Documentation: move locks.txt in filesystems/

This documentation (about file locking) belongs in filesystems/.

Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>

diff --git a/Documentation/00-INDEX b/Documentation/00-INDEX
index 910473cb1c1c3324c7ee4d73e92a2243ef496056..cc10ce7dc339913b7c17c25f2e35533a67fb34e1 100644 (file)
--- a/Documentation/00-INDEX
+++ b/Documentation/00-INDEX
@@ -230,8 +230,6 @@ local_ops.txt
        - semantics and behavior of local atomic operations.
 lockdep-design.txt
        - documentation on the runtime locking correctness validator.
-locks.txt
-       - info on file locking implementations, flock() vs. fcntl(), etc.
 logo.gif
        - full colour GIF image of Linux logo (penguin - Tux).
 logo.txt

diff --git a/Documentation/filesystems/00-INDEX b/Documentation/filesystems/00-INDEX
index e801076812a4cc44bf6291bbccffab57fbd7efa1..599593a170679b55589fca87263b7406c6aad609 100644 (file)
--- a/Documentation/filesystems/00-INDEX
+++ b/Documentation/filesystems/00-INDEX
@@ -52,6 +52,8 @@ isofs.txt
        - info and mount options for the ISO 9660 (CDROM) filesystem.
 jfs.txt
        - info and mount options for the JFS filesystem.
+locks.txt
+       - info on file locking implementations, flock() vs. fcntl(), etc.
 mandatory-locking.txt
        - info on the Linux implementation of Sys V mandatory file locking.
 ncpfs.txt

diff --git a/Documentation/filesystems/locks.txt b/Documentation/filesystems/locks.txt
new file mode 100644 (file)
index 0000000..fab857a
--- /dev/null
+++ b/Documentation/filesystems/locks.txt
@@ -0,0 +1,67 @@
+                     File Locking Release Notes
+
+               Andy Walker <andy@lysaker.kvaerner.no>
+
+                           12 May 1997
+
+
+1. What's New?
+--------------
+
+1.1 Broken Flock Emulation
+--------------------------
+
+The old flock(2) emulation in the kernel was swapped for proper BSD
+compatible flock(2) support in the 1.3.x series of kernels. With the
+release of the 2.1.x kernel series, support for the old emulation has
+been totally removed, so that we don't need to carry this baggage
+forever.
+
+This should not cause problems for anybody, since everybody using a
+2.1.x kernel should have updated their C library to a suitable version
+anyway (see the file "Documentation/Changes".)
+
+1.2 Allow Mixed Locks Again
+---------------------------
+
+1.2.1 Typical Problems - Sendmail
+---------------------------------
+Because sendmail was unable to use the old flock() emulation, many sendmail
+installations use fcntl() instead of flock(). This is true of Slackware 3.0
+for example. This gave rise to some other subtle problems if sendmail was
+configured to rebuild the alias file. Sendmail tried to lock the aliases.dir
+file with fcntl() at the same time as the GDBM routines tried to lock this
+file with flock(). With pre 1.3.96 kernels this could result in deadlocks that,
+over time, or under a very heavy mail load, would eventually cause the kernel
+to lock solid with deadlocked processes.
+
+
+1.2.2 The Solution
+------------------
+The solution I have chosen, after much experimentation and discussion,
+is to make flock() and fcntl() locks oblivious to each other. Both can
+exists, and neither will have any effect on the other.
+
+I wanted the two lock styles to be cooperative, but there were so many
+race and deadlock conditions that the current solution was the only
+practical one. It puts us in the same position as, for example, SunOS
+4.1.x and several other commercial Unices. The only OS's that support
+cooperative flock()/fcntl() are those that emulate flock() using
+fcntl(), with all the problems that implies.
+
+
+1.3 Mandatory Locking As A Mount Option
+---------------------------------------
+
+Mandatory locking, as described in 'Documentation/filesystems/mandatory.txt'
+was prior to this release a 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 freeze an NFS server by asking it to read
+a file for which a mandatory lock existed.
+
+From this release of the kernel, mandatory locking can be turned on and off
+on a per-filesystem basis, using the mount options 'mand' and 'nomand'.
+The default is to disallow mandatory locking. The intention is that
+mandatory locking only be enabled on a local filesystem as the specific need
+arises.
+

diff --git a/Documentation/locks.txt b/Documentation/locks.txt
deleted file mode 100644 (file)
index fab857a..0000000
--- a/Documentation/locks.txt
+++ /dev/null
@@ -1,67 +0,0 @@
-                     File Locking Release Notes
-
-               Andy Walker <andy@lysaker.kvaerner.no>
-
-                           12 May 1997
-
-
-1. What's New?
---------------
-
-1.1 Broken Flock Emulation
---------------------------
-
-The old flock(2) emulation in the kernel was swapped for proper BSD
-compatible flock(2) support in the 1.3.x series of kernels. With the
-release of the 2.1.x kernel series, support for the old emulation has
-been totally removed, so that we don't need to carry this baggage
-forever.
-
-This should not cause problems for anybody, since everybody using a
-2.1.x kernel should have updated their C library to a suitable version
-anyway (see the file "Documentation/Changes".)
-
-1.2 Allow Mixed Locks Again
----------------------------
-
-1.2.1 Typical Problems - Sendmail
----------------------------------
-Because sendmail was unable to use the old flock() emulation, many sendmail
-installations use fcntl() instead of flock(). This is true of Slackware 3.0
-for example. This gave rise to some other subtle problems if sendmail was
-configured to rebuild the alias file. Sendmail tried to lock the aliases.dir
-file with fcntl() at the same time as the GDBM routines tried to lock this
-file with flock(). With pre 1.3.96 kernels this could result in deadlocks that,
-over time, or under a very heavy mail load, would eventually cause the kernel
-to lock solid with deadlocked processes.
-
-
-1.2.2 The Solution
-------------------
-The solution I have chosen, after much experimentation and discussion,
-is to make flock() and fcntl() locks oblivious to each other. Both can
-exists, and neither will have any effect on the other.
-
-I wanted the two lock styles to be cooperative, but there were so many
-race and deadlock conditions that the current solution was the only
-practical one. It puts us in the same position as, for example, SunOS
-4.1.x and several other commercial Unices. The only OS's that support
-cooperative flock()/fcntl() are those that emulate flock() using
-fcntl(), with all the problems that implies.
-
-
-1.3 Mandatory Locking As A Mount Option
----------------------------------------
-
-Mandatory locking, as described in 'Documentation/filesystems/mandatory.txt'
-was prior to this release a 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 freeze an NFS server by asking it to read
-a file for which a mandatory lock existed.
-
-From this release of the kernel, mandatory locking can be turned on and off
-on a per-filesystem basis, using the mount options 'mand' and 'nomand'.
-The default is to disallow mandatory locking. The intention is that
-mandatory locking only be enabled on a local filesystem as the specific need
-arises.
-