From bfab36e81611e60573b84eb4e4b4c8d8545b2320 Mon Sep 17 00:00:00 2001 From: Anton Altaparmakov Date: Fri, 12 Oct 2007 09:37:15 +0100 Subject: NTFS: Fix a mount time deadlock. Big thanks go to Mathias Kolehmainen for reporting the bug, providing debug output and testing the patches I sent him to get it working. The fix was to stop calling ntfs_attr_set() at mount time as that causes balance_dirty_pages_ratelimited() to be called which on systems with little memory actually tries to go and balance the dirty pages which tries to take the s_umount semaphore but because we are still in fill_super() across which the VFS holds s_umount for writing this results in a deadlock. We now do the dirty work by hand by submitting individual buffers. This has the annoying "feature" that mounting can take a few seconds if the journal is large as we have clear it all. One day someone should improve on this by deferring the journal clearing to a helper kernel thread so it can be done in the background but I don't have time for this at the moment and the current solution works fine so I am leaving it like this for now. Signed-off-by: Anton Altaparmakov Signed-off-by: Linus Torvalds --- fs/ntfs/ChangeLog | 12 ++++++++++++ 1 file changed, 12 insertions(+) (limited to 'fs/ntfs/ChangeLog') diff --git a/fs/ntfs/ChangeLog b/fs/ntfs/ChangeLog index af4ef808fa9..345798ebd36 100644 --- a/fs/ntfs/ChangeLog +++ b/fs/ntfs/ChangeLog @@ -17,6 +17,18 @@ ToDo/Notes: happen is unclear however so it is worth waiting until someone hits the problem. +2.1.29 - Fix a deadlock at mount time. + + - During mount the VFS holds s_umount lock on the superblock. So when + we try to empty the journal $LogFile contents by calling + ntfs_attr_set() when the machine does not have much memory and the + journal is large ntfs_attr_set() results in the VM trying to balance + dirty pages which in turn tries to that the s_umount lock and thus we + get a deadlock. The solution is to not use ntfs_attr_set() and + instead do the zeroing by hand at the block level rather than page + cache level. + - Fix sparse warnings. + 2.1.28 - Fix a deadlock. - Fix deadlock in fs/ntfs/inode.c::ntfs_put_inode(). Thanks to Sergey -- cgit v1.2.3