as they both interact with the tty code (!MPSAFE) and may sleep if the
tty buffer is full (per comment).
Modify all consumers of uprintf() and tprintf() to hold Giant around
calls into these functions. In most cases, this means adding an
acquisition of Giant immediately around the function. In some cases
(nfs_timer()), it means acquiring Giant higher up in the callout.
With these changes, UFS no longer panics on SMP when either blocks are
exhausted or inodes are exhausted under load due to races in the tty
code when running without Giant.
NB: Some reduction in calls to uprintf() in the svr4 code is probably
desirable.
NB: In the case of nfs_timer(), calling uprintf() while holding a mutex,
or even in a callout at all, is a bad idea, and will generate warnings
and potential upset. This needs to be fixed, but was a problem before
this change.
NB: uprintf()/tprintf() sleeping is generally a bad ideas, as is having
non-MPSAFE tty code.
MFC after: 1 week
writers that want to extend the file. It was also used to serialize
readers that might want to read the last block of the file (with a
writer extending the file). Now that we support vnode locking for
NFS, the rslock is unnecessary. Writers grab the exclusive vnode
lock before writing and readers grab the shared (or in some cases
the exclusive) lock.
Submitted by: Mohan Srinivasan
- Fix nfsm_disct() so that after pulling up data, the remaining data
is aligned if necessary.
- Fix nfs_clnt_tcp_soupcall() to bcopy() the rpc length out of the
mbuf (instead of casting m_data to a uint32).
Submitted by: Pyun YongHyeon
Reviewed by: Mohan Srinivasan
pending discussion of how implementation would proceed. Applications
like -lc_r expect select(3) to match the EAGAIN-status of IO
functions.
Approved by: re
atomic write request, it can fill the buffer cache with the entirety
of that write in order to handle retries. However, it never drops
the vnode lock, or else it wouldn't be atomic, so it ends up waiting
indefinitely for more buf memory that cannot be gotten as it has it
all, and it waits in an uncancellable state.
To fix this, hibufspace is exported and scaled to a reasonable
fraction. This is used as the limit of how much of an atomic write
request by the NFS client will be handled asynchronously. If the
request is larger than this, it will be turned into a synchronous
request which won't deadlock the system. It's possible this value is
far off from what is required by some, so it shall be tunable as soon
as mount_nfs(8) learns of the new field.
The slowdown between an asynchronous and a synchronous write on NFS
appears to be on the order of 2x-4x.
General nod by: gad
MFC after: 2 weeks
More testing: wes
PR: kern/79208
re-sent instead of timing out.
don't log an error message on reconnection, which is not an error.
remove unused nfs_mrep_before_tsleep.
Reviewed by: Mohan Srinivasan
Approved by: alfred
as they have no connection with the expected MNT_* flags. This bug
was exposed 18 months ago when the assignments to f_flags in
vfs_syscalls.c were moved to before the VFS_STATFS() call. It was
fixed in the CSRG source 10 years ago, but we never picked up that
change.
PR: kern/80390
MFC after: 1 week
the MNT_RDONLY flag if the "ro" option was passed in from userland, and
clears it otherwise. In the diskless case, the MNT_RDONLY flag is already
set when this code is reached, but there are no mount options, so it was
incorrectly cleared. Change the logic so the MNT_RDONLY flag is set if the
"ro" option was specified, and left alone otherwise.
Note that the NFS code will still happily let you mount a filesystem RW
even if the server exports it RO. I'm not sure how to fix that.
- Network filesystems are written with a special idiom that checks the
cache first, and may even unlock dvp before discovering that a network
round-trip is required to resolve the name. I believe dvp is prevented
from being recycled even in the forced unmount case by the shared lock
on the mount point. If not, this code should grow checks for VI_DOOMED
after it relocks dvp or it will access NULL v_data fields.
Sponsored by: Isilon Systems, Inc.
these filesystems will support shared locks until they are explicitly
modified to do so. Careful review must be done to ensure that this
is safe for each individual filesystem.
Sponsored by: Isilon Systems, Inc.
non-maskable).
- The NFS client needs to guard against spurious wakeups
while waiting for the response. ltrace causes the process
under question to wakeup (possibly from ptrace()), which
causes NFS to wakeup from tsleep without the response being
delivered.
Submitted by: Mohan Srinivasan
that NFS ever started using it. Long time ago I added the necessary
vhold()/vdrop() calls to replace it, but forgot to remove the v_id code.
Do it now.
patch from kan@).
Pull bufobj_invalbuf() out of vinvalbuf() and make g_vfs call it on
close. This is not yet a generally safe function, but for this very
specific use it is safe. This solves the problem with buffers not
being flushed by unmount or after failed mount attempts.
and tweaks. The code was actually quite broken because it discarded the
upper bits of the 64 bit division. We only had a 50% chance of scaling up
the blocksize for large NFS client mounts when it was needed. For 5.x and
beyond, this was harmless because we could represent the result in either
case. For 4.x this was a big problem though. (4.x also has a df(1) bug to
compound the problem)
I'm not sure why a credential was added to these in the first place, it is
not used anywhere and it doesn't make much sense:
The credentials for syncing a file (ability to write to the
file) should be checked at the system call level.
Credentials for syncing one or more filesystems ("none")
should be checked at the system call level as well.
If the filesystem implementation needs a particular credential
to carry out the syncing it would logically have to the
cached mount credential, or a credential cached along with
any delayed write data.
Discussed with: rwatson
and if the client (erroneously) reads the RPC length as 0 bytes, the
client can loop around in the socket callback. Explicitly check for
the length being 0 case and teardown/re-connect.
Submitted by: Mohan Srinivasan
of sillyrenames (which were limited to 58 per pid per directory,
for no good reason). The new format of sillyrenames looks like
.nfs.0000b31a.00d24.4
^^^^^^^^ ^^^^^
ticks pid
Submitted by: Mohan Srinivasan mohans at yahoo-inc dot com
Obtained from: Yahoo!
