Change the signature of netfs helper functions to take a struct netfs_inode
pointer rather than a struct inode pointer where appropriate, thereby
relieving the need for the network filesystem to convert its internal inode
format down to the VFS inode only for netfslib to bounce it back up.  For
type safety, it's better not to do that (and it's less typing too).

Give netfs_write_begin() an extra argument to pass in a pointer to the
netfs_inode struct rather than deriving it internally from the file
pointer.  Note that the ->write_begin() and ->write_end() ops are intended
to be replaced in the future by netfslib code that manages this without the
need to call in twice for each page.

netfs_readpage() and similar are intended to be pointed at directly by the
address_space_operations table, so must stick to the signature dictated by
the function pointers there.

Changes
=======
- Updated the kerneldoc comments and documentation [DH].
Signed-off-by: NDavid Howells <dhowells@redhat.com>
cc: linux-cachefs@redhat.com
Link: https://lore.kernel.org/r/CAHk-=wgkwKyNmNdKpQkqZ6DnmUL-x9hp0YBnUGjaPFEAdxDTbw@mail.gmail.com/

While randstruct was satisfied with using an open-coded "void *" offset
cast for the netfs_i_context <-> inode casting, __builtin_object_size() as
used by FORTIFY_SOURCE was not as easily fooled.  This was causing the
following complaint[1] from gcc v12:

  In file included from include/linux/string.h:253,
                   from include/linux/ceph/ceph_debug.h:7,
                   from fs/ceph/inode.c:2:
  In function 'fortify_memset_chk',
      inlined from 'netfs_i_context_init' at include/linux/netfs.h:326:2,
      inlined from 'ceph_alloc_inode' at fs/ceph/inode.c:463:2:
  include/linux/fortify-string.h:242:25: warning: call to '__write_overflow_field' declared with attribute warning: detected write beyond size of field (1st parameter); maybe use struct_group()? [-Wattribute-warning]
    242 |                         __write_overflow_field(p_size_field, size);
        |                         ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Fix this by embedding a struct inode into struct netfs_i_context (which
should perhaps be renamed to struct netfs_inode).  The struct inode
vfs_inode fields are then removed from the 9p, afs, ceph and cifs inode
structs and vfs_inode is then simply changed to "netfs.inode" in those
filesystems.

Further, rename netfs_i_context to netfs_inode, get rid of the
netfs_inode() function that converted a netfs_i_context pointer to an
inode pointer (that can now be done with &ctx->inode) and rename the
netfs_i_context() function to netfs_inode() (which is now a wrapper
around container_of()).

Most of the changes were done with:

  perl -p -i -e 's/vfs_inode/netfs.inode/'g \
        `git grep -l 'vfs_inode' -- fs/{9p,afs,ceph,cifs}/*.[ch]`

Kees suggested doing it with a pair structure[2] and a special
declarator to insert that into the network filesystem's inode
wrapper[3], but I think it's cleaner to embed it - and then it doesn't
matter if struct randomisation reorders things.

Dave Chinner suggested using a filesystem-specific VFS_I() function in
each filesystem to convert that filesystem's own inode wrapper struct
into the VFS inode struct[4].

Version #2:
 - Fix a couple of missed name changes due to a disabled cifs option.
 - Rename nfs_i_context to nfs_inode
 - Use "netfs" instead of "nic" as the member name in per-fs inode wrapper
   structs.

[ This also undoes commit 507160f4 ("netfs: gcc-12: temporarily
  disable '-Wattribute-warning' for now") that is no longer needed ]

Fixes: bc899ee1 ("netfs: Add a netfs inode context")
Reported-by: NJeff Layton <jlayton@kernel.org>
Signed-off-by: NDavid Howells <dhowells@redhat.com>
Reviewed-by: NJeff Layton <jlayton@kernel.org>
Reviewed-by: NKees Cook <keescook@chromium.org>
Reviewed-by: NXiubo Li <xiubli@redhat.com>
cc: Jonathan Corbet <corbet@lwn.net>
cc: Eric Van Hensbergen <ericvh@gmail.com>
cc: Latchesar Ionkov <lucho@ionkov.net>
cc: Dominique Martinet <asmadeus@codewreck.org>
cc: Christian Schoenebeck <linux_oss@crudebyte.com>
cc: Marc Dionne <marc.dionne@auristor.com>
cc: Ilya Dryomov <idryomov@gmail.com>
cc: Steve French <smfrench@gmail.com>
cc: William Kucharski <william.kucharski@oracle.com>
cc: "Matthew Wilcox (Oracle)" <willy@infradead.org>
cc: Dave Chinner <david@fromorbit.com>
cc: linux-doc@vger.kernel.org
cc: v9fs-developer@lists.sourceforge.net
cc: linux-afs@lists.infradead.org
cc: ceph-devel@vger.kernel.org
cc: linux-cifs@vger.kernel.org
cc: samba-technical@lists.samba.org
cc: linux-fsdevel@vger.kernel.org
cc: linux-hardening@vger.kernel.org
Link: https://lore.kernel.org/r/d2ad3a3d7bdd794c6efb562d2f2b655fb67756b9.camel@kernel.org/ [1]
Link: https://lore.kernel.org/r/20220517210230.864239-1-keescook@chromium.org/ [2]
Link: https://lore.kernel.org/r/20220518202212.2322058-1-keescook@chromium.org/ [3]
Link: https://lore.kernel.org/r/20220524101205.GI2306852@dread.disaster.area/ [4]
Link: https://lore.kernel.org/r/165296786831.3591209.12111293034669289733.stgit@warthog.procyon.org.uk/ # v1
Link: https://lore.kernel.org/r/165305805651.4094995.7763502506786714216.stgit@warthog.procyon.org.uk # v2
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

This is a pure band-aid so that I can continue merging stuff from people
while some of the gcc-12 fallout gets sorted out.

In particular, gcc-12 is very unhappy about the kinds of pointer
arithmetic tricks that netfs does, and that makes the fortify checks
trigger in afs and ceph:

  In function ‘fortify_memset_chk’,
      inlined from ‘netfs_i_context_init’ at include/linux/netfs.h:327:2,
      inlined from ‘afs_set_netfs_context’ at fs/afs/inode.c:61:2,
      inlined from ‘afs_root_iget’ at fs/afs/inode.c:543:2:
  include/linux/fortify-string.h:258:25: warning: call to ‘__write_overflow_field’ declared with attribute warning: detected write beyond size of field (1st parameter); maybe use struct_group()? [-Wattribute-warning]
    258 |                         __write_overflow_field(p_size_field, size);
        |                         ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

and the reason is that netfs_i_context_init() is passed a 'struct inode'
pointer, and then it does

        struct netfs_i_context *ctx = netfs_i_context(inode);

        memset(ctx, 0, sizeof(*ctx));

where that netfs_i_context() function just does pointer arithmetic on
the inode pointer, knowing that the netfs_i_context is laid out
immediately after it in memory.

This is all truly disgusting, since the whole "netfs_i_context is laid
out immediately after it in memory" is not actually remotely true in
general, but is just made to be that way for afs and ceph.

See for example fs/cifs/cifsglob.h:

  struct cifsInodeInfo {
        struct {
                /* These must be contiguous */
                struct inode    vfs_inode;      /* the VFS's inode record */
                struct netfs_i_context netfs_ctx; /* Netfslib context */
        };
	[...]

and realize that this is all entirely wrong, and the pointer arithmetic
that netfs_i_context() is doing is also very very wrong and wouldn't
give the right answer if netfs_ctx had different alignment rules from a
'struct inode', for example).

Anyway, that's just a long-winded way to say "the gcc-12 warning is
actually quite reasonable, and our code happens to work but is pretty
disgusting".

This is getting fixed properly, but for now I made the mistake of
thinking "the week right after the merge window tends to be calm for me
as people take a breather" and I did a sustem upgrade.  And I got gcc-12
as a result, so to continue merging fixes from people and not have the
end result drown in warnings, I am fixing all these gcc-12 issues I hit.

Including with these kinds of temporary fixes.

Cc: Kees Cook <keescook@chromium.org>
Cc: David Howells <dhowells@redhat.com>
Link: https://lore.kernel.org/all/AEEBCF5D-8402-441D-940B-105AA718C71F@chromium.org/Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

When doing a mount using as base a directory that has 'max_bytes' quotas
statfs uses that value as the total; if a subdirectory is used instead,
the same 'max_bytes' too in statfs, unless there is another quota set.

Unfortunately, if this subdirectory only has the 'max_files' quota set,
then statfs uses the filesystem total.  Fix this by making sure we only
lookup realms that contain the 'max_bytes' quota.

Cc: Ryan Taylor <rptaylor@uvic.ca>
URL: https://tracker.ceph.com/issues/55090Signed-off-by: NLuís Henriques <lhenriques@suse.de>
Reviewed-by: NJeff Layton <jlayton@kernel.org>
Reviewed-by: NXiubo Li <xiubli@redhat.com>
Signed-off-by: NIlya Dryomov <idryomov@gmail.com>

If any 'x' caps is issued we can just choose the auth MDS instead
of the random replica MDSes. Because only when the Locker is in
LOCK_EXEC state will the loner client could get the 'x' caps. And
if we send the getattr requests to any replica MDS it must auth pin
and tries to rdlock from the auth MDS, and then the auth MDS need
to do the Locker state transition to LOCK_SYNC. And after that the
lock state will change back.

This cost much when doing the Locker state transition and usually
will need to revoke caps from clients.

URL: https://tracker.ceph.com/issues/55240Signed-off-by: NXiubo Li <xiubli@redhat.com>
Reviewed-by: NJeff Layton <jlayton@kernel.org>
Signed-off-by: NIlya Dryomov <idryomov@gmail.com>

From the posix and the initial statx supporting commit comments,
the AT_STATX_DONT_SYNC is a lightweight stat and the
AT_STATX_FORCE_SYNC is a heaverweight one. And also checked all
the other current usage about these two flags they are all doing
the same, that is only when the AT_STATX_FORCE_SYNC is not set
and the AT_STATX_DONT_SYNC is set will they skip sync retriving
the attributes from storage.
Signed-off-by: NXiubo Li <xiubli@redhat.com>
Reviewed-by: NDavid Howells <dhowells@redhat.com>
Signed-off-by: NIlya Dryomov <idryomov@gmail.com>

Fixes: 400e1286 ("ceph: conversion to new fscache API")
Signed-off-by: NXiubo Li <xiubli@redhat.com>
Reviewed-by: NJeff Layton <jlayton@kernel.org>
Signed-off-by: NIlya Dryomov <idryomov@gmail.com>

The MDS will always refresh the dentry lease when removing the files
or directories. And if the dentry is still hashed, we can update
the dentry lease and no need to do the lookup from the MDS later.
Signed-off-by: NXiubo Li <xiubli@redhat.com>
Reviewed-by: NJeff Layton <jlayton@kernel.org>
Signed-off-by: NIlya Dryomov <idryomov@gmail.com>

The inode allocation is supposed to use alloc_inode_sb(), so convert
kmem_cache_alloc() of all filesystems to alloc_inode_sb().

Link: https://lkml.kernel.org/r/20220228122126.37293-5-songmuchun@bytedance.comSigned-off-by: NMuchun Song <songmuchun@bytedance.com>
Acked-by: Theodore Ts'o <tytso@mit.edu>		[ext4]
Acked-by: NRoman Gushchin <roman.gushchin@linux.dev>
Cc: Alex Shi <alexs@kernel.org>
Cc: Anna Schumaker <Anna.Schumaker@Netapp.com>
Cc: Chao Yu <chao@kernel.org>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Fam Zheng <fam.zheng@bytedance.com>
Cc: Jaegeuk Kim <jaegeuk@kernel.org>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Kari Argillander <kari.argillander@gmail.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Qi Zheng <zhengqi.arch@bytedance.com>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Trond Myklebust <trond.myklebust@hammerspace.com>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Wei Yang <richard.weiyang@gmail.com>
Cc: Xiongchun Duan <duanxiongchun@bytedance.com>
Cc: Yang Shi <shy828301@gmail.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The ceph_get_inode() will search for or insert a new inode into the
hash for the given vino, and return a reference to it. If new is
non-NULL, its reference is consumed.

We should release the reference when in error handing cases.
Signed-off-by: NXiubo Li <xiubli@redhat.com>
Reviewed-by: NJeff Layton <jlayton@kernel.org>
Signed-off-by: NIlya Dryomov <idryomov@gmail.com>

Add a netfs_i_context struct that should be included in the network
filesystem's own inode struct wrapper, directly after the VFS's inode
struct, e.g.:

	struct my_inode {
		struct {
			/* These must be contiguous */
			struct inode		vfs_inode;
			struct netfs_i_context	netfs_ctx;
		};
	};

The netfs_i_context struct so far contains a single field for the network
filesystem to use - the cache cookie:

	struct netfs_i_context {
		...
		struct fscache_cookie	*cache;
	};

Three functions are provided to help with this:

 (1) void netfs_i_context_init(struct inode *inode,
			       const struct netfs_request_ops *ops);

     Initialise the netfs context and set the operations.

 (2) struct netfs_i_context *netfs_i_context(struct inode *inode);

     Find the netfs context from the VFS inode.

 (3) struct inode *netfs_inode(struct netfs_i_context *ctx);

     Find the VFS inode from the netfs context.

Changes
=======
ver #4)
 - Fix netfs_is_cache_enabled() to check cookie->cache_priv to see if a
   cache is present[3].
 - Fix netfs_skip_folio_read() to zero out all of the page, not just some
   of it[3].

ver #3)
 - Split out the bit to move ceph cap-getting on readahead into
   ceph_init_request()[1].
 - Stick in a comment to the netfs inode structs indicating the contiguity
   requirements[2].

ver #2)
 - Adjust documentation to match.
 - Use "#if IS_ENABLED()" in netfs_i_cookie(), not "#ifdef".
 - Move the cap check from ceph_readahead() to ceph_init_request() to be
   called from netfslib.
 - Remove ceph_readahead() and use  netfs_readahead() directly instead.
Signed-off-by: NDavid Howells <dhowells@redhat.com>
Acked-by: NJeff Layton <jlayton@kernel.org>
cc: linux-cachefs@redhat.com

Link: https://lore.kernel.org/r/8af0d47f17d89c06bbf602496dd845f2b0bf25b3.camel@kernel.org/ [1]
Link: https://lore.kernel.org/r/beaf4f6a6c2575ed489adb14b257253c868f9a5c.camel@kernel.org/ [2]
Link: https://lore.kernel.org/r/3536452.1647421585@warthog.procyon.org.uk/ [3]
Link: https://lore.kernel.org/r/164622984545.3564931.15691742939278418580.stgit@warthog.procyon.org.uk/ # v1
Link: https://lore.kernel.org/r/164678213320.1200972.16807551936267647470.stgit@warthog.procyon.org.uk/ # v2
Link: https://lore.kernel.org/r/164692909854.2099075.9535537286264248057.stgit@warthog.procyon.org.uk/ # v3
Link: https://lore.kernel.org/r/306388.1647595110@warthog.procyon.org.uk/ # v4

Problem:
Some directory vxattrs (e.g. ceph.dir.pin.random) are governed by
information that isn't necessarily shared with the client. Add support
for the new GETVXATTR operation, which allows the client to query the
MDS directly for vxattrs.
When the client is queried for a vxattr that doesn't have a special
handler, have it issue a GETVXATTR to the MDS directly.

Solution:
Adds new getvxattr op to fetch ceph.dir.pin*, ceph.dir.layout* and
ceph.file.layout* vxattrs.
If the entire layout for a dir or a file is being set, then it is
expected that the layout be set in standard JSON format. Individual
field value retrieval is not wrapped in JSON. The JSON format also
applies while setting the vxattr if the entire layout is being set in
one go.
As a temporary measure, setting a vxattr can also be done in the old
format. The old format will be deprecated in the future.

URL: https://tracker.ceph.com/issues/51062Signed-off-by: NMilind Changire <mchangir@redhat.com>
Reviewed-by: NJeff Layton <jlayton@kernel.org>
Signed-off-by: NIlya Dryomov <idryomov@gmail.com>

inode->i_mutex has been replaced with inode->i_rwsem long ago. Fix
comments still mentioning i_mutex.
Signed-off-by: Nhongnanli <hongnan.li@linux.alibaba.com>
Reviewed-by: NJeff Layton <jlayton@kernel.org>
Signed-off-by: NIlya Dryomov <idryomov@gmail.com>

Now that the fscache API has been reworked and simplified, change ceph
over to use it.

With the old API, we would only instantiate a cookie when the file was
open for reads. Change it to instantiate the cookie when the inode is
instantiated and call use/unuse when the file is opened/closed.

Also, ensure we resize the cached data on truncates, and invalidate the
cache in response to the appropriate events. This will allow us to
plumb in write support later.
Signed-off-by: NJeff Layton <jlayton@kernel.org>
Signed-off-by: NDavid Howells <dhowells@redhat.com>
Link: https://lore.kernel.org/r/20211129162907.149445-2-jlayton@kernel.org/ # v1
Link: https://lore.kernel.org/r/20211207134451.66296-2-jlayton@kernel.org/ # v2
Link: https://lore.kernel.org/r/163906984277.143852.14697110691303589000.stgit@warthog.procyon.org.uk/ # v2
Link: https://lore.kernel.org/r/163967188351.1823006.5065634844099079351.stgit@warthog.procyon.org.uk/ # v3
Link: https://lore.kernel.org/r/164021581427.640689.14128682147127509264.stgit@warthog.procyon.org.uk/ # v4

If the new size is the same as the current size, the MDS will do nothing
but change the mtime/atime. POSIX doesn't mandate that the filesystems
must update them in this case, so just ignore it instead.
Signed-off-by: NXiubo Li <xiubli@redhat.com>
Reviewed-by: NJeff Layton <jlayton@kernel.org>
Signed-off-by: NIlya Dryomov <idryomov@gmail.com>

Add proper error handling for when an async create fails. The inode
never existed, so any dirty caps or data are now toast. We already
d_drop the dentry in that case, but the now-stale inode may still be
around. We want to shut down access to these inodes, and ensure that
they can't harbor any more dirty data, which can cause problems at
umount time.

When this occurs, flag such inodes as being SHUTDOWN, and trash any caps
and cap flushes that may be in flight for them, and invalidate the
pagecache for the inode. Add a new helper that can check whether an
inode or an entire mount is now shut down, and call it instead of
accessing the mount_state directly in places where we test that now.

URL: https://tracker.ceph.com/issues/51279Signed-off-by: NJeff Layton <jlayton@kernel.org>
Signed-off-by: NIlya Dryomov <idryomov@gmail.com>

We have a lot of log messages that print inode pointer values. This is
of dubious utility. Switch a random assortment of the ones I've found
most useful to use ceph_vinop to print the snap:inum tuple instead.

[ idryomov: use . as a separator, break unnecessarily long lines ]
Signed-off-by: NJeff Layton <jlayton@kernel.org>
Reviewed-by: NIlya Dryomov <idryomov@gmail.com>
Signed-off-by: NIlya Dryomov <idryomov@gmail.com>

Currently, we check the wb_err too early for directories, before all of
the unsafe child requests have been waited on. In order to fix that we
need to check the mapping->wb_err later nearer to the end of ceph_fsync.

We also have an overly-complex method for tracking errors after
blocklisting. The errors recorded in cleanup_session_requests go to a
completely separate field in the inode, but we end up reporting them the
same way we would for any other error (in fsync).

There's no real benefit to tracking these errors in two different
places, since the only reporting mechanism for them is in fsync, and
we'd need to advance them both every time.

Given that, we can just remove i_meta_err, and convert the places that
used it to instead just use mapping->wb_err instead. That also fixes
the original problem by ensuring that we do a check_and_advance of the
wb_err at the end of the fsync op.

Cc: stable@vger.kernel.org
URL: https://tracker.ceph.com/issues/52864Reported-by: NPatrick Donnelly <pdonnell@redhat.com>
Signed-off-by: NJeff Layton <jlayton@kernel.org>
Reviewed-by: NXiubo Li <xiubli@redhat.com>
Signed-off-by: NIlya Dryomov <idryomov@gmail.com>

Consolidate some fiddly code for changing an inode's snap_realm
into a new helper function, and change the callers to use it.

While we're in here, nothing uses the i_snap_realm_counter field, so
remove that from the inode.
Signed-off-by: NJeff Layton <jlayton@kernel.org>
Reviewed-by: NLuis Henriques <lhenriques@suse.de>
Signed-off-by: NIlya Dryomov <idryomov@gmail.com>

Now that we don't need to hold session->s_mutex or the snap_rwsem when
calling ceph_check_caps, we can eliminate ceph_async_iput and just use
normal iput calls.
Signed-off-by: NJeff Layton <jlayton@kernel.org>
Signed-off-by: NIlya Dryomov <idryomov@gmail.com>

Turn s_cap_gen field into an atomic_t, and just rely on the fact that we
hold the s_mutex when changing the s_cap_ttl field.
Signed-off-by: NJeff Layton <jlayton@kernel.org>
Reviewed-by: NLuis Henriques <lhenriques@suse.de>
Signed-off-by: NIlya Dryomov <idryomov@gmail.com>

...to simplify some error paths.
Signed-off-by: NJeff Layton <jlayton@kernel.org>
Reviewed-by: NLuis Henriques <lhenriques@suse.de>
Signed-off-by: NIlya Dryomov <idryomov@gmail.com>

...and add a lockdep assertion for it to ceph_fill_inode().

Cc: stable@vger.kernel.org # v5.7+
Fixes: 9a8d03ca ("ceph: attempt to do async create when possible")
Signed-off-by: NJeff Layton <jlayton@kernel.org>
Reviewed-by: NIlya Dryomov <idryomov@gmail.com>
Signed-off-by: NIlya Dryomov <idryomov@gmail.com>

The MDS reserves a set of inodes for its own usage, and these should
never be accessible to clients. Add a new helper to vet a proposed
inode number against that range, and complain loudly and refuse to
create or look it up if it's in it.

Also, ensure that the MDS doesn't try to delegate inodes that are in
that range or lower. Print a warning if it does, and don't save the
range in the xarray.

URL: https://tracker.ceph.com/issues/49922Signed-off-by: NJeff Layton <jlayton@kernel.org>
Reviewed-by: NXiubo Li <xiubli@redhat.com>
Signed-off-by: NIlya Dryomov <idryomov@gmail.com>

We need to use i_size_read(), which properly handles the torn read
case on 32-bit arches.
Signed-off-by: NJeff Layton <jlayton@kernel.org>
Signed-off-by: NIlya Dryomov <idryomov@gmail.com>

Add support for grabbing the rsnaps value out of the inode info in
traces, and exposing that via ceph.dir.rsnaps xattr.
Signed-off-by: NYanhu Cao <gmayyyha@gmail.com>
Reviewed-by: NJeff Layton <jlayton@kernel.org>
Signed-off-by: NIlya Dryomov <idryomov@gmail.com>

We want the snapdir to mirror the non-snapped directory's attributes for
most things, but i_snap_caps represents the caps granted on the snapshot
directory by the MDS itself. A misbehaving MDS could issue different
caps for the snapdir and we lose them here.

Only reset i_snap_caps when the inode is I_NEW. Also, move the setting
of i_op and i_fop inside the if block since they should never change
anyway.
Reported-by: NAl Viro <viro@zeniv.linux.org.uk>
Signed-off-by: NJeff Layton <jlayton@kernel.org>
Signed-off-by: NIlya Dryomov <idryomov@gmail.com>

Ensure that we invalidate the fscache whenever we invalidate the
pagecache.
Signed-off-by: NJeff Layton <jlayton@kernel.org>
Signed-off-by: NIlya Dryomov <idryomov@gmail.com>

Al pointed out that a malicious or broken MDS could change the type or
device number of a given inode number. It may also be possible for the
MDS to reuse an old inode number.

Ensure that we never allow fill_inode to change the type part of the
i_mode or the i_rdev unless I_NEW is set. Throw warnings if the MDS ever
changes these on us mid-stream, and return an error.

Don't set i_rdev directly, and rely on init_special_inode to do it.
Also, fix up error handling in the callers of ceph_get_inode.

In handle_cap_grant, check for and warn if the inode type changes, and
only overwrite the mode if it didn't.
Reported-by: NAl Viro <viro@zeniv.linux.org.uk>
Signed-off-by: NJeff Layton <jlayton@kernel.org>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

There are several warts in the snapdir error handling. The -EOPNOTSUPP
return in __snapfh_to_dentry is currently lost, and the call to
ceph_handle_snapdir is not currently checked at all.

Fix all of this up and eliminate a BUG_ON in ceph_get_snapdir. We can
handle that case with a warning and return an error.
Signed-off-by: NJeff Layton <jlayton@kernel.org>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Testing with the fscache overhaul has triggered some lockdep warnings
about circular lock dependencies involving page_mkwrite and the
mmap_lock. It'd be better to do the "real work" without the mmap lock
being held.

Change the skip_checking_caps parameter in __ceph_put_cap_refs to an
enum, and use that to determine whether to queue check_caps, do it
synchronously or not at all. Change ceph_page_mkwrite to do a
ceph_put_cap_refs_async().
Signed-off-by: NJeff Layton <jlayton@kernel.org>
Reviewed-by: NIlya Dryomov <idryomov@gmail.com>
Signed-off-by: NIlya Dryomov <idryomov@gmail.com>

Add a generic function for taking an inode reference, setting the I_WORK
bit and queueing i_work. Turn the ceph_queue_* functions into static
inline wrappers that pass in the right bit.
Signed-off-by: NJeff Layton <jlayton@kernel.org>
Reviewed-by: NIlya Dryomov <idryomov@gmail.com>
Signed-off-by: NIlya Dryomov <idryomov@gmail.com>

Extend some inode methods with an additional user namespace argument. A
filesystem that is aware of idmapped mounts will receive the user
namespace the mount has been marked with. This can be used for
additional permission checking and also to enable filesystems to
translate between uids and gids if they need to. We have implemented all
relevant helpers in earlier patches.

As requested we simply extend the exisiting inode method instead of
introducing new ones. This is a little more code churn but it's mostly
mechanical and doesnt't leave us with additional inode methods.

Link: https://lore.kernel.org/r/20210121131959.646623-25-christian.brauner@ubuntu.com
Cc: Christoph Hellwig <hch@lst.de>
Cc: David Howells <dhowells@redhat.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: linux-fsdevel@vger.kernel.org
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NChristian Brauner <christian.brauner@ubuntu.com>

The generic_fillattr() helper fills in the basic attributes associated
with an inode. Enable it to handle idmapped mounts. If the inode is
accessed through an idmapped mount map it into the mount's user
namespace before we store the uid and gid. If the initial user namespace
is passed nothing changes so non-idmapped mounts will see identical
behavior as before.

Link: https://lore.kernel.org/r/20210121131959.646623-12-christian.brauner@ubuntu.com
Cc: Christoph Hellwig <hch@lst.de>
Cc: David Howells <dhowells@redhat.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: linux-fsdevel@vger.kernel.org
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NJames Morris <jamorris@linux.microsoft.com>
Signed-off-by: NChristian Brauner <christian.brauner@ubuntu.com>

The posix acl permission checking helpers determine whether a caller is
privileged over an inode according to the acls associated with the
inode. Add helpers that make it possible to handle acls on idmapped
mounts.

The vfs and the filesystems targeted by this first iteration make use of
posix_acl_fix_xattr_from_user() and posix_acl_fix_xattr_to_user() to
translate basic posix access and default permissions such as the
ACL_USER and ACL_GROUP type according to the initial user namespace (or
the superblock's user namespace) to and from the caller's current user
namespace. Adapt these two helpers to handle idmapped mounts whereby we
either map from or into the mount's user namespace depending on in which
direction we're translating.
Similarly, cap_convert_nscap() is used by the vfs to translate user
namespace and non-user namespace aware filesystem capabilities from the
superblock's user namespace to the caller's user namespace. Enable it to
handle idmapped mounts by accounting for the mount's user namespace.

In addition the fileystems targeted in the first iteration of this patch
series make use of the posix_acl_chmod() and, posix_acl_update_mode()
helpers. Both helpers perform permission checks on the target inode. Let
them handle idmapped mounts. These two helpers are called when posix
acls are set by the respective filesystems to handle this case we extend
the ->set() method to take an additional user namespace argument to pass
the mount's user namespace down.

Link: https://lore.kernel.org/r/20210121131959.646623-9-christian.brauner@ubuntu.com
Cc: Christoph Hellwig <hch@lst.de>
Cc: David Howells <dhowells@redhat.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: linux-fsdevel@vger.kernel.org
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NChristian Brauner <christian.brauner@ubuntu.com>

When file attributes are changed most filesystems rely on the
setattr_prepare(), setattr_copy(), and notify_change() helpers for
initialization and permission checking. Let them handle idmapped mounts.
If the inode is accessed through an idmapped mount map it into the
mount's user namespace. Afterwards the checks are identical to
non-idmapped mounts. If the initial user namespace is passed nothing
changes so non-idmapped mounts will see identical behavior as before.

Helpers that perform checks on the ia_uid and ia_gid fields in struct
iattr assume that ia_uid and ia_gid are intended values and have already
been mapped correctly at the userspace-kernelspace boundary as we
already do today. If the initial user namespace is passed nothing
changes so non-idmapped mounts will see identical behavior as before.

Link: https://lore.kernel.org/r/20210121131959.646623-8-christian.brauner@ubuntu.com
Cc: Christoph Hellwig <hch@lst.de>
Cc: David Howells <dhowells@redhat.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: linux-fsdevel@vger.kernel.org
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NChristian Brauner <christian.brauner@ubuntu.com>

The two helpers inode_permission() and generic_permission() are used by
the vfs to perform basic permission checking by verifying that the
caller is privileged over an inode. In order to handle idmapped mounts
we extend the two helpers with an additional user namespace argument.
On idmapped mounts the two helpers will make sure to map the inode
according to the mount's user namespace and then peform identical
permission checks to inode_permission() and generic_permission(). If the
initial user namespace is passed nothing changes so non-idmapped mounts
will see identical behavior as before.

Link: https://lore.kernel.org/r/20210121131959.646623-6-christian.brauner@ubuntu.com
Cc: Christoph Hellwig <hch@lst.de>
Cc: David Howells <dhowells@redhat.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: linux-fsdevel@vger.kernel.org
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NJames Morris <jamorris@linux.microsoft.com>
Acked-by: NSerge Hallyn <serge@hallyn.com>
Signed-off-by: NChristian Brauner <christian.brauner@ubuntu.com>

We already have a pointer to the argument struct in req->r_args. Use that
instead of groveling around in the ceph_mds_request_head.
Signed-off-by: NJeff Layton <jlayton@kernel.org>
Reviewed-by: NXiubo Li <xiubli@redhat.com>
Signed-off-by: NIlya Dryomov <idryomov@gmail.com>

Geng Jichao reported a rather complex deadlock involving several
moving parts:

1) readahead is issued against an inode and some of its pages are locked
   while the read is in flight

2) the same inode is evicted from the cache, and this task gets stuck
   waiting for the page lock because of the above readahead

3) another task is processing a reply trace, and looks up the inode
   being evicted while holding the s_mutex. That ends up waiting for the
   eviction to complete

4) a write reply for an unrelated inode is then processed in the
   ceph_con_workfn job. It calls ceph_check_caps after putting wrbuffer
   caps, and that gets stuck waiting on the s_mutex held by 3.

The reply to "1" is stuck behind the write reply in "4", so we deadlock
at that point.

This patch changes the trace processing to call ceph_get_inode outside
of the s_mutex and snap_rwsem, which should break the cycle above.

[ idryomov: break unnecessarily long lines ]

URL: https://tracker.ceph.com/issues/47998Reported-by: NGeng Jichao <gengjichao@jd.com>
Signed-off-by: NJeff Layton <jlayton@kernel.org>
Reviewed-by: NLuis Henriques <lhenriques@suse.de>
Signed-off-by: NIlya Dryomov <idryomov@gmail.com>

Signed-off-by: NJeff Layton <jlayton@kernel.org>
Reviewed-by: NIlya Dryomov <idryomov@gmail.com>
Signed-off-by: NIlya Dryomov <idryomov@gmail.com>