Merge topic branch t/misc into pu

[aple.git] / Filesystems.m4

diff --git a/Filesystems.m4 b/Filesystems.m4
index e04f799cc5a4e810a2133fba9f8804517511730e..7750dab91c6fdbd2ef701e0d355fbd51b731ebfd 100644 (file)
--- a/Filesystems.m4
+++ b/Filesystems.m4
@@ -829,6 +829,27 @@ it's best to make the LV slightly larger than necessary and then
 enlarge the filesystem to the maximal possible size by running
 <code>resize2fs(8)</code> without specifying the new size. </p>
 
+SUBSECTION(«Fast Commits»)
+
+<p>
+
+Optimization introduced in 2020 (Linux-5.10).
+
+activated at mkfs time
+
+light-weight journaling method
+
+Idea: parts of the metadata written to the log can instead be derived
+from the inode. Leads to more compact format.
+
+Implementation: additional journal for fast commits, i.e., for those
+operations that can be optimized. Contains changes at the *file* level
+
+<li> Check <code>/proc/fs/ext4/dev/fc_info</code> to see whether fast
+commits are supported in the runing kernel. </li>
+
+</p>
+
 EXERCISES()
 
 <ul>
@@ -1385,7 +1406,7 @@ silly renames: An NFS4.1 server knows when it its safe to unlink a
 file and communicates this information to the client. </p>
 
 <p> The file handle which an nfs client received through some earlier
-rpc can become invalid at any time due to operations on a different
+rpc can become invalid at any time due to operations on different
 hosts. This happens, for example, if the file was deleted on the server
 or on a different nfs client, or when the directory that contains
 the file is no longer exported by the server due to a configuration
@@ -1432,7 +1453,7 @@ EXERCISES()
        <li> In an nfs-mounted directory (nfs version 4.0 or earlier), run
        <code>cat > foo &</code>. Note that the cat process automatically
        receives the STOP signal. Run <code>rm foo; ls -ltra</code>. Read
-       section D2 of the <a href="http://nfs.sourceforge.net/">nfs HOWTO</a>
+       section D2 of the <a href="https://nfs.sourceforge.net/">nfs HOWTO</a>
        for the explanation. </li>
 
        <li> In an nfs-mounted directory, run <code>{ while :; do echo; sleep
@@ -1441,7 +1462,7 @@ EXERCISES()
 
        <li> Discuss the pros and cons of hard vs. soft mounts. </li>
 
-       <li> Read section A10 of the <a href="http://nfs.sourceforge.net/">nfs
+       <li> Read section A10 of the <a href="https://nfs.sourceforge.net/">nfs
        HOWTO</a> to learn about common reasons for stale nfs handles. </li>
 
        <li> Can every local filesystem be exported via nfs? </li>