* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ryusuke/nilfs2: nilfs2: wait for discard to finish
* 'bugfixes' of git://git.linux-nfs.org/projects/trondmy/nfs-2.6: NFS: Fix an Oops in the NFSv4 atomic open code NFS: Fix the selection of security flavours in Kconfig NFS: fix the return value of nfs_file_fsync() rpcrdma: Fix SQ size calculation when memreg is FRMR xprtrdma: Do not truncate iova_start values in frmr registrations. nfs: Remove redundant NULL check upon kfree() nfs: Add "lookupcache" to displayed mount options NFS: allow close-to-open cache semantics to apply to root of NFS filesystem SUNRPC: fix NFS client over TCP hangs due to packet loss (Bug 16494)
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs-2.6: fs: brlock vfsmount_lock fs: scale files_lock lglock: introduce special lglock and brlock spin locks tty: fix fu_list abuse fs: cleanup files_lock locking fs: remove extra lookup in __lookup_hash fs: fs_struct rwlock to spinlock apparmor: use task path helpers fs: dentry allocation consolidation fs: fix do_lookup false negative mbcache: Limit the maximum number of cache entries hostfs ->follow_link() braino hostfs: dumb (and usually harmless) tpyo - strncpy instead of strlcpy remove SWRITE* I/O types kill BH_Ordered flag vfs: update ctime when changing the file's permission by setfacl cramfs: only unlock new inodes fix reiserfs_evict_inode end_writeback second call
nilfs_discard_segment() doesn't wait for completion of discard requests. This specifies BLKDEV_IFL_WAIT flag when calling blkdev_issue_discard() in order to fix the sync failure. Reported-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp> Cc: Christoph Hellwig <hch@lst.de>
Adam Lackorzynski reports: with 2.6.35.2 I'm getting this reproducible Oops: [ 110.825396] BUG: unable to handle kernel NULL pointer dereference at (null) [ 110.828638] IP: [<ffffffff811247b7>] encode_attrs+0x1a/0x2a4 [ 110.828638] PGD be89f067 PUD bf18f067 PMD 0 [ 110.828638] Oops: 0000 [#1] SMP [ 110.828638] last sysfs file: /sys/class/net/lo/operstate [ 110.828638] CPU 2 [ 110.828638] Modules linked in: rtc_cmos rtc_core rtc_lib amd64_edac_mod i2c_amd756 edac_core i2c_core dm_mirror dm_region_hash dm_log dm_snapshot sg sr_mod usb_storage ohci_hcd mptspi tg3 mptscsih mptbase usbcore nls_base [last unloaded: scsi_wait_scan] [ 110.828638] [ 110.828638] Pid: 11264, comm: setchecksum Not tainted 2.6.35.2 #1 [ 110.828638] RIP: 0010:[<ffffffff811247b7>] [<ffffffff811247b7>] encode_attrs+0x1a/0x2a4 [ 110.828638] RSP: 0000:ffff88003bf5b878 EFLAGS: 00010296 [ 110.828638] RAX: ffff8800bddb48a8 RBX: ffff88003bf5bb18 RCX: 0000000000000000 [ 110.828638] RDX: ffff8800be258800 RSI: 0000000000000000 RDI: ffff88003bf5b9f8 [ 110.828638] RBP: 0000000000000000 R08: ffff8800bddb48a8 R09: 0000000000000004 [ 110.828638] R10: 0000000000000003 R11: ffff8800be779000 R12: ffff8800be258800 [ 110.828638] R13: ffff88003bf5b9f8 R14: ffff88003bf5bb20 R15: ffff8800be258800 [ 110.828638] FS: 0000000000000000(0000) GS:ffff880041e00000(0063) knlGS:00000000556bd6b0 [ 110.828638] CS: 0010 DS: 002b ES: 002b CR0: 000000008005003b [ 110.828638] CR2: 0000000000000000 CR3: 00000000be8ef000 CR4: 00000000000006e0 [ 110.828638] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [ 110.828638] DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400 [ 110.828638] Process setchecksum (pid: 11264, threadinfo ffff88003bf5a000, task ffff88003f232210) [ 110.828638] Stack: [ 110.828638] 0000000000000000 ffff8800bfbcf920 0000000000000000 0000000000000ffe [ 110.828638] <0> 0000000000000000 0000000000000000 0000000000000000 0000000000000000 [ 110.828638] <0> 0000000000000000 0000000000000000 0000000000000000 0000000000000000 [ 110.828638] Call Trace: [ 110.828638] [<ffffffff81124c1f>] ? nfs4_xdr_enc_setattr+0x90/0xb4 [ 110.828638] [<ffffffff81371161>] ? call_transmit+0x1c3/0x24a [ 110.828638] [<ffffffff813774d9>] ? __rpc_execute+0x78/0x22a [ 110.828638] [<ffffffff81371a91>] ? rpc_run_task+0x21/0x2b [ 110.828638] [<ffffffff81371b7e>] ? rpc_call_sync+0x3d/0x5d [ 110.828638] [<ffffffff8111e284>] ? _nfs4_do_setattr+0x11b/0x147 [ 110.828638] [<ffffffff81109466>] ? nfs_init_locked+0x0/0x32 [ 110.828638] [<ffffffff810ac521>] ? ifind+0x4e/0x90 [ 110.828638] [<ffffffff8111e2fb>] ? nfs4_do_setattr+0x4b/0x6e [ 110.828638] [<ffffffff8111e634>] ? nfs4_do_open+0x291/0x3a6 [ 110.828638] [<ffffffff8111ed81>] ? nfs4_open_revalidate+0x63/0x14a [ 110.828638] [<ffffffff811056c4>] ? nfs_open_revalidate+0xd7/0x161 [ 110.828638] [<ffffffff810a2de4>] ? do_lookup+0x1a4/0x201 [ 110.828638] [<ffffffff810a4733>] ? link_path_walk+0x6a/0x9d5 [ 110.828638] [<ffffffff810a42b6>] ? do_last+0x17b/0x58e [ 110.828638] [<ffffffff810a5fbe>] ? do_filp_open+0x1bd/0x56e [ 110.828638] [<ffffffff811cd5e0>] ? _atomic_dec_and_lock+0x30/0x48 [ 110.828638] [<ffffffff810a9b1b>] ? dput+0x37/0x152 [ 110.828638] [<ffffffff810ae063>] ? alloc_fd+0x69/0x10a [ 110.828638] [<ffffffff81099f39>] ? do_sys_open+0x56/0x100 [ 110.828638] [<ffffffff81027a22>] ? ia32_sysret+0x0/0x5 [ 110.828638] Code: 83 f1 01 e8 f5 ca ff ff 48 83 c4 50 5b 5d 41 5c c3 41 57 41 56 41 55 49 89 fd 41 54 49 89 d4 55 48 89 f5 53 48 81 ec 18 01 00 00 <8b> 06 89 c2 83 e2 08 83 fa 01 19 db 83 e3 f8 83 c3 18 a8 01 8d [ 110.828638] RIP [<ffffffff811247b7>] encode_attrs+0x1a/0x2a4 [ 110.828638] RSP <ffff88003bf5b878> [ 110.828638] CR2: 0000000000000000 [ 112.840396] ---[ end trace 95282e83fd77358f ]--- We need to ensure that the O_EXCL flag is turned off if the user doesn't set O_CREAT. Cc: stable@kernel.org Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
fs: brlock vfsmount_lock Use a brlock for the vfsmount lock. It must be taken for write whenever modifying the mount hash or associated fields, and may be taken for read when performing mount hash lookups. A new lock is added for the mnt-id allocator, so it doesn't need to take the heavy vfsmount write-lock. The number of atomics should remain the same for fastpath rlock cases, though code would be slightly slower due to per-cpu access. Scalability is not not be much improved in common cases yet, due to other locks (ie. dcache_lock) getting in the way. However path lookups crossing mountpoints should be one case where scalability is improved (currently requiring the global lock). The slowpath is slower due to use of brlock. On a 64 core, 64 socket, 32 node Altix system (high latency to remote nodes), a simple umount microbenchmark (mount --bind mnt mnt2 ; umount mnt2 loop 1000 times), before this patch it took 6.8s, afterwards took 7.1s, about 5% slower. Cc: Al Viro <viro@ZenIV.linux.org.uk> Signed-off-by: Nick Piggin <npiggin@kernel.dk> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
fs: scale files_lock
Improve scalability of files_lock by adding per-cpu, per-sb files lists,
protected with an lglock. The lglock provides fast access to the per-cpu lists
to add and remove files. It also provides a snapshot of all the per-cpu lists
(although this is very slow).
One difficulty with this approach is that a file can be removed from the list
by another CPU. We must track which per-cpu list the file is on with a new
variale in the file struct (packed into a hole on 64-bit archs). Scalability
could suffer if files are frequently removed from different cpu's list.
However loads with frequent removal of files imply short interval between
adding and removing the files, and the scheduler attempts to avoid moving
processes too far away. Also, even in the case of cross-CPU removal, the
hardware has much more opportunity to parallelise cacheline transfers with N
cachelines than with 1.
A worst-case test of 1 CPU allocating files subsequently being freed by N CPUs
degenerates to contending on a single lock, which is no worse than before. When
more than one CPU are allocating files, even if they are always freed by
different CPUs, there will be more parallelism than the single-lock case.
Testing results:
On a 2 socket, 8 core opteron, I measure the number of times the lock is taken
to remove the file, the number of times it is removed by the same CPU that
added it, and the number of times it is removed by the same node that added it.
Booting: locks= 25049 cpu-hits= 23174 (92.5%) node-hits= 23945 (95.6%)
kbuild -j16 locks=2281913 cpu-hits=2208126 (96.8%) node-hits=2252674 (98.7%)
dbench 64 locks=4306582 cpu-hits=4287247 (99.6%) node-hits=4299527 (99.8%)
So a file is removed from the same CPU it was added by over 90% of the time.
It remains within the same node 95% of the time.
Tim Chen ran some numbers for a 64 thread Nehalem system performing a compile.
throughput
2.6.34-rc2 24.5
+patch 24.9
us sys idle IO wait (in %)
2.6.34-rc2 51.25 28.25 17.25 3.25
+patch 53.75 18.5 19 8.75
So significantly less CPU time spent in kernel code, higher idle time and
slightly higher throughput.
Single threaded performance difference was within the noise of microbenchmarks.
That is not to say penalty does not exist, the code is larger and more memory
accesses required so it will be slightly slower.
Cc: linux-kernel@vger.kernel.org
Cc: Tim Chen <tim.c.chen@linux.intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Nick Piggin <npiggin@kernel.dk>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
tty: fix fu_list abuse tty code abuses fu_list, which causes a bug in remount,ro handling. If a tty device node is opened on a filesystem, then the last link to the inode removed, the filesystem will be allowed to be remounted readonly. This is because fs_may_remount_ro does not find the 0 link tty inode on the file sb list (because the tty code incorrectly removed it to use for its own purpose). This can result in a filesystem with errors after it is marked "clean". Taking idea from Christoph's initial patch, allocate a tty private struct at file->private_data and put our required list fields in there, linking file and tty. This makes tty nodes behave the same way as other device nodes and avoid meddling with the vfs, and avoids this bug. The error handling is not trivial in the tty code, so for this bugfix, I take the simple approach of using __GFP_NOFAIL and don't worry about memory errors. This is not a problem because our allocator doesn't fail small allocs as a rule anyway. So proper error handling is left as an exercise for tty hackers. [ Arguably filesystem's device inode would ideally be divorced from the driver's pseudo inode when it is opened, but in practice it's not clear whether that will ever be worth implementing. ] Cc: linux-kernel@vger.kernel.org Cc: Christoph Hellwig <hch@infradead.org> Cc: Alan Cox <alan@lxorguk.ukuu.org.uk> Cc: Greg Kroah-Hartman <gregkh@suse.de> Signed-off-by: Nick Piggin <npiggin@kernel.dk> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
fs: cleanup files_lock locking Lock tty_files with a new spinlock, tty_files_lock; provide helpers to manipulate the per-sb files list; unexport the files_lock spinlock. Cc: linux-kernel@vger.kernel.org Cc: Christoph Hellwig <hch@infradead.org> Cc: Alan Cox <alan@lxorguk.ukuu.org.uk> Acked-by: Andi Kleen <ak@linux.intel.com> Acked-by: Greg Kroah-Hartman <gregkh@suse.de> Signed-off-by: Nick Piggin <npiggin@kernel.dk> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
fs: remove extra lookup in __lookup_hash Optimize lookup for create operations, where no dentry should often be common-case. In cases where it is not, such as unlink, the added overhead is much smaller than the removed. Also, move comments about __d_lookup racyness to the __d_lookup call site. d_lookup is intuitive; __d_lookup is what needs commenting. So in that same vein, add kerneldoc comments to __d_lookup and clean up some of the comments: - We are interested in how the RCU lookup works here, particularly with renames. Make that explicit, and point to the document where it is explained in more detail. - RCU is pretty standard now, and macros make implementations pretty mindless. If we want to know about RCU barrier details, we look in RCU code. - Delete some boring legacy comments because we don't care much about how the code used to work, more about the interesting parts of how it works now. So comments about lazy LRU may be interesting, but would better be done in the LRU or refcount management code. Signed-off-by: Nick Piggin <npiggin@kernel.dk> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>