<feed xmlns='http://www.w3.org/2005/Atom'>
<title>linux-toradex.git/fs/afs/dir_silly.c, branch v7.0-rc2</title>
<subtitle>Linux kernel for Apalis and Colibri modules</subtitle>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/'/>
<entry>
<title>Convert 'alloc_obj' family to use the new default GFP_KERNEL argument</title>
<updated>2026-02-22T01:09:51+00:00</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2026-02-22T00:37:42+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=bf4afc53b77aeaa48b5409da5c8da6bb4eff7f43'/>
<id>bf4afc53b77aeaa48b5409da5c8da6bb4eff7f43</id>
<content type='text'>
This was done entirely with mindless brute force, using

    git grep -l '\&lt;k[vmz]*alloc_objs*(.*, GFP_KERNEL)' |
        xargs sed -i 's/\(alloc_objs*(.*\), GFP_KERNEL)/\1)/'

to convert the new alloc_obj() users that had a simple GFP_KERNEL
argument to just drop that argument.

Note that due to the extreme simplicity of the scripting, any slightly
more complex cases spread over multiple lines would not be triggered:
they definitely exist, but this covers the vast bulk of the cases, and
the resulting diff is also then easier to check automatically.

For the same reason the 'flex' versions will be done as a separate
conversion.

Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
This was done entirely with mindless brute force, using

    git grep -l '\&lt;k[vmz]*alloc_objs*(.*, GFP_KERNEL)' |
        xargs sed -i 's/\(alloc_objs*(.*\), GFP_KERNEL)/\1)/'

to convert the new alloc_obj() users that had a simple GFP_KERNEL
argument to just drop that argument.

Note that due to the extreme simplicity of the scripting, any slightly
more complex cases spread over multiple lines would not be triggered:
they definitely exist, but this covers the vast bulk of the cases, and
the resulting diff is also then easier to check automatically.

For the same reason the 'flex' versions will be done as a separate
conversion.

Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>treewide: Replace kmalloc with kmalloc_obj for non-scalar types</title>
<updated>2026-02-21T09:02:28+00:00</updated>
<author>
<name>Kees Cook</name>
<email>kees@kernel.org</email>
</author>
<published>2026-02-21T07:49:23+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=69050f8d6d075dc01af7a5f2f550a8067510366f'/>
<id>69050f8d6d075dc01af7a5f2f550a8067510366f</id>
<content type='text'>
This is the result of running the Coccinelle script from
scripts/coccinelle/api/kmalloc_objs.cocci. The script is designed to
avoid scalar types (which need careful case-by-case checking), and
instead replace kmalloc-family calls that allocate struct or union
object instances:

Single allocations:	kmalloc(sizeof(TYPE), ...)
are replaced with:	kmalloc_obj(TYPE, ...)

Array allocations:	kmalloc_array(COUNT, sizeof(TYPE), ...)
are replaced with:	kmalloc_objs(TYPE, COUNT, ...)

Flex array allocations:	kmalloc(struct_size(PTR, FAM, COUNT), ...)
are replaced with:	kmalloc_flex(*PTR, FAM, COUNT, ...)

(where TYPE may also be *VAR)

The resulting allocations no longer return "void *", instead returning
"TYPE *".

Signed-off-by: Kees Cook &lt;kees@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
This is the result of running the Coccinelle script from
scripts/coccinelle/api/kmalloc_objs.cocci. The script is designed to
avoid scalar types (which need careful case-by-case checking), and
instead replace kmalloc-family calls that allocate struct or union
object instances:

Single allocations:	kmalloc(sizeof(TYPE), ...)
are replaced with:	kmalloc_obj(TYPE, ...)

Array allocations:	kmalloc_array(COUNT, sizeof(TYPE), ...)
are replaced with:	kmalloc_objs(TYPE, COUNT, ...)

Flex array allocations:	kmalloc(struct_size(PTR, FAM, COUNT), ...)
are replaced with:	kmalloc_flex(*PTR, FAM, COUNT, ...)

(where TYPE may also be *VAR)

The resulting allocations no longer return "void *", instead returning
"TYPE *".

Signed-off-by: Kees Cook &lt;kees@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>afs: Add support for RENAME_NOREPLACE and RENAME_EXCHANGE</title>
<updated>2025-09-25T07:19:07+00:00</updated>
<author>
<name>David Howells</name>
<email>dhowells@redhat.com</email>
</author>
<published>2025-09-24T12:49:49+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=a19239ba14525c26ad097d59fd52cd9198b5bcdb'/>
<id>a19239ba14525c26ad097d59fd52cd9198b5bcdb</id>
<content type='text'>
Add support for RENAME_NOREPLACE and RENAME_EXCHANGE, if the server
supports them.

The default is translated to YFS.Rename_Replace, falling back to
YFS.Rename; RENAME_NOREPLACE is translated to YFS.Rename_NoReplace and
RENAME_EXCHANGE to YFS.Rename_Exchange, both of which fall back to
reporting EINVAL.

Signed-off-by: David Howells &lt;dhowells@redhat.com&gt;
Link: https://lore.kernel.org/740476.1758718189@warthog.procyon.org.uk
cc: Marc Dionne &lt;marc.dionne@auristor.com&gt;
cc: Dan Carpenter &lt;dan.carpenter@linaro.org&gt;
cc: linux-afs@lists.infradead.org
Signed-off-by: Christian Brauner &lt;brauner@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Add support for RENAME_NOREPLACE and RENAME_EXCHANGE, if the server
supports them.

The default is translated to YFS.Rename_Replace, falling back to
YFS.Rename; RENAME_NOREPLACE is translated to YFS.Rename_NoReplace and
RENAME_EXCHANGE to YFS.Rename_Exchange, both of which fall back to
reporting EINVAL.

Signed-off-by: David Howells &lt;dhowells@redhat.com&gt;
Link: https://lore.kernel.org/740476.1758718189@warthog.procyon.org.uk
cc: Marc Dionne &lt;marc.dionne@auristor.com&gt;
cc: Dan Carpenter &lt;dan.carpenter@linaro.org&gt;
cc: linux-afs@lists.infradead.org
Signed-off-by: Christian Brauner &lt;brauner@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>VFS: rename lookup_one_len family to lookup_noperm and remove permission check</title>
<updated>2025-04-08T09:24:36+00:00</updated>
<author>
<name>NeilBrown</name>
<email>neil@brown.name</email>
</author>
<published>2025-03-19T03:01:35+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=fa6fe07d1536361a227d655e69ca270faf28fdbe'/>
<id>fa6fe07d1536361a227d655e69ca270faf28fdbe</id>
<content type='text'>
The lookup_one_len family of functions is (now) only used internally by
a filesystem on itself either
- in a context where permission checking is irrelevant such as by a
  virtual filesystem populating itself, or xfs accessing its ORPHANAGE
  or dquota accessing the quota file; or
- in a context where a permission check (MAY_EXEC on the parent) has just
  been performed such as a network filesystem finding in "silly-rename"
  file in the same directory.  This is also the context after the
  _parentat() functions where currently lookup_one_qstr_excl() is used.

So the permission check is pointless.

The name "one_len" is unhelpful in understanding the purpose of these
functions and should be changed.  Most of the callers pass the len as
"strlen()" so using a qstr and QSTR() can simplify the code.

This patch renames these functions (include lookup_positive_unlocked()
which is part of the family despite the name) to have a name based on
"lookup_noperm".  They are changed to receive a 'struct qstr' instead
of separate name and len.  In a few cases the use of QSTR() results in a
new call to strlen().

try_lookup_noperm() takes a pointer to a qstr instead of the whole
qstr.  This is consistent with d_hash_and_lookup() (which is nearly
identical) and useful for lookup_noperm_unlocked().

The new lookup_noperm_common() doesn't take a qstr yet.  That will be
tidied up in a subsequent patch.

Signed-off-by: NeilBrown &lt;neil@brown.name&gt;
Link: https://lore.kernel.org/r/20250319031545.2999807-5-neil@brown.name
Signed-off-by: Christian Brauner &lt;brauner@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
The lookup_one_len family of functions is (now) only used internally by
a filesystem on itself either
- in a context where permission checking is irrelevant such as by a
  virtual filesystem populating itself, or xfs accessing its ORPHANAGE
  or dquota accessing the quota file; or
- in a context where a permission check (MAY_EXEC on the parent) has just
  been performed such as a network filesystem finding in "silly-rename"
  file in the same directory.  This is also the context after the
  _parentat() functions where currently lookup_one_qstr_excl() is used.

So the permission check is pointless.

The name "one_len" is unhelpful in understanding the purpose of these
functions and should be changed.  Most of the callers pass the len as
"strlen()" so using a qstr and QSTR() can simplify the code.

This patch renames these functions (include lookup_positive_unlocked()
which is part of the family despite the name) to have a name based on
"lookup_noperm".  They are changed to receive a 'struct qstr' instead
of separate name and len.  In a few cases the use of QSTR() results in a
new call to strlen().

try_lookup_noperm() takes a pointer to a qstr instead of the whole
qstr.  This is consistent with d_hash_and_lookup() (which is nearly
identical) and useful for lookup_noperm_unlocked().

The new lookup_noperm_common() doesn't take a qstr yet.  That will be
tidied up in a subsequent patch.

Signed-off-by: NeilBrown &lt;neil@brown.name&gt;
Link: https://lore.kernel.org/r/20250319031545.2999807-5-neil@brown.name
Signed-off-by: Christian Brauner &lt;brauner@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>afs: Simplify error handling</title>
<updated>2023-12-24T15:22:53+00:00</updated>
<author>
<name>David Howells</name>
<email>dhowells@redhat.com</email>
</author>
<published>2023-10-25T16:53:33+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=aa453becce5d1ae1b94b7fc22f47d7b05d22b14e'/>
<id>aa453becce5d1ae1b94b7fc22f47d7b05d22b14e</id>
<content type='text'>
Simplify error handling a bit by moving it from the afs_addr_cursor struct
to the afs_operation and afs_vl_cursor structs and using the error
prioritisation function for accumulating errors from multiple sources (AFS
tries to rotate between multiple fileservers, some of which may be
inaccessible or in some state of offlinedness).

Signed-off-by: David Howells &lt;dhowells@redhat.com&gt;
cc: Marc Dionne &lt;marc.dionne@auristor.com&gt;
cc: linux-afs@lists.infradead.org
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Simplify error handling a bit by moving it from the afs_addr_cursor struct
to the afs_operation and afs_vl_cursor structs and using the error
prioritisation function for accumulating errors from multiple sources (AFS
tries to rotate between multiple fileservers, some of which may be
inaccessible or in some state of offlinedness).

Signed-off-by: David Howells &lt;dhowells@redhat.com&gt;
cc: Marc Dionne &lt;marc.dionne@auristor.com&gt;
cc: linux-afs@lists.infradead.org
</pre>
</div>
</content>
</entry>
<entry>
<title>netfs: Fix gcc-12 warning by embedding vfs inode in netfs_i_context</title>
<updated>2022-06-09T20:55:00+00:00</updated>
<author>
<name>David Howells</name>
<email>dhowells@redhat.com</email>
</author>
<published>2022-06-09T20:46:04+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=874c8ca1e60b2c564a48f7e7acc40d328d5c8733'/>
<id>874c8ca1e60b2c564a48f7e7acc40d328d5c8733</id>
<content type='text'>
While randstruct was satisfied with using an open-coded "void *" offset
cast for the netfs_i_context &lt;-&gt; 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 &amp;ctx-&gt;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 507160f46c55 ("netfs: gcc-12: temporarily
  disable '-Wattribute-warning' for now") that is no longer needed ]

Fixes: bc899ee1c898 ("netfs: Add a netfs inode context")
Reported-by: Jeff Layton &lt;jlayton@kernel.org&gt;
Signed-off-by: David Howells &lt;dhowells@redhat.com&gt;
Reviewed-by: Jeff Layton &lt;jlayton@kernel.org&gt;
Reviewed-by: Kees Cook &lt;keescook@chromium.org&gt;
Reviewed-by: Xiubo Li &lt;xiubli@redhat.com&gt;
cc: Jonathan Corbet &lt;corbet@lwn.net&gt;
cc: Eric Van Hensbergen &lt;ericvh@gmail.com&gt;
cc: Latchesar Ionkov &lt;lucho@ionkov.net&gt;
cc: Dominique Martinet &lt;asmadeus@codewreck.org&gt;
cc: Christian Schoenebeck &lt;linux_oss@crudebyte.com&gt;
cc: Marc Dionne &lt;marc.dionne@auristor.com&gt;
cc: Ilya Dryomov &lt;idryomov@gmail.com&gt;
cc: Steve French &lt;smfrench@gmail.com&gt;
cc: William Kucharski &lt;william.kucharski@oracle.com&gt;
cc: "Matthew Wilcox (Oracle)" &lt;willy@infradead.org&gt;
cc: Dave Chinner &lt;david@fromorbit.com&gt;
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: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
While randstruct was satisfied with using an open-coded "void *" offset
cast for the netfs_i_context &lt;-&gt; 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 &amp;ctx-&gt;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 507160f46c55 ("netfs: gcc-12: temporarily
  disable '-Wattribute-warning' for now") that is no longer needed ]

Fixes: bc899ee1c898 ("netfs: Add a netfs inode context")
Reported-by: Jeff Layton &lt;jlayton@kernel.org&gt;
Signed-off-by: David Howells &lt;dhowells@redhat.com&gt;
Reviewed-by: Jeff Layton &lt;jlayton@kernel.org&gt;
Reviewed-by: Kees Cook &lt;keescook@chromium.org&gt;
Reviewed-by: Xiubo Li &lt;xiubli@redhat.com&gt;
cc: Jonathan Corbet &lt;corbet@lwn.net&gt;
cc: Eric Van Hensbergen &lt;ericvh@gmail.com&gt;
cc: Latchesar Ionkov &lt;lucho@ionkov.net&gt;
cc: Dominique Martinet &lt;asmadeus@codewreck.org&gt;
cc: Christian Schoenebeck &lt;linux_oss@crudebyte.com&gt;
cc: Marc Dionne &lt;marc.dionne@auristor.com&gt;
cc: Ilya Dryomov &lt;idryomov@gmail.com&gt;
cc: Steve French &lt;smfrench@gmail.com&gt;
cc: William Kucharski &lt;william.kucharski@oracle.com&gt;
cc: "Matthew Wilcox (Oracle)" &lt;willy@infradead.org&gt;
cc: Dave Chinner &lt;david@fromorbit.com&gt;
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: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>afs: Fix kerneldoc warning shown up by W=1</title>
<updated>2021-10-04T21:04:44+00:00</updated>
<author>
<name>David Howells</name>
<email>dhowells@redhat.com</email>
</author>
<published>2021-10-04T21:04:33+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=dcb442b133642c507c81da6990860549b19d4e78'/>
<id>dcb442b133642c507c81da6990860549b19d4e78</id>
<content type='text'>
Fix a kerneldoc warning in afs due to a partially documented internal
function by removing the kerneldoc marker.

Signed-off-by: David Howells &lt;dhowells@redhat.com&gt;
Reviewed-by: Jeff Layton &lt;jlayton@kernel.org&gt;
cc: Marc Dionne &lt;marc.dionne@auristor.com&gt;
cc: linux-afs@lists.infradead.org
cc: linux-fsdevel@vger.kernel.org
cc: linux-doc@vger.kernel.org
Link: https://lore.kernel.org/r/163214005516.2945267.7000234432243167892.stgit@warthog.procyon.org.uk/ # rfc v1
Link: https://lore.kernel.org/r/163281899704.2790286.9177774252843775348.stgit@warthog.procyon.org.uk/ # rfc v2
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Fix a kerneldoc warning in afs due to a partially documented internal
function by removing the kerneldoc marker.

Signed-off-by: David Howells &lt;dhowells@redhat.com&gt;
Reviewed-by: Jeff Layton &lt;jlayton@kernel.org&gt;
cc: Marc Dionne &lt;marc.dionne@auristor.com&gt;
cc: linux-afs@lists.infradead.org
cc: linux-fsdevel@vger.kernel.org
cc: linux-doc@vger.kernel.org
Link: https://lore.kernel.org/r/163214005516.2945267.7000234432243167892.stgit@warthog.procyon.org.uk/ # rfc v1
Link: https://lore.kernel.org/r/163281899704.2790286.9177774252843775348.stgit@warthog.procyon.org.uk/ # rfc v2
</pre>
</div>
</content>
</entry>
<entry>
<title>afs: Fix speculative status fetches</title>
<updated>2021-05-01T18:55:36+00:00</updated>
<author>
<name>David Howells</name>
<email>dhowells@redhat.com</email>
</author>
<published>2021-04-30T12:47:08+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=22650f148126571be1098d34160eb4931fc77241'/>
<id>22650f148126571be1098d34160eb4931fc77241</id>
<content type='text'>
The generic/464 xfstest causes kAFS to emit occasional warnings of the
form:

        kAFS: vnode modified {100055:8a} 30-&gt;31 YFS.StoreData64 (c=6015)

This indicates that the data version received back from the server did not
match the expected value (the DV should be incremented monotonically for
each individual modification op committed to a vnode).

What is happening is that a lookup call is doing a bulk status fetch
speculatively on a bunch of vnodes in a directory besides getting the
status of the vnode it's actually interested in.  This is racing with a
StoreData operation (though it could also occur with, say, a MakeDir op).

On the client, a modification operation locks the vnode, but the bulk
status fetch only locks the parent directory, so no ordering is imposed
there (thereby avoiding an avenue to deadlock).

On the server, the StoreData op handler doesn't lock the vnode until it's
received all the request data, and downgrades the lock after committing the
data until it has finished sending change notifications to other clients -
which allows the status fetch to occur before it has finished.

This means that:

 - a status fetch can access the target vnode either side of the exclusive
   section of the modification

 - the status fetch could start before the modification, yet finish after,
   and vice-versa.

 - the status fetch and the modification RPCs can complete in either order.

 - the status fetch can return either the before or the after DV from the
   modification.

 - the status fetch might regress the locally cached DV.

Some of these are handled by the previous fix[1], but that's not sufficient
because it checks the DV it received against the DV it cached at the start
of the op, but the DV might've been updated in the meantime by a locally
generated modification op.

Fix this by the following means:

 (1) Keep track of when we're performing a modification operation on a
     vnode.  This is done by marking vnode parameters with a 'modification'
     note that causes the AFS_VNODE_MODIFYING flag to be set on the vnode
     for the duration.

 (2) Alter the speculation race detection to ignore speculative status
     fetches if either the vnode is marked as being modified or the data
     version number is not what we expected.

Note that whilst the "vnode modified" warning does get recovered from as it
causes the client to refetch the status at the next opportunity, it will
also invalidate the pagecache, so changes might get lost.

Fixes: a9e5c87ca744 ("afs: Fix speculative status fetch going out of order wrt to modifications")
Reported-by: Marc Dionne &lt;marc.dionne@auristor.com&gt;
Signed-off-by: David Howells &lt;dhowells@redhat.com&gt;
Tested-and-reviewed-by: Marc Dionne &lt;marc.dionne@auristor.com&gt;
cc: linux-afs@lists.infradead.org
Link: https://lore.kernel.org/r/160605082531.252452.14708077925602709042.stgit@warthog.procyon.org.uk/ [1]
Link: https://lore.kernel.org/linux-fsdevel/161961335926.39335.2552653972195467566.stgit@warthog.procyon.org.uk/ # v1
Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
The generic/464 xfstest causes kAFS to emit occasional warnings of the
form:

        kAFS: vnode modified {100055:8a} 30-&gt;31 YFS.StoreData64 (c=6015)

This indicates that the data version received back from the server did not
match the expected value (the DV should be incremented monotonically for
each individual modification op committed to a vnode).

What is happening is that a lookup call is doing a bulk status fetch
speculatively on a bunch of vnodes in a directory besides getting the
status of the vnode it's actually interested in.  This is racing with a
StoreData operation (though it could also occur with, say, a MakeDir op).

On the client, a modification operation locks the vnode, but the bulk
status fetch only locks the parent directory, so no ordering is imposed
there (thereby avoiding an avenue to deadlock).

On the server, the StoreData op handler doesn't lock the vnode until it's
received all the request data, and downgrades the lock after committing the
data until it has finished sending change notifications to other clients -
which allows the status fetch to occur before it has finished.

This means that:

 - a status fetch can access the target vnode either side of the exclusive
   section of the modification

 - the status fetch could start before the modification, yet finish after,
   and vice-versa.

 - the status fetch and the modification RPCs can complete in either order.

 - the status fetch can return either the before or the after DV from the
   modification.

 - the status fetch might regress the locally cached DV.

Some of these are handled by the previous fix[1], but that's not sufficient
because it checks the DV it received against the DV it cached at the start
of the op, but the DV might've been updated in the meantime by a locally
generated modification op.

Fix this by the following means:

 (1) Keep track of when we're performing a modification operation on a
     vnode.  This is done by marking vnode parameters with a 'modification'
     note that causes the AFS_VNODE_MODIFYING flag to be set on the vnode
     for the duration.

 (2) Alter the speculation race detection to ignore speculative status
     fetches if either the vnode is marked as being modified or the data
     version number is not what we expected.

Note that whilst the "vnode modified" warning does get recovered from as it
causes the client to refetch the status at the next opportunity, it will
also invalidate the pagecache, so changes might get lost.

Fixes: a9e5c87ca744 ("afs: Fix speculative status fetch going out of order wrt to modifications")
Reported-by: Marc Dionne &lt;marc.dionne@auristor.com&gt;
Signed-off-by: David Howells &lt;dhowells@redhat.com&gt;
Tested-and-reviewed-by: Marc Dionne &lt;marc.dionne@auristor.com&gt;
cc: linux-afs@lists.infradead.org
Link: https://lore.kernel.org/r/160605082531.252452.14708077925602709042.stgit@warthog.procyon.org.uk/ [1]
Link: https://lore.kernel.org/linux-fsdevel/161961335926.39335.2552653972195467566.stgit@warthog.procyon.org.uk/ # v1
Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>afs: Fix silly rename</title>
<updated>2020-06-16T21:00:28+00:00</updated>
<author>
<name>David Howells</name>
<email>dhowells@redhat.com</email>
</author>
<published>2020-06-15T16:36:58+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=b6489a49f7b71964e37978d6f89bbdbdb263f6f5'/>
<id>b6489a49f7b71964e37978d6f89bbdbdb263f6f5</id>
<content type='text'>
Fix AFS's silly rename by the following means:

 (1) Set the destination directory in afs_do_silly_rename() so as to avoid
     misbehaviour and indicate that the directory data version will
     increment by 1 so as to avoid warnings about unexpected changes in the
     DV.  Also indicate that the ctime should be updated to avoid xfstest
     grumbling.

 (2) Note when the server indicates that a directory changed more than we
     expected (AFS_OPERATION_DIR_CONFLICT), indicating a conflict with a
     third party change, checking on successful completion of unlink and
     rename.

     The problem is that the FS.RemoveFile RPC op doesn't report the status
     of the unlinked file, though YFS.RemoveFile2 does.  This can be
     mitigated by the assumption that if the directory DV cranked by
     exactly 1, we can be sure we removed one link from the file; further,
     ordinarily in AFS, files cannot be hardlinked across directories, so
     if we reduce nlink to 0, the file is deleted.

     However, if the directory DV jumps by more than 1, we cannot know if a
     third party intervened by adding or removing a link on the file we
     just removed a link from.

     The same also goes for any vnode that is at the destination of the
     FS.Rename RPC op.

 (3) Make afs_vnode_commit_status() apply the nlink drop inside the cb_lock
     section along with the other attribute updates if -&gt;op_unlinked is set
     on the descriptor for the appropriate vnode.

 (4) Issue a follow up status fetch to the unlinked file in the event of a
     third party conflict that makes it impossible for us to know if we
     actually deleted the file or not.

 (5) Provide a flag, AFS_VNODE_SILLY_DELETED, to make afs_getattr() lie to
     the user about the nlink of a silly deleted file so that it appears as
     0, not 1.

Found with the generic/035 and generic/084 xfstests.

Fixes: e49c7b2f6de7 ("afs: Build an abstraction around an "operation" concept")
Reported-by: Marc Dionne &lt;marc.dionne@auristor.com&gt;
Signed-off-by: David Howells &lt;dhowells@redhat.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Fix AFS's silly rename by the following means:

 (1) Set the destination directory in afs_do_silly_rename() so as to avoid
     misbehaviour and indicate that the directory data version will
     increment by 1 so as to avoid warnings about unexpected changes in the
     DV.  Also indicate that the ctime should be updated to avoid xfstest
     grumbling.

 (2) Note when the server indicates that a directory changed more than we
     expected (AFS_OPERATION_DIR_CONFLICT), indicating a conflict with a
     third party change, checking on successful completion of unlink and
     rename.

     The problem is that the FS.RemoveFile RPC op doesn't report the status
     of the unlinked file, though YFS.RemoveFile2 does.  This can be
     mitigated by the assumption that if the directory DV cranked by
     exactly 1, we can be sure we removed one link from the file; further,
     ordinarily in AFS, files cannot be hardlinked across directories, so
     if we reduce nlink to 0, the file is deleted.

     However, if the directory DV jumps by more than 1, we cannot know if a
     third party intervened by adding or removing a link on the file we
     just removed a link from.

     The same also goes for any vnode that is at the destination of the
     FS.Rename RPC op.

 (3) Make afs_vnode_commit_status() apply the nlink drop inside the cb_lock
     section along with the other attribute updates if -&gt;op_unlinked is set
     on the descriptor for the appropriate vnode.

 (4) Issue a follow up status fetch to the unlinked file in the event of a
     third party conflict that makes it impossible for us to know if we
     actually deleted the file or not.

 (5) Provide a flag, AFS_VNODE_SILLY_DELETED, to make afs_getattr() lie to
     the user about the nlink of a silly deleted file so that it appears as
     0, not 1.

Found with the generic/035 and generic/084 xfstests.

Fixes: e49c7b2f6de7 ("afs: Build an abstraction around an "operation" concept")
Reported-by: Marc Dionne &lt;marc.dionne@auristor.com&gt;
Signed-off-by: David Howells &lt;dhowells@redhat.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>afs: Fix use of afs_check_for_remote_deletion()</title>
<updated>2020-06-16T15:26:57+00:00</updated>
<author>
<name>David Howells</name>
<email>dhowells@redhat.com</email>
</author>
<published>2020-06-15T23:34:09+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=728279a5a1fd9fa9fa268f807391c4d19ad2822c'/>
<id>728279a5a1fd9fa9fa268f807391c4d19ad2822c</id>
<content type='text'>
afs_check_for_remote_deletion() checks to see if error ENOENT is returned
by the server in response to an operation and, if so, marks the primary
vnode as having been deleted as the FID is no longer valid.

However, it's being called from the operation success functions, where no
abort has happened - and if an inline abort is recorded, it's handled by
afs_vnode_commit_status().

Fix this by actually calling the operation aborted method if provided and
having that point to afs_check_for_remote_deletion().

Fixes: e49c7b2f6de7 ("afs: Build an abstraction around an "operation" concept")
Signed-off-by: David Howells &lt;dhowells@redhat.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
afs_check_for_remote_deletion() checks to see if error ENOENT is returned
by the server in response to an operation and, if so, marks the primary
vnode as having been deleted as the FID is no longer valid.

However, it's being called from the operation success functions, where no
abort has happened - and if an inline abort is recorded, it's handled by
afs_vnode_commit_status().

Fix this by actually calling the operation aborted method if provided and
having that point to afs_check_for_remote_deletion().

Fixes: e49c7b2f6de7 ("afs: Build an abstraction around an "operation" concept")
Signed-off-by: David Howells &lt;dhowells@redhat.com&gt;
</pre>
</div>
</content>
</entry>
</feed>
