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| author | Anton Altaparmakov <aia21@cam.ac.uk> | 2007-10-12 09:37:15 +0100 |
|---|---|---|
| committer | Linus Torvalds <torvalds@woody.linux-foundation.org> | 2007-10-12 09:16:30 -0700 |
| commit | bfab36e81611e60573b84eb4e4b4c8d8545b2320 (patch) | |
| tree | acd151a4c85459dcd2f6575ceb385090ebaaf984 /fs/ntfs/ChangeLog | |
| parent | f26e51f67ae6a75ffc57b96cf5fe096f75e778cb (diff) | |
| download | linux-bfab36e81611e60573b84eb4e4b4c8d8545b2320.tar.gz linux-bfab36e81611e60573b84eb4e4b4c8d8545b2320.tar.bz2 linux-bfab36e81611e60573b84eb4e4b4c8d8545b2320.zip | |
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 <aia21@cantab.net>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'fs/ntfs/ChangeLog')
| -rw-r--r-- | fs/ntfs/ChangeLog | 12 |
1 files changed, 12 insertions, 0 deletions
diff --git a/fs/ntfs/ChangeLog b/fs/ntfs/ChangeLog index af4ef808fa94..345798ebd366 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 |