Commit a02dcdf6 authored by Mauro Carvalho Chehab's avatar Mauro Carvalho Chehab Committed by Jonathan Corbet
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docs: filesystems: convert mandatory-locking.txt to ReST 



- Add a SPDX header;
- Adjust document title;
- Some whitespace fixes and new line breaks;
- Use notes markups;
- Add it to filesystems/index.rst.

Signed-off-by: default avatarMauro Carvalho Chehab <mchehab+huawei@kernel.org>
Link: https://lore.kernel.org/r/aecd6259fe9f99b2c2b3440eab6a2b989125e00d.1588021877.git.mchehab+huawei@kernel.org


Signed-off-by: default avatarJonathan Corbet <corbet@lwn.net>
parent 63526525

Documentation/filesystems/index.rst

+1 −0
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@@ -29,6 +29,7 @@ algorithms work. 
   fiemap

   fiemap

   files

   files

   locks

   locks

   mandatory-locking





   automount-support

   automount-support

Documentation/filesystems/locks.rst

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@@ -58,7 +58,7 @@ fcntl(), with all the problems that implies. 
---------------------------------------

---------------------------------------





Mandatory locking, as described in

Mandatory locking, as described in

'Documentation/filesystems/mandatory-locking.txt' was prior to this release a

'Documentation/filesystems/mandatory-locking.rst' was prior to this release a

general configuration option that was valid for all mounted filesystems.  This

general configuration option that was valid for all mounted filesystems.  This

had a number of inherent dangers, not the least of which was the ability to

had a number of inherent dangers, not the least of which was the ability to

freeze an NFS server by asking it to read a file for which a mandatory lock

freeze an NFS server by asking it to read a file for which a mandatory lock

Documentation/filesystems/mandatory-locking.txt→Documentation/filesystems/mandatory-locking.rst

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.. SPDX-License-Identifier: GPL-2.0



=====================================================

Mandatory File Locking For The Linux Operating System

Mandatory File Locking For The Linux Operating System

=====================================================





		Andy Walker <andy@lysaker.kvaerner.no>

		Andy Walker <andy@lysaker.kvaerner.no>





			   15 April 1996

			   15 April 1996



		     (Updated September 2007)

		     (Updated September 2007)





0. Why you should avoid mandatory locking

0. Why you should avoid mandatory locking
@@ -53,13 +58,15 @@ possible on existing user code. The scheme is based on marking individual files 
as candidates for mandatory locking, and using the existing fcntl()/lockf()

as candidates for mandatory locking, and using the existing fcntl()/lockf()

interface for applying locks just as if they were normal, advisory locks.

interface for applying locks just as if they were normal, advisory locks.





Note 1: In saying "file" in the paragraphs above I am actually not telling

.. Note::



   1. In saying "file" in the paragraphs above I am actually not telling

      the whole truth. System V locking is based on fcntl(). The granularity of

      the whole truth. System V locking is based on fcntl(). The granularity of

fcntl() is such that it allows the locking of byte ranges in files, in addition

      fcntl() is such that it allows the locking of byte ranges in files, in

to entire files, so the mandatory locking rules also have byte level

      addition to entire files, so the mandatory locking rules also have byte

granularity.

      level granularity.





Note 2: POSIX.1 does not specify any scheme for mandatory locking, despite

   2. POSIX.1 does not specify any scheme for mandatory locking, despite

      borrowing the fcntl() locking scheme from System V. The mandatory locking

      borrowing the fcntl() locking scheme from System V. The mandatory locking

      scheme is defined by the System V Interface Definition (SVID) Version 3.

      scheme is defined by the System V Interface Definition (SVID) Version 3.

fs/locks.c

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@@ -61,7 +61,7 @@ 
 *

 *

 *  Initial implementation of mandatory locks. SunOS turned out to be

 *  Initial implementation of mandatory locks. SunOS turned out to be

 *  a rotten model, so I implemented the "obvious" semantics.

 *  a rotten model, so I implemented the "obvious" semantics.

 *  See 'Documentation/filesystems/mandatory-locking.txt' for details.

 *  See 'Documentation/filesystems/mandatory-locking.rst' for details.

 *  Andy Walker (andy@lysaker.kvaerner.no), April 06, 1996.

 *  Andy Walker (andy@lysaker.kvaerner.no), April 06, 1996.

 *

 *

 *  Don't allow mandatory locks on mmap()'ed files. Added simple functions to

 *  Don't allow mandatory locks on mmap()'ed files. Added simple functions to