Commits · 4ed5e82fe77f4147cf386327c9a63a2dd7eff518 · Kirill Smelkov / linux

07 Jan, 2012 9 commits

vfs: protect remounting superblock read-only · 4ed5e82f

Miklos Szeredi authored Nov 21, 2011

Currently remouting superblock read-only is racy in a major way.

With the per mount read-only infrastructure it is now possible to
prevent most races, which this patch attempts.

Before starting the remount read-only, iterate through all mounts
belonging to the superblock and if none of them have any pending
writes, set sb->s_readonly_remount.  This indicates that remount is in
progress and no further write requests are allowed.  If the remount
succeeds set MS_RDONLY and reset s_readonly_remount.

If the remounting is unsuccessful just reset s_readonly_remount.
This can result in transient EROFS errors, despite the fact the
remount failed.  Unfortunately hodling off writes is difficult as
remount itself may touch the filesystem (e.g. through load_nls())
which would deadlock.

A later patch deals with delayed writes due to nlink going to zero.
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Tested-by: Toshiyuki Okajima <toshi.okajima@jp.fujitsu.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

4ed5e82f

vfs: keep list of mounts for each superblock · 39f7c4db

Miklos Szeredi authored Nov 21, 2011

Keep track of vfsmounts belonging to a superblock.  List is protected
by vfsmount_lock.
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Tested-by: Toshiyuki Okajima <toshi.okajima@jp.fujitsu.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

39f7c4db

vfs: switch ->show_options() to struct dentry * · 34c80b1d
Al Viro authored Dec 08, 2011
```
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
```
34c80b1d
vfs: switch ->show_path() to struct dentry * · a6322de6
Al Viro authored Dec 08, 2011
```
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
```
a6322de6
vfs: switch ->show_devname() to struct dentry * · d861c630
Al Viro authored Dec 08, 2011
```
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
```
d861c630
vfs: switch ->show_stats to struct dentry * · 64132379
Al Viro authored Dec 08, 2011
```
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
```
64132379
switch security_path_chmod() to struct path * · cdcf116d
Al Viro authored Dec 08, 2011
```
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
```
cdcf116d
vfs: prefer ->dentry->d_sb to ->mnt->mnt_sb · d8c9584e
Al Viro authored Dec 07, 2011
```
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
```
d8c9584e
Merge branches 'vfsmount-guts', 'umode_t' and 'partitions' into Z · ece2ccb6
Al Viro authored Jan 06, 2012

ece2ccb6

04 Jan, 2012 31 commits
- vfs: trim includes a bit · d10577a8
  Al Viro authored Dec 07, 2011
```
[folded fix for missing magic.h from Tetsuo Handa]
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
```
  d10577a8
- switch mnt_namespace ->root to struct mount · be08d6d2
  Al Viro authored Dec 06, 2011
```
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
```
  be08d6d2
- vfs: take /proc/*/mounts and friends to fs/proc_namespace.c · 0226f492
  Al Viro authored Dec 06, 2011
```
rationale: that stuff is far tighter bound to fs/namespace.c than to
the guts of procfs proper.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
```
  0226f492
- vfs: opencode mntget() mnt_set_mountpoint() · 3a2393d7
  Al Viro authored Nov 25, 2011
```
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
```
  3a2393d7
- vfs: spread struct mount - remaining argument of next_mnt() · 909b0a88
  Al Viro authored Nov 25, 2011
```
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
```
  909b0a88
- vfs: move fsnotify junk to struct mount · c63181e6
  Al Viro authored Nov 25, 2011
```
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
```
  c63181e6
- vfs: move mnt_devname · 52ba1621
  Al Viro authored Nov 25, 2011
```
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
```
  52ba1621
- vfs: move mnt_list to struct mount · 1a4eeaf2
  Al Viro authored Nov 25, 2011
```
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
```
  1a4eeaf2
- vfs: switch pnode.h macros to struct mount * · fc7be130
  Al Viro authored Nov 25, 2011
```
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
```
  fc7be130
- vfs: move the rest of int fields to struct mount · 863d684f
  Al Viro authored Nov 25, 2011
```
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
```
  863d684f
- vfs: mnt_id/mnt_group_id moved · 15169fe7
  Al Viro authored Nov 25, 2011
```
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
```
  15169fe7
- vfs: mnt_ns moved to struct mount · 143c8c91
  Al Viro authored Nov 25, 2011
```
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
```
  143c8c91
- vfs: spread struct mount - mntput_no_expire · 900148dc
  Al Viro authored Nov 25, 2011
```
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
```
  900148dc
- vfs: spread struct mount - do_add_mount and graft_tree · 95bc5f25
  Al Viro authored Nov 25, 2011
```
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
```
  95bc5f25
- vfs: take mnt_share/mnt_slave/mnt_slave_list and mnt_expire to struct mount · 6776db3d
  Al Viro authored Nov 25, 2011
```
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
```
  6776db3d
- vfs: and now we can make ->mnt_master point to struct mount · 32301920
  Al Viro authored Nov 25, 2011
```
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
```
  32301920
- vfs: take mnt_master to struct mount · d10e8def
  Al Viro authored Nov 25, 2011
```
make IS_MNT_SLAVE take struct mount * at the same time
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
```
  d10e8def
- vfs: spread struct mount - remaining argument of mnt_set_mountpoint() · 14cf1fa8
  Al Viro authored Nov 25, 2011
```
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
```
  14cf1fa8
- vfs: spread struct mount - propagate_mnt() · a8d56d8e
  Al Viro authored Nov 24, 2011
```
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
```
  a8d56d8e
- vfs: spread struct mount - shared subtree iterators · c937135d
  Al Viro authored Nov 24, 2011
```
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
```
  c937135d
- vfs: spread struct mount - get_dominating_id / do_make_slave · 6fc7871f
  Al Viro authored Nov 24, 2011
```
next pile of horrors, similar to mnt_parent one; this time it's
mnt_master.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
```
  6fc7871f
- vfs: take mnt_child/mnt_mounts to struct mount · 6b41d536
  Al Viro authored Nov 24, 2011
```
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
```
  6b41d536
- vfs: all counters taken to struct mount · 68e8a9fe
  Al Viro authored Nov 24, 2011
```
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
```
  68e8a9fe
- vfs: spread struct mount - work with counters · 83adc753
  Al Viro authored Nov 24, 2011
```
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
```
  83adc753
- vfs: move mnt_mountpoint to struct mount · a73324da
  Al Viro authored Nov 24, 2011
```
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
```
  a73324da
- vfs: now it can be done - make mnt_parent point to struct mount · 0714a533
  Al Viro authored Nov 24, 2011
```
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
```
  0714a533
- vfs: mnt_parent moved to struct mount · 3376f34f
  Al Viro authored Nov 24, 2011
```
the second victim...
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
```
  3376f34f
- vfs: spread struct mount - is_path_reachable · 643822b4
  Al Viro authored Nov 24, 2011
```
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
```
  643822b4
- vfs: spread struct mount - mnt_has_parent · 676da58d
  Al Viro authored Nov 24, 2011
```
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
```
  676da58d
- vfs: spread struct mount - do_umount/propagate_mount_busy · 1ab59738
  Al Viro authored Nov 24, 2011
```
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
```
  1ab59738
- vfs: spread struct mount mnt_set_mountpoint child argument · 44d964d6
  Al Viro authored Nov 24, 2011
```
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
```
  44d964d6