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<title>linux-toradex.git/fs/ext4/acl.c, branch v3.0.29</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>userns: rename is_owner_or_cap to inode_owner_or_capable</title>
<updated>2011-03-24T02:47:13+00:00</updated>
<author>
<name>Serge E. Hallyn</name>
<email>serge@hallyn.com</email>
</author>
<published>2011-03-23T23:43:26+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=2e1496707560ecf98e9b0604622c0990f94861d3'/>
<id>2e1496707560ecf98e9b0604622c0990f94861d3</id>
<content type='text'>
And give it a kernel-doc comment.

[akpm@linux-foundation.org: btrfs changed in linux-next]
Signed-off-by: Serge E. Hallyn &lt;serge.hallyn@canonical.com&gt;
Cc: "Eric W. Biederman" &lt;ebiederm@xmission.com&gt;
Cc: Daniel Lezcano &lt;daniel.lezcano@free.fr&gt;
Acked-by: David Howells &lt;dhowells@redhat.com&gt;
Cc: James Morris &lt;jmorris@namei.org&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
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<pre>
And give it a kernel-doc comment.

[akpm@linux-foundation.org: btrfs changed in linux-next]
Signed-off-by: Serge E. Hallyn &lt;serge.hallyn@canonical.com&gt;
Cc: "Eric W. Biederman" &lt;ebiederm@xmission.com&gt;
Cc: Daniel Lezcano &lt;daniel.lezcano@free.fr&gt;
Acked-by: David Howells &lt;dhowells@redhat.com&gt;
Cc: James Morris &lt;jmorris@namei.org&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>ext2,3,4: provide simple rcu-walk ACL implementation</title>
<updated>2011-01-07T06:50:30+00:00</updated>
<author>
<name>Nick Piggin</name>
<email>npiggin@kernel.dk</email>
</author>
<published>2011-01-07T06:50:00+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=73598611ade7c85f0c3d52ba5130103f6709c6d3'/>
<id>73598611ade7c85f0c3d52ba5130103f6709c6d3</id>
<content type='text'>
This simple implementation just checks for no ACLs on the inode, and
if so, then the rcu-walk may proceed, otherwise fail it.

Signed-off-by: Nick Piggin &lt;npiggin@kernel.dk&gt;
</content>
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<pre>
This simple implementation just checks for no ACLs on the inode, and
if so, then the rcu-walk may proceed, otherwise fail it.

Signed-off-by: Nick Piggin &lt;npiggin@kernel.dk&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>fs: provide rcu-walk aware permission i_ops</title>
<updated>2011-01-07T06:50:29+00:00</updated>
<author>
<name>Nick Piggin</name>
<email>npiggin@kernel.dk</email>
</author>
<published>2011-01-07T06:49:58+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=b74c79e99389cd79b31fcc08f82c24e492e63c7e'/>
<id>b74c79e99389cd79b31fcc08f82c24e492e63c7e</id>
<content type='text'>
Signed-off-by: Nick Piggin &lt;npiggin@kernel.dk&gt;
</content>
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<pre>
Signed-off-by: Nick Piggin &lt;npiggin@kernel.dk&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>ext4: update ctime when changing the file's permission by setfacl</title>
<updated>2010-06-15T16:19:59+00:00</updated>
<author>
<name>Jan Kara</name>
<email>jack@suse.cz</email>
</author>
<published>2010-06-15T16:19:59+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=c6ac12a6159c802ae8b757dd13563564e64333df'/>
<id>c6ac12a6159c802ae8b757dd13563564e64333df</id>
<content type='text'>
ext4 didn't update the ctime of the file when its permission was
changed.

Steps to reproduce:
 # touch aaa
 # stat -c %Z aaa
 1275289822
 # setfacl -m  'u::x,g::x,o::x' aaa
 # stat -c %Z aaa
 1275289822                         &lt;- unchanged

But, according to the spec of the ctime, ext4 must update it.

Port of ext3 patch by Miao Xie &lt;miaox@cn.fujitsu.com&gt;.

CC: linux-ext4@vger.kernel.org
Signed-off-by: Jan Kara &lt;jack@suse.cz&gt;
Signed-off-by: "Theodore Ts'o" &lt;tytso@mit.edu&gt;
</content>
<content type='xhtml'>
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<pre>
ext4 didn't update the ctime of the file when its permission was
changed.

Steps to reproduce:
 # touch aaa
 # stat -c %Z aaa
 1275289822
 # setfacl -m  'u::x,g::x,o::x' aaa
 # stat -c %Z aaa
 1275289822                         &lt;- unchanged

But, according to the spec of the ctime, ext4 must update it.

Port of ext3 patch by Miao Xie &lt;miaox@cn.fujitsu.com&gt;.

CC: linux-ext4@vger.kernel.org
Signed-off-by: Jan Kara &lt;jack@suse.cz&gt;
Signed-off-by: "Theodore Ts'o" &lt;tytso@mit.edu&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>ext4: constify xattr_handler</title>
<updated>2010-05-21T22:31:19+00:00</updated>
<author>
<name>Stephen Hemminger</name>
<email>shemminger@vyatta.com</email>
</author>
<published>2010-05-14T00:53:18+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=11e27528076e7dee63f1db78bffbef6310f076f4'/>
<id>11e27528076e7dee63f1db78bffbef6310f076f4</id>
<content type='text'>
Signed-off-by: Stephen Hemminger &lt;shemminger@vyatta.com&gt;
Signed-off-by: Al Viro &lt;viro@zeniv.linux.org.uk&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Signed-off-by: Stephen Hemminger &lt;shemminger@vyatta.com&gt;
Signed-off-by: Al Viro &lt;viro@zeniv.linux.org.uk&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>sanitize xattr handler prototypes</title>
<updated>2009-12-16T17:16:49+00:00</updated>
<author>
<name>Christoph Hellwig</name>
<email>hch@lst.de</email>
</author>
<published>2009-11-13T09:52:56+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=431547b3c4533b8c7fd150ab36980b9a3147797b'/>
<id>431547b3c4533b8c7fd150ab36980b9a3147797b</id>
<content type='text'>
Add a flags argument to struct xattr_handler and pass it to all xattr
handler methods.  This allows using the same methods for multiple
handlers, e.g. for the ACL methods which perform exactly the same action
for the access and default ACLs, just using a different underlying
attribute.  With a little more groundwork it'll also allow sharing the
methods for the regular user/trusted/secure handlers in extN, ocfs2 and
jffs2 like it's already done for xfs in this patch.

Also change the inode argument to the handlers to a dentry to allow
using the handlers mechnism for filesystems that require it later,
e.g. cifs.

[with GFS2 bits updated by Steven Whitehouse &lt;swhiteho@redhat.com&gt;]

Signed-off-by: Christoph Hellwig &lt;hch@lst.de&gt;
Reviewed-by: James Morris &lt;jmorris@namei.org&gt;
Acked-by: Joel Becker &lt;joel.becker@oracle.com&gt;
Signed-off-by: Al Viro &lt;viro@zeniv.linux.org.uk&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Add a flags argument to struct xattr_handler and pass it to all xattr
handler methods.  This allows using the same methods for multiple
handlers, e.g. for the ACL methods which perform exactly the same action
for the access and default ACLs, just using a different underlying
attribute.  With a little more groundwork it'll also allow sharing the
methods for the regular user/trusted/secure handlers in extN, ocfs2 and
jffs2 like it's already done for xfs in this patch.

Also change the inode argument to the handlers to a dentry to allow
using the handlers mechnism for filesystems that require it later,
e.g. cifs.

[with GFS2 bits updated by Steven Whitehouse &lt;swhiteho@redhat.com&gt;]

Signed-off-by: Christoph Hellwig &lt;hch@lst.de&gt;
Reviewed-by: James Morris &lt;jmorris@namei.org&gt;
Acked-by: Joel Becker &lt;joel.becker@oracle.com&gt;
Signed-off-by: Al Viro &lt;viro@zeniv.linux.org.uk&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>ext[234]: move over to 'check_acl' permission model</title>
<updated>2009-09-08T18:09:04+00:00</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2009-08-28T19:12:24+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=1d5ccd1c422d7d292a9e45248aa36771900c6331'/>
<id>1d5ccd1c422d7d292a9e45248aa36771900c6331</id>
<content type='text'>
Don't implement per-filesystem 'extX_permission()' functions that have
to be called for every path component operation, and instead just expose
the actual ACL checking so that the VFS layer can now do it for us.

Reviewed-by: James Morris &lt;jmorris@namei.org&gt;
Acked-by: Serge Hallyn &lt;serue@us.ibm.com&gt;
Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Don't implement per-filesystem 'extX_permission()' functions that have
to be called for every path component operation, and instead just expose
the actual ACL checking so that the VFS layer can now do it for us.

Reviewed-by: James Morris &lt;jmorris@namei.org&gt;
Acked-by: Serge Hallyn &lt;serue@us.ibm.com&gt;
Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>helpers for acl caching + switch to those</title>
<updated>2009-06-24T12:17:07+00:00</updated>
<author>
<name>Al Viro</name>
<email>viro@zeniv.linux.org.uk</email>
</author>
<published>2009-06-09T16:11:54+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=073aaa1b142461d91f83da66db1184d7c1b1edea'/>
<id>073aaa1b142461d91f83da66db1184d7c1b1edea</id>
<content type='text'>
helpers: get_cached_acl(inode, type), set_cached_acl(inode, type, acl),
forget_cached_acl(inode, type).

ubifs/xattr.c needed includes reordered, the rest is a plain switchover.

Signed-off-by: Al Viro &lt;viro@zeniv.linux.org.uk&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
helpers: get_cached_acl(inode, type), set_cached_acl(inode, type, acl),
forget_cached_acl(inode, type).

ubifs/xattr.c needed includes reordered, the rest is a plain switchover.

Signed-off-by: Al Viro &lt;viro@zeniv.linux.org.uk&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>switch ext4 to inode-&gt;i_acl</title>
<updated>2009-06-24T12:17:04+00:00</updated>
<author>
<name>Al Viro</name>
<email>viro@zeniv.linux.org.uk</email>
</author>
<published>2009-06-08T23:54:26+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=d4bfe2f76d785cc77611a4bda8cedaff358d8c7d'/>
<id>d4bfe2f76d785cc77611a4bda8cedaff358d8c7d</id>
<content type='text'>
Signed-off-by: Al Viro &lt;viro@zeniv.linux.org.uk&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Signed-off-by: Al Viro &lt;viro@zeniv.linux.org.uk&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>ext4: avoid unnecessary spinlock in critical POSIX ACL path</title>
<updated>2009-06-17T04:36:35+00:00</updated>
<author>
<name>Theodore Ts'o</name>
<email>tytso@mit.edu</email>
</author>
<published>2009-06-08T19:22:25+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=210ad6aedb332e73167ece5af9bd47f0da8c2aca'/>
<id>210ad6aedb332e73167ece5af9bd47f0da8c2aca</id>
<content type='text'>
If a filesystem supports POSIX ACL's, the VFS layer expects the filesystem
to do POSIX ACL checks on any files not owned by the caller, and it does
this for every single pathname component that it looks up.

That obviously can be pretty expensive if the filesystem isn't careful
about it, especially with locking. That's doubly sad, since the common
case tends to be that there are no ACL's associated with the files in
question.

ext4 already caches the ACL data so that it doesn't have to look it up
over and over again, but it does so by taking the inode-&gt;i_lock spinlock
on every lookup. Which is a noticeable overhead even if it's a private
lock, especially on CPU's where the serialization is expensive (eg Intel
Netburst aka 'P4').

For the special case of not actually having any ACL's, all that locking is
unnecessary. Even if somebody else were to be changing the ACL's on
another CPU, we simply don't care - if we've seen a NULL ACL, we might as
well use it.

So just load the ACL speculatively without any locking, and if it was
NULL, just use it. If it's non-NULL (either because we had a cached
entry, or because the cache hasn't been filled in at all), it means that
we'll need to get the lock and re-load it properly.

(This commit was ported from a patch originally authored by Linus for
ext3.)

Signed-off-by: "Theodore Ts'o" &lt;tytso@mit.edu&gt;
Signed-off-by: Al Viro &lt;viro@zeniv.linux.org.uk&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
If a filesystem supports POSIX ACL's, the VFS layer expects the filesystem
to do POSIX ACL checks on any files not owned by the caller, and it does
this for every single pathname component that it looks up.

That obviously can be pretty expensive if the filesystem isn't careful
about it, especially with locking. That's doubly sad, since the common
case tends to be that there are no ACL's associated with the files in
question.

ext4 already caches the ACL data so that it doesn't have to look it up
over and over again, but it does so by taking the inode-&gt;i_lock spinlock
on every lookup. Which is a noticeable overhead even if it's a private
lock, especially on CPU's where the serialization is expensive (eg Intel
Netburst aka 'P4').

For the special case of not actually having any ACL's, all that locking is
unnecessary. Even if somebody else were to be changing the ACL's on
another CPU, we simply don't care - if we've seen a NULL ACL, we might as
well use it.

So just load the ACL speculatively without any locking, and if it was
NULL, just use it. If it's non-NULL (either because we had a cached
entry, or because the cache hasn't been filled in at all), it means that
we'll need to get the lock and re-load it properly.

(This commit was ported from a patch originally authored by Linus for
ext3.)

Signed-off-by: "Theodore Ts'o" &lt;tytso@mit.edu&gt;
Signed-off-by: Al Viro &lt;viro@zeniv.linux.org.uk&gt;
</pre>
</div>
</content>
</entry>
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