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The Linux client assumes that all filehandles are non-volatile for
renames within the same directory (otherwise sillyrename cannot work).
However, the existence of the Linux 'subtree_check' export option has
meant that nfs_rename() has always assumed it needs to flush writes
before attempting to rename.
Since NFSv4 does allow the client to query whether or not the server
exhibits this behaviour, and since knfsd does actually set the
appropriate flag when 'subtree_check' is enabled on an export, it
should be OK to optimise away the write flushing behaviour in the cases
where it is clearly not needed.
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
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Pull NFS client updates from Trond Myklebust:
"Bugfixes:
- Three fixes for looping in the NFSv4 state manager delegation code
- Fix for the NFSv4 state XDR code (Neil Brown)
- Fix a leaked reference in nfs_lock_and_join_requests()
- Fix a use-after-free in the delegation return code
Features:
- Implement the NFSv4.2 copy offload OFFLOAD_STATUS operation to
allow monitoring of an in-progress copy
- Add a mount option to force NFSv3/NFSv4 to use READDIRPLUS in a
getdents() call
- SUNRPC now allows some basic management of an existing RPC client's
connections using sysfs
- Improvements to the automated teardown of a NFS client when the
container it was initiated from gets killed
- Improvements to prevent tasks from getting stuck in a killable wait
state after calling exit_signals()"
* tag 'nfs-for-6.15-1' of git://git.linux-nfs.org/projects/trondmy/linux-nfs: (29 commits)
nfs: Add missing release on error in nfs_lock_and_join_requests()
NFSv4: Check for delegation validity in nfs_start_delegation_return_locked()
NFS: Don't allow waiting for exiting tasks
SUNRPC: Don't allow waiting for exiting tasks
NFSv4: Treat ENETUNREACH errors as fatal for state recovery
NFSv4: clp->cl_cons_state < 0 signifies an invalid nfs_client
NFSv4: Further cleanups to shutdown loops
NFS: Shut down the nfs_client only after all the superblocks
SUNRPC: rpc_clnt_set_transport() must not change the autobind setting
SUNRPC: rpcbind should never reset the port to the value '0'
pNFS/flexfiles: Report ENETDOWN as a connection error
pNFS/flexfiles: Treat ENETUNREACH errors as fatal in containers
NFS: Treat ENETUNREACH errors as fatal in containers
NFS: Add a mount option to make ENETUNREACH errors fatal
sunrpc: Add a sysfs file for one-step xprt deletion
sunrpc: Add a sysfs file for adding a new xprt
sunrpc: Add a sysfs files for rpc_clnt information
sunrpc: Add a sysfs attr for xprtsec
NFS: Add implid to sysfs
NFS: Extend rdirplus mount option with "force|none"
...
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There are certain users that wish to force the NFS client to choose
READDIRPLUS over READDIR for a particular mount. Update the "rdirplus" mount
option to optionally accept values. For "rdirplus=force", the NFS client
will always attempt to use READDDIRPLUS. The setting of "rdirplus=none" is
aliased to the existing "nordirplus".
Signed-off-by: Benjamin Coddington <bcodding@redhat.com>
Link: https://lore.kernel.org/r/c4cf0de4c8be0930b91bc74bee310d289781cd3b.1741885071.git.bcodding@redhat.com
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
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mkdir now allows a different dentry to be returned which is sometimes
relevant for nfs.
This patch changes the nfs_rpc_ops mkdir op to return a dentry, and
passes that back to the caller.
The mkdir nfs_rpc_op will return NULL if the original dentry should be
used. This matches the mkdir inode_operation.
nfs4_do_create() is duplicated to nfs4_do_mkdir() which is changed to
handle the specifics of directories. Consequently the current special
handling for directories is removed from nfs4_do_create()
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: NeilBrown <neilb@suse.de>
Link: https://lore.kernel.org/r/20250227013949.536172-6-neilb@suse.de
Signed-off-by: Christian Brauner <brauner@kernel.org>
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Some filesystems, such as NFS, cifs, ceph, and fuse, do not have
complete control of sequencing on the actual filesystem (e.g. on a
different server) and may find that the inode created for a mkdir
request already exists in the icache and dcache by the time the mkdir
request returns. For example, if the filesystem is mounted twice the
directory could be visible on the other mount before it is on the
original mount, and a pair of name_to_handle_at(), open_by_handle_at()
calls could instantiate the directory inode with an IS_ROOT() dentry
before the first mkdir returns.
This means that the dentry passed to ->mkdir() may not be the one that
is associated with the inode after the ->mkdir() completes. Some
callers need to interact with the inode after the ->mkdir completes and
they currently need to perform a lookup in the (rare) case that the
dentry is no longer hashed.
This lookup-after-mkdir requires that the directory remains locked to
avoid races. Planned future patches to lock the dentry rather than the
directory will mean that this lookup cannot be performed atomically with
the mkdir.
To remove this barrier, this patch changes ->mkdir to return the
resulting dentry if it is different from the one passed in.
Possible returns are:
NULL - the directory was created and no other dentry was used
ERR_PTR() - an error occurred
non-NULL - this other dentry was spliced in
This patch only changes file-systems to return "ERR_PTR(err)" instead of
"err" or equivalent transformations. Subsequent patches will make
further changes to some file-systems to return a correct dentry.
Not all filesystems reliably result in a positive hashed dentry:
- NFS, cifs, hostfs will sometimes need to perform a lookup of
the name to get inode information. Races could result in this
returning something different. Note that this lookup is
non-atomic which is what we are trying to avoid. Placing the
lookup in filesystem code means it only happens when the filesystem
has no other option.
- kernfs and tracefs leave the dentry negative and the ->revalidate
operation ensures that lookup will be called to correctly populate
the dentry. This could be fixed but I don't think it is important
to any of the users of vfs_mkdir() which look at the dentry.
The recommendation to use
d_drop();d_splice_alias()
is ugly but fits with current practice. A planned future patch will
change this.
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: NeilBrown <neilb@suse.de>
Link: https://lore.kernel.org/r/20250227013949.536172-2-neilb@suse.de
Signed-off-by: Christian Brauner <brauner@kernel.org>
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Callers of lookup_one_qstr_excl() often check if the result is negative or
positive.
These changes can easily be moved into lookup_one_qstr_excl() by checking the
lookup flags:
LOOKUP_CREATE means it is NOT an error if the name doesn't exist.
LOOKUP_EXCL means it IS an error if the name DOES exist.
This patch adds these checks, then removes error checks from callers,
and ensures that appropriate flags are passed.
This subtly changes the meaning of LOOKUP_EXCL. Previously it could
only accompany LOOKUP_CREATE. Now it can accompany LOOKUP_RENAME_TARGET
as well. A couple of small changes are needed to accommodate this. The
NFS change is functionally a no-op but ensures nfs_is_exclusive_create() does
exactly what the name says.
Signed-off-by: NeilBrown <neilb@suse.de>
Link: https://lore.kernel.org/r/20250217003020.3170652-3-neilb@suse.de
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Christian Brauner <brauner@kernel.org>
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Pass the stable name all the way down to ->rpc_ops->lookup() instances.
Note that passing &dentry->d_name is safe in e.g. nfs_lookup() - it *is*
stable there, as it is in ->create() et.al.
dget_parent() in nfs_instantiate() should be redundant - it'd better be
stable there; if it's not, we have more trouble, since ->d_name would
also be unsafe in such case.
nfs_submount() and nfs4_submount() may or may not require fixes - if
they ever get moved on server with fhandle preserved, we are in trouble
there...
UAF window is fairly narrow here and exfiltration requires the ability
to watch the traffic.
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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we can't kill __nfs_lookup_revalidate() completely, but ->d_parent boilerplate
in it is gone
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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->d_revalidate() often needs to access dentry parent and name; that has
to be done carefully, since the locking environment varies from caller
to caller. We are not guaranteed that dentry in question will not be
moved right under us - not unless the filesystem is such that nothing
on it ever gets renamed.
It can be dealt with, but that results in boilerplate code that isn't
even needed - the callers normally have just found the dentry via dcache
lookup and want to verify that it's in the right place; they already
have the values of ->d_parent and ->d_name stable. There is a couple
of exceptions (overlayfs and, to less extent, ecryptfs), but for the
majority of calls that song and dance is not needed at all.
It's easier to make ecryptfs and overlayfs find and pass those values if
there's a ->d_revalidate() instance to be called, rather than doing that
in the instances.
This commit only changes the calling conventions; making use of supplied
values is left to followups.
NOTE: some instances need more than just the parent - things like CIFS
may need to build an entire path from filesystem root, so they need
more precautions than the usual boilerplate. This series doesn't
do anything to that need - these filesystems have to keep their locking
mechanisms (rename_lock loops, use of dentry_path_raw(), private rwsem
a-la v9fs).
One thing to keep in mind when using name is that name->name will normally
point into the pathname being resolved; the filename in question occupies
name->len bytes starting at name->name, and there is NUL somewhere after it,
but it the next byte might very well be '/' rather than '\0'. Do not
ignore name->len.
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Reviewed-by: Gabriel Krisman Bertazi <gabriel@krisman.be>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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Add the __counted_by compiler attribute to the flexible array member
array to improve access bounds-checking via CONFIG_UBSAN_BOUNDS and
CONFIG_FORTIFY_SOURCE.
Increment size before adding a new struct to the array.
Signed-off-by: Thorsten Blum <thorsten.blum@toblux.com>
Signed-off-by: Anna Schumaker <anna.schumaker@oracle.com>
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This argument will be used to allow the caller to specify whether or not
they need to know that this is an attribute delegation.
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
Signed-off-by: Lance Shelton <lance.shelton@hammerspace.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
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dentry->d_fsdata is set to NFS_FSDATA_BLOCKED while unlinking or
renaming-over a file to ensure that no open succeeds while the NFS
operation progressed on the server.
Setting dentry->d_fsdata to NFS_FSDATA_BLOCKED is done under ->d_lock
after checking the refcount is not elevated. Any attempt to open the
file (through that name) will go through lookp_open() which will take
->d_lock while incrementing the refcount, we can be sure that once the
new value is set, __nfs_lookup_revalidate() *will* see the new value and
will block.
We don't have any locking guarantee that when we set ->d_fsdata to NULL,
the wait_var_event() in __nfs_lookup_revalidate() will notice.
wait/wake primitives do NOT provide barriers to guarantee order. We
must use smp_load_acquire() in wait_var_event() to ensure we look at an
up-to-date value, and must use smp_store_release() before wake_up_var().
This patch adds those barrier functions and factors out
block_revalidate() and unblock_revalidate() far clarity.
There is also a hypothetical bug in that if memory allocation fails
(which never happens in practice) we might leave ->d_fsdata locked.
This patch adds the missing call to unblock_revalidate().
Reported-and-tested-by: Richard Kojedzinszky <richard+debian+bugreport@kojedz.in>
Closes: https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=1071501
Fixes: 3c59366c207e ("NFS: don't unhash dentry during unlink/rename")
Signed-off-by: NeilBrown <neilb@suse.de>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
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An attempt to open a file with a name longer than NFS3_MAXNAMLEN will
trigger a WARN_ON_ONCE in encode_filename3() because
nfs_atomic_open_v23() doesn't have the test on ->d_name.len that
nfs_atomic_open() has.
So add that test.
Reported-by: James Clark <james.clark@arm.com>
Closes: https://lore.kernel.org/all/20240528105249.69200-1-james.clark@arm.com/
Fixes: 7c6c5249f061 ("NFS: add atomic_open for NFSv3 to handle O_TRUNC correctly.")
Signed-off-by: NeilBrown <neilb@suse.de>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
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This is a slight variation on a patch previously proposed by Neil Brown
that never got merged.
Prior to commit 5ceb9d7fdaaf ("NFS: Refactor nfs_lookup_revalidate()"),
any error from nfs_lookup_verify_inode() other than -ESTALE would result
in nfs_lookup_revalidate() returning that error (-ESTALE is mapped to
zero).
Since that commit, all errors result in nfs_lookup_revalidate()
returning zero, resulting in dentries being invalidated where they
previously were not (particularly in the case of -ERESTARTSYS).
Fix it by passing the actual error code to nfs_lookup_revalidate_done(),
and leaving the decision on whether to map the error code to zero or
one to nfs_lookup_revalidate_done().
A simple reproducer is to run the following python code in a
subdirectory of an NFS mount (not in the root of the NFS mount):
---8<---
import os
import multiprocessing
import time
if __name__=="__main__":
multiprocessing.set_start_method("spawn")
count = 0
while True:
try:
os.getcwd()
pool = multiprocessing.Pool(10)
pool.close()
pool.terminate()
count += 1
except Exception as e:
print(f"Failed after {count} iterations")
print(e)
break
---8<---
Prior to commit 5ceb9d7fdaaf, the above code would run indefinitely.
After commit 5ceb9d7fdaaf, it fails almost immediately with -ENOENT.
Signed-off-by: Scott Mayhew <smayhew@redhat.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
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With two clients, each with NFSv3 mounts of the same directory, the sequence:
client1 client2
ls -l afile
echo hello there > afile
echo HELLO > afile
cat afile
will show
HELLO
there
because the O_TRUNC requested in the final 'echo' doesn't take effect.
This is because the "Negative dentry, just create a file" section in
lookup_open() assumes that the file *does* get created since the dentry
was negative, so it sets FMODE_CREATED, and this causes do_open() to
clear O_TRUNC and so the file doesn't get truncated.
Even mounting with -o lookupcache=none does not help as
nfs_neg_need_reval() always returns false if LOOKUP_CREATE is set.
This patch fixes the problem by providing an atomic_open inode operation
for NFSv3 (and v2). The code is largely the code from the branch in
lookup_open() when atomic_open is not provided. The significant change
is that the O_TRUNC flag is passed a new nfs_do_create() which add
'trunc' handling to nfs_create().
With this change we also optimise away an unnecessary LOOKUP before the
file is created.
Signed-off-by: NeilBrown <neilb@suse.de>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
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nfs_set_verifier() relies upon dentry being pinned; if that's
the case, grabbing ->d_lock stabilizes ->d_parent and guarantees
that ->d_parent points to a positive dentry. For something
we'd run into in RCU mode that is *not* true - dentry might've
been through dentry_kill() just as we grabbed ->d_lock, with
its parent going through the same just as we get to into
nfs_set_verifier_locked(). It might get to detaching inode
(and zeroing ->d_inode) before nfs_set_verifier_locked() gets
to fetching that; we get an oops as the result.
That can happen in nfs{,4} ->d_revalidate(); the call chain in
question is nfs_set_verifier_locked() <- nfs_set_verifier() <-
nfs_lookup_revalidate_delegated() <- nfs{,4}_do_lookup_revalidate().
We have checked that the parent had been positive, but that's
done before we get to nfs_set_verifier() and it's possible for
memory pressure to pick our dentry as eviction candidate by that
time. If that happens, back-to-back attempts to kill dentry and
its parent are quite normal. Sure, in case of eviction we'll
fail the ->d_seq check in the caller, but we need to survive
until we return there...
Acked-by: Christian Brauner <brauner@kernel.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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Add a call to the v4 d_revalidate entrypoint, just like the v3 one.
Signed-off-by: Jeff Layton <jlayton@kernel.org>
Reviewed-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
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The subjective cred (task->cred) can potentially be overridden and
subsquently freed in non-RCU context, which could lead to a panic if we
try to use it in cred_fscmp(). Use __task_cred(), which returns the
objective cred (task->real_cred) instead.
Fixes: 0eb43812c027 ("NFS: Clear the file access cache upon login")
Fixes: 5e9a7b9c2ea1 ("NFS: Fix up a sparse warning")
Signed-off-by: Scott Mayhew <smayhew@redhat.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
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Use the folio APIs, saving about four calls to compound_head().
Convert back to a page in each of the individual protocol implementations.
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
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When a directory contains 17 files (except . and ..), nfs client sends
a redundant readdir request after get eof.
A simple reproduce,
At NFS server, create a directory with 17 files under exported directory.
# mkdir test
# cd test
# for i in {0..16} ; do touch $i; done
At NFS client, no matter mounting through nfsv3 or nfsv4,
does ls (or ll) at the created test directory.
A tshark output likes following (for nfsv4),
# tshark -i eth0 tcp port 2049 -Tfields -e ip.src -e ip.dst -e nfs -e nfs.cookie4
srcip dstip SEQUENCE, PUTFH, READDIR 0
dstip srcip SEQUENCE PUTFH READDIR 909539109313539306,2108391201987888856,2305312124304486544,2566335452463141496,2978225129081509984,4263037479923412583,4304697173036510679,4666703455469210097,4759208201298769007,4776701232145978803,5338408478512081262,5949498658935544804,5971526429894832903,6294060338267709855,6528840566229532529,8600463293536422524,9223372036854775807
srcip dstip
srcip dstip SEQUENCE, PUTFH, READDIR 9223372036854775807
dstip srcip SEQUENCE PUTFH READDIR
The READDIR with cookie 9223372036854775807(0x7FFFFFFFFFFFFFFF) is redundant.
Reviewed-by: Benjamin Coddington <bcodding@redhat.com>
Signed-off-by: Kinglong Mee <kinglongmee@gmail.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
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kmap_atomic() is deprecated in favor of kmap_local_{folio,page}().
Therefore, replace kmap_atomic() with kmap_local_folio() in
nfs_readdir_folio_array_append().
kmap_atomic() disables page-faults and preemption (the latter only for
!PREEMPT_RT kernels), However, the code within the mapping/un-mapping in
nfs_readdir_folio_array_append() does not depend on the above-mentioned
side effects.
Therefore, a mere replacement of the old API with the new one is all that
is required (i.e., there is no need to explicitly add any calls to
pagefault_disable() and/or preempt_disable()).
Tested with (x)fstests in a QEMU/KVM x86_32 VM, 6GB RAM, booting a kernel
with HIGHMEM64GB enabled.
Cc: Ira Weiny <ira.weiny@intel.com>
Signed-off-by: Fabio M. De Francesco <fmdefrancesco@gmail.com>
Fixes: ec108d3cc766 ("NFS: Convert readdir page array functions to use a folio")
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
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Dan has been improving on the smatch error pointer checks, and pointed
at another case where the __filemap_get_folio() conversion to error
pointers had been overlooked. This time because it was hidden behind
the filemap_grab_folio() helper function that is a wrapper around it.
Reported-by: Dan Carpenter <dan.carpenter@linaro.org>
Cc: Anna Schumaker <anna@kernel.org>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Fix another case of an incorrect check for the returned 'folio' value
from __filemap_get_folio().
The failure case used to return NULL, but was changed by commit
66dabbb65d67 ("mm: return an ERR_PTR from __filemap_get_folio").
But in the meantime, commit ec108d3cc766 ("NFS: Convert readdir page
array functions to use a folio") added a new user of that function.
And my merge of the two did not fix this up correctly.
The ext4 merge had the same issue, but that one had been caught in
linux-next and got properly fixed while merging.
Fixes: 0127f25b5dfc ("Merge tag 'nfs-for-6.4-1' of git://git.linux-nfs.org/projects/anna/linux-nfs")
Cc: Anna Schumaker <anna@kernel.org>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
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This patch only converts the actual array, but doesn't touch the
individual nfs_cache_array pages and related functions (that will be
done in the next patch).
I also adjust the names of the fields in the nfs_readdir_descriptor to
say "folio" instead of "page".
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
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When the user's login time is newer than the cache's timestamp,
the original entry in the RB-tree will be replaced by a new entry.
Currently, the timestamp is only set if the entry is not found in
the RB-tree, which can cause the timestamp to be undefined when
the entry exists. This may result in a significant increase in
ACCESS operations if the timestamp is set to zero.
Signed-off-by: Chengen Du <chengen.du@canonical.com>
Fixes: 0eb43812c027 ("NFS: Clear the file access cache upon login”)
Reviewed-by: Benjamin Coddington <bcodding@redhat.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
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Pull NFS client updates from Anna Schumaker:
"New Features:
- Convert the read and write paths to use folios
Bugfixes and Cleanups:
- Fix tracepoint state manager flag printing
- Fix disabling swap files
- Fix NFSv4 client identifier sysfs path in the documentation
- Don't clear NFS_CAP_COPY if server returns NFS4ERR_OFFLOAD_DENIED
- Treat GETDEVICEINFO errors as a layout failure
- Replace kmap_atomic() calls with kmap_local_page()
- Constify sunrpc sysfs kobj_type structures"
* tag 'nfs-for-6.3-1' of git://git.linux-nfs.org/projects/anna/linux-nfs: (25 commits)
fs/nfs: Replace kmap_atomic() with kmap_local_page() in dir.c
pNFS/filelayout: treat GETDEVICEINFO errors as layout failure
Documentation: Fix sysfs path for the NFSv4 client identifier
nfs42: do not fail with EIO if ssc returns NFS4ERR_OFFLOAD_DENIED
NFS: fix disabling of swap
SUNRPC: make kobj_type structures constant
nfs4trace: fix state manager flag printing
NFS: Remove unnecessary check in nfs_read_folio()
NFS: Improve tracing of nfs_wb_folio()
NFS: Enable tracing of nfs_invalidate_folio() and nfs_launder_folio()
NFS: fix up nfs_release_folio() to try to release the page
NFS: Clean up O_DIRECT request allocation
NFS: Fix up nfs_vm_page_mkwrite() for folios
NFS: Convert nfs_write_begin/end to use folios
NFS: Remove unused function nfs_wb_page()
NFS: Convert buffered writes to use folios
NFS: Convert the function nfs_wb_page() to use folios
NFS: Convert buffered reads to use folios
NFS: Add a helper nfs_wb_folio()
NFS: Convert the remaining pagelist helper functions to support folios
...
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git://git.kernel.org/pub/scm/linux/kernel/git/vfs/idmapping
Pull vfs idmapping updates from Christian Brauner:
- Last cycle we introduced the dedicated struct mnt_idmap type for
mount idmapping and the required infrastucture in 256c8aed2b42 ("fs:
introduce dedicated idmap type for mounts"). As promised in last
cycle's pull request message this converts everything to rely on
struct mnt_idmap.
Currently we still pass around the plain namespace that was attached
to a mount. This is in general pretty convenient but it makes it easy
to conflate namespaces that are relevant on the filesystem with
namespaces that are relevant on the mount level. Especially for
non-vfs developers without detailed knowledge in this area this was a
potential source for bugs.
This finishes the conversion. Instead of passing the plain namespace
around this updates all places that currently take a pointer to a
mnt_userns with a pointer to struct mnt_idmap.
Now that the conversion is done all helpers down to the really
low-level helpers only accept a struct mnt_idmap argument instead of
two namespace arguments.
Conflating mount and other idmappings will now cause the compiler to
complain loudly thus eliminating the possibility of any bugs. This
makes it impossible for filesystem developers to mix up mount and
filesystem idmappings as they are two distinct types and require
distinct helpers that cannot be used interchangeably.
Everything associated with struct mnt_idmap is moved into a single
separate file. With that change no code can poke around in struct
mnt_idmap. It can only be interacted with through dedicated helpers.
That means all filesystems are and all of the vfs is completely
oblivious to the actual implementation of idmappings.
We are now also able to extend struct mnt_idmap as we see fit. For
example, we can decouple it completely from namespaces for users that
don't require or don't want to use them at all. We can also extend
the concept of idmappings so we can cover filesystem specific
requirements.
In combination with the vfs{g,u}id_t work we finished in v6.2 this
makes this feature substantially more robust and thus difficult to
implement wrong by a given filesystem and also protects the vfs.
- Enable idmapped mounts for tmpfs and fulfill a longstanding request.
A long-standing request from users had been to make it possible to
create idmapped mounts for tmpfs. For example, to share the host's
tmpfs mount between multiple sandboxes. This is a prerequisite for
some advanced Kubernetes cases. Systemd also has a range of use-cases
to increase service isolation. And there are more users of this.
However, with all of the other work going on this was way down on the
priority list but luckily someone other than ourselves picked this
up.
As usual the patch is tiny as all the infrastructure work had been
done multiple kernel releases ago. In addition to all the tests that
we already have I requested that Rodrigo add a dedicated tmpfs
testsuite for idmapped mounts to xfstests. It is to be included into
xfstests during the v6.3 development cycle. This should add a slew of
additional tests.
* tag 'fs.idmapped.v6.3' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/idmapping: (26 commits)
shmem: support idmapped mounts for tmpfs
fs: move mnt_idmap
fs: port vfs{g,u}id helpers to mnt_idmap
fs: port fs{g,u}id helpers to mnt_idmap
fs: port i_{g,u}id_into_vfs{g,u}id() to mnt_idmap
fs: port i_{g,u}id_{needs_}update() to mnt_idmap
quota: port to mnt_idmap
fs: port privilege checking helpers to mnt_idmap
fs: port inode_owner_or_capable() to mnt_idmap
fs: port inode_init_owner() to mnt_idmap
fs: port acl to mnt_idmap
fs: port xattr to mnt_idmap
fs: port ->permission() to pass mnt_idmap
fs: port ->fileattr_set() to pass mnt_idmap
fs: port ->set_acl() to pass mnt_idmap
fs: port ->get_acl() to pass mnt_idmap
fs: port ->tmpfile() to pass mnt_idmap
fs: port ->rename() to pass mnt_idmap
fs: port ->mknod() to pass mnt_idmap
fs: port ->mkdir() to pass mnt_idmap
...
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kmap_atomic() is deprecated in favor of kmap_local_page().
With kmap_local_page() the mappings are per thread, CPU local, can take
page-faults, and can be called from any context (including interrupts).
Furthermore, the tasks can be preempted and, when they are scheduled to
run again, the kernel virtual addresses are restored and still valid.
kmap_atomic() is implemented like a kmap_local_page() which also disables
page-faults and preemption (the latter only for !PREEMPT_RT kernels,
otherwise it only disables migration).
The code within the mappings/un-mappings in the functions of dir.c don't
depend on the above-mentioned side effects of kmap_atomic(), so that mere
replacements of the old API with the new one is all that is required
(i.e., there is no need to explicitly add calls to pagefault_disable()
and/or preempt_disable()).
Therefore, replace kmap_atomic() with kmap_local_page() in fs/nfs/dir.c.
Tested in a QEMU/KVM x86_32 VM, 6GB RAM, booting a kernel with
HIGHMEM64GB enabled.
Suggested-by: Ira Weiny <ira.weiny@intel.com>
Signed-off-by: Fabio M. De Francesco <fmdefrancesco@gmail.com>
Reviewed-by: Luis Chamberlain <mcgrof@kernel.org>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
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Convert to struct mnt_idmap.
Last cycle we merged the necessary infrastructure in
256c8aed2b42 ("fs: introduce dedicated idmap type for mounts").
This is just the conversion to struct mnt_idmap.
Currently we still pass around the plain namespace that was attached to a
mount. This is in general pretty convenient but it makes it easy to
conflate namespaces that are relevant on the filesystem with namespaces
that are relevent on the mount level. Especially for non-vfs developers
without detailed knowledge in this area this can be a potential source for
bugs.
Once the conversion to struct mnt_idmap is done all helpers down to the
really low-level helpers will take a struct mnt_idmap argument instead of
two namespace arguments. This way it becomes impossible to conflate the two
eliminating the possibility of any bugs. All of the vfs and all filesystems
only operate on struct mnt_idmap.
Acked-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Christian Brauner (Microsoft) <brauner@kernel.org>
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Convert to struct mnt_idmap.
Last cycle we merged the necessary infrastructure in
256c8aed2b42 ("fs: introduce dedicated idmap type for mounts").
This is just the conversion to struct mnt_idmap.
Currently we still pass around the plain namespace that was attached to a
mount. This is in general pretty convenient but it makes it easy to
conflate namespaces that are relevant on the filesystem with namespaces
that are relevent on the mount level. Especially for non-vfs developers
without detailed knowledge in this area this can be a potential source for
bugs.
Once the conversion to struct mnt_idmap is done all helpers down to the
really low-level helpers will take a struct mnt_idmap argument instead of
two namespace arguments. This way it becomes impossible to conflate the two
eliminating the possibility of any bugs. All of the vfs and all filesystems
only operate on struct mnt_idmap.
Acked-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Christian Brauner (Microsoft) <brauner@kernel.org>
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Convert to struct mnt_idmap.
Last cycle we merged the necessary infrastructure in
256c8aed2b42 ("fs: introduce dedicated idmap type for mounts").
This is just the conversion to struct mnt_idmap.
Currently we still pass around the plain namespace that was attached to a
mount. This is in general pretty convenient but it makes it easy to
conflate namespaces that are relevant on the filesystem with namespaces
that are relevent on the mount level. Especially for non-vfs developers
without detailed knowledge in this area this can be a potential source for
bugs.
Once the conversion to struct mnt_idmap is done all helpers down to the
really low-level helpers will take a struct mnt_idmap argument instead of
two namespace arguments. This way it becomes impossible to conflate the two
eliminating the possibility of any bugs. All of the vfs and all filesystems
only operate on struct mnt_idmap.
Acked-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Christian Brauner (Microsoft) <brauner@kernel.org>
|
|
Convert to struct mnt_idmap.
Last cycle we merged the necessary infrastructure in
256c8aed2b42 ("fs: introduce dedicated idmap type for mounts").
This is just the conversion to struct mnt_idmap.
Currently we still pass around the plain namespace that was attached to a
mount. This is in general pretty convenient but it makes it easy to
conflate namespaces that are relevant on the filesystem with namespaces
that are relevent on the mount level. Especially for non-vfs developers
without detailed knowledge in this area this can be a potential source for
bugs.
Once the conversion to struct mnt_idmap is done all helpers down to the
really low-level helpers will take a struct mnt_idmap argument instead of
two namespace arguments. This way it becomes impossible to conflate the two
eliminating the possibility of any bugs. All of the vfs and all filesystems
only operate on struct mnt_idmap.
Acked-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Christian Brauner (Microsoft) <brauner@kernel.org>
|
|
Convert to struct mnt_idmap.
Last cycle we merged the necessary infrastructure in
256c8aed2b42 ("fs: introduce dedicated idmap type for mounts").
This is just the conversion to struct mnt_idmap.
Currently we still pass around the plain namespace that was attached to a
mount. This is in general pretty convenient but it makes it easy to
conflate namespaces that are relevant on the filesystem with namespaces
that are relevent on the mount level. Especially for non-vfs developers
without detailed knowledge in this area this can be a potential source for
bugs.
Once the conversion to struct mnt_idmap is done all helpers down to the
really low-level helpers will take a struct mnt_idmap argument instead of
two namespace arguments. This way it becomes impossible to conflate the two
eliminating the possibility of any bugs. All of the vfs and all filesystems
only operate on struct mnt_idmap.
Acked-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Christian Brauner (Microsoft) <brauner@kernel.org>
|
|
Convert to struct mnt_idmap.
Last cycle we merged the necessary infrastructure in
256c8aed2b42 ("fs: introduce dedicated idmap type for mounts").
This is just the conversion to struct mnt_idmap.
Currently we still pass around the plain namespace that was attached to a
mount. This is in general pretty convenient but it makes it easy to
conflate namespaces that are relevant on the filesystem with namespaces
that are relevent on the mount level. Especially for non-vfs developers
without detailed knowledge in this area this can be a potential source for
bugs.
Once the conversion to struct mnt_idmap is done all helpers down to the
really low-level helpers will take a struct mnt_idmap argument instead of
two namespace arguments. This way it becomes impossible to conflate the two
eliminating the possibility of any bugs. All of the vfs and all filesystems
only operate on struct mnt_idmap.
Acked-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Christian Brauner (Microsoft) <brauner@kernel.org>
|
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sparse is warning about an incorrect RCU dereference.
fs/nfs/dir.c:2965:56: warning: incorrect type in argument 1 (different address spaces)
fs/nfs/dir.c:2965:56: expected struct cred const *
fs/nfs/dir.c:2965:56: got struct cred const [noderef] __rcu *const cred
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
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If the user's login time is newer than the cache's timestamp,
we expect the cache may be stale and need to clear.
The stale cache will remain in the list's tail if no other
users operate on that inode.
Once the user accesses the inode, the stale cache will be
returned in rcu path.
Signed-off-by: Chengen Du <chengen.du@canonical.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
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Since commit 1a34c8c9a49e ("NFS: Support larger readdir buffers") has
updated dtsize, and with recent improvements to the READDIRPLUS helper
heuristic, the heuristic may not trigger until many dentries are emitted
to userspace. This will cause many thousands of GETATTR calls for "ls
-l" when the directory's pagecache has already been populated. This
manifests as poor performance for long directory listings after an
initially fast "ls -l".
Fix this by emitting only 17 entries for any first pass through the NFS
directory's ->iterate_shared(), which allows userpace to prime the
counters for the heuristic.
Signed-off-by: Benjamin Coddington <bcodding@redhat.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
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POSIX typically only refreshes the user's supplementary group
information upon login. Since NFS servers may often refresh their
concept of the user supplementary group membership at their own cadence,
it is possible for the NFS client's access cache to become stale due to
the user's group membership changing on the server after the user has
already logged in on the client.
While it is reasonable to expect that such group membership changes are
rare, and that we do not want to optimise the cache to accommodate them,
it is also not unreasonable for the user to expect that if they log out
and log back in again, that the staleness would clear up.
Reviewed-by: Benjamin Coddington <bcodding@redhat.com>
Tested-by: Benjamin Coddington <bcodding@redhat.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
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Fix the following coccicheck warning:
fs/nfs/dir.c:2494:2-7: WARNING:
NULL check before some freeing functions is not needed.
Signed-off-by: Yushan Zhou <katrinzhou@tencent.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
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git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs
Pull file_inode() updates from Al Vrio:
"whack-a-mole: cropped up open-coded file_inode() uses..."
* tag 'pull-file_inode' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
orangefs: use ->f_mapping
_nfs42_proc_copy(): use ->f_mapping instead of file_inode()->i_mapping
dma_buf: no need to bother with file_inode()->i_mapping
nfs_finish_open(): don't open-code file_inode()
bprm_fill_uid(): don't open-code file_inode()
sgx: use ->f_mapping...
exfat_iterate(): don't open-code file_inode(file)
ibmvmc: don't open-code file_inode()
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Reviewed-by: Christian Brauner (Microsoft) <brauner@kernel.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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nfs_unlink() calls d_delete() twice if it receives ENOENT from the
server - once in nfs_dentry_handle_enoent() from nfs_safe_remove and
once in nfs_dentry_remove_handle_error().
nfs_rmddir() also calls it twice - the nfs_dentry_handle_enoent() call
is direct and inside a region locked with ->rmdir_sem
It is safe to call d_delete() twice if the refcount > 1 as the dentry is
simply unhashed.
If the refcount is 1, the first call sets d_inode to NULL and the second
call crashes.
This patch guards the d_delete() call from nfs_dentry_handle_enoent()
leaving the one under ->remdir_sem in case that is important.
In mainline it would be safe to remove the d_delete() call. However in
older kernels to which this might be backported, that would change the
behaviour of nfs_unlink(). nfs_unlink() used to unhash the dentry which
resulted in nfs_dentry_handle_enoent() not calling d_delete(). So in
older kernels we need the d_delete() in nfs_dentry_remove_handle_error()
when called from nfs_unlink() but not when called from nfs_rmdir().
To make the code work correctly for old and new kernels, and from both
nfs_unlink() and nfs_rmdir(), we protect the d_delete() call with
simple_positive(). This ensures it is never called in a circumstance
where it could crash.
Fixes: 3c59366c207e ("NFS: don't unhash dentry during unlink/rename")
Fixes: 9019fb391de0 ("NFS: Label the dentry with a verifier in nfs_rmdir() and nfs_unlink()")
Signed-off-by: NeilBrown <neilb@suse.de>
Tested-by: Olga Kornievskaia <aglo@umich.edu>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
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Add the missing unlock before goto.
Fixes: 3c59366c207e ("NFS: don't unhash dentry during unlink/rename")
Signed-off-by: Sun Ke <sunke32@huawei.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
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NFS unlink() (and rename over existing target) must determine if the
file is open, and must perform a "silly rename" instead of an unlink (or
before rename) if it is. Otherwise the client might hold a file open
which has been removed on the server.
Consequently if it determines that the file isn't open, it must block
any subsequent opens until the unlink/rename has been completed on the
server.
This is currently achieved by unhashing the dentry. This forces any
open attempt to the slow-path for lookup which will block on i_rwsem on
the directory until the unlink/rename completes. A future patch will
change the VFS to only get a shared lock on i_rwsem for unlink, so this
will no longer work.
Instead we introduce an explicit interlock. A special value is stored
in dentry->d_fsdata while the unlink/rename is running and
->d_revalidate blocks while that value is present. When ->d_revalidate
unblocks, the dentry will be invalid. This closes the race
without requiring exclusion on i_rwsem.
d_fsdata is already used in two different ways.
1/ an IS_ROOT directory dentry might have a "devname" stored in
d_fsdata. Such a dentry doesn't have a name and so cannot be the
target of unlink or rename. For safety we check if an old devname
is still stored, and remove it if it is.
2/ a dentry with DCACHE_NFSFS_RENAMED set will have a 'struct
nfs_unlinkdata' stored in d_fsdata. While this is set maydelete()
will fail, so an unlink or rename will never proceed on such
a dentry.
Neither of these can be in effect when a dentry is the target of unlink
or rename. So we can expect d_fsdata to be NULL, and store a special
value ((void*)1) which is given the name NFS_FSDATA_BLOCKED to indicate
that any lookup will be blocked.
The d_count() is incremented under d_lock() when a lookup finds the
dentry, so we check d_count() is low, and set NFS_FSDATA_BLOCKED under
the same lock to avoid any races.
Signed-off-by: NeilBrown <neilb@suse.de>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
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The use of kmap() is being deprecated in favor of kmap_local_page().
With kmap_local_page(), the mapping is per thread, CPU local and not
globally visible. Furthermore, the mapping can be acquired from any context
(including interrupts).
Therefore, use kmap_local_page() in nfs_do_filldir() because this mapping
is per thread, CPU local, and not globally visible.
Suggested-by: Ira Weiny <ira.weiny@intel.com>
Signed-off-by: Fabio M. De Francesco <fmdefrancesco@gmail.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
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For filesystems that are case insensitive and case preserving, we need
to be able to rename from one case folded variant of the filename to
another.
Currently, if we have looked up the target filename before the call to
rename, then we may have a hashed dentry with that target name in the
dcache, causing the vfs to optimise away the rename.
To avoid that, let's drop the target dentry, and leave it to the server
to optimise away the rename if that is the correct thing to do.
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
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Commit a2ad63daa88b ("VFS: add FMODE_CAN_ODIRECT file flag")
added the FMODE_CAN_ODIRECT flag for NFSv3 but neglected to add
it for NFSv4.x. This causes direct io on NFSv4.x to fail open
with EINVAL:
mount -o vers=4.2 127.0.0.1:/export /mnt/nfs4
dd if=/dev/zero of=/mnt/nfs4/file.bin bs=128k count=1 oflag=direct
dd: failed to open '/mnt/nfs4/file.bin': Invalid argument
dd of=/dev/null if=/mnt/nfs4/file.bin bs=128k count=1 iflag=direct
dd: failed to open '/mnt/dir1/file1.bin': Invalid argument
Fixes: a2ad63daa88b ("VFS: add FMODE_CAN_ODIRECT file flag")
Signed-off-by: Dave Wysochanski <dwysocha@redhat.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
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Add a wrapper that converts back from the folio to the page. This
entire file needs to be converted to use folios, but that's a
task for a different set of patches.
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
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Both xxhash() and hash_64() appear to give similarly low collision
rates with a standard linearly increasing readdir offset. They both give
similarly higher collision rates when applied to ext4's offsets.
So switch to using the standard hash_64().
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
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