linux/fs, branch v3.7-rc6

mm, oom: reintroduce /proc/pid/oom_adj

2012-11-16T18:15:35Z

This is mostly a revert of 01dc52ebdf47 ("oom: remove deprecated oom_adj") from Davidlohr Bueso. It reintroduces /proc/pid/oom_adj for backwards compatibility with earlier kernels. It simply scales the value linearly when /proc/pid/oom_score_adj is written. The major difference is that its scheduled removal is no longer included in Documentation/feature-removal-schedule.txt. We do warn users with a single printk, though, to suggest the more powerful and supported /proc/pid/oom_score_adj interface. Reported-by: Artem S. Tashkinov Signed-off-by: David Rientjes Signed-off-by: Linus Torvalds

Merge tag 'upstream-3.7-rc6' of git://git.infradead.org/linux-ubifs

2012-11-15T19:28:43Z

Pull UBIFS fixes from Artem Bityutskiy: "Two patches which fix a problem reported by several people in the past, but only fixed now because no one gave enough material for debugging. Anyway, these fix the problem that sometimes after a power cut the file-system is not mountable with the following symptom: grab_empty_leb: could not find an empty LEB The fixes make the file-system mountable again." * tag 'upstream-3.7-rc6' of git://git.infradead.org/linux-ubifs: UBIFS: fix mounting problems after power cuts UBIFS: introduce categorized lprops counter

pstore: Fix NULL pointer dereference in console writes

2012-11-15T02:30:21Z

Passing a NULL id causes a NULL pointer deference in writers such as erst_writer and efi_pstore_write because they expect to update this id. Pass a dummy id instead. This avoids a cascade of oopses caused when the initial pstore_console_write passes a null which in turn causes writes to the console causing further oopses in subsequent pstore_console_write calls. Signed-off-by: Colin Ian King Acked-by: Kees Cook Cc: stable@vger.kernel.org Signed-off-by: Anton Vorontsov

Merge branch 'for-linus' of git://git.samba.org/sfrench/cifs-2.6

2012-11-10T05:59:35Z

Pull cifs fixes from Jeff Layton. * 'for-linus' of git://git.samba.org/sfrench/cifs-2.6: cifs: Do not lookup hashed negative dentry in cifs_atomic_open cifs: fix potential buffer overrun in cifs.idmap handling code

Merge branch 'akpm' (Fixes from Andrew)

2012-11-09T05:53:02Z

Merge misc fixes from Andrew Morton: "Five fixes" * emailed patches from Andrew Morton : (5 patches) h8300: add missing L1_CACHE_SHIFT mm: bugfix: set current->reclaim_state to NULL while returning from kswapd() fanotify: fix missing break revert "epoll: support for disabling items, and a self-test app" checkpatch: improve network block comment style checking

Merge tag 'for-linus-v3.7-rc5' of git://oss.sgi.com/xfs/xfs

2012-11-09T05:42:51Z

Pull xfs bugfixes from Ben Myers: - fix for large transactions spanning multiple iclog buffers - zero the allocation_args structure on the stack before using it to determine whether to use a worker for allocation - move allocation stack switch to xfs_bmapi_allocate in order to prevent deadlock on AGF buffers - growfs no longer reads in garbage for new secondary superblocks - silence a build warning - ensure that invalid buffers never get written to disk while on free list - don't vmap inode cluster buffers during free - fix buffer shutdown reference count mismatch - fix reading of wrapped log data * tag 'for-linus-v3.7-rc5' of git://oss.sgi.com/xfs/xfs: xfs: fix reading of wrapped log data xfs: fix buffer shudown reference count mismatch xfs: don't vmap inode cluster buffers during free xfs: invalidate allocbt blocks moved to the free list xfs: silence uninitialised f.file warning. xfs: growfs: don't read garbage for new secondary superblocks xfs: move allocation stack switch up to xfs_bmapi_allocate xfs: introduce XFS_BMAPI_STACK_SWITCH xfs: zero allocation_args on the kernel stack xfs: only update the last_sync_lsn when a transaction completes

fanotify: fix missing break

2012-11-09T05:41:47Z

Anders Blomdell noted in 2010 that Fanotify lost events and provided a test case. Eric Paris confirmed it was a bug and posted a fix to the list https://groups.google.com/forum/?fromgroups=#!topic/linux.kernel/RrJfTfyW2BE but never applied it. Repeated attempts over time to actually get him to apply it have never had a reply from anyone who has raised it So apply it anyway Signed-off-by: Alan Cox Reported-by: Anders Blomdell Cc: Eric Paris Cc: Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

revert "epoll: support for disabling items, and a self-test app"

2012-11-09T05:41:46Z

Revert commit 03a7beb55b9f ("epoll: support for disabling items, and a self-test app") pending resolution of the issues identified by Michael Kerrisk, copied below. We'll revisit this for 3.8. : I've taken a look at this patch as it currently stands in 3.7-rc1, and : done a bit of testing. (By the way, the test program : tools/testing/selftests/epoll/test_epoll.c does not compile...) : : There are one or two places where the behavior seems a little strange, : so I have a question or two at the end of this mail. But other than : that, I want to check my understanding so that the interface can be : correctly documented. : : Just to go though my understanding, the problem is the following : scenario in a multithreaded application: : : 1. Multiple threads are performing epoll_wait() operations, : and maintaining a user-space cache that contains information : corresponding to each file descriptor being monitored by : epoll_wait(). : : 2. At some point, a thread wants to delete (EPOLL_CTL_DEL) : a file descriptor from the epoll interest list, and : delete the corresponding record from the user-space cache. : : 3. The problem with (2) is that some other thread may have : previously done an epoll_wait() that retrieved information : about the fd in question, and may be in the middle of using : information in the cache that relates to that fd. Thus, : there is a potential race. : : 4. The race can't solved purely in user space, because doing : so would require applying a mutex across the epoll_wait() : call, which would of course blow thread concurrency. : : Right? : : Your solution is the EPOLL_CTL_DISABLE operation. I want to : confirm my understanding about how to use this flag, since : the description that has accompanied the patches so far : has been a bit sparse : : 0. In the scenario you're concerned about, deleting a file : descriptor means (safely) doing the following: : (a) Deleting the file descriptor from the epoll interest list : using EPOLL_CTL_DEL : (b) Deleting the corresponding record in the user-space cache : : 1. It's only meaningful to use this EPOLL_CTL_DISABLE in : conjunction with EPOLLONESHOT. : : 2. Using EPOLL_CTL_DISABLE without using EPOLLONESHOT in : conjunction is a logical error. : : 3. The correct way to code multithreaded applications using : EPOLL_CTL_DISABLE and EPOLLONESHOT is as follows: : : a. All EPOLL_CTL_ADD and EPOLL_CTL_MOD operations should : should EPOLLONESHOT. : : b. When a thread wants to delete a file descriptor, it : should do the following: : : [1] Call epoll_ctl(EPOLL_CTL_DISABLE) : [2] If the return status from epoll_ctl(EPOLL_CTL_DISABLE) : was zero, then the file descriptor can be safely : deleted by the thread that made this call. : [3] If the epoll_ctl(EPOLL_CTL_DISABLE) fails with EBUSY, : then the descriptor is in use. In this case, the calling : thread should set a flag in the user-space cache to : indicate that the thread that is using the descriptor : should perform the deletion operation. : : Is all of the above correct? : : The implementation depends on checking on whether : (events & ~EP_PRIVATE_BITS) == 0 : This replies on the fact that EPOLL_CTL_AD and EPOLL_CTL_MOD always : set EPOLLHUP and EPOLLERR in the 'events' mask, and EPOLLONESHOT : causes those flags (as well as all others in ~EP_PRIVATE_BITS) to be : cleared. : : A corollary to the previous paragraph is that using EPOLL_CTL_DISABLE : is only useful in conjunction with EPOLLONESHOT. However, as things : stand, one can use EPOLL_CTL_DISABLE on a file descriptor that does : not have EPOLLONESHOT set in 'events' This results in the following : (slightly surprising) behavior: : : (a) The first call to epoll_ctl(EPOLL_CTL_DISABLE) returns 0 : (the indicator that the file descriptor can be safely deleted). : (b) The next call to epoll_ctl(EPOLL_CTL_DISABLE) fails with EBUSY. : : This doesn't seem particularly useful, and in fact is probably an : indication that the user made a logic error: they should only be using : epoll_ctl(EPOLL_CTL_DISABLE) on a file descriptor for which : EPOLLONESHOT was set in 'events'. If that is correct, then would it : not make sense to return an error to user space for this case? Cc: Michael Kerrisk Cc: "Paton J. Lewis" Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

xfs: fix reading of wrapped log data

2012-11-08T17:10:51Z

Commit 4439647 ("xfs: reset buffer pointers before freeing them") in 3.0-rc1 introduced a regression when recovering log buffers that wrapped around the end of log. The second part of the log buffer at the start of the physical log was being read into the header buffer rather than the data buffer, and hence recovery was seeing garbage in the data buffer when it got to the region of the log buffer that was incorrectly read. Cc: # 3.0.x, 3.2.x, 3.4.x 3.6.x Reported-by: Torsten Kaiser Signed-off-by: Dave Chinner Reviewed-by: Christoph Hellwig Reviewed-by: Mark Tinguely Signed-off-by: Ben Myers

xfs: fix buffer shudown reference count mismatch

2012-11-08T17:10:35Z

When we shut down the filesystem, we have to unpin and free all the buffers currently active in the CIL. To do this we unpin and remove them in one operation as a result of a failed iclogbuf write. For buffers, we do this removal via a simultated IO completion of after marking the buffer stale. At the time we do this, we have two references to the buffer - the active LRU reference and the buf log item. The LRU reference is removed by marking the buffer stale, and the active CIL reference is by the xfs_buf_iodone() callback that is run by xfs_buf_do_callbacks() during ioend processing (via the bp->b_iodone callback). However, ioend processing requires one more reference - that of the IO that it is completing. We don't have this reference, so we free the buffer prematurely and use it after it is freed. For buffers marked with XBF_ASYNC, this leads to assert failures in xfs_buf_rele() on debug kernels because the b_hold count is zero. Fix this by making sure we take the necessary IO reference before starting IO completion processing on the stale buffer, and set the XBF_ASYNC flag to ensure that IO completion processing removes all the active references from the buffer to ensure it is fully torn down. Cc: Signed-off-by: Dave Chinner Reviewed-by: Mark Tinguely Signed-off-by: Ben Myers