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![]() The /dev/ptmx device node is changed to lookup the directory entry "pts" in the same directory as the /dev/ptmx device node was opened in. If there is a "pts" entry and that entry is a devpts filesystem /dev/ptmx uses that filesystem. Otherwise the open of /dev/ptmx fails. The DEVPTS_MULTIPLE_INSTANCES configuration option is removed, so that userspace can now safely depend on each mount of devpts creating a new instance of the filesystem. Each mount of devpts is now a separate and equal filesystem. Reserved ttys are now available to all instances of devpts where the mounter is in the initial mount namespace. A new vfs helper path_pts is introduced that finds a directory entry named "pts" in the directory of the passed in path, and changes the passed in path to point to it. The helper path_pts uses a function path_parent_directory that was factored out of follow_dotdot. In the implementation of devpts: - devpts_mnt is killed as it is no longer meaningful if all mounts of devpts are equal. - pts_sb_from_inode is replaced by just inode->i_sb as all cached inodes in the tty layer are now from the devpts filesystem. - devpts_add_ref is rolled into the new function devpts_ptmx. And the unnecessary inode hold is removed. - devpts_del_ref is renamed devpts_release and reduced to just a deacrivate_super. - The newinstance mount option continues to be accepted but is now ignored. In devpts_fs.h definitions for when !CONFIG_UNIX98_PTYS are removed as they are never used. Documentation/filesystems/devices.txt is updated to describe the current situation. This has been verified to work properly on openwrt-15.05, centos5, centos6, centos7, debian-6.0.2, debian-7.9, debian-8.2, ubuntu-14.04.3, ubuntu-15.10, fedora23, magia-5, mint-17.3, opensuse-42.1, slackware-14.1, gentoo-20151225 (13.0?), archlinux-2015-12-01. With the caveat that on centos6 and on slackware-14.1 that there wind up being two instances of the devpts filesystem mounted on /dev/pts, the lower copy does not end up getting used. Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com> Cc: Greg KH <greg@kroah.com> Cc: Peter Hurley <peter@hurleysoftware.com> Cc: Peter Anvin <hpa@zytor.com> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Serge Hallyn <serge.hallyn@ubuntu.com> Cc: Willy Tarreau <w@1wt.eu> Cc: Aurelien Jarno <aurelien@aurel32.net> Cc: One Thousand Gnomes <gnomes@lxorguk.ukuu.org.uk> Cc: Jann Horn <jann@thejh.net> Cc: Jiri Slaby <jslaby@suse.com> Cc: Florian Weimer <fw@deneb.enyo.de> Cc: Konstantin Khlebnikov <koct9i@gmail.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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.. | ||
caching | ||
cifs | ||
configfs | ||
nfs | ||
pohmelfs | ||
.gitignore | ||
00-INDEX | ||
9p.txt | ||
adfs.txt | ||
affs.txt | ||
afs.txt | ||
autofs4-mount-control.txt | ||
autofs4.txt | ||
automount-support.txt | ||
befs.txt | ||
bfs.txt | ||
btrfs.txt | ||
ceph.txt | ||
coda.txt | ||
cramfs.txt | ||
dax.txt | ||
debugfs.txt | ||
devpts.txt | ||
directory-locking | ||
dlmfs.txt | ||
dnotify.txt | ||
dnotify_test.c | ||
ecryptfs.txt | ||
efivarfs.txt | ||
exofs.txt | ||
ext2.txt | ||
ext3.txt | ||
ext4.txt | ||
f2fs.txt | ||
fiemap.txt | ||
files.txt | ||
fuse.txt | ||
gfs2-glocks.txt | ||
gfs2-uevents.txt | ||
gfs2.txt | ||
hfs.txt | ||
hfsplus.txt | ||
hpfs.txt | ||
inotify.txt | ||
isofs.txt | ||
jfs.txt | ||
Locking | ||
locks.txt | ||
logfs.txt | ||
Makefile | ||
mandatory-locking.txt | ||
ncpfs.txt | ||
nilfs2.txt | ||
ntfs.txt | ||
ocfs2-online-filecheck.txt | ||
ocfs2.txt | ||
omfs.txt | ||
orangefs.txt | ||
overlayfs.txt | ||
path-lookup.md | ||
path-lookup.txt | ||
porting | ||
proc.txt | ||
qnx6.txt | ||
quota.txt | ||
ramfs-rootfs-initramfs.txt | ||
relay.txt | ||
romfs.txt | ||
seq_file.txt | ||
sharedsubtree.txt | ||
spufs.txt | ||
squashfs.txt | ||
sysfs-pci.txt | ||
sysfs-tagging.txt | ||
sysfs.txt | ||
sysv-fs.txt | ||
tmpfs.txt | ||
ubifs.txt | ||
udf.txt | ||
ufs.txt | ||
vfat.txt | ||
vfs.txt | ||
xfs-delayed-logging-design.txt | ||
xfs-self-describing-metadata.txt | ||
xfs.txt |