lookup() and sillyrename() can race one another because the sillyrename()
completion cannot take the parent directory's inode->i_mutex since the
latter may be held by whoever is calling dput().
We therefore have little option but to add extra locking to ensure that
nfs_lookup() and nfs_atomic_open() do not race with the sillyrename
completion.
If somebody has looked up the sillyrenamed file in the meantime, we just
transfer the sillydelete information to the new dentry.
Please refer to the bug-report at
http://bugzilla.linux-nfs.org/show_bug.cgi?id=150
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
This boot parameter will allow legacy 32-bit applications which call stat()
to continue to function even if the NFSv3/v4 server uses 64-bit inode
numbers.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
- NFS_READTIME, NFS_CHANGE_ATTR are completely unused.
- Inline the few remaining uses of NFS_ATTRTIMEO, and remove.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
We don't need to call nfs_revalidate_inode() on the directory if we already
know that the verifiers don't match.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
The lower level routines in fs/nfs/proc.c, fs/nfs/nfs3proc.c and
fs/nfs/nfs4proc.c should already be dealing with the revalidation issues.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
The fact that we're in the process of modifying the inode does not mean
that we should not invalidate the attribute and data caches. The defensive
thing is to always invalidate when we're confronted with inode
mtime/ctime or change_attribute updates that we do not immediately
recognise.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
If the ->lookup() call causes the directory verifier to change, then there
is still no need to use the old verifier, since our dentry has been
verified.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
We don't want to leave an unverified hashed negative dentry if the
exclusive create fails to complete.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
That will also allow us to remove the calls in mknod and mkdir.
In addition it will ensure that symlinks set it correctly.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
We don't care about whether or not some other process on our client is
changing the directory while we're in nfs_lookup_revalidate(), because the
dcache will take care of ensuring local atomicity.
We can therefore remove the test for nfs_caches_unstable().
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
NFSv3 will correctly update atime on a readdir call, so there is no need to
set the NFS_INO_INVALID_ATIME flag unless the call to nfs_refresh_inode()
fails.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
We don't need to force a dentry lookup just because we're making changes to
the directory.
Don't update nfsi->cache_change_attribute in nfs_end_data_update: that
overrides the NFSv3/v4 weak consistency checking that tells us our update
was the only one, and that tells us the dcache is still valid.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Currently, _nfs4_do_access() is just a copy of nfs_do_access() with added
conversion of the open flags into an access mask. This patch merges the
duplicate functionality.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
nfs_set_verifier() and nfs_refresh_verifier() do exactly the same thing, so
replace one with the other.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
The nfs_renew_times() function plants the current time in jiffies in
dentry->d_time. But a call to nfs_renew_times() is always followed by
another call that overwrites dentry->d_time. Get rid of the
nfs_renew_times() calls.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Negative dentries need to be reverified after an asynchronous unlink.
Quoth Trond:
"Unfortunately I don't think that we can avoid revalidating the
resulting negative dentry since the UNLINK call is asynchronous,
and so the new verifier on the directory will only be known a
posteriori."
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
I would like to discuss the idea that the current checks for attribute
timeout using time_after are inadequate for 32bit architectures, since
time_after works correctly only when the two timestamps being compared
are within 2^31 jiffies of each other. The signed overflow caused by
comparing values more than 2^31 jiffies apart will flip the result,
causing incorrect assumptions of validity.
2^31 jiffies is a fairly large period of time (~25 days) when compared
to the lifetime of most kernel data structures, but for long lived NFS
mounts that can sit idle for months (think that for some reason autofs
cannot be used), it is easy to compare inode attribute timestamps with
very disparate or even bogus values (as in when jiffies have wrapped
many times, where the comparison doesn't even make sense).
Currently the code tests for attribute timeout by simply adding the
desired amount of jiffies to the stored timestamp and comparing that
with the current timestamp of obtained attribute data with time_after.
This is incorrect, as it returns true for the desired timeout period
and another full 2^31 range of jiffies.
In testing with artificial jumps (several small jumps, not one big
crank) of the jiffies I was able to reproduce a problem found in a
server with very long lived NFS mounts, where attributes would not be
refreshed even after touching files and directories in the server:
Initial uptime:
03:42:01 up 6 min, 0 users, load average: 0.01, 0.12, 0.07
NFS volume is mounted and time is advanced:
03:38:09 up 25 days, 2 min, 0 users, load average: 1.22, 1.05, 1.08
# ls -l /local/A/foo/bar /nfs/A/foo/bar
-rw-r--r-- 1 root root 0 Dec 17 03:38 /local/A/foo/bar
-rw-r--r-- 1 root root 0 Nov 22 00:36 /nfs/A/foo/bar
# touch /local/A/foo/bar
# ls -l /local/A/foo/bar /nfs/A/foo/bar
-rw-r--r-- 1 root root 0 Dec 17 03:47 /local/A/foo/bar
-rw-r--r-- 1 root root 0 Nov 22 00:36 /nfs/A/foo/bar
We can see the local mtime is updated, but the NFS mount still shows
the old value. The patch below makes it work:
Initial setup...
07:11:02 up 25 days, 1 min, 0 users, load average: 0.15, 0.03, 0.04
# ls -l /local/A/foo/bar /nfs/A/foo/bar
-rw-r--r-- 1 root root 0 Jan 11 07:11 /local/A/foo/bar
-rw-r--r-- 1 root root 0 Jan 11 07:11 /nfs/A/foo/bar
# touch /local/A/foo/bar
# ls -l /local/A/foo/bar /nfs/A/foo/bar
-rw-r--r-- 1 root root 0 Jan 11 07:14 /local/A/foo/bar
-rw-r--r-- 1 root root 0 Jan 11 07:14 /nfs/A/foo/bar
Signed-off-by: Fabio Olive Leite <fleite@redhat.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Hi.
Attached is a patch to modify the NFS client code to support
64 bit ino's, as appropriate for the system and the NFS
protocol version.
The code basically just expand the NFS interfaces for routines
which handle ino's from using ino_t to u64 and then uses the
fileid in the nfs_inode instead of i_ino in the inode. The
code paths that were updated are in the getattr method and
the readdir methods.
This should be no real change on 64 bit platforms. Since
the ino_t is an unsigned long, it would already be 64 bits
wide.
Thanx...
ps
Signed-off-by: Peter Staubach <staubach@redhat.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
It doesn't look as if the NFS file name limit is being initialised correctly
in the struct nfs_server. Make sure that we limit whatever is being set in
nfs_probe_fsinfo() and nfs_init_server().
Also ensure that readdirplus and nfs4_path_walk respect our file name
limits.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Fix a couple of bugs:
- Don't rely on the parent dentry still being valid when the call completes.
Fixes a race with shrink_dcache_for_umount_subtree()
- Don't remove the file if the filehandle has been labelled as stale.
Fix a couple of inefficiencies
- Remove the global list of sillyrenamed files. Instead we can cache the
sillyrename information in the dentry->d_fsdata
- Move common code from unlink_setup/unlink_done into fs/nfs/unlink.c
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
nfs_symlink() allocates a GFP_KERNEL page for the pagecache. Most
pagecache pages are allocated using GFP_HIGHUSER, and there's no reason
not to do that in nfs_symlink() as well.
Signed-off-by: Jeff Layton <jlayton@redhat.com>
We don't need to revalidate the fsid on the root directory. It suffices to
revalidate it on the current directory.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
A number of race conditions may currently ensue if the user presses ^C
and then unmounts the partition while an asynchronous open() is in
progress.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
First thing mm.h does is including sched.h solely for can_do_mlock() inline
function which has "current" dereference inside. By dealing with can_do_mlock()
mm.h can be detached from sched.h which is good. See below, why.
This patch
a) removes unconditional inclusion of sched.h from mm.h
b) makes can_do_mlock() normal function in mm/mlock.c
c) exports can_do_mlock() to not break compilation
d) adds sched.h inclusions back to files that were getting it indirectly.
e) adds less bloated headers to some files (asm/signal.h, jiffies.h) that were
getting them indirectly
Net result is:
a) mm.h users would get less code to open, read, preprocess, parse, ... if
they don't need sched.h
b) sched.h stops being dependency for significant number of files:
on x86_64 allmodconfig touching sched.h results in recompile of 4083 files,
after patch it's only 3744 (-8.3%).
Cross-compile tested on
all arm defconfigs, all mips defconfigs, all powerpc defconfigs,
alpha alpha-up
arm
i386 i386-up i386-defconfig i386-allnoconfig
ia64 ia64-up
m68k
mips
parisc parisc-up
powerpc powerpc-up
s390 s390-up
sparc sparc-up
sparc64 sparc64-up
um-x86_64
x86_64 x86_64-up x86_64-defconfig x86_64-allnoconfig
as well as my two usual configs.
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
- fs/nfs/dir.c:610:8: warning: symbol 'nfs_llseek_dir' was not declared.
Should it be static?
- fs/nfs/dir.c:636:5: warning: symbol 'nfs_fsync_dir' was not declared.
Should it be static?
- fs/nfs/write.c:925:19: warning: symbol 'req' shadows an earlier one
- fs/nfs/write.c:61:6: warning: symbol 'nfs_commit_rcu_free' was not
declared. Should it be static?
- fs/nfs/nfs4proc.c:793:5: warning: symbol 'nfs4_recover_expired_lease'
was not declared. Should it be static?
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
The check for nfs_attribute_timeout(dir) in nfs_check_verifier is
redundant: nfs_lookup_revalidate() will already call nfs_revalidate_inode()
on the parent dir when necessary.
The only case where this is not done is the case of a negative dentry. Fix
this case by moving up the revalidation code.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
dentry verifiers are always set to the parent directory's
cache_change_attribute. There is no reason to be testing for anything other
than equality when we're trying to find out if the dentry has been checked
since the last time the directory was modified.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Ensure pages are uptodate after returning from read_cache_page, which allows
us to cut out most of the filesystem-internal PageUptodate calls.
I didn't have a great look down the call chains, but this appears to fixes 7
possible use-before uptodate in hfs, 2 in hfsplus, 1 in jfs, a few in
ecryptfs, 1 in jffs2, and a possible cleared data overwritten with readpage in
block2mtd. All depending on whether the filler is async and/or can return
with a !uptodate page.
Signed-off-by: Nick Piggin <npiggin@suse.de>
Cc: Hugh Dickins <hugh@veritas.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Try running this script in an NFS mounted directory (Client relatively
recent - 2.6.18 has the problem as does 2.6.20).
------------------------------------------------------
#!/bin/bash
#
# This script will produce the following errormessage from tar:
#
# tar: newdir/innerdir/innerfile: file changed as we read it
# create dirs
rm -rf nfstest
mkdir -p nfstest/dir/innerdir
# create files (should not be empty)
echo "Hello World!" >nfstest/dir/file
echo "Hello World!" >nfstest/dir/innerdir/innerfile
# problem only happens if we sleep before chmod
sleep 1
# change file modes
chmod -R a+r nfstest
# rename dir
mv nfstest/dir nfstest/newdir
# tar it
tar -cf nfstest/nfstest.tar -C nfstest newdir
# restore old dir name
mv nfstest/newdir nfstest/dir
--------------------------------------------------------
What happens:
The 'chmod -R' does a readdir_plus in each directory and the results
get cached in the page cache. It then updates the ctime on each file
by one second. When this happens, the post-op attributes are used to
update the ctime stored on the client to match the value in the kernel.
The 'mv' calls shrink_dcache_parent on the directory tree which
flushes all the dentries (so a new lookup will be required) but
doesn't flush the inodes or pagecache.
The 'tar' does a readdir on each directory, but (in the case of
'innerdir' at least) satisfies it from the pagecache and uses the
READDIRPLUS data to update all the inodes. In the case of
'innerdir/innerfile', the ctime is out of date.
'tar' then calls 'lstat' on innerdir/innerfile getting an old ctime.
It then opens the file (triggering a GETATTR), reads the content, and
then calls fstat to see if anything has changed. It finds that ctime
has changed and so complains.
The problem seems to be that the cache readdirplus info is kept around
for too long.
My patch below discards pagecache data for directories when
dentry_iput is called on them. This effectively removes the symptom
which convinces me that I correctly understand the problem. However
I'm not convinced that is a proper solution, as there could easily be
other races that trigger the same problem without being affected by
this 'fix'.
One possibility would be to require that readdirplus pagecache data be
only used *once* to instantiate an inode. Somehow it should then be
invalidated so that if the dentry subsequently disappears, it will
cause a new request to the server to fill in the stat data.
Another possibility is to compare the cache_change_attribute on the
inode with something similar for the readdirplus info and reject the
info from readdirplus if it is too old.
I haven't tried to implement these and would value other opinions
before I do.
Thanks,
NeilBrown
Signed-off-by: Neil Brown <neilb@suse.de>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Don't use uninitialsed value for fattr->time_start in readdirplus results.
The 'fattr' structure filled in by nfs3_decode_direct does not get a
value for ->time_start set.
Thus if an entry is for an inode that we already have in cache,
when nfs_readdir_lookup calls nfs_fhget, it will call nfs_refresh_inode
and may update the inode with out-of-date information.
Directories are read a page at a time, so each page could have a
different timestamp that "should" be used to set the time_start for
the fattr for info in that page. However storing the timestamp per
page is awkward. (We could stick in the first 4 bytes and only read 4092
bytes, but that is a bigger code change than I am interested it).
This patch ignores the readdir_plus attributes if a readdir finds the
information already in cache, and otherwise sets ->time_start to the time
the readdir request was sent to the server.
It might be nice to store - in the directory inode - the time stamp for
the earliest readdir request that is still in the page cache, so that we
don't ignore attribute data that we don't have to. This patch doesn't do
that.
Signed-off-by: Neil Brown <neilb@suse.de>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
It looks like nfs_setattr() and nfs_rename() also need to test whether the
target is a regular file before calling nfs_wb_all()...
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Many struct inode_operations in the kernel can be "const". Marking them const
moves these to the .rodata section, which avoids false sharing with potential
dirty data. In addition it'll catch accidental writes at compile time to
these shared resources.
Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
nfs_lookup_revalidate and friends are not serialised, so it is currently
quite possible for the dentry to be revalidated, and then have the
updated verifier replaced with an older value by another process.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
