Deadlock occurs when `getActivate` function opens new blobovnicza and that
invokes evict in LRU cache of open blobovniczas. `getActivate` makes
`activeMtx.Lock()` and then cache evict makes `activeMtx.RLock()` and deadlock
happens.
Fix contains two steps:
- add separate mutex to open blobovniczas (1),
- split single Lock outside of `updateAndGet` (2).
As for the (1) `bbolt.Open()` locks when it tries to open the same file from
two threads. So separate mutex will prevent that.
As for the (2) `updateAndGet` function contains from two parts. At first it
checks if required blobovnicza is ready and it returns it. In this case we can
use the simple RLock. But then there is an option when we should open new
blobovnicza and update map of active blobovniczas.
In this case we call `openBlobovnicza` without activeMtx lock. Cache evict
happens there and it won't cause deadlock.
Then we lock activeMtx to update the map of active blobovniczas. Concurrency can
happen there. However `openBlobovnicza` will not open the same blobovnicza twice,
so we can make one more check if opened blobovnicza was activated while thread was
locked in activeMtx. If so, then return active blobovnicza, else finish activation.
Signed-off-by: Alex Vanin <alexey@nspcc.ru>
In previous implementation Blobovnicza's stored objects in protocol format
which did not allow working with externally compressed objects. To achieve
this goal, operations Get and Put no longer work with the structure of the
object, but only with abstract binary data. Operation GetRange has become
incorrect in its original purpose to receive the payload range. In this
regard, BlobStor receives the payload range of the object through Get
operation. In the future either Blobovnicza will learn to compress objects
by itself, or the GetRange operation will be eliminated.
Signed-off-by: Leonard Lyubich <leonard@nspcc.ru>
Blobovnicza returns object, so we can't put compressed
data there. Compressed data won't be deserialized correctly.
Signed-off-by: Alex Vanin <alexey@nspcc.ru>
Replace ErrNotFound and ErrRangeOutOfBounds to core/object package in order
to share them across the libraries.
Signed-off-by: Leonard Lyubich <leonard@nspcc.ru>
Add blobovnicza instance to BlobStor structure. Create blobovnicza tree in
BlobStor constructor. Implement Open/Init/Close methods.
Signed-off-by: Leonard Lyubich <leonard@nspcc.ru>
There is a need to support single blobovnicza in blobovnicza tree. This can
be achieved with a width of 1, and a depth of 0 or 1. With depth = 1 one
redundant directory is created, inside which there is a blobovnicza. If the
depth is zero, the blobobnivza will be in the root path. Fix negative
capacity in iterateDeepest method with zero depth.
Signed-off-by: Leonard Lyubich <leonard@nspcc.ru>
Place the root of blobovnicza tree in a subdirectory of BlobStor with same
permissions. Abolish WithBlobovniczaRootPath and WithBlobovniczaPersmissions
options.
Signed-off-by: Leonard Lyubich <leonard@nspcc.ru>
Blobovnicza ID parameter provides the ability to specify particular
blobovnicza to delete object from. In this case only specified blobovnicza
is processed.
Signed-off-by: Leonard Lyubich <leonard@nspcc.ru>
In previous implementation objects were classified by size according to
payload size. From now they are classified by the size of their binary
representation.
Signed-off-by: Leonard Lyubich <leonard@nspcc.ru>
Implement "big or small" property classifier (only the size of the payload
is temporarily considered). Save "big" objects in shallow dir. Save "small"
objects in shallow dir until the moment of implementation of blobovnicza.
Signed-off-by: Leonard Lyubich <leonard@nspcc.ru>
In previous implementation WithCompressObjects returned Option
than could panic if zstd (de)compressor creation failed with error.
From now errors with (de)compressor creation result in an option
without using data compression. In this case, the error is written
to the log passed to the option constructor.
Signed-off-by: Leonard Lyubich <leonard@nspcc.ru>
Correct the calculation of maximum value of fs tree depth. Fix check
of the max depth overflow in WithShallowDepth function.
Signed-off-by: Leonard Lyubich <leonard@nspcc.ru>
