Before this change, if a file shrunk in size on the remote then rclone
could get into an loop trying to download the file forever.
The symptom was repeating errors like this:
vfs cache: restart download failed: failed to start downloader: failed to open downloader: vfs reader: failed to open source file: invalid seek position
The fix was to check that file size in various places and makes sure
that we weren't trying to download too much data.
This was a problems with backends (like s3) which update the size of
the object on Open to the actual size of the object.
Before this change the VFS cache could get into a state where when an
object was updated remotely, the fingerprint of the item was correct
for the new object but the data in the VFS cache was for the old
object.
This fixes the problem by updating the fingerprint of the item at the
point we remove the stale data. The empty cache item now represents
the new item even though it has no data in.
This stops the fallback code for an empty fingerprint running (used
when we are writing items to the cache instead of reading them) which
was causing the problem.
Fixes#6053
See: https://forum.rclone.org/t/cached-webdav-mount-fingerprints-get-nuked-on-ls/43974/
Before this change if a backend can't upload 0 length files and
`--vfs-cache-mode writes` was in use then the writeback logic would
try to upload the 0 length file forever.
This change causes it to exit on the first failure to upload.
Before this patch a deadlock could occur if the cache cleaner was
running when an object upload finished.
This fixes the problem by delaying marking the object as clean until
we have notified the VFS layer. This means that the cache cleaner
won't consider the object until **after** the VFS layer has been
notified, thus avoiding the deadlock.
See: https://forum.rclone.org/t/rclone-mount-deadlock-when-dir-cache-time-strikes/33486/
Before this change we truncated files in the backing store regardless
of whether we needed to or not.
After, we check to see if the file is the right size and don't
truncate if it is.
Apparently Windows Defender likes to check executables each time they
are modified, and truncating a file to its existing size is enough to
trigger the Windows Defender scan. This was causing a big slowdown for
operations which opened and closed the file a lot, such as looking at
properties on an executable.
See: https://forum.rclone.org/t/for-mount-sftp-why-right-click-on-exe-file-is-so-slow-until-it-freezes/33830
This message is a double panic and was actually caused by an assertion
panic in:
vfs/vfscache/downloaders/downloaders.go
This is triggered by the code added relatively recently to fix a bug
with renaming files:
ec72432cec vfs: fix failed to _ensure cache internal error: downloaders is nil error
So it appears that item.o may be nil at this point.
This patch detects item.o being nil and fetches it again with NewObject.
Fixes#6190Fixes#6235
This error was caused by renaming an open file.
When the file was renamed in the cache, the downloaders were cleared,
however the downloaders were not re-opened when needed again, instead
this error was generated.
This fix re-opens the downloaders if they have been closed by renaming
the file.
Fixes#5984
This is possible now that we no longer support go1.12 and brings
rclone into line with standard practices in the Go world.
This also removes errors.New and errors.Errorf from lib/errors and
prefers the stdlib errors package over lib/errors.
Before this change but after:
aea8776a43 vfs: fix modtimes not updating when writing via cache #4763
When a file was opened read-only the modtime was read from the cached
file. However this modtime wasn't correct leading to an incorrect
result.
This change fixes the definition of `item.IsDirty` to be true only
when the data is dirty. This fixes the problem as a read only file
isn't considered dirty.
This is done by making fs.Config private and attaching it to the
context instead.
The Config should be obtained with fs.GetConfig and fs.AddConfig
should be used to get a new mutable config that can be changed.
Before this change if a file was uploaded through a mount, then
deleted externally, trying to upload that file again could give EEXIST
"file already exists".
This was because the file already existing in the cache was confusing
rclone into thinking it already had the file.
The fix is to check that if rclone has a stale cache file then to
ignore it in this situation.
See: https://forum.rclone.org/t/rclone-cant-reuse-filenames/20400
Add an exponentially increasing delay during retries up ENOSPC error
to avoid exhausting the 10 retries too soon when the cache space
recovery from item resets is not available from the file system yet
or consumed by other large cache writes.
Item reset is invoked by cache cleaner for synchronous recovery
from ENOSPC errors. The reset operation removes the cache file and
closes/reopens the downloaders. Although most parts of reset and
other item operations are done with the item mutex held, the mutex
is released during fd.WriteAt and downloaders calls. We used preAccess
and postAccess calls to serialize Reset, ReadAt, and Open, but missed
some other item operations. The patch adds preAccess/postAccess
calls in Sync, Truncate, Close, WriteAt, and rename.
Before this change if a file was removed from the cache while rclone
is running then rclone would not notice and proceed to re-create it
full of zeros.
This change notices files that we expect to have data in going missing
and if they do logs an ERROR recovers.
It isn't recommended deleting files from the cache manually with
rclone running!
See: https://forum.rclone.org/t/corrupted-data-streaming-after-vfs-meta-files-removed/18997Fixes#4602
Before this change the error message was produced for every file which
was confusing users.
After this change we check for EOF and return from ReadAt at that
point.
See: https://forum.rclone.org/t/rclone-1-53-release/18880/10
This patch provides the support of synchronous cache space recovery
to allow read threads to recover from ENOSPC errors when cache space
can be recovered from cache items that are not in use or safe to be
reset/emptied .
The patch complements the existing cache cleaning process in two ways.
Firstly, the existing cache cleaning process is time-driven that runs
periodically. The cache space can run out while the cache cleaner
thread is still waiting for its next scheduled run. The io threads
encountering ENOSPC return an internal error to the applications
in this case even when cache space can be recovered to avoid this
error. This patch addresses this problem by having the read threads
kick the cache cleaner thread in this condition to recover cache
space preventing unnecessary ENOSPC errors from being seen by the
applications.
Secondly, this patch enhances the cache cleaner to support cache
item reset. Currently the cache purge process removes cache
items that are not in use. This may not be sufficient when the
total size of the working set exceeds the cache directory's
capacity. Like in the current code, this patch starts the purge
process by removing cache files that are not in use. Cache items
whose access times are older than vfs-cache-max-age are removed first.
After that, other not-in-use items are removed in LRU order until
vfs-cache-max-size is reached. If the vfs-cache-max-size (the quota)
is still not reached at this time, this patch adds a cache reset
step to reset/empty cache files that are still in use but not
dirtied. This enables application processes to continue without
seeing an error even when the working set depletes the cache space
as long as there is not a large write working set hoarding the
entire cache space.
By design this patch does not add ENOSPC error recovery for write
IOs. Rclone does not empty a write cache item until the file data
is written back to the backend upon close. Allowing more cache
space to be consumed by dirty cache items when the cache space is
already running low would increase the risk of exhausting the cache
space in a way that the vfs mount becomes unreadable.
Before this change we set the modtime of the cache file when all
writers had finished.
This has the unfortunate effect that the file is uploaded with the
wrong modtime which means on backends which can't set modtimes except
when uploading files it is wrong.
This change sets the modtime of the cache file immediately in the
cache and in turn sets the modtime in the file info.
Previous to the fix, if an item was being uploaded and it was renamed,
the upload would fail with missing checksum errors.
This change cancels any uploads in progress if the file is renamed.
Before this change, if we restarted an upload after a restart then the
file would get uploaded but never added to the directory listings.
This change makes sure we add virtual items to the directory cache
when reloading the cache so that they show up properly.
- fix deadlock when cancelling upload
- fix double upload and panic after cancelled upload
- fix cancelation strategy of uploading files
- don't cancel uploads if we don't modify the file
- cancel uploads if we do modify the file
- fix deadlock between Item and writeback
- fix confusion about whether writeback item was being uploaded
- fix cornercases in cancelling uploads and removing files
Item
- Remove unused method getName
- Fix Truncate on unopened file
- Fix bug when downloading segments to fill out file on close
- Fix bug when WriteAt extends the file and we don't mark space as used
downloader
- Retry failed waiters every 5 seconds
- Download to multiple places at once in the stream
- Restart as necessary
- Timeout unused downloaders
- Close reader if too much data skipped
- Only use one file handle as use item for writing
- Implement --vfs-read-chunk-size and --vfs-read-chunk-limit
- fix deadlock between asyncbuffer and vfs cache downloader
- fix display of stream abandoned error which should be ignored
On file Remove
- cancel any writebacks in progress
- ignore error message deleting non existent file if file was in the
process of being uploaded
Writeback
- Don't transfer the file if it has disappeared in the meantime
- Take our own copy of the file name to avoid deadlocks
- Fix delayed retry logic
- Wait for upload to finish when cancelling upload
Fix race condition in item saving
Fix race condition in vfscache test
Make sure we delete the file on the error path - this makes cascading
failures much less likely
This allows reads to only read part of the file and it keeps on disk a
cache of what parts of each file have been loaded.
File data itself is kept in sparse files.
