rejects attempts to read such shares.
This fixes http://allmydata.org/trac/tahoe/ticket/346 (increase share-size field to 8 bytes, remove 12GiB filesize limit), although there remains open a question of how clients know that a given server can handle large shares (by using the new versioning scheme, probably).
Note that share size is also limited by another factor -- how big of a file we can store on the local filesystem on the server. Currently allmydata.com typically uses ext3 and I think we typically have block size = 4 KiB, which means that the largest file is about 2 TiB. Also, the hard drives themselves are only 1 TB, so the largest share is definitely slightly less than 1 TB, which means (when K == 3), the largest file is less than 3 TB.
This patch also refactors the creation of new sharefiles so that only a single fopen() is used.
This patch also helps with the unit-testing of repairer, since formerly it was unclear what repairer should expect to find if the "share data size" field was corrupted (some corruptions would have no effect, others would cause failure to download). Now it is clear that repairer is not required to notice if this field is corrupted since it has no effect on download. :-)
rrefutil: generically wrap any errback from callRemote() in a ServerFailure instance
This facilitates client code to easily catch ServerFailures without also catching exceptions arising from client-side code.
See also:
http://foolscap.lothar.com/trac/ticket/105 # make it easy to distinguish server-side failures/exceptions from client-side
immutable: more detailed tests for checker/verifier/repairer
There are a lot of different ways that a share could be corrupted, or that attempting to download it might fail. These tests attempt to exercise many of those ways and require the checker/verifier/repairer to handle each kind of failure well.
cli: make startstop_node wait 20 seconds instead of 5 for a process to go away after we signalled it to go away
Because the unit tests on the VirtualZooko buildslave failed when it took 16 seconds for a process to go away.
Perhaps getting notification after only 5 seconds instead of 20 seconds is desirable, and we should change the unit tests and set this back to 5, but I don't know exactly how to change the unit tests. Perhaps match this particular warning message about the shutdown taking a while and allow the code under test to pass if the only stderr that it emits is this warning.
docs: split historical/historical_known_issues.txt out of known_issues.txt
All issues which are relevant to users of v1.1, v1.2, or v1.3 go in known_issues.txt. All issues which are relevant to users of v1.0 go in historical/historical_known_issues.txt.
cli: undo the effects of [http://allmydata.org/trac/tahoe/changeset/20081222235453-92b7f-f841e18afb94e1fd95e6dafb799a3d876dd85c69]
We're just going to mark unicode in the cli as unsupported for tahoe-lafs-1.3.0. Unicode filenames on the command-line do actually work for some platforms and probably only if the platform encoding is utf-8, but I'm not sure, and in any case for it to be marked as "supported" it would have to work on all platforms, be thoroughly tested, and also we would have to understand why it worked. :-)
test: extend timeout on the hotline file that prevents the client from stopping itself
The 20-second timeout was apparently tripped on my Powerbook G4 "draco".
cli: decode all cli arguments, assuming that they are utf-8 encoded
Also encode all args to urllib as utf-8 because urllib doesn't handle unicode objects.
I'm not sure if it is appropriate to *assume* utf-8 encoding of cli args. Perhaps the Right thing to do is to detect the platform encoding. Any ideas?
This patch is mostly due to François Deppierraz.
util/base32: loosen the precondition forbidding unicode and requiring str -- now it requires either unicode or str
Hopefully this will make it so that tests pass with François Deppierraz's patch to fix the tahoe cli's handling of unicode argument.
immutable: invent download.BadOrMissingHashError which is raised if either hashtree.BadHashError, hashtree.NotEnoughHashesError, and which is a subclass of IntegrityCheckReject
dirnode: don't check MAC on entries in dirnodes
In an ancient version of directories, we needed a MAC on each entry. In modern times, the entire dirnode comes with a digital signature, so the MAC on each entry is redundant.
With this patch, we no longer check those MACs when reading directories, but we still produce them so that older readers will accept directories that we write.
cli: if response code from wapi server is not 200 then stop instead of proceeding
Also, include the data that failed to json parse in an exception raised by the json parser.
immutable: when downloading an immutable file, use primary shares if they are available
Primary shares require no erasure decoding so the more primary shares you have, the less CPU is used.
try to tidy up uri-as-string vs. uri-as-object
I get confused about whether a given argument or return value is a uri-as-string or uri-as-object. This patch adds a lot of assertions that it is one or the other, and also changes CheckerResults to take objects not strings.
In the future, I hope that we generally use Python objects except when importing into or exporting from the Python interpreter e.g. over the wire, the UI, or a stored file.
pyutil: assertutil: simplify handling of exception during formatting of precondition message, and reduce dependency to just the Python Standard Library's logging module
Brian Warner [Wed, 10 Dec 2008 05:44:49 +0000 (22:44 -0700)]
mutable publish: if we are surprised by shares that match what we would have written anyways, don't be surprised. This should fix one of the two #546 problems, in which we re-use a server and forget that we already sent them a share.
setup: loosen requirement on simplejson to >= 1.4
That's the version of simplejson that comes with ubuntu feisty, and the one that we've required for most of our history. Currently the Ubuntu dapper buildslave fails (see issue #534), and setting the simplejson requirement to be >= 2.0 would fix that failure, but I don't understand why.
setup: require simplejson >= 1.7.1
That's the version that comes with gutsy, and we don't really understand why increasing the required version number helped with issue #553.
mutable: rename mutable/node.py to mutable/filenode.py and mutable/repair.py to mutable/repairer.py
To be more consistent with the immutable layout that I am working on.
francois [Tue, 18 Nov 2008 14:41:35 +0000 (07:41 -0700)]
filenode.py: Fix partial HTTP Range header handling according to RFC2616
Tahoe webapi was failing on HTTP request containing a partial Range header.
This change allows movies players like mplayer to seek in movie files stored in
tahoe.
Associated tests for GET and HEAD methods are also included
web: "More Info" link describes the same file that the "file" link points to, rather than to the file under the same name in this directory
It's a subtle but real difference.
Fixes #553 -- "More Info" link should point to a file/dir, not a dir+childname .
download: refactor handling of URI Extension Block and crypttext hash tree, simplify things
Refactor into a class the logic of asking each server in turn until one of them gives an answer
that validates. It is called ValidatedThingObtainer.
Refactor the downloading and verification of the URI Extension Block into a class named
ValidatedExtendedURIProxy.
The new logic of validating UEBs is minimalist: it doesn't require the UEB to contain any
unncessary information, but of course it still accepts such information for backwards
compatibility (so that this new download code is able to download files uploaded with old, and
for that matter with current, upload code).
The new logic of validating UEBs follows the practice of doing all validation up front. This
practice advises one to isolate the validation of incoming data into one place, so that all of
the rest of the code can assume only valid data.
If any redundant information is present in the UEB+URI, the new code cross-checks and asserts
that it is all fully consistent. This closes some issues where the uploader could have
uploaded inconsistent redundant data, which would probably have caused the old downloader to
simply reject that download after getting a Python exception, but perhaps could have caused
greater harm to the old downloader.
I removed the notion of selecting an erasure codec from codec.py based on the string that was
passed in the UEB. Currently "crs" is the only such string that works, so
"_assert(codec_name == 'crs')" is simpler and more explicit. This is also in keeping with the
"validate up front" strategy -- now if someone sets a different string than "crs" in their UEB,
the downloader will reject the download in the "validate this UEB" function instead of in a
separate "select the codec instance" function.
I removed the code to check plaintext hashes and plaintext Merkle Trees. Uploaders do not
produce this information any more (since it potentially exposes confidential information about
the file), and the unit tests for it were disabled. The downloader before this patch would
check that plaintext hash or plaintext merkle tree if they were present, but not complain if
they were absent. The new downloader in this patch complains if they are present and doesn't
check them. (We might in the future re-introduce such hashes over the plaintext, but encrypt
the hashes which are stored in the UEB to preserve confidentiality. This would be a double-
check on the correctness of our own source code -- the current Merkle Tree over the ciphertext
is already sufficient to guarantee the integrity of the download unless there is a bug in our
Merkle Tree or AES implementation.)
This patch increases the lines-of-code count by 8 (from 17,770 to 17,778), and reduces the
uncovered-by-tests lines-of-code count by 24 (from 1408 to 1384). Those numbers would be more
meaningful if we omitted src/allmydata/util/ from the test-coverage statistics.
Brian Warner [Thu, 4 Dec 2008 22:00:53 +0000 (15:00 -0700)]
test_system.py: don't ask the stats-gatherer to poll: it tolerates failures, so it isn't really giving us enough test coverage. Removing the call will make it more clear that we need to improve the tests later
setup: move the requirement on simplejson from setup.py to _auto_deps.py, and loosen it from >= 2.0.5 to > 1.8.1
We'll see if this fixes the tests on all of our current buildslaves, and if it does then I'll be happy to leave it at "> 1.8.1" for now, even though I don't know exactly what versions of simplejson changed exactly what behavior that interacts with exactly what environment. See http://allmydata.org/trac/tahoe/ticket/534 for uncertainties.
Brian Warner [Tue, 25 Nov 2008 21:27:35 +0000 (14:27 -0700)]
mutable publish: reinstate the foolscap-reference-token-bug workaround, both for the original reasons and because of an apparent new foolscap bug that's triggered by reference tokens. See #541 for details.
Brian Warner [Mon, 24 Nov 2008 21:40:46 +0000 (14:40 -0700)]
dirnode manifest: add verifycaps, both to internal API and to webapi. This will give the manual-GC tools more to work with, so they can estimate how much space will be freed.
Brian Warner [Sat, 22 Nov 2008 03:28:12 +0000 (20:28 -0700)]
upload: don't use servers which can't support the share size we need. This ought to avoid #439 problems. Some day we'll have a storage server which advertises support for a larger share size. No tests yet.
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