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2011-01-28NFS: NFSv4 readdir loses entriesChuck Lever
On recent 2.6.38-rc kernels, connectathon basic test 6 fails on NFSv4 mounts of OpenSolaris with something like: > ./test6: readdir > ./test6: (/mnt/klimt/matisse.test) didn't read expected 'file.12' dir entry, pass 0 > ./test6: (/mnt/klimt/matisse.test) didn't read expected 'file.82' dir entry, pass 0 > ./test6: (/mnt/klimt/matisse.test) didn't read expected 'file.164' dir entry, pass 0 > ./test6: (/mnt/klimt/matisse.test) Test failed with 3 errors > basic tests failed > Tests failed, leaving /mnt/klimt mounted > [cel@matisse cthon04]$ I narrowed the problem down to nfs4_decode_dirent() reporting that the decode buffer had overflowed while decoding the entries for those missing files. verify_attr_len() assumes both it's pointer arguments reside on the same page. When these arguments point to locations on two different pages, verify_attr_len() can report false errors. This can happen now that a large NFSv4 readdir result can span pages. We have reasonably good checking in nfs4_decode_dirent() anyway, so it should be safe to simply remove the extra checking. At a guess, this was introduced by commit 6650239a, "NFS: Don't use vm_map_ram() in readdir". Cc: stable@kernel.org [2.6.37] Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2011-01-28NFS: Micro-optimize nfs4_decode_dirent()Chuck Lever
Make the decoding of NFSv4 directory entries slightly more efficient by: 1. Avoiding unnecessary byte swapping when checking XDR booleans, and 2. Not bumping "p" when its value will be immediately replaced by xdr_inline_decode() This commit makes nfs4_decode_dirent() consistent with similar logic in the other two decode_dirent() functions. Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2011-01-28NFS: Fix an NFS client lockdep issueTrond Myklebust
There is no reason to be freeing the delegation cred in the rcu callback, and doing so is resulting in a lockdep complaint that rpc_credcache_lock is being called from both softirq and non-softirq contexts. Reported-by: Chuck Lever <chuck.lever@oracle.com> Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com> Cc: stable@kernel.org
2011-01-25NFS construct consistent co_ownerid for v4.1Andy Adamson
As stated in section 2.4 of RFC 5661, subsequent instances of the client need to present the same co_ownerid. Concatinate the client's IP dot address, host name, and the rpc_auth pseudoflavor to form the co_ownerid. Signed-off-by: Andy Adamson <andros@netapp.com> Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2011-01-25NFS: nfs_wcc_update_inode() should set nfsi->attr_gencountTrond Myklebust
If the call to nfs_wcc_update_inode() results in an attribute update, we need to ensure that the inode's attr_gencount gets bumped too, otherwise we are not protected against races with other GETATTR calls. Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2011-01-25NFS improve pnfs_put_deviceid_cache debug printAndy Adamson
What we really want to know is the ref count. Signed-off-by: Andy Adamson <andros@netapp.com> Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2011-01-25NFS fix cb_sequence error processingAndy Adamson
Always assign the cb_process_state nfs_client pointer so a processing error in cb_sequence after the nfs_client is found and referenced returns a non-NULL cb_process_state nfs_client and the matching nfs_put_client in nfs4_callback_compound dereferences the client. Signed-off-by: Andy Adamson <andros@netapp.com> Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2011-01-25NFS do not find client in NFSv4 pg_authenticateAndy Adamson
The information required to find the nfs_client cooresponding to the incoming back channel request is contained in the NFS layer. Perform minimal checking in the RPC layer pg_authenticate method, and push more detailed checking into the NFS layer where the nfs_client can be found. Signed-off-by: Andy Adamson <andros@netapp.com> Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2011-01-25NFS: Prevent memory allocation failure in nfsacl_encode()Chuck Lever
nfsacl_encode() allocates memory in certain cases. This of course is not guaranteed to work. Since commit 9f06c719 "SUNRPC: New xdr_streams XDR encoder API", the kernel's XDR encoders can't return a result indicating possibly a failure, so a memory allocation failure in nfsacl_encode() has become fatal (ie, the XDR code Oopses) in some cases. However, the allocated memory is a tiny fixed amount, on the order of 40-50 bytes. We can easily use a stack-allocated buffer for this, with only a wee bit of nose-holding. Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2011-01-25NFS: Fix "kernel BUG at fs/nfs/nfs3xdr.c:1338!"Chuck Lever
Milan Broz <mbroz@redhat.com> reports: > on today Linus' tree I get OOps if using nfs. > > server (2.6.36) exports dir: > /dir 172.16.1.0/24(rw,async,all_squash,no_subtree_check,anonuid=500,anongid=500) > > on client it is mounted in fstab > server:/dir /mnt/tst nfs rw,soft 0 0 > > and these commands OOpses it (simplified from a configure script): > > cd /dir > touch x > install x y > > [ 105.327701] ------------[ cut here ]------------ > [ 105.327979] kernel BUG at fs/nfs/nfs3xdr.c:1338! > [ 105.328075] invalid opcode: 0000 [#1] PREEMPT SMP > [ 105.328223] last sysfs file: /sys/devices/virtual/bdi/0:16/uevent > [ 105.328349] Modules linked in: usbcore dm_mod > [ 105.328553] > [ 105.328678] Pid: 3710, comm: install Not tainted 2.6.37+ #423 440BX Desktop Reference Platform/VMware Virtual Platform > [ 105.328853] EIP: 0060:[<c116c06c>] EFLAGS: 00010282 CPU: 0 > [ 105.329152] EIP is at nfs3_xdr_enc_setacl3args+0x61/0x98 > [ 105.329249] EAX: ffffffea EBX: ce941d98 ECX: 00000000 EDX: 00000004 > [ 105.329340] ESI: ce941cd0 EDI: 000000a4 EBP: ce941cc0 ESP: ce941cb4 > [ 105.329431] DS: 007b ES: 007b FS: 00d8 GS: 00e0 SS: 0068 > [ 105.329525] Process install (pid: 3710, ti=ce940000 task=ced36f20 task.ti=ce940000) > [ 105.336600] Stack: > [ 105.336693] ce941cd0 ce9dc000 00000000 ce941cf8 c12ecd02 c12f43e0 c116c00b cf754158 > [ 105.336982] ce9dc004 cf754284 ce9dc004 cf7ffee8 ceff9978 ce9dc000 cf7ffee8 ce9dc000 > [ 105.337182] ce9dc000 ce941d14 c12e698d cf75412c ce941d98 cf7ffee8 cf7fff20 00000000 > [ 105.337405] Call Trace: > [ 105.337695] [<c12ecd02>] rpcauth_wrap_req+0x75/0x7f > [ 105.337806] [<c12f43e0>] ? xdr_encode_opaque+0x12/0x15 > [ 105.337898] [<c116c00b>] ? nfs3_xdr_enc_setacl3args+0x0/0x98 > [ 105.337988] [<c12e698d>] call_transmit+0x17e/0x1e8 > [ 105.338072] [<c12ec307>] __rpc_execute+0x6d/0x1a6 > [ 105.338155] [<c12ec474>] rpc_execute+0x34/0x37 > [ 105.338235] [<c12e738d>] rpc_run_task+0xb5/0xbd > [ 105.338316] [<c12e7474>] rpc_call_sync+0x3d/0x58 > [ 105.338402] [<c116d0c6>] nfs3_proc_setacls+0x18e/0x24f > [ 105.338493] [<c10b3f76>] ? __kmalloc+0x148/0x1c4 > [ 105.338579] [<c10ecd01>] ? posix_acl_alloc+0x12/0x22 > [ 105.338665] [<c116d5c8>] nfs3_proc_setacl+0xa0/0xca > [ 105.338748] [<c116d69c>] nfs3_setxattr+0x62/0x88 > [ 105.338834] [<c1317042>] ? sub_preempt_count+0x7c/0x89 > [ 105.338926] [<c116d63a>] ? nfs3_setxattr+0x0/0x88 > [ 105.339026] [<c10cfa79>] __vfs_setxattr_noperm+0x26/0x95 > [ 105.339114] [<c10cfb43>] vfs_setxattr+0x5b/0x76 > [ 105.339211] [<c10cfbfb>] setxattr+0x9d/0xc3 > [ 105.339298] [<c10a2ea8>] ? handle_pte_fault+0x258/0x5cb > [ 105.339428] [<c1091ff6>] ? __free_pages+0x1a/0x23 > [ 105.339517] [<c10498ea>] ? up_read+0x16/0x2c > [ 105.339599] [<c10b8365>] ? fget+0x0/0xa3 > [ 105.339677] [<c10b8365>] ? fget+0x0/0xa3 > [ 105.339760] [<c1025d23>] ? get_parent_ip+0xb/0x31 > [ 105.339843] [<c1317042>] ? sub_preempt_count+0x7c/0x89 > [ 105.339931] [<c10cfc72>] sys_fsetxattr+0x51/0x79 > [ 105.340014] [<c1002853>] sysenter_do_call+0x12/0x32 > [ 105.340133] Code: 2e 76 18 00 58 31 d2 8b 7f 28 f6 43 04 01 74 03 8b 53 08 6a 00 8b 46 04 6a 01 8b 0b 52 89 fa e8 85 10 f8 ff 83 c4 0c 85 c0 79 04 <0f> 0b eb fe 31 c9 f6 43 04 04 74 03 8b 4b 0c 68 00 10 00 00 8d > [ 105.350321] EIP: [<c116c06c>] nfs3_xdr_enc_setacl3args+0x61/0x98 SS:ESP 0068:ce941cb4 > [ 105.364385] ---[ end trace 01fcfe7f0f7f6e4a ]--- nfs3_xdr_enc_setacl3args() is not properly setting up the target buffer before nfsacl_encode() attempts to encode the ACL. Introduced by commit d9c407b1 "NFS: Introduce new-style XDR encoding functions for NFSv3." Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2011-01-25NFS: Fix "kernel BUG at fs/aio.c:554!"Chuck Lever
Nick Piggin reports: > I'm getting use after frees in aio code in NFS > > [ 2703.396766] Call Trace: > [ 2703.396858] [<ffffffff8100b057>] ? native_sched_clock+0x27/0x80 > [ 2703.396959] [<ffffffff8108509e>] ? put_lock_stats+0xe/0x40 > [ 2703.397058] [<ffffffff81088348>] ? lock_release_holdtime+0xa8/0x140 > [ 2703.397159] [<ffffffff8108a2a5>] lock_acquire+0x95/0x1b0 > [ 2703.397260] [<ffffffff811627db>] ? aio_put_req+0x2b/0x60 > [ 2703.397361] [<ffffffff81039701>] ? get_parent_ip+0x11/0x50 > [ 2703.397464] [<ffffffff81612a31>] _raw_spin_lock_irq+0x41/0x80 > [ 2703.397564] [<ffffffff811627db>] ? aio_put_req+0x2b/0x60 > [ 2703.397662] [<ffffffff811627db>] aio_put_req+0x2b/0x60 > [ 2703.397761] [<ffffffff811647fe>] do_io_submit+0x2be/0x7c0 > [ 2703.397895] [<ffffffff81164d0b>] sys_io_submit+0xb/0x10 > [ 2703.397995] [<ffffffff8100307b>] system_call_fastpath+0x16/0x1b > > Adding some tracing, it is due to nfs completing the request then > returning something other than -EIOCBQUEUED, so aio.c > also completes the request. To address this, prevent the NFS direct I/O engine from completing async iocbs when the forward path returns an error without starting any I/O. This fix appears to survive ^C during both "xfstest no. 208" and "fsx -Z." It's likely this bug has existed for a very long while, as we are seeing very similar symptoms in OEL 5. Copying stable. Cc: Stable <stable@kernel.org> Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2011-01-25NFS4: Avoid potential NULL pointer dereference in decode_and_add_ds().Jesper Juhl
On Mon, 17 Jan 2011, Mi Jinlong wrote: > > > Jesper Juhl: > > strrchr() can return NULL if nothing is found. If this happens we'll > > dereference a NULL pointer in > > fs/nfs/nfs4filelayoutdev.c::decode_and_add_ds(). > > > > I tried to find some other code that guarantees that this can never > > happen but I was unsuccessful. So, unless someone else can point to some > > code that ensures this can never be a problem, I believe this patch is > > needed. > > > > While I was changing this code I also noticed that all the dprintk() > > statements, except one, start with "%s:". The one missing the ":" I added > > it to. > > Maybe another one also should be changed at decode_and_add_ds() at line 243: > > 243 printk("%s Decoded address and port %s\n", __func__, buf); > Missed that one. Thanks. Signed-off-by: Jesper Juhl <jj@chaosbits.net> Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2011-01-19NFS: fix handling of malloc failure during nfs_flush_multi()Fred Isaman
Cleanup of the allocated list entries should not call put_nfs_open_context() on each entry, as the context will always be NULL, causing an oops. Signed-off-by: Fred Isaman <iisaman@netapp.com> Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2011-01-15Unexport do_add_mount() and add in follow_automount(), not ->d_automount()David Howells
Unexport do_add_mount() and make ->d_automount() return the vfsmount to be added rather than calling do_add_mount() itself. follow_automount() will then do the addition. This slightly complicates things as ->d_automount() normally wants to add the new vfsmount to an expiration list and start an expiration timer. The problem with that is that the vfsmount will be deleted if it has a refcount of 1 and the timer will not repeat if the expiration list is empty. To this end, we require the vfsmount to be returned from d_automount() with a refcount of (at least) 2. One of these refs will be dropped unconditionally. In addition, follow_automount() must get a 3rd ref around the call to do_add_mount() lest it eat a ref and return an error, leaving the mount we have open to being expired as we would otherwise have only 1 ref on it. d_automount() should also add the the vfsmount to the expiration list (by calling mnt_set_expiry()) and start the expiration timer before returning, if this mechanism is to be used. The vfsmount will be unlinked from the expiration list by follow_automount() if do_add_mount() fails. This patch also fixes the call to do_add_mount() for AFS to propagate the mount flags from the parent vfsmount. Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2011-01-15NFS: Use d_automount() rather than abusing follow_link()David Howells
Make NFS use the new d_automount() dentry operation rather than abusing follow_link() on directories. Signed-off-by: David Howells <dhowells@redhat.com> Acked-by: Trond Myklebust <Trond.Myklebust@netapp.com> Acked-by: Ian Kent <raven@themaw.net> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2011-01-15Add a dentry op to allow processes to be held during pathwalk transitDavid Howells
Add a dentry op (d_manage) to permit a filesystem to hold a process and make it sleep when it tries to transit away from one of that filesystem's directories during a pathwalk. The operation is keyed off a new dentry flag (DCACHE_MANAGE_TRANSIT). The filesystem is allowed to be selective about which processes it holds and which it permits to continue on or prohibits from transiting from each flagged directory. This will allow autofs to hold up client processes whilst letting its userspace daemon through to maintain the directory or the stuff behind it or mounted upon it. The ->d_manage() dentry operation: int (*d_manage)(struct path *path, bool mounting_here); takes a pointer to the directory about to be transited away from and a flag indicating whether the transit is undertaken by do_add_mount() or do_move_mount() skipping through a pile of filesystems mounted on a mountpoint. It should return 0 if successful and to let the process continue on its way; -EISDIR to prohibit the caller from skipping to overmounted filesystems or automounting, and to use this directory; or some other error code to return to the user. ->d_manage() is called with namespace_sem writelocked if mounting_here is true and no other locks held, so it may sleep. However, if mounting_here is true, it may not initiate or wait for a mount or unmount upon the parameter directory, even if the act is actually performed by userspace. Within fs/namei.c, follow_managed() is extended to check with d_manage() first on each managed directory, before transiting away from it or attempting to automount upon it. follow_down() is renamed follow_down_one() and should only be used where the filesystem deliberately intends to avoid management steps (e.g. autofs). A new follow_down() is added that incorporates the loop done by all other callers of follow_down() (do_add/move_mount(), autofs and NFSD; whilst AFS, NFS and CIFS do use it, their use is removed by converting them to use d_automount()). The new follow_down() calls d_manage() as appropriate. It also takes an extra parameter to indicate if it is being called from mount code (with namespace_sem writelocked) which it passes to d_manage(). follow_down() ignores automount points so that it can be used to mount on them. __follow_mount_rcu() is made to abort rcu-walk mode if it hits a directory with DCACHE_MANAGE_TRANSIT set on the basis that we're probably going to have to sleep. It would be possible to enter d_manage() in rcu-walk mode too, and have that determine whether to abort or not itself. That would allow the autofs daemon to continue on in rcu-walk mode. Note that DCACHE_MANAGE_TRANSIT on a directory should be cleared when it isn't required as every tranist from that directory will cause d_manage() to be invoked. It can always be set again when necessary. ========================== WHAT THIS MEANS FOR AUTOFS ========================== Autofs currently uses the lookup() inode op and the d_revalidate() dentry op to trigger the automounting of indirect mounts, and both of these can be called with i_mutex held. autofs knows that the i_mutex will be held by the caller in lookup(), and so can drop it before invoking the daemon - but this isn't so for d_revalidate(), since the lock is only held on _some_ of the code paths that call it. This means that autofs can't risk dropping i_mutex from its d_revalidate() function before it calls the daemon. The bug could manifest itself as, for example, a process that's trying to validate an automount dentry that gets made to wait because that dentry is expired and needs cleaning up: mkdir S ffffffff8014e05a 0 32580 24956 Call Trace: [<ffffffff885371fd>] :autofs4:autofs4_wait+0x674/0x897 [<ffffffff80127f7d>] avc_has_perm+0x46/0x58 [<ffffffff8009fdcf>] autoremove_wake_function+0x0/0x2e [<ffffffff88537be6>] :autofs4:autofs4_expire_wait+0x41/0x6b [<ffffffff88535cfc>] :autofs4:autofs4_revalidate+0x91/0x149 [<ffffffff80036d96>] __lookup_hash+0xa0/0x12f [<ffffffff80057a2f>] lookup_create+0x46/0x80 [<ffffffff800e6e31>] sys_mkdirat+0x56/0xe4 versus the automount daemon which wants to remove that dentry, but can't because the normal process is holding the i_mutex lock: automount D ffffffff8014e05a 0 32581 1 32561 Call Trace: [<ffffffff80063c3f>] __mutex_lock_slowpath+0x60/0x9b [<ffffffff8000ccf1>] do_path_lookup+0x2ca/0x2f1 [<ffffffff80063c89>] .text.lock.mutex+0xf/0x14 [<ffffffff800e6d55>] do_rmdir+0x77/0xde [<ffffffff8005d229>] tracesys+0x71/0xe0 [<ffffffff8005d28d>] tracesys+0xd5/0xe0 which means that the system is deadlocked. This patch allows autofs to hold up normal processes whilst the daemon goes ahead and does things to the dentry tree behind the automouter point without risking a deadlock as almost no locks are held in d_manage() and none in d_automount(). Signed-off-by: David Howells <dhowells@redhat.com> Was-Acked-by: Ian Kent <raven@themaw.net> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2011-01-13Merge branch 'vfs-scale-working' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/npiggin/linux-npiggin * 'vfs-scale-working' of git://git.kernel.org/pub/scm/linux/kernel/git/npiggin/linux-npiggin: fs: fix do_last error case when need_reval_dot nfs: add missing rcu-walk check fs: hlist UP debug fixup fs: fix dropping of rcu-walk from force_reval_path fs: force_reval_path drop rcu-walk before d_invalidate fs: small rcu-walk documentation fixes Fixed up trivial conflicts in Documentation/filesystems/porting
2011-01-14nfs: add missing rcu-walk checkNick Piggin
Signed-off-by: Nick Piggin <npiggin@kernel.dk>
2011-01-13NFS: Fix NFSv3 exclusive open semanticsTrond Myklebust
Commit c0204fd2b8fe047b18b67e07e1bf2a03691240cd (NFS: Clean up nfs4_proc_create()) broke NFSv3 exclusive open by removing the code that passes the O_EXCL flag down to nfs3_proc_create(). This patch reverts that offending hunk from the original commit. Reported-by: Nick Bowler <nbowler@elliptictech.com> Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com> Cc: stable@kernel.org [2.6.37] Tested-by: Nick Bowler <nbowler@elliptictech.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-01-12switch nfs to ->s_d_opAl Viro
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2011-01-11Merge branch 'nfs-for-2.6.38' of ↵Linus Torvalds
git://git.linux-nfs.org/projects/trondmy/nfs-2.6 * 'nfs-for-2.6.38' of git://git.linux-nfs.org/projects/trondmy/nfs-2.6: (89 commits) NFS fix the setting of exchange id flag NFS: Don't use vm_map_ram() in readdir NFSv4: Ensure continued open and lockowner name uniqueness NFS: Move cl_delegations to the nfs_server struct NFS: Introduce nfs_detach_delegations() NFS: Move cl_state_owners and related fields to the nfs_server struct NFS: Allow walking nfs_client.cl_superblocks list outside client.c pnfs: layout roc code pnfs: update nfs4_callback_recallany to handle layouts pnfs: add CB_LAYOUTRECALL handling pnfs: CB_LAYOUTRECALL xdr code pnfs: change lo refcounting to atomic_t pnfs: check that partial LAYOUTGET return is ignored pnfs: add layout to client list before sending rpc pnfs: serialize LAYOUTGET(openstateid) pnfs: layoutget rpc code cleanup pnfs: change how lsegs are removed from layout list pnfs: change layout state seqlock to a spinlock pnfs: add prefix to struct pnfs_layout_hdr fields pnfs: add prefix to struct pnfs_layout_segment fields ...
2011-01-11NFS fix the setting of exchange id flagAndy Adamson
Indicate support for referrals. Do not set any PNFS roles. Check the flags returned by the server for validity. Do not use exchange flags from an old client ID instance when recovering a client ID. Update the EXCHID4_FLAG_XXX set to RFC 5661. Signed-off-by: Andy Adamson <andros@netapp.com> Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2011-01-10Merge branch 'bugfixes' into nfs-for-2.6.38Trond Myklebust
Conflicts: fs/nfs/nfs2xdr.c fs/nfs/nfs3xdr.c fs/nfs/nfs4xdr.c
2011-01-10NFS: Don't use vm_map_ram() in readdirTrond Myklebust
vm_map_ram() is not available on NOMMU platforms, and causes trouble on incoherrent architectures such as ARM when we access the page data through both the direct and the virtual mapping. The alternative is to use the direct mapping to access page data for the case when we are not crossing a page boundary, but to copy the data into a linear scratch buffer when we are accessing data that spans page boundaries. Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com> Tested-by: Marc Kleine-Budde <mkl@pengutronix.de> Cc: stable@kernel.org [2.6.37]
2011-01-07fs: dcache per-inode inode alias lockingNick Piggin
dcache_inode_lock can be replaced with per-inode locking. Use existing inode->i_lock for this. This is slightly non-trivial because we sometimes need to find the inode from the dentry, which requires d_inode to be stabilised (either with refcount or d_lock). Signed-off-by: Nick Piggin <npiggin@kernel.dk>
2011-01-07fs: provide rcu-walk aware permission i_opsNick Piggin
Signed-off-by: Nick Piggin <npiggin@kernel.dk>
2011-01-07fs: rcu-walk aware d_revalidate methodNick Piggin
Require filesystems be aware of .d_revalidate being called in rcu-walk mode (nd->flags & LOOKUP_RCU). For now do a simple push down, returning -ECHILD from all implementations. Signed-off-by: Nick Piggin <npiggin@kernel.dk>
2011-01-07fs: dcache reduce branches in lookup pathNick Piggin
Reduce some branches and memory accesses in dcache lookup by adding dentry flags to indicate common d_ops are set, rather than having to check them. This saves a pointer memory access (dentry->d_op) in common path lookup situations, and saves another pointer load and branch in cases where we have d_op but not the particular operation. Patched with: git grep -E '[.>]([[:space:]])*d_op([[:space:]])*=' | xargs sed -e 's/\([^\t ]*\)->d_op = \(.*\);/d_set_d_op(\1, \2);/' -e 's/\([^\t ]*\)\.d_op = \(.*\);/d_set_d_op(\&\1, \2);/' -i Signed-off-by: Nick Piggin <npiggin@kernel.dk>
2011-01-07fs: icache RCU free inodesNick Piggin
RCU free the struct inode. This will allow: - Subsequent store-free path walking patch. The inode must be consulted for permissions when walking, so an RCU inode reference is a must. - sb_inode_list_lock to be moved inside i_lock because sb list walkers who want to take i_lock no longer need to take sb_inode_list_lock to walk the list in the first place. This will simplify and optimize locking. - Could remove some nested trylock loops in dcache code - Could potentially simplify things a bit in VM land. Do not need to take the page lock to follow page->mapping. The downsides of this is the performance cost of using RCU. In a simple creat/unlink microbenchmark, performance drops by about 10% due to inability to reuse cache-hot slab objects. As iterations increase and RCU freeing starts kicking over, this increases to about 20%. In cases where inode lifetimes are longer (ie. many inodes may be allocated during the average life span of a single inode), a lot of this cache reuse is not applicable, so the regression caused by this patch is smaller. The cache-hot regression could largely be avoided by using SLAB_DESTROY_BY_RCU, however this adds some complexity to list walking and store-free path walking, so I prefer to implement this at a later date, if it is shown to be a win in real situations. I haven't found a regression in any non-micro benchmark so I doubt it will be a problem. Signed-off-by: Nick Piggin <npiggin@kernel.dk>
2011-01-07fs: dcache remove dcache_lockNick Piggin
dcache_lock no longer protects anything. remove it. Signed-off-by: Nick Piggin <npiggin@kernel.dk>
2011-01-07fs: Use rename lock and RCU for multi-step operationsNick Piggin
The remaining usages for dcache_lock is to allow atomic, multi-step read-side operations over the directory tree by excluding modifications to the tree. Also, to walk in the leaf->root direction in the tree where we don't have a natural d_lock ordering. This could be accomplished by taking every d_lock, but this would mean a huge number of locks and actually gets very tricky. Solve this instead by using the rename seqlock for multi-step read-side operations, retry in case of a rename so we don't walk up the wrong parent. Concurrent dentry insertions are not serialised against. Concurrent deletes are tricky when walking up the directory: our parent might have been deleted when dropping locks so also need to check and retry for that. We can also use the rename lock in cases where livelock is a worry (and it is introduced in subsequent patch). Signed-off-by: Nick Piggin <npiggin@kernel.dk>
2011-01-07fs: scale inode alias listNick Piggin
Add a new lock, dcache_inode_lock, to protect the inode's i_dentry list from concurrent modification. d_alias is also protected by d_lock. Signed-off-by: Nick Piggin <npiggin@kernel.dk>
2011-01-07fs: dcache scale dentry refcountNick Piggin
Make d_count non-atomic and protect it with d_lock. This allows us to ensure a 0 refcount dentry remains 0 without dcache_lock. It is also fairly natural when we start protecting many other dentry members with d_lock. Signed-off-by: Nick Piggin <npiggin@kernel.dk>
2011-01-07fs: change d_delete semanticsNick Piggin
Change d_delete from a dentry deletion notification to a dentry caching advise, more like ->drop_inode. Require it to be constant and idempotent, and not take d_lock. This is how all existing filesystems use the callback anyway. This makes fine grained dentry locking of dput and dentry lru scanning much simpler. Signed-off-by: Nick Piggin <npiggin@kernel.dk>
2011-01-06NFSv4: Ensure continued open and lockowner name uniquenessTrond Myklebust
In order to enable migration support, we will want to move some of the structures that are subject to migration into the struct nfs_server. In particular, if we are to move the state_owner and state_owner_id to being a per-filesystem structure, then we should label the resulting open/lock owners with a per-filesytem label to ensure global uniqueness. This patch does so by adding the super block s_dev to the open/lock owner name. Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2011-01-06NFS: Move cl_delegations to the nfs_server structChuck Lever
Delegations are per-inode, not per-nfs_client. When a server file system is migrated, delegations on the client must be moved from the source to the destination nfs_server. Make it easier to manage a mount point's delegation list across a migration event by moving the list to the nfs_server struct. Clean up: I added documenting comments to public functions I changed in this patch. For consistency I added comments to all the other public functions in fs/nfs/delegation.c. Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2011-01-06NFS: Introduce nfs_detach_delegations()Chuck Lever
Clean up: Refactor code that takes clp->cl_lock and calls nfs_detach_delegations_locked() into its own function. While we're changing the call sites, get rid of the second parameter and the logic in nfs_detach_delegations_locked() that uses it, since callers always set that parameter of nfs_detach_delegations_locked() to NULL. Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2011-01-06NFS: Move cl_state_owners and related fields to the nfs_server structChuck Lever
NFSv4 migration needs to reassociate state owners from the source to the destination nfs_server data structures. To make that easier, move the cl_state_owners field to the nfs_server struct. cl_openowner_id and cl_lockowner_id accompany this move, as they are used in conjunction with cl_state_owners. The cl_lock field in the parent nfs_client continues to protect all three of these fields. Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2011-01-06NFS: Allow walking nfs_client.cl_superblocks list outside client.cChuck Lever
We're about to move some fields from struct nfs_client to struct nfs_server. There is a many-to-one relationship between nfs_servers and nfs_clients. After these fields are moved to the nfs_server struct, to visit all of the data in these fields that is owned by one nfs_client, code will need to visit each nfs_server on the cl_superblocks list for that nfs_client. To serialize changes to the cl_superblocks list during these little expeditions, protect the list with RCU. Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2011-01-06pnfs: layout roc codeFred Isaman
A layout can request return-on-close. How this interacts with the forgetful model of never sending LAYOUTRETURNS is a bit ambiguous. We forget any layouts marked roc, and wait for them to be completely forgotten before continuing with the close. In addition, to compensate for races with any inflight LAYOUTGETs, and the fact that we do not get any layout stateid back from the server, we set the barrier to the worst case scenario of current_seqid + number of outstanding LAYOUTGETS. Signed-off-by: Fred Isaman <iisaman@netapp.com> Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2011-01-06pnfs: update nfs4_callback_recallany to handle layoutsAlexandros Batsakis
While here, update the code a bit. Signed-off-by: Alexandros Batsakis <batsakis@netapp.com> Signed-off-by: Fred Isaman <iisaman@netapp.com> Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2011-01-06pnfs: add CB_LAYOUTRECALL handlingFred Isaman
This is the heart of the wave 2 submission. Add the code to trigger drain and forget of any afected layouts. In addition, we set a "barrier", below which any LAYOUTGET reply is ignored. This is to compensate for the fact that we do not wait for outstanding LAYOUTGETs to complete as per section 12.5.5.2.1 of RFC 5661. Signed-off-by: Fred Isaman <iisaman@netapp.com> Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2011-01-06pnfs: CB_LAYOUTRECALL xdr codeFred Isaman
This is the xdr decoding for CB_LAYOUTRECALL. Signed-off-by: Alexandros Batsakis <batsakis@netapp.com> Signed-off-by: Dean Hildebrand <dhildeb@us.ibm.com> Signed-off-by: Marc Eshel <eshel@almaden.ibm.com> Signed-off-by: Andy Adamson <andros@netapp.com> Signed-off-by: Benny Halevy <bhalevy@panasas.com> Signed-off-by: Fred Isaman <iisaman@netapp.com> Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2011-01-06pnfs: change lo refcounting to atomic_tFred Isaman
This will be required to allow us to grab reference outside of i_lock. While we are at it, make put_layout_hdr take the same argument as all the related functions. Signed-off-by: Fred Isaman <iisaman@netapp.com> Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2011-01-06pnfs: check that partial LAYOUTGET return is ignoredFred Isaman
Either a bad server reply, or our ignoring of multiple array segments in a reply, can cause a reply to not meet our requirements. Ensure that we ignore such replies. Signed-off-by: Fred Isaman <iisaman@netapp.com> Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2011-01-06pnfs: add layout to client list before sending rpcFred Isaman
Since this list will be used to search for layouts to recall, this is necessary to avoid a race where the recall comes in, sees there is nothing in the client list, and prepares to return NOMATCHING, while the LAYOUTGET gets processed before the recall updates the stateid. Signed-off-by: Fred Isaman <iisaman@netapp.com> Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2011-01-06pnfs: serialize LAYOUTGET(openstateid)Fred Isaman
We shouldn't send a LAYOUTGET(openstateid) unless all outstanding RPCs using the previous stateid are completed. This requires choosing the stateid to encode earlier, so we can abort if one is not available (we want to use the open stateid, but a LAYOUTGET is already out using it), and adding a count of the number of outstanding rpc calls using layout state (which for now consist solely of LAYOUTGETs). Signed-off-by: Fred Isaman <iisaman@netapp.com> Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2011-01-06pnfs: layoutget rpc code cleanupFred Isaman
No functional changes, just some code minor code rearrangement and comments. Signed-off-by: Fred Isaman <iisaman@netapp.com> Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2011-01-06pnfs: change how lsegs are removed from layout listFred Isaman
This is to prepare the way for sensible io draining. Instead of just removing the lseg from the list, we instead clear the VALID flag (preventing new io from grabbing references to the lseg) and remove the reference holding it in the list. Thus the lseg will be removed once any io in progress completes and any references still held are dropped. Signed-off-by: Fred Isaman <iisaman@netapp.com> Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2011-01-06pnfs: change layout state seqlock to a spinlockFred Isaman
This prepares for future changes, where the layout state needs to change atomically with several other variables. In particular, it will need to know if lo->segs is empty, as we test that instead of manipulating the NFS_LAYOUT_STATEID_SET bit. Moreover, the layoutstateid is not really a read-mostly structure, as it is written almost as often as it is read. The behavior of pnfs_get_layout_stateid is also slightly changed, so that it no longer changes the stateid. Its name is changed to +pnfs_choose_layoutget_stateid. Signed-off-by: Fred Isaman <iisaman@netapp.com> Signed-off-by: Benny Halevy <bhalevy@panasas.com> Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>