Messages in this thread | | | Date | Thu, 13 Apr 2023 17:23:13 -0700 | From | Richard Cochran <> | Subject | Weirdness with bind mounts and moving files from tmpfs |
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Dear list,
If a file is copied from tmpfs onto a bind mount, the contents update as expected. However if a file is _moved_ from tmpfs onto a bind mount, the old content persists.
For example, my PC has a tmpfs on /run:
# findmnt /run TARGET SOURCE FSTYPE OPTIONS /run tmpfs tmpfs rw,nosuid,nodev,noexec,relatime,size=5737612k,mode=755,inode64
Set up a bind mounted file...
# touch /opt/file # echo one > /home/file # mount -o bind /home/file /opt/file # cat /opt/file one
Coping a file onto the bind mount via the tmpfs on /run yields...
# echo two > /run/file # cp /run/file /home/file # cat /opt/file two
So far, so good. Now do the same, but with 'mv' instead of 'cp'...
# echo three > /run/file # mv /run/file /home/file # cat /opt/file two
At this point, the contents of /opt/file are stuck forever with "two"...
# echo three > /run/file # cp /run/file /home/file # cat /opt/file two # echo three > /home/file # cat /opt/file two
What is going on here? Is this a bug or a feature?
Thanks, Richard
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