kernel/fs/nfsd, branch linux-5.1.y

nfsd: Fix overflow causing non-working mounts on 1 TB machines

2019-07-10T07:52:31Z

commit 3b2d4dcf71c4a91b420f835e52ddea8192300a3b upstream. Since commit 10a68cdf10 (nfsd: fix performance-limiting session calculation) (Linux 5.1-rc1 and 4.19.31), shares from NFS servers with 1 TB of memory cannot be mounted anymore. The mount just hangs on the client. The gist of commit 10a68cdf10 is the change below. -avail = clamp_t(int, avail, slotsize, avail/3); +avail = clamp_t(int, avail, slotsize, total_avail/3); Here are the macros. #define min_t(type, x, y) __careful_cmp((type)(x), (type)(y), <) #define clamp_t(type, val, lo, hi) min_t(type, max_t(type, val, lo), hi) `total_avail` is 8,434,659,328 on the 1 TB machine. `clamp_t()` casts the values to `int`, which for 32-bit integers can only hold values −2,147,483,648 (−2^31) through 2,147,483,647 (2^31 − 1). `avail` (in the function signature) is just 65536, so that no overflow was happening. Before the commit the assignment would result in 21845, and `num = 4`. When using `total_avail`, it is causing the assignment to be 18446744072226137429 (printed as %lu), and `num` is then 4164608182. My next guess is, that `nfsd_drc_mem_used` is then exceeded, and the server thinks there is no memory available any more for this client. Updating the arguments of `clamp_t()` and `min_t()` to `unsigned long` fixes the issue. Now, `avail = 65536` (before commit 10a68cdf10 `avail = 21845`), but `num = 4` remains the same. Fixes: c54f24e338ed (nfsd: fix performance-limiting session calculation) Cc: stable@vger.kernel.org Signed-off-by: Paul Menzel Signed-off-by: J. Bruce Fields Signed-off-by: Greg Kroah-Hartman

nfsd: avoid uninitialized variable warning

2019-06-15T09:53:00Z

[ Upstream commit 0ab88ca4bcf18ba21058d8f19220f60afe0d34d8 ] clang warns that 'contextlen' may be accessed without an initialization: fs/nfsd/nfs4xdr.c:2911:9: error: variable 'contextlen' is uninitialized when used here [-Werror,-Wuninitialized] contextlen); ^~~~~~~~~~ fs/nfsd/nfs4xdr.c:2424:16: note: initialize the variable 'contextlen' to silence this warning int contextlen; ^ = 0 Presumably this cannot happen, as FATTR4_WORD2_SECURITY_LABEL is set if CONFIG_NFSD_V4_SECURITY_LABEL is enabled. Adding another #ifdef like the other two in this function avoids the warning. Signed-off-by: Arnd Bergmann Signed-off-by: J. Bruce Fields Signed-off-by: Sasha Levin

nfsd: allow fh_want_write to be called twice

2019-06-15T09:53:00Z

[ Upstream commit 0b8f62625dc309651d0efcb6a6247c933acd8b45 ] A fuzzer recently triggered lockdep warnings about potential sb_writers deadlocks caused by fh_want_write(). Looks like we aren't careful to pair each fh_want_write() with an fh_drop_write(). It's not normally a problem since fh_put() will call fh_drop_write() for us. And was OK for NFSv3 where we'd do one operation that might call fh_want_write(), and then put the filehandle. But an NFSv4 protocol fuzzer can do weird things like call unlink twice in a compound, and then we get into trouble. I'm a little worried about this approach of just leaving everything to fh_put(). But I think there are probably a lot of fh_want_write()/fh_drop_write() imbalances so for now I think we need it to be more forgiving. Signed-off-by: J. Bruce Fields Signed-off-by: Sasha Levin

nfsd: wake blocked file lock waiters before sending callback

2019-04-22T19:38:41Z

When a blocked NFS lock is "awoken" we send a callback to the server and then wake any hosts waiting on it. If a client attempts to get a lock and then drops off the net, we could end up waiting for a long time until we end up waking locks blocked on that request. So, wake any other waiting lock requests before sending the callback. Do this by calling locks_delete_block in a new "prepare" phase for CB_NOTIFY_LOCK callbacks. URL: https://bugzilla.kernel.org/show_bug.cgi?id=203363 Fixes: 16306a61d3b7 ("fs/locks: always delete_block after waiting.") Reported-by: Slawomir Pryczek Cc: Neil Brown Cc: stable@vger.kernel.org Signed-off-by: Jeff Layton Signed-off-by: J. Bruce Fields

nfsd: wake waiters blocked on file_lock before deleting it

2019-04-22T19:31:54Z

After a blocked nfsd file_lock request is deleted, knfsd will send a callback to the client and then free the request. Commit 16306a61d3b7 ("fs/locks: always delete_block after waiting.") changed it such that locks_delete_block is always called on a request after it is awoken, but that patch missed fixing up blocked nfsd request handling. Call locks_delete_block on the block to wake up any locks still blocked on the nfsd lock request before freeing it. Some of its callers already do this however, so just remove those calls. URL: https://bugzilla.kernel.org/show_bug.cgi?id=203363 Fixes: 16306a61d3b7 ("fs/locks: always delete_block after waiting.") Reported-by: Slawomir Pryczek Cc: Neil Brown Cc: stable@vger.kernel.org Signed-off-by: Jeff Layton Signed-off-by: J. Bruce Fields

nfsd: Don't release the callback slot unless it was actually held

2019-04-08T16:43:15Z

If there are multiple callbacks queued, waiting for the callback slot when the callback gets shut down, then they all currently end up acting as if they hold the slot, and call nfsd4_cb_sequence_done() resulting in interesting side-effects. In addition, the 'retry_nowait' path in nfsd4_cb_sequence_done() causes a loop back to nfsd4_cb_prepare() without first freeing the slot, which causes a deadlock when nfsd41_cb_get_slot() gets called a second time. This patch therefore adds a boolean to track whether or not the callback did pick up the slot, so that it can do the right thing in these 2 cases. Cc: stable@vger.kernel.org Signed-off-by: Trond Myklebust Signed-off-by: J. Bruce Fields

nfsd/nfsd3_proc_readdir: fix buffer count and page pointers

2019-04-05T23:57:24Z

After this commit f875a79 nfsd: allow nfsv3 readdir request to be larger. nfsv3 readdir request size can be larger than PAGE_SIZE. So if the directory been read is large enough, we can use multiple pages in rq_respages. Update buffer count and page pointers like we do in readdirplus to make this happen. Now listing a directory within 3000 files will panic because we are counting in a wrong way and would write on random page. Fixes: f875a79 "nfsd: allow nfsv3 readdir request to be larger" Signed-off-by: Murphy Zhou Signed-off-by: J. Bruce Fields

Merge tag 'nfsd-5.1' of git://linux-nfs.org/~bfields/linux

2019-03-12T22:06:54Z

Pull NFS server updates from Bruce Fields: "Miscellaneous NFS server fixes. Probably the most visible bug is one that could artificially limit NFSv4.1 performance by limiting the number of oustanding rpcs from a single client. Neil Brown also gets a special mention for fixing a 14.5-year-old memory-corruption bug in the encoding of NFSv3 readdir responses" * tag 'nfsd-5.1' of git://linux-nfs.org/~bfields/linux: nfsd: allow nfsv3 readdir request to be larger. nfsd: fix wrong check in write_v4_end_grace() nfsd: fix memory corruption caused by readdir nfsd: fix performance-limiting session calculation svcrpc: fix UDP on servers with lots of threads svcrdma: Remove syslog warnings in work completion handlers svcrdma: Squelch compiler warning when SUNRPC_DEBUG is disabled svcrdma: Use struct_size() in kmalloc() svcrpc: fix unlikely races preventing queueing of sockets svcrpc: svc_xprt_has_something_to_do seems a little long SUNRPC: Don't allow compiler optimisation of svc_xprt_release_slot() nfsd: fix an IS_ERR() vs NULL check

nfsd: allow nfsv3 readdir request to be larger.

2019-03-08T19:30:31Z

nfsd currently reports the NFSv3 dtpref FSINFO parameter to be PAGE_SIZE, so NFS clients will typically ask for one page of directory entries at a time. This is needlessly restrictive as nfsd can handle larger replies easily. Also, a READDIR request (but not a READDIRPLUS request) has the count size clipped to PAGE_SIE, again unnecessary. This patch lifts these limits so that larger readdir requests can be used. Signed-off-by: NeilBrown Signed-off-by: J. Bruce Fields

nfsd: fix wrong check in write_v4_end_grace()

2019-03-06T14:58:20Z

Commit 62a063b8e7d1 "nfsd4: fix crash on writing v4_end_grace before nfsd startup" is trying to fix a NULL dereference issue, but it mistakenly checks if the nfsd server is started. So fix it. Fixes: 62a063b8e7d1 "nfsd4: fix crash on writing v4_end_grace before nfsd startup" Cc: stable@vger.kernel.org Reviewed-by: Joseph Qi Signed-off-by: Yihao Wu Signed-off-by: J. Bruce Fields