chmod of active swap file blocks

[Paul Jakma]

Hi,

Trying to chmod a file being used for swap causes chmod() to block,
with permissions change /not/ having taken effect, until the swap
file is swapoff'd, at which point chmod() carries on and chmod (the
command) finishes.

# swapon /.swapfile 
# cat /proc/swaps 
Filename				Type		Size	Used	Priority
/dev/ide/host0/bus0/target0/lun0/part1   partition	200772	51748	-1
/.swapfile                               file		131064	0	-5
# strace chmod g-w /.swapfile 2> /tmp/strace-chmod &
[3] 29208
# tail /tmp/strace-chmod 
[ snip ]
stat64("/.swapfile", {st_mode=S_IFREG|0600, st_size=134217728, ...}) = 0
chmod("/.swapfile", 0600
# swapoff /.swapfile 
# 
[3]   Done                    strace chmod g-w /.swapfile 2>/tmp/strace-chmod

NB: no, i dont use devfs :) (just same namespace.)

regards,
-- 
Paul Jakma	paul@xxxxxxxx	paul@xxxxxxxxx	Key ID: 64A2FF6A
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