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2020-06-11NFS: Add a tracepoint in nfs_set_pgio_error()Chuck Lever1-0/+44
Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
2020-06-11NFS: Trace short NFS READsChuck Lever1-0/+47
A short read can generate an -EIO error without there being an error on the wire. This tracepoint acts as an eyecatcher when there is no obvious I/O error. Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
2020-06-11NFS: nfs_xdr_status should record the procedure nameChuck Lever1-2/+13
When sunrpc trace points are not enabled, the recorded task ID information alone is not helpful. Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
2020-04-06NFS: Clean up process of marking inode stale.Trond Myklebust1-0/+1
Instead of the various open coded calls to set the NFS_INO_STALE bit and call nfs_zap_caches(), consolidate them into a single function nfs_set_inode_stale(). Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
2020-02-07Merge tag 'nfs-for-5.6-1' of git://git.linux-nfs.org/projects/anna/linux-nfsLinus Torvalds1-73/+206
Puyll NFS client updates from Anna Schumaker: "Stable bugfixes: - Fix memory leaks and corruption in readdir # v2.6.37+ - Directory page cache needs to be locked when read # v2.6.37+ New features: - Convert NFS to use the new mount API - Add "softreval" mount option to let clients use cache if server goes down - Add a config option to compile without UDP support - Limit the number of inactive delegations the client can cache at once - Improved readdir concurrency using iterate_shared() Other bugfixes and cleanups: - More 64-bit time conversions - Add additional diagnostic tracepoints - Check for holes in swapfiles, and add dependency on CONFIG_SWAP - Various xprtrdma cleanups to prepare for 5.7's changes - Several fixes for NFS writeback and commit handling - Fix acls over krb5i/krb5p mounts - Recover from premature loss of openstateids - Fix NFS v3 chacl and chmod bug - Compare creds using cred_fscmp() - Use kmemdup_nul() in more places - Optimize readdir cache page invalidation - Lease renewal and recovery fixes" * tag 'nfs-for-5.6-1' of git://git.linux-nfs.org/projects/anna/linux-nfs: (93 commits) NFSv4.0: nfs4_do_fsinfo() should not do implicit lease renewals NFSv4: try lease recovery on NFS4ERR_EXPIRED NFS: Fix memory leaks nfs: optimise readdir cache page invalidation NFS: Switch readdir to using iterate_shared() NFS: Use kmemdup_nul() in nfs_readdir_make_qstr() NFS: Directory page cache pages need to be locked when read NFS: Fix memory leaks and corruption in readdir SUNRPC: Use kmemdup_nul() in rpc_parse_scope_id() NFS: Replace various occurrences of kstrndup() with kmemdup_nul() NFSv4: Limit the total number of cached delegations NFSv4: Add accounting for the number of active delegations held NFSv4: Try to return the delegation immediately when marked for return on close NFS: Clear NFS_DELEGATION_RETURN_IF_CLOSED when the delegation is returned NFSv4: nfs_inode_evict_delegation() should set NFS_DELEGATION_RETURNING NFS: nfs_find_open_context() should use cred_fscmp() NFS: nfs_access_get_cached_rcu() should use cred_fscmp() NFSv4: pnfs_roc() must use cred_fscmp() to compare creds NFS: remove unused macros nfs: Return EINVAL rather than ERANGE for mount parse errors ...
2020-01-15NFS: Improve tracing of permission callsTrond Myklebust1-1/+60
On exit from nfs_do_access(), record the mask representing the requested permissions, as well as the server-supplied set of access rights for this user. Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com> Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
2020-01-15NFS: Clean up generic file commit tracepointTrond Myklebust1-16/+26
Clean up the generic file commit tracepoints to use a 64-bit value for the verifier, and to display the pNFS filehandle, if it exists. Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com> Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
2020-01-15NFS: Clean up generic writeback tracepointsTrond Myklebust1-32/+41
Clean up the generic writeback tracepoints so they do pass the full structures as arguments. Also ensure we report the number of bytes actually written. Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com> Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
2020-01-15NFS: Clean up generic file read tracepointsTrond Myklebust1-23/+33
Clean up the generic file read tracepoints so they do pass the full structures as arguments. Also ensure we report the number of bytes actually read. Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com> Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
2020-01-15NFS: Introduce trace events triggered by page writeback errorsChuck Lever1-0/+45
Try to capture the reason for the writeback path tagging an error on a page. Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
2020-01-15reimplement path_mountpoint() with less magicAl Viro1-2/+0
... and get rid of a bunch of bugs in it. Background: the reason for path_mountpoint() is that umount() really doesn't want attempts to revalidate the root of what it's trying to umount. The thing we want to avoid actually happen from complete_walk(); solution was to do something parallel to normal path_lookupat() and it both went overboard and got the boilerplate subtly (and not so subtly) wrong. A better solution is to do pretty much what the normal path_lookupat() does, but instead of complete_walk() do unlazy_walk(). All it takes to avoid that ->d_weak_revalidate() call... mountpoint_last() goes away, along with everything it got wrong, and so does the magic around LOOKUP_NO_REVAL. Another source of bugs is that when we traverse mounts at the final location (and we need to do that - umount . expects to get whatever's overmounting ., if any, out of the lookup) we really ought to take care of ->d_manage() - as it is, manual umount of autofs automount in progress can lead to unpleasant surprises for the daemon. Easily solved by using handle_lookup_down() instead of follow_mount(). Tested-by: Ian Kent <raven@themaw.net> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2019-11-03NFS: Add a tracepoint in nfs_fh_to_dentry()Trond Myklebust1-0/+33
Add a tracepoint in nfs_fh_to_dentry() for debugging issues with bad userspace filehandles. Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
2019-08-30kill LOOKUP_NO_EVAL, don't bother including namei.h from audit.hAl Viro1-2/+0
The former has no users left; the latter was only to get LOOKUP_... values to remapper in audit_inode() and that's an ex-parrot now. All places that use symbols from namei.h include it either directly or (in a few cases) via a local header, like fs/autofs/autofs_i.h Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2019-07-09NFS: Record task, client ID, and XID in xdr_status trace pointsChuck Lever1-2/+13
When triggering an nfs_xdr_status trace point, record the task ID and XID of the failing RPC to better pinpoint the problem. This feels like a bit of a layering violation. Suggested-by: Trond Myklebust <trondmy@hammerspace.com> Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
2019-07-09NFS: Update symbolic flags displayed by trace eventsChuck Lever1-26/+124
Add missing symbolic flag names and display flags variables in hexadecimal to improve observability. Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
2019-07-09NFS: Display symbolic status code names in trace logChuck Lever1-35/+41
For improved readability, add nfs_show_status() call-sites in the generic NFS trace points so that the symbolic status code name is displayed. Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
2019-02-13NFS: Add trace events to report non-zero NFS status codesChuck Lever1-0/+85
These can help field troubleshooting without needing the overhead of a full network capture (ie, tcpdump). Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
2018-01-30Merge tag 'nfs-for-4.16-1' of git://git.linux-nfs.org/projects/trondmy/linux-nfsLinus Torvalds1-11/+11
Pull NFS client updates from Trond Myklebust: "Highlights include: Stable bugfixes: - Fix breakages in the nfsstat utility due to the inclusion of the NFSv4 LOOKUPP operation - Fix a NULL pointer dereference in nfs_idmap_prepare_pipe_upcall() due to nfs_idmap_legacy_upcall() being called without an 'aux' parameter - Fix a refcount leak in the standard O_DIRECT error path - Fix a refcount leak in the pNFS O_DIRECT fallback to MDS path - Fix CPU latency issues with nfs_commit_release_pages() - Fix the LAYOUTUNAVAILABLE error case in the file layout type - NFS: Fix a race between mmap() and O_DIRECT Features: - Support the statx() mask and query flags to enable optimisations when the user is requesting only attributes that are already up to date in the inode cache, or is specifying the AT_STATX_DONT_SYNC flag - Add a module alias for the SCSI pNFS layout type Bugfixes: - Automounting when resolving a NFSv4 referral should preserve the RDMA transport protocol settings - Various other RDMA bugfixes from Chuck - pNFS block layout fixes - Always set NFS_LOCK_LOST when a lock is lost" * tag 'nfs-for-4.16-1' of git://git.linux-nfs.org/projects/trondmy/linux-nfs: (69 commits) NFS: Fix a race between mmap() and O_DIRECT NFS: Remove a redundant call to unmap_mapping_range() pnfs/blocklayout: Ensure disk address in block device map pnfs/blocklayout: pnfs_block_dev_map uses bytes, not sectors lockd: Fix server refcounting SUNRPC: Fix null rpc_clnt dereference in rpc_task_queued tracepoint SUNRPC: Micro-optimize __rpc_execute SUNRPC: task_run_action should display tk_callback sunrpc: Format RPC events consistently for display SUNRPC: Trace xprt_timer events xprtrdma: Correct some documenting comments xprtrdma: Fix "bytes registered" accounting xprtrdma: Instrument allocation/release of rpcrdma_req/rep objects xprtrdma: Add trace points to instrument QP and CQ access upcalls xprtrdma: Add trace points in the client-side backchannel code paths xprtrdma: Add trace points for connect events xprtrdma: Add trace points to instrument MR allocation and recovery xprtrdma: Add trace points to instrument memory invalidation xprtrdma: Add trace points in reply decoder path xprtrdma: Add trace points to instrument memory registration ..
2018-01-29nfs: convert to new i_version APIJeff Layton1-2/+3
For NFS, we just use the "raw" API since the i_version is mostly managed by the server. The exception there is when the client holds a write delegation, but we only need to bump it once there anyway to handle CB_GETATTR. Tested-by: Krzysztof Kozlowski <krzk@kernel.org> Signed-off-by: Jeff Layton <jlayton@redhat.com>
2018-01-18nfs: Use proper enum definitions for nfs_show_stableChuck Lever1-11/+11
Commit 8224b2734ab1 ("NFS: Add static NFS I/O tracepoints") had a hack to work around some odd behavior observed with __print_symbolic. I couldn't ever get it to display NFS_FILE_SYNC when using TRACE_DEFINE_ENUM macros to set up the enum values. I tracked down the actual bug that forced me to add the workaround. That issue will be addressed soon, so replace the hack with a proper implementation. Fixes: 8224b2734ab1 ("NFS: Add static NFS I/O tracepoints") Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
2017-11-02License cleanup: add SPDX GPL-2.0 license identifier to files with no licenseGreg Kroah-Hartman1-0/+1
Many source files in the tree are missing licensing information, which makes it harder for compliance tools to determine the correct license. By default all files without license information are under the default license of the kernel, which is GPL version 2. Update the files which contain no license information with the 'GPL-2.0' SPDX license identifier. The SPDX identifier is a legally binding shorthand, which can be used instead of the full boiler plate text. This patch is based on work done by Thomas Gleixner and Kate Stewart and Philippe Ombredanne. How this work was done: Patches were generated and checked against linux-4.14-rc6 for a subset of the use cases: - file had no licensing information it it. - file was a */uapi/* one with no licensing information in it, - file was a */uapi/* one with existing licensing information, Further patches will be generated in subsequent months to fix up cases where non-standard license headers were used, and references to license had to be inferred by heuristics based on keywords. The analysis to determine which SPDX License Identifier to be applied to a file was done in a spreadsheet of side by side results from of the output of two independent scanners (ScanCode & Windriver) producing SPDX tag:value files created by Philippe Ombredanne. Philippe prepared the base worksheet, and did an initial spot review of a few 1000 files. The 4.13 kernel was the starting point of the analysis with 60,537 files assessed. Kate Stewart did a file by file comparison of the scanner results in the spreadsheet to determine which SPDX license identifier(s) to be applied to the file. She confirmed any determination that was not immediately clear with lawyers working with the Linux Foundation. Criteria used to select files for SPDX license identifier tagging was: - Files considered eligible had to be source code files. - Make and config files were included as candidates if they contained >5 lines of source - File already had some variant of a license header in it (even if <5 lines). All documentation files were explicitly excluded. The following heuristics were used to determine which SPDX license identifiers to apply. - when both scanners couldn't find any license traces, file was considered to have no license information in it, and the top level COPYING file license applied. For non */uapi/* files that summary was: SPDX license identifier # files ---------------------------------------------------|------- GPL-2.0 11139 and resulted in the first patch in this series. If that file was a */uapi/* path one, it was "GPL-2.0 WITH Linux-syscall-note" otherwise it was "GPL-2.0". Results of that was: SPDX license identifier # files ---------------------------------------------------|------- GPL-2.0 WITH Linux-syscall-note 930 and resulted in the second patch in this series. - if a file had some form of licensing information in it, and was one of the */uapi/* ones, it was denoted with the Linux-syscall-note if any GPL family license was found in the file or had no licensing in it (per prior point). Results summary: SPDX license identifier # files ---------------------------------------------------|------ GPL-2.0 WITH Linux-syscall-note 270 GPL-2.0+ WITH Linux-syscall-note 169 ((GPL-2.0 WITH Linux-syscall-note) OR BSD-2-Clause) 21 ((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause) 17 LGPL-2.1+ WITH Linux-syscall-note 15 GPL-1.0+ WITH Linux-syscall-note 14 ((GPL-2.0+ WITH Linux-syscall-note) OR BSD-3-Clause) 5 LGPL-2.0+ WITH Linux-syscall-note 4 LGPL-2.1 WITH Linux-syscall-note 3 ((GPL-2.0 WITH Linux-syscall-note) OR MIT) 3 ((GPL-2.0 WITH Linux-syscall-note) AND MIT) 1 and that resulted in the third patch in this series. - when the two scanners agreed on the detected license(s), that became the concluded license(s). - when there was disagreement between the two scanners (one detected a license but the other didn't, or they both detected different licenses) a manual inspection of the file occurred. - In most cases a manual inspection of the information in the file resulted in a clear resolution of the license that should apply (and which scanner probably needed to revisit its heuristics). - When it was not immediately clear, the license identifier was confirmed with lawyers working with the Linux Foundation. - If there was any question as to the appropriate license identifier, the file was flagged for further research and to be revisited later in time. In total, over 70 hours of logged manual review was done on the spreadsheet to determine the SPDX license identifiers to apply to the source files by Kate, Philippe, Thomas and, in some cases, confirmation by lawyers working with the Linux Foundation. Kate also obtained a third independent scan of the 4.13 code base from FOSSology, and compared selected files where the other two scanners disagreed against that SPDX file, to see if there was new insights. The Windriver scanner is based on an older version of FOSSology in part, so they are related. Thomas did random spot checks in about 500 files from the spreadsheets for the uapi headers and agreed with SPDX license identifier in the files he inspected. For the non-uapi files Thomas did random spot checks in about 15000 files. In initial set of patches against 4.14-rc6, 3 files were found to have copy/paste license identifier errors, and have been fixed to reflect the correct identifier. Additionally Philippe spent 10 hours this week doing a detailed manual inspection and review of the 12,461 patched files from the initial patch version early this week with: - a full scancode scan run, collecting the matched texts, detected license ids and scores - reviewing anything where there was a license detected (about 500+ files) to ensure that the applied SPDX license was correct - reviewing anything where there was no detection but the patch license was not GPL-2.0 WITH Linux-syscall-note to ensure that the applied SPDX license was correct This produced a worksheet with 20 files needing minor correction. This worksheet was then exported into 3 different .csv files for the different types of files to be modified. These .csv files were then reviewed by Greg. Thomas wrote a script to parse the csv files and add the proper SPDX tag to the file, in the format that the file expected. This script was further refined by Greg based on the output to detect more types of files automatically and to distinguish between header and source .c files (which need different comment types.) Finally Greg ran the script using the .csv files to generate the patches. Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org> Reviewed-by: Philippe Ombredanne <pombredanne@nexb.com> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-09-11NFS: Add static NFS I/O tracepointsChuck Lever1-0/+248
Tools like tcpdump and rpcdebug can be very useful. But there are plenty of environments where they are difficult or impossible to use. For example, we've had customers report I/O failures during workloads so heavy that collecting network traffic or enabling RPC debugging are themselves onerous. The kernel's static tracepoints are lightweight (less likely to introduce timing changes) and efficient (the trace data is compact). They also work in scenarios where capturing network traffic is not possible due to lack of hardware support (some InfiniBand HCAs) or where data or network privacy is a concern. Introduce tracepoints that show when an NFS READ, WRITE, or COMMIT is initiated, and when it completes. Record the arguments and results of each operation, which are not shown by existing sunrpc module's tracepoints. For instance, the recorded offset and count can be used to match an "initiate" event to a "done" event. If an NFS READ result returns fewer bytes than requested or zero, seeing the EOF flag can be probative. Seeing an NFS4ERR_BAD_STATEID result is also indication of a particular class of problems. The timing information attached to each event record can often be useful as well. Usage example: [root@manet tmp]# trace-cmd record -e nfs:*initiate* -e nfs:*done /sys/kernel/debug/tracing/events/nfs/*initiate*/filter /sys/kernel/debug/tracing/events/nfs/*done/filter Hit Ctrl^C to stop recording ^CKernel buffer statistics: Note: "entries" are the entries left in the kernel ring buffer and are not recorded in the trace data. They should all be zero. CPU: 0 entries: 0 overrun: 0 commit overrun: 0 bytes: 3680 oldest event ts: 78.367422 now ts: 100.124419 dropped events: 0 read events: 74 ... and so on. Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
2016-07-30Merge tag 'nfs-for-4.8-1' of git://git.linux-nfs.org/projects/trondmy/linux-nfsLinus Torvalds1-1/+0
Pull NFS client updates from Trond Myklebust: "Highlights include: Stable bugfixes: - nfs: don't create zero-length requests - several LAYOUTGET bugfixes Features: - several performance related features - more aggressive caching when we can rely on close-to-open cache consistency - remove serialisation of O_DIRECT reads and writes - optimise several code paths to not flush to disk unnecessarily. However allow for the idiosyncracies of pNFS for those layout types that need to issue a LAYOUTCOMMIT before the metadata can be updated on the server. - SUNRPC updates to the client data receive path - pNFS/SCSI support RH/Fedora dm-mpath device nodes - pNFS files/flexfiles can now use unprivileged ports when the generic NFS mount options allow it. Bugfixes: - Don't use RDMA direct data placement together with data integrity or privacy security flavours - Remove the RDMA ALLPHYSICAL memory registration mode as it has potential security holes. - Several layout recall fixes to improve NFSv4.1 protocol compliance. - Fix an Oops in the pNFS files and flexfiles connection setup to the DS - Allow retry of operations that used a returned delegation stateid - Don't mark the inode as revalidated if a LAYOUTCOMMIT is outstanding - Fix writeback races in nfs4_copy_range() and nfs42_proc_deallocate()" * tag 'nfs-for-4.8-1' of git://git.linux-nfs.org/projects/trondmy/linux-nfs: (104 commits) pNFS: Actively set attributes as invalid if LAYOUTCOMMIT is outstanding NFSv4: Clean up lookup of SECINFO_NO_NAME NFSv4.2: Fix warning "variable ‘stateids’ set but not used" NFSv4: Fix warning "no previous prototype for ‘nfs4_listxattr’" SUNRPC: Fix a compiler warning in fs/nfs/clnt.c pNFS: Remove redundant smp_mb() from pnfs_init_lseg() pNFS: Cleanup - do layout segment initialisation in one place pNFS: Remove redundant stateid invalidation pNFS: Remove redundant pnfs_mark_layout_returned_if_empty() pNFS: Clear the layout metadata if the server changed the layout stateid pNFS: Cleanup - don't open code pnfs_mark_layout_stateid_invalid() NFS: pnfs_mark_matching_lsegs_return() should match the layout sequence id pNFS: Do not set plh_return_seq for non-callback related layoutreturns pNFS: Ensure layoutreturn acts as a completion for layout callbacks pNFS: Fix CB_LAYOUTRECALL stateid verification pNFS: Always update the layout barrier seqid on LAYOUTGET pNFS: Always update the layout stateid if NFS_LAYOUT_INVALID_STID is set pNFS: Clear the layout return tracking on layout reinitialisation pNFS: LAYOUTRETURN should only update the stateid if the layout is valid nfs: don't create zero-length requests ...
2016-07-15tracing: Use __get_str() when manipulating stringsDaniel Bristot de Oliveira1-2/+2
Use __get_str(str) rather than __get_dynamic_array(str) when deadling with strings. It is just a code cleanup, no changes on tracepoint ABI. Link: http://lkml.kernel.org/r/ea260df91817411cca2a1f3db2abd88860094788.1467407618.git.bristot@redhat.com Cc: Trond Myklebust <trond.myklebust@primarydata.com> Cc: Anna Schumaker <anna.schumaker@netapp.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: linux-nfs@vger.kernel.org Suggested-by: Steven Rostedt <rostedt@goodmis.org> Reviewed-by: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Daniel Bristot de Oliveira <bristot@redhat.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2016-06-22NFS: Kill NFS_INO_NFS_INO_FLUSHING: it is a performance killerTrond Myklebust1-1/+0
filemap_datawrite() and friends already deal just fine with livelock. Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
2016-05-09nfs: per-name sillyunlink exclusionAl Viro1-1/+1
use d_alloc_parallel() for sillyunlink/lookup exclusion and explicit rwsem (nfs_rmdir() being a writer and nfs_call_unlink() - a reader) for rmdir/sillyunlink one. That ought to make lookup/readdir/!O_CREAT atomic_open really parallel on NFS. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2015-12-31NFS: Allow multiple commit requests in flight per fileTrond Myklebust1-1/+0
Allow synchronous RPC calls to wait for pending RPC calls to finish, but also allow asynchronous ones to just fire off another commit. With this patch, the xfstests generic/074 test completes in 226s instead of 242s Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
2014-01-27NFS: fix the handling of NFS_INO_INVALID_DATA flag in nfs_revalidate_mappingJeff Layton1-0/+1
There is a possible race in how the nfs_invalidate_mapping function is handled. Currently, we go and invalidate the pages in the file and then clear NFS_INO_INVALID_DATA. The problem is that it's possible for a stale page to creep into the mapping after the page was invalidated (i.e., via readahead). If another writer comes along and sets the flag after that happens but before invalidate_inode_pages2 returns then we could clear the flag without the cache having been properly invalidated. So, we must clear the flag first and then invalidate the pages. Doing this however, opens another race: It's possible to have two concurrent read() calls that end up in nfs_revalidate_mapping at the same time. The first one clears the NFS_INO_INVALID_DATA flag and then goes to call nfs_invalidate_mapping. Just before calling that though, the other task races in, checks the flag and finds it cleared. At that point, it trusts that the mapping is good and gets the lock on the page, allowing the read() to be satisfied from the cache even though the data is no longer valid. These effects are easily manifested by running diotest3 from the LTP test suite on NFS. That program does a series of DIO writes and buffered reads. The operations are serialized and page-aligned but the existing code fails the test since it occasionally allows a read to come out of the cache incorrectly. While mixing direct and buffered I/O isn't recommended, I believe it's possible to hit this in other ways that just use buffered I/O, though that situation is much harder to reproduce. The problem is that the checking/clearing of that flag and the invalidation of the mapping really need to be atomic. Fix this by serializing concurrent invalidations with a bitlock. At the same time, we also need to allow other places that check NFS_INO_INVALID_DATA to check whether we might be in the middle of invalidating the file, so fix up a couple of places that do that to look for the new NFS_INO_INVALIDATING flag. Doing this requires us to be careful not to set the bitlock unnecessarily, so this code only does that if it believes it will be doing an invalidation. Signed-off-by: Jeff Layton <jlayton@redhat.com> Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
2013-08-22NFS: Add tracepoints for debugging NFS hard linksTrond Myklebust1-0/+70
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2013-08-22NFS: Add tracepoints for debugging NFS rename and sillyrename issuesTrond Myklebust1-0/+138
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2013-08-22NFS: Add tracepoints for debugging directory changesTrond Myklebust1-0/+90
Add tracepoints for mknod, mkdir, rmdir, remove (unlink) and symlink. Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2013-08-22NFS: Add tracepoints for debugging generic file create eventsTrond Myklebust1-0/+70
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2013-08-22NFS: Add event tracing for generic NFS lookupsTrond Myklebust1-0/+195
Add tracepoints for lookup, lookup_revalidate and atomic_open Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2013-08-22NFS: Add event tracing for generic NFS eventsTrond Myklebust1-0/+166
Add tracepoints for inode attribute updates, attribute revalidation, writeback start/end fsync start/end, attribute change start/end, permission check start/end. The intention is to enable performance tracing using 'perf'as well as improving debugging. Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>