handle running out of watch descriptors

This commit is contained in:
Joey Hess 2012-06-06 16:50:28 -04:00
parent db8effb8f3
commit c5b11561f0
2 changed files with 52 additions and 10 deletions

View file

@ -14,6 +14,8 @@ import Utility.ThreadLock
import System.INotify
import qualified System.Posix.Files as Files
import System.IO.Error
import Control.Exception (throw)
type Hook = Maybe (FilePath -> IO ())
@ -45,18 +47,22 @@ type Hook = Maybe (FilePath -> IO ())
-
- Note: inotify has a limit to the number of watches allowed,
- /proc/sys/fs/inotify/max_user_watches (default 8192).
- So this will fail if there are too many subdirectories.
- So this will fail if there are too many subdirectories. The
- toomany hook is called when this happens.
-}
watchDir :: INotify -> FilePath -> (FilePath -> Bool) -> Hook -> Hook -> Hook -> Hook -> IO ()
watchDir i dir ignored add addsymlink del deldir = unless (ignored dir) $ do
lock <- newLock
void $ addWatch i watchevents dir $ \event ->
withLock lock (void $ go event)
withLock lock $
mapM_ walk =<< filter (not . dirCruft) <$>
getDirectoryContents dir
watchDir :: INotify -> FilePath -> (FilePath -> Bool) -> Hook -> Hook -> Hook -> Hook -> Hook -> IO ()
watchDir i dir ignored toomany add addsymlink del deldir
| ignored dir = noop
| otherwise = do
lock <- newLock
let handler event = withLock lock (void $ go event)
void (addWatch i watchevents dir handler)
`catchIO` failedaddwatch
withLock lock $
mapM_ walk =<< filter (not . dirCruft) <$>
getDirectoryContents dir
where
recurse d = watchDir i d ignored add addsymlink del deldir
recurse d = watchDir i d ignored toomany add addsymlink del deldir
-- Select only inotify events required by the enabled
-- hooks, but always include Create so new directories can
@ -116,3 +122,12 @@ watchDir i dir ignored add addsymlink del deldir = unless (ignored dir) $ do
indir f = dir </> f
filetype t f = catchBoolIO $ t <$> getSymbolicLinkStatus (indir f)
-- Inotify fails when there are too many watches with a
-- disk full error.
failedaddwatch e
| isFullError e =
case toomany of
Nothing -> throw e
Just hook -> hook dir
| otherwise = throw e