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POfile rename on ext3 appears to break POSIX spec
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copied!<p>I am struggling to understand what is going on in a test I am running. Test is two shell scripts running on the same machine.</p> <p>A:</p> <pre><code> #!/bin/bash touch target; for ((i=0; i < 1000; i=i+1)); do echo "snafu$i" > $1/file$i; mv -f $1/file$i $1/target; done; </code></pre> <p>B:</p> <pre><code> #!/bin/bash while(true);do cat $1/target; done </code></pre> <p>So I run A /ext3_dir, then run B /ext3_dir > out (so only errors go to std out). </p> <p>This all works fine and as expected according to the POSIX spec for 'rename': </p> <blockquote> <p>If the link named by the new argument exists, it shall be removed and old renamed to new. In this case, a link named new shall remain visible to other processes throughout the renaming operation and refer either to the file referred to by new or old before the operation began.</p> </blockquote> <p>However if I add a hard-link to the temporary file before doing the move:</p> <pre><code> #!/bin/bash touch target; for ((i=0; i < 1000; i=i+1)); do echo "snafu$i" > $1/file$i; ln $1/file$i $1/link$i mv -f $1/file$i $1/target; done; </code></pre> <p>I get "No such file or directory" errors on the reading side - seemingly in contravention of the POSIX spec. </p> <p>Can anyone shed any light on this behaviour? Is the test valid? I can't figure out why creating an extra link to the file I'm moving should impact the ability to read from the move destination.</p>

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