Because it caused a chroot ttyname regression in 2.6.36.
As of 2.6.36 ttyname does not work in a chroot. It has already been
reported that screen breaks, and for me this breaks an automated
distribution testsuite, that I need to preserve the ability to run the
existing binaries on for several more years. glibc 2.11.3 which has a
fix for this is not an option.
The root cause of this breakage is:
commit 8df9d1a4142311c084ffeeacb67cd34d190eff74
Author: Miklos Szeredi <mszeredi@suse.cz>
Date: Tue Aug 10 11:41:41 2010 +0200
vfs: show unreachable paths in getcwd and proc
Prepend "(unreachable)" to path strings if the path is not reachable
from the current root.
Two places updated are
- the return string from getcwd()
- and symlinks under /proc/$PID.
Other uses of d_path() are left unchanged (we know that some old
software crashes if /proc/mounts is changed).
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
So remove the nice sounding, but ultimately ill advised change to how
/proc/fd symlinks work.
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
reiserfs_acl_chmod() can be called by reiserfs_set_attr() and then take the reiserfs lock a second time. Thereafter it may call journal_begin() that definitely requires the lock not to be nested in order to release it before taking the journal mutex because the reiserfs lock depends on the journal mutex already. So, aviod nesting the lock in reiserfs_acl_chmod(). Reported-by: Pawel Zawora <pzawora@gmail.com> Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Tested-by: Pawel Zawora <pzawora@gmail.com> Cc: Jeff Mahoney <jeffm@suse.com> Cc: <stable@kernel.org> [2.6.32.x+] Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* 'for-linus' of git://oss.sgi.com/xfs/xfs: xfs: only run xfs_error_test if error injection is active xfs: avoid moving stale inodes in the AIL xfs: delayed alloc blocks beyond EOF are valid after writeback xfs: push stale, pinned buffers on trylock failures xfs: fix failed write truncation handling.
* git://git.kernel.org/pub/scm/linux/kernel/git/sfrench/cifs-2.6: cifs: fix parsing of hostname in dfs referrals cifs: display fsc in /proc/mounts cifs: enable fscache iff fsc mount option is used explicitly cifs: allow fsc mount option only if CONFIG_CIFS_FSCACHE is set cifs: Handle extended attribute name cifs_acl to generate cifs acl blob (try #4) cifs: Misc. cleanup in cifsacl handling [try #4] cifs: trivial comment fix for cifs_invalidate_mapping [CIFS] fs/cifs/Kconfig: CIFS depends on CRYPTO_HMAC cifs: don't take extra tlink reference in initiate_cifs_search cifs: Percolate error up to the caller during get/set acls [try #4] cifs: fix another memleak, in cifs_root_iget cifs: fix potential use-after-free in cifs_oplock_break_put
Recent tests writing lots of small files showed the flusher thread
being CPU bound and taking a long time to do allocations on a debug
kernel. perf showed this as the prime reason:
samples pcnt function DSO
_______ _____ ___________________________ _________________
224648.00 36.8% xfs_error_test [kernel.kallsyms]
86045.00 14.1% xfs_btree_check_sblock [kernel.kallsyms]
39778.00 6.5% prandom32 [kernel.kallsyms]
37436.00 6.1% xfs_btree_increment [kernel.kallsyms]
29278.00 4.8% xfs_btree_get_rec [kernel.kallsyms]
27717.00 4.5% random32 [kernel.kallsyms]
Walking btree blocks during allocation checking them requires each
block (a cache hit, so no I/O) call xfs_error_test(), which then
does a random32() call as the first operation. IOWs, ~50% of the
CPU is being consumed just testing whether we need to inject an
error, even though error injection is not active.
Kill this overhead when error injection is not active by adding a
global counter of active error traps and only calling into
xfs_error_test when fault injection is active.
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
When an inode has been marked stale because the cluster is being freed, we don't want to (re-)insert this inode into the AIL. There is a race condition where the cluster buffer may be unpinned before the inode is inserted into the AIL during transaction committed processing. If the buffer is unpinned before the inode item has been committed and inserted, then it is possible for the buffer to be released and hence processthe stale inode callbacks before the inode is inserted into the AIL. In this case, we then insert a clean, stale inode into the AIL which will never get removed by an IO completion. It will, however, get reclaimed and that triggers an assert in xfs_inode_free() complaining about freeing an inode still in the AIL. This race can be avoided by not moving stale inodes forward in the AIL during transaction commit completion processing. This closes the race condition by ensuring we never insert clean stale inodes into the AIL. It is safe to do this because a dirty stale inode, by definition, must already be in the AIL. Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de>
There is an assumption in the parts of XFS that flushing a dirty file will make all the delayed allocation blocks disappear from an inode. That is, that after calling xfs_flush_pages() then ip->i_delayed_blks will be zero. This is an invalid assumption as we may have specualtive preallocation beyond EOF and they are recorded in ip->i_delayed_blks. A flush of the dirty pages of an inode will not change the state of these blocks beyond EOF, so a non-zero deeelalloc block count after a flush is valid. The bmap code has an invalid ASSERT() that needs to be removed, and the swapext code has a bug in that while it swaps the data forks around, it fails to swap the i_delayed_blks counter associated with the fork and hence can get the block accounting wrong. Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de>
As reported by Nick Piggin, XFS is suffering from long pauses under highly concurrent workloads when hosted on ramdisks. The problem is that an inode buffer is stuck in the pinned state in memory and as a result either the inode buffer or one of the inodes within the buffer is stopping the tail of the log from being moved forward. The system remains in this state until a periodic log force issued by xfssyncd causes the buffer to be unpinned. The main problem is that these are stale buffers, and are hence held locked until the transaction/checkpoint that marked them state has been committed to disk. When the filesystem gets into this state, only the xfssyncd can cause the async transactions to be committed to disk and hence unpin the inode buffer. This problem was encountered when scaling the busy extent list, but only the blocking lock interface was fixed to solve the problem. Extend the same fix to the buffer trylock operations - if we fail to lock a pinned, stale buffer, then force the log immediately so that when the next attempt to lock it comes around, it will have been unpinned. Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de>
Since the move to the new truncate sequence we call xfs_setattr to truncate down excessively instanciated blocks. As shown by the testcase in kernel.org BZ #22452 that doesn't work too well. Due to the confusion of the internal inode size, and the VFS inode i_size it zeroes data that it shouldn't. But full blown truncate seems like overkill here. We only instanciate delayed allocations in the write path, and given that we never released the iolock we can't have converted them to real allocations yet either. The only nasty case is pre-existing preallocation which we need to skip. We already do this for page discard during writeback, so make the delayed allocation block punching a generic function and call it from the failed write path as well as xfs_aops_discard_page. The callers are responsible for ensuring that partial blocks are not truncated away, and that they hold the ilock. Based on a fix originally from Christoph Hellwig. This version used filesystem blocks as the range unit. Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de>
Note: this patch targets 2.6.37 and tries to be as simple as possible. That is why it adds more copy-and-paste horror into fs/compat.c and uglifies fs/exec.c, this will be cleanuped later. compat_copy_strings() plays with bprm->vma/mm directly and thus has two problems: it lacks the RLIMIT_STACK check and argv/envp memory is not visible to oom killer. Export acct_arg_size() and get_arg_page(), change compat_copy_strings() to use get_arg_page(), change compat_do_execve() to do acct_arg_size(0) as do_execve() does. Add the fatal_signal_pending/cond_resched checks into compat_count() and compat_copy_strings(), this matches the code in fs/exec.c and certainly makes sense. Signed-off-by: Oleg Nesterov <oleg@redhat.com> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: stable@kernel.org Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>