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File creation timesFile creation timesPosted Jul 29, 2010 7:34 UTC (Thu) by dlang (✭ supporter ✭, #313)Parent article: File creation times
if a file gets larger so that another block needs to be allocated, doesn't this change the metadata for the file?
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File creation times Posted Jul 29, 2010 9:18 UTC (Thu) by saffroy (subscriber, #43999) [Link]
Any change to file data will require updating mtime, which is metadata, hence ctime will be updated too. If you enlarge the file with truncate() without touching its content, you still change the file length, again a metadata.
File creation times Posted Jul 29, 2010 9:48 UTC (Thu) by fperrin (guest, #61941) [Link]
> Any change to file data will require updating mtime, which is metadata, hence ctime will be updated too.
Does this mean that ctime is always more recent than mtime ?
File creation times Posted Jul 29, 2010 10:01 UTC (Thu) by Mog (subscriber, #29529) [Link]
> Does this mean that ctime is always more recent than mtime ?
Since mtime can be set to any value (using touch for example), not always.
File creation times Posted Jul 29, 2010 17:10 UTC (Thu) by docwhat (subscriber, #40373) [Link] I had to try it for myself...$ mkdir -p /tmp/tmp.e0EkZhvZQR $ touch /tmp/tmp.e0EkZhvZQR/somefile $ stat /tmp/tmp.e0EkZhvZQR/somefile File: `/tmp/tmp.e0EkZhvZQR/somefile' Size: 0 Blocks: 0 IO Block: 4096 regular empty file Device: 801h/2049d Inode: 2760536 Links: 1 Access: (0644/-rw-r--r--) Uid: ( 1000/ holtje) Gid: ( 1000/ holtje) Access: 2010-07-29 13:09:14.990815140 -0400 Modify: 2010-07-29 13:09:14.990815140 -0400 Change: 2010-07-29 13:09:14.990815140 -0400 $ touch -m -d 2110-01-01 /tmp/tmp.e0EkZhvZQR/somefile $ stat /tmp/tmp.e0EkZhvZQR/somefile File: `/tmp/tmp.e0EkZhvZQR/somefile' Size: 0 Blocks: 0 IO Block: 4096 regular empty file Device: 801h/2049d Inode: 2760536 Links: 1 Access: (0644/-rw-r--r--) Uid: ( 1000/ holtje) Gid: ( 1000/ holtje) Access: 2010-07-29 13:09:14.990815140 -0400 Modify: 2110-01-01 00:00:00.000000000 -0500 Change: 2010-07-29 13:09:14.990815140 -0400Yup!
File creation times Posted Jul 29, 2010 23:45 UTC (Thu) by jzbiciak (✭ supporter ✭, #5246) [Link]
So how come ctime did *not* change? The metadata (ie. mtime) changed. I'm willing to believe that mtime is *not* in the set of metadata that ctime represents.
File creation times Posted Jul 30, 2010 0:13 UTC (Fri) by docwhat (subscriber, #40373) [Link] It happened too fast. I'm using a script. Here it is with a sleep.$ mkdir -p /tmp/tmp.RZFIqs7625 $ touch /tmp/tmp.RZFIqs7625/somefile $ stat /tmp/tmp.RZFIqs7625/somefile File: `/tmp/tmp.RZFIqs7625/somefile' Size: 0 Blocks: 0 IO Block: 4096 regular empty file Device: ca02h/51714d Inode: 1622396 Links: 1 Access: (0644/-rw-r--r--) Uid: ( 1002/ docwhat) Gid: ( 1002/ docwhat) Access: 2010-07-29 19:50:55.000000000 -0400 Modify: 2010-07-29 19:50:55.000000000 -0400 Change: 2010-07-29 19:50:55.000000000 -0400 $ sleep 2 $ touch -m -d 2110-01-01 /tmp/tmp.RZFIqs7625/somefile $ stat /tmp/tmp.RZFIqs7625/somefile File: `/tmp/tmp.RZFIqs7625/somefile' Size: 0 Blocks: 0 IO Block: 4096 regular empty file Device: ca02h/51714d Inode: 1622396 Links: 1 Access: (0644/-rw-r--r--) Uid: ( 1002/ docwhat) Gid: ( 1002/ docwhat) Access: 2010-07-29 19:50:55.000000000 -0400 Modify: 2110-01-01 00:00:00.000000000 -0500 Change: 2010-07-29 19:50:57.000000000 -0400The script I used: #!/bin/bash set -x mkdir -p /tmp/tmp.e0EkZhvZQR touch /tmp/tmp.e0EkZhvZQR/somefile stat /tmp/tmp.e0EkZhvZQR/somefile sleep 2 touch -m -d 2110-01-01 /tmp/tmp.e0EkZhvZQR/somefile stat /tmp/tmp.e0EkZhvZQR/somefileHere's how I ran it: $ /tmp/foo.sh |& perl -p -e 's@^\+@\$@'I just cut-and-pasted the middle of the output. Ciao!
File creation times Posted Jul 30, 2010 13:49 UTC (Fri) by jzbiciak (✭ supporter ✭, #5246) [Link]
Ah, ok. Mystery solved!
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