git-annex/Command/Lock.hs

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{- git-annex command
-
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- Copyright 2010,2015 Joey Hess <id@joeyh.name>
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-
- Licensed under the GNU AGPL version 3 or higher.
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-}
module Command.Lock where
import Command
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import qualified Annex.Queue
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import qualified Annex
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import Annex.Content
import Annex.Link
import Annex.InodeSentinal
import Annex.Perms
import Annex.ReplaceFile
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import Utility.InodeCache
import qualified Database.Keys
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import Annex.Ingest
import Logs.Location
import Git.FilePath
import qualified Utility.RawFilePath as R
cmd :: Command
cmd = withGlobalOptions [jsonOptions, annexedMatchingOptions] $
command "lock" SectionCommon
"undo unlock command"
paramPaths (withParams seek)
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seek :: CmdParams -> CommandSeek
seek ps = do
l <- workTreeItems ps
withFilesInGit (commandAction . (whenAnnexed startNew)) l
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startNew :: RawFilePath -> Key -> CommandStart
startNew file key = ifM (isJust <$> isAnnexLink file)
( stop
make CommandStart return a StartMessage The goal is to be able to run CommandStart in the main thread when -J is used, rather than unncessarily passing it off to a worker thread, which incurs overhead that is signficant when the CommandStart is going to quickly decide to stop. To do that, the message it displays needs to be displayed in the worker thread, after the CommandStart has run. Also, the change will mean that CommandStart will no longer necessarily run with the same Annex state as CommandPerform. While its docs already said it should avoid modifying Annex state, I audited all the CommandStart code as part of the conversion. (Note that CommandSeek already sometimes runs with a different Annex state, and that has not been a source of any problems, so I am not too worried that this change will lead to breakage going forward.) The only modification of Annex state I found was it calling allowMessages in some Commands that default to noMessages. Dealt with that by adding a startCustomOutput and a startingUsualMessages. This lets a command start with noMessages and then select the output it wants for each CommandStart. One bit of breakage: onlyActionOn has been removed from commands that used it. The plan is that, since a StartMessage contains an ActionItem, when a Key can be extracted from that, the parallel job runner can run onlyActionOn' automatically. Then commands won't need to worry about this detail. Future work. Otherwise, this was a fairly straightforward process of making each CommandStart compile again. Hopefully other behavior changes were mostly avoided. In a few cases, a command had a CommandStart that called a CommandPerform that then called showStart multiple times. I have collapsed those down to a single start action. The main command to perhaps suffer from it is Command.Direct, which used to show a start for each file, and no longer does. Another minor behavior change is that some commands used showStart before, but had an associated file and a Key available, so were changed to ShowStart with an ActionItemAssociatedFile. That will not change the normal output or behavior, but --json output will now include the key. This should not break it for anyone using a real json parser.
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, starting "lock" (mkActionItem (key, file)) $
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go =<< liftIO (isPointerFile file)
)
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where
go (Just key')
lock: Fix edge cases where data loss could occur in v6 mode. In the case where the pointer file is in place, and not the content of the object, lock's performNew was called with filemodified=True, which caused it to try to repopulate the object from an unmodified associated file, of which there were none. So, the content of the object got thrown away incorrectly. This was the cause (although not the root cause) of data loss in https://github.com/datalad/datalad/issues/1020 The same problem could also occur when the work tree file is modified, but the object is not, and lock is called with --force. Added a test case for this, since it's excercising the same code path and is easier to set up than the problem above. Note that this only occurred when the keys database did not have an inode cache recorded for the annex object. Normally, the annex object would be in there, but there are of course circumstances where the inode cache is out of sync with reality, since it's only a cache. Fixed by checking if the object is unmodified; if so we don't need to try to repopulate it. This does add an additional checksum to the unlock path, but it's already checksumming the worktree file in another case, so it doesn't slow it down overall. Further investigation found a similar problem occurred when smudge --clean is called on a file and the inode cache is not populated. cleanOldKeys deleted the unmodified old object file in this case. This was also fixed by checking if the object is unmodified. In general, use of getInodeCaches and sameInodeCache is potentially dangerous if the inode cache has not gotten populated for some reason. Better to use isUnmodified. I breifly auited other places that check the inode cache, and did not see any immediate problems, but it would be easy to miss this kind of problem.
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| key' == key = cont
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| otherwise = errorModified
go Nothing =
ifM (isUnmodified key file)
lock: Fix edge cases where data loss could occur in v6 mode. In the case where the pointer file is in place, and not the content of the object, lock's performNew was called with filemodified=True, which caused it to try to repopulate the object from an unmodified associated file, of which there were none. So, the content of the object got thrown away incorrectly. This was the cause (although not the root cause) of data loss in https://github.com/datalad/datalad/issues/1020 The same problem could also occur when the work tree file is modified, but the object is not, and lock is called with --force. Added a test case for this, since it's excercising the same code path and is easier to set up than the problem above. Note that this only occurred when the keys database did not have an inode cache recorded for the annex object. Normally, the annex object would be in there, but there are of course circumstances where the inode cache is out of sync with reality, since it's only a cache. Fixed by checking if the object is unmodified; if so we don't need to try to repopulate it. This does add an additional checksum to the unlock path, but it's already checksumming the worktree file in another case, so it doesn't slow it down overall. Further investigation found a similar problem occurred when smudge --clean is called on a file and the inode cache is not populated. cleanOldKeys deleted the unmodified old object file in this case. This was also fixed by checking if the object is unmodified. In general, use of getInodeCaches and sameInodeCache is potentially dangerous if the inode cache has not gotten populated for some reason. Better to use isUnmodified. I breifly auited other places that check the inode cache, and did not see any immediate problems, but it would be easy to miss this kind of problem.
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( cont
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, ifM (Annex.getState Annex.force)
lock: Fix edge cases where data loss could occur in v6 mode. In the case where the pointer file is in place, and not the content of the object, lock's performNew was called with filemodified=True, which caused it to try to repopulate the object from an unmodified associated file, of which there were none. So, the content of the object got thrown away incorrectly. This was the cause (although not the root cause) of data loss in https://github.com/datalad/datalad/issues/1020 The same problem could also occur when the work tree file is modified, but the object is not, and lock is called with --force. Added a test case for this, since it's excercising the same code path and is easier to set up than the problem above. Note that this only occurred when the keys database did not have an inode cache recorded for the annex object. Normally, the annex object would be in there, but there are of course circumstances where the inode cache is out of sync with reality, since it's only a cache. Fixed by checking if the object is unmodified; if so we don't need to try to repopulate it. This does add an additional checksum to the unlock path, but it's already checksumming the worktree file in another case, so it doesn't slow it down overall. Further investigation found a similar problem occurred when smudge --clean is called on a file and the inode cache is not populated. cleanOldKeys deleted the unmodified old object file in this case. This was also fixed by checking if the object is unmodified. In general, use of getInodeCaches and sameInodeCache is potentially dangerous if the inode cache has not gotten populated for some reason. Better to use isUnmodified. I breifly auited other places that check the inode cache, and did not see any immediate problems, but it would be easy to miss this kind of problem.
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( cont
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, errorModified
)
)
make CommandStart return a StartMessage The goal is to be able to run CommandStart in the main thread when -J is used, rather than unncessarily passing it off to a worker thread, which incurs overhead that is signficant when the CommandStart is going to quickly decide to stop. To do that, the message it displays needs to be displayed in the worker thread, after the CommandStart has run. Also, the change will mean that CommandStart will no longer necessarily run with the same Annex state as CommandPerform. While its docs already said it should avoid modifying Annex state, I audited all the CommandStart code as part of the conversion. (Note that CommandSeek already sometimes runs with a different Annex state, and that has not been a source of any problems, so I am not too worried that this change will lead to breakage going forward.) The only modification of Annex state I found was it calling allowMessages in some Commands that default to noMessages. Dealt with that by adding a startCustomOutput and a startingUsualMessages. This lets a command start with noMessages and then select the output it wants for each CommandStart. One bit of breakage: onlyActionOn has been removed from commands that used it. The plan is that, since a StartMessage contains an ActionItem, when a Key can be extracted from that, the parallel job runner can run onlyActionOn' automatically. Then commands won't need to worry about this detail. Future work. Otherwise, this was a fairly straightforward process of making each CommandStart compile again. Hopefully other behavior changes were mostly avoided. In a few cases, a command had a CommandStart that called a CommandPerform that then called showStart multiple times. I have collapsed those down to a single start action. The main command to perhaps suffer from it is Command.Direct, which used to show a start for each file, and no longer does. Another minor behavior change is that some commands used showStart before, but had an associated file and a Key available, so were changed to ShowStart with an ActionItemAssociatedFile. That will not change the normal output or behavior, but --json output will now include the key. This should not break it for anyone using a real json parser.
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cont = performNew file key
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performNew :: RawFilePath -> Key -> CommandPerform
lock: Fix edge cases where data loss could occur in v6 mode. In the case where the pointer file is in place, and not the content of the object, lock's performNew was called with filemodified=True, which caused it to try to repopulate the object from an unmodified associated file, of which there were none. So, the content of the object got thrown away incorrectly. This was the cause (although not the root cause) of data loss in https://github.com/datalad/datalad/issues/1020 The same problem could also occur when the work tree file is modified, but the object is not, and lock is called with --force. Added a test case for this, since it's excercising the same code path and is easier to set up than the problem above. Note that this only occurred when the keys database did not have an inode cache recorded for the annex object. Normally, the annex object would be in there, but there are of course circumstances where the inode cache is out of sync with reality, since it's only a cache. Fixed by checking if the object is unmodified; if so we don't need to try to repopulate it. This does add an additional checksum to the unlock path, but it's already checksumming the worktree file in another case, so it doesn't slow it down overall. Further investigation found a similar problem occurred when smudge --clean is called on a file and the inode cache is not populated. cleanOldKeys deleted the unmodified old object file in this case. This was also fixed by checking if the object is unmodified. In general, use of getInodeCaches and sameInodeCache is potentially dangerous if the inode cache has not gotten populated for some reason. Better to use isUnmodified. I breifly auited other places that check the inode cache, and did not see any immediate problems, but it would be easy to miss this kind of problem.
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performNew file key = do
lockdown =<< calcRepo (gitAnnexLocation key)
addLink (fromRawFilePath file) key
=<< withTSDelta (liftIO . genInodeCache file)
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next $ cleanupNew file key
where
lockdown obj = do
lock: Fix edge cases where data loss could occur in v6 mode. In the case where the pointer file is in place, and not the content of the object, lock's performNew was called with filemodified=True, which caused it to try to repopulate the object from an unmodified associated file, of which there were none. So, the content of the object got thrown away incorrectly. This was the cause (although not the root cause) of data loss in https://github.com/datalad/datalad/issues/1020 The same problem could also occur when the work tree file is modified, but the object is not, and lock is called with --force. Added a test case for this, since it's excercising the same code path and is easier to set up than the problem above. Note that this only occurred when the keys database did not have an inode cache recorded for the annex object. Normally, the annex object would be in there, but there are of course circumstances where the inode cache is out of sync with reality, since it's only a cache. Fixed by checking if the object is unmodified; if so we don't need to try to repopulate it. This does add an additional checksum to the unlock path, but it's already checksumming the worktree file in another case, so it doesn't slow it down overall. Further investigation found a similar problem occurred when smudge --clean is called on a file and the inode cache is not populated. cleanOldKeys deleted the unmodified old object file in this case. This was also fixed by checking if the object is unmodified. In general, use of getInodeCaches and sameInodeCache is potentially dangerous if the inode cache has not gotten populated for some reason. Better to use isUnmodified. I breifly auited other places that check the inode cache, and did not see any immediate problems, but it would be easy to miss this kind of problem.
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ifM (isUnmodified key obj)
( breakhardlink obj
, repopulate (fromRawFilePath obj)
)
whenM (liftIO $ R.doesPathExist obj) $
freezeContent $ fromRawFilePath obj
-- It's ok if the file is hard linked to obj, but if some other
-- associated file is, we need to break that link to lock down obj.
breakhardlink obj = whenM (catchBoolIO $ (> 1) . linkCount <$> liftIO (R.getFileStatus obj)) $ do
mfc <- withTSDelta (liftIO . genInodeCache file)
unlessM (sameInodeCache obj (maybeToList mfc)) $ do
let obj' = fromRawFilePath obj
modifyContent obj' $ replaceGitAnnexDirFile obj' $ \tmp -> do
unlessM (checkedCopyFile key obj' tmp Nothing) $
giveup "unable to lock file"
Database.Keys.storeInodeCaches key [obj]
-- Try to repopulate obj from an unmodified associated file.
lock: Fix edge cases where data loss could occur in v6 mode. In the case where the pointer file is in place, and not the content of the object, lock's performNew was called with filemodified=True, which caused it to try to repopulate the object from an unmodified associated file, of which there were none. So, the content of the object got thrown away incorrectly. This was the cause (although not the root cause) of data loss in https://github.com/datalad/datalad/issues/1020 The same problem could also occur when the work tree file is modified, but the object is not, and lock is called with --force. Added a test case for this, since it's excercising the same code path and is easier to set up than the problem above. Note that this only occurred when the keys database did not have an inode cache recorded for the annex object. Normally, the annex object would be in there, but there are of course circumstances where the inode cache is out of sync with reality, since it's only a cache. Fixed by checking if the object is unmodified; if so we don't need to try to repopulate it. This does add an additional checksum to the unlock path, but it's already checksumming the worktree file in another case, so it doesn't slow it down overall. Further investigation found a similar problem occurred when smudge --clean is called on a file and the inode cache is not populated. cleanOldKeys deleted the unmodified old object file in this case. This was also fixed by checking if the object is unmodified. In general, use of getInodeCaches and sameInodeCache is potentially dangerous if the inode cache has not gotten populated for some reason. Better to use isUnmodified. I breifly auited other places that check the inode cache, and did not see any immediate problems, but it would be easy to miss this kind of problem.
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repopulate obj = modifyContent obj $ do
g <- Annex.gitRepo
fs <- map (`fromTopFilePath` g)
lock: Fix edge cases where data loss could occur in v6 mode. In the case where the pointer file is in place, and not the content of the object, lock's performNew was called with filemodified=True, which caused it to try to repopulate the object from an unmodified associated file, of which there were none. So, the content of the object got thrown away incorrectly. This was the cause (although not the root cause) of data loss in https://github.com/datalad/datalad/issues/1020 The same problem could also occur when the work tree file is modified, but the object is not, and lock is called with --force. Added a test case for this, since it's excercising the same code path and is easier to set up than the problem above. Note that this only occurred when the keys database did not have an inode cache recorded for the annex object. Normally, the annex object would be in there, but there are of course circumstances where the inode cache is out of sync with reality, since it's only a cache. Fixed by checking if the object is unmodified; if so we don't need to try to repopulate it. This does add an additional checksum to the unlock path, but it's already checksumming the worktree file in another case, so it doesn't slow it down overall. Further investigation found a similar problem occurred when smudge --clean is called on a file and the inode cache is not populated. cleanOldKeys deleted the unmodified old object file in this case. This was also fixed by checking if the object is unmodified. In general, use of getInodeCaches and sameInodeCache is potentially dangerous if the inode cache has not gotten populated for some reason. Better to use isUnmodified. I breifly auited other places that check the inode cache, and did not see any immediate problems, but it would be easy to miss this kind of problem.
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<$> Database.Keys.getAssociatedFiles key
mfile <- firstM (isUnmodified key) fs
liftIO $ nukeFile obj
case mfile of
Just unmodified ->
unlessM (checkedCopyFile key (fromRawFilePath unmodified) obj Nothing)
lock: Fix edge cases where data loss could occur in v6 mode. In the case where the pointer file is in place, and not the content of the object, lock's performNew was called with filemodified=True, which caused it to try to repopulate the object from an unmodified associated file, of which there were none. So, the content of the object got thrown away incorrectly. This was the cause (although not the root cause) of data loss in https://github.com/datalad/datalad/issues/1020 The same problem could also occur when the work tree file is modified, but the object is not, and lock is called with --force. Added a test case for this, since it's excercising the same code path and is easier to set up than the problem above. Note that this only occurred when the keys database did not have an inode cache recorded for the annex object. Normally, the annex object would be in there, but there are of course circumstances where the inode cache is out of sync with reality, since it's only a cache. Fixed by checking if the object is unmodified; if so we don't need to try to repopulate it. This does add an additional checksum to the unlock path, but it's already checksumming the worktree file in another case, so it doesn't slow it down overall. Further investigation found a similar problem occurred when smudge --clean is called on a file and the inode cache is not populated. cleanOldKeys deleted the unmodified old object file in this case. This was also fixed by checking if the object is unmodified. In general, use of getInodeCaches and sameInodeCache is potentially dangerous if the inode cache has not gotten populated for some reason. Better to use isUnmodified. I breifly auited other places that check the inode cache, and did not see any immediate problems, but it would be easy to miss this kind of problem.
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lostcontent
Nothing -> lostcontent
lostcontent = logStatus key InfoMissing
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cleanupNew :: RawFilePath -> Key -> CommandCleanup
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cleanupNew file key = do
Database.Keys.removeAssociatedFile key =<< inRepo (toTopFilePath file)
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return True
startOld :: RawFilePath -> CommandStart
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startOld file = do
unlessM (Annex.getState Annex.force)
errorModified
make CommandStart return a StartMessage The goal is to be able to run CommandStart in the main thread when -J is used, rather than unncessarily passing it off to a worker thread, which incurs overhead that is signficant when the CommandStart is going to quickly decide to stop. To do that, the message it displays needs to be displayed in the worker thread, after the CommandStart has run. Also, the change will mean that CommandStart will no longer necessarily run with the same Annex state as CommandPerform. While its docs already said it should avoid modifying Annex state, I audited all the CommandStart code as part of the conversion. (Note that CommandSeek already sometimes runs with a different Annex state, and that has not been a source of any problems, so I am not too worried that this change will lead to breakage going forward.) The only modification of Annex state I found was it calling allowMessages in some Commands that default to noMessages. Dealt with that by adding a startCustomOutput and a startingUsualMessages. This lets a command start with noMessages and then select the output it wants for each CommandStart. One bit of breakage: onlyActionOn has been removed from commands that used it. The plan is that, since a StartMessage contains an ActionItem, when a Key can be extracted from that, the parallel job runner can run onlyActionOn' automatically. Then commands won't need to worry about this detail. Future work. Otherwise, this was a fairly straightforward process of making each CommandStart compile again. Hopefully other behavior changes were mostly avoided. In a few cases, a command had a CommandStart that called a CommandPerform that then called showStart multiple times. I have collapsed those down to a single start action. The main command to perhaps suffer from it is Command.Direct, which used to show a start for each file, and no longer does. Another minor behavior change is that some commands used showStart before, but had an associated file and a Key available, so were changed to ShowStart with an ActionItemAssociatedFile. That will not change the normal output or behavior, but --json output will now include the key. This should not break it for anyone using a real json parser.
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starting "lock" (ActionItemWorkTreeFile file) $
performOld file
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performOld :: RawFilePath -> CommandPerform
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performOld file = do
Annex.Queue.addCommand "checkout" [Param "--"] [fromRawFilePath file]
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next $ return True
errorModified :: a
errorModified = giveup "Locking this file would discard any changes you have made to it. Use 'git annex add' to stage your changes. (Or, use --force to override)"