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Date: Fri, 31 Dec 2021 16:15:04 +0800 From: zhanchengbin <zhanchengbin1@...wei.com> To: Theodore Ts'o <tytso@....edu> CC: <linux-ext4@...r.kernel.org>, <liuzhiqiang26@...wei.com>, <linfeilong@...wei.com> Subject: Re: [PATCH] resize2fs : resize2fs failed due to the same name of tmpfs To clarify, commit ea4d53b7b9079fd6e2cc34cf569a993a183bfbd2 does solve the problem for mounting a disk with the same name as file system "tmpfs". However, after mounting it, "ln" command (creating a hard link) and "resize2fs" command still report an error. example: dev_name="/dev/sdc" (ps: a disk in you self) mkdir /root/tmp mkdir /root/mnt mkfs.ext4 -F -b 1024 -E "resize=10000000" "${dev_name}" 32768 mount -t tmpfs "${dev_name}" /root/tmp mount "${dev_name}" /root/mnt ln "${dev_name}" "${dev_name}"-ln resize2fs "${dev_name}"-ln 6G You can see the disk is mounted on /root/tmp, but it should be mounted on /root/mnt actually. I will modify the commit message and submit the v2 patch to solve this problem. 在 2021/12/22 4:57, Theodore Ts'o 写道: > On Tue, Nov 30, 2021 at 12:04:48PM +0800, zhanchengbin wrote: >> If there is a tmpfs with the same name as the disk, and mount before the >> disk,example: >> /dev/sdd /root/tmp tmpfs rw,seclabel,relatime 0 0 >> /dev/sdd /root/mnt ext4 rw,seclabel,relatime 0 0 > > This should already be fixed e2fsprogs 1.45.5+ via this commit: > > commit ea4d53b7b9079fd6e2cc34cf569a993a183bfbd2 > Author: Theodore Ts'o <tytso@....edu> > Date: Sun Nov 10 12:11:49 2019 -0500 > > libext2fs/ismounted.c: check device id in advance to skip false device names > > If there is a trickster which tries to use device names as the mount > device for pseudo-file systems, the resulting /proc/mounts can confuse > ext2fs_check_mount_point(). (So far as I can tell, there's no good > reason to do this, but sysadmins do the darnest things.) > > An example of this might be the following /proc/mounts excerpt: > > /dev/sdb /mnt2 tmpfs rw,relatime 0 0 > /dev/sdb /mnt ext4 rw,relatime 0 0 > > This is created via "mount -t tmpfs /dev/sdb /mnt2" followed via > "mount -t ext4 /dev/sdb /mnt". (Normally, a sane mount of tmpfs would > use something like "mount -t tmpfs tmpfs /mnt2".) > > Fix this by double checking the st_rdev of the claimed mountpoint and > match it with the dev_t of the device. (Note that the GNU HURD > doesn't support st_rdev, so we can't solve this problem for the HURD.) > > Reported-by: GuiYao <guiyao@...wei.com> > Signed-off-by: Theodore Ts'o <tytso@....edu> > > I've tested via tst_ismounted and I can't replicate the issue you've described. > > % cd /build/e2fsprogs-maint/lib/ext2fs > % make tst_ismounted > % sudo ./tst_ismounted /dev/dm-7 > Bogus entry in /proc/mounts! (/dev/dm-7 is not mounted on /root/tmp) > Device /dev/dm-7 reports flags 11 > /dev/dm-7 is apparently in use. > /dev/dm-7 is mounted. > /dev/dm-7 is mounted on /root/mnt. > > Cheers, > > - Ted > . >
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