4ed5e82fe7
vfs: protect remounting superblock read-only
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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 >
2012-01-06 23:20:12 -05:00
39f7c4db1d
vfs: keep list of mounts for each superblock
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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 >
2012-01-06 23:20:12 -05:00
34c80b1d93
vfs: switch ->show_options() to struct dentry *
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Signed-off-by: Al Viro <viro@zeniv.linux.org.uk >
2012-01-06 23:19:54 -05:00
a6322de67b
vfs: switch ->show_path() to struct dentry *
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Signed-off-by: Al Viro <viro@zeniv.linux.org.uk >
2012-01-06 23:16:55 -05:00
d861c630e9
vfs: switch ->show_devname() to struct dentry *
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Signed-off-by: Al Viro <viro@zeniv.linux.org.uk >
2012-01-06 23:16:54 -05:00
64132379d5
vfs: switch ->show_stats to struct dentry *
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Signed-off-by: Al Viro <viro@zeniv.linux.org.uk >
2012-01-06 23:16:54 -05:00
cdcf116d44
switch security_path_chmod() to struct path *
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Signed-off-by: Al Viro <viro@zeniv.linux.org.uk >
2012-01-06 23:16:53 -05:00
d8c9584ea2
vfs: prefer ->dentry->d_sb to ->mnt->mnt_sb
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Signed-off-by: Al Viro <viro@zeniv.linux.org.uk >
2012-01-06 23:16:53 -05:00
ece2ccb668
Merge branches 'vfsmount-guts', 'umode_t' and 'partitions' into Z
2012-01-06 23:15:54 -05:00
d10577a8d8
vfs: trim includes a bit
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[folded fix for missing magic.h from Tetsuo Handa]
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk >
2012-01-03 22:57:13 -05:00
be08d6d260
switch mnt_namespace ->root to struct mount
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Signed-off-by: Al Viro <viro@zeniv.linux.org.uk >
2012-01-03 22:57:13 -05:00
0226f4923f
vfs: take /proc/*/mounts and friends to fs/proc_namespace.c
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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 >
2012-01-03 22:57:13 -05:00
3a2393d71d
vfs: opencode mntget() mnt_set_mountpoint()
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Signed-off-by: Al Viro <viro@zeniv.linux.org.uk >
2012-01-03 22:57:12 -05:00
909b0a88ef
vfs: spread struct mount - remaining argument of next_mnt()
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Signed-off-by: Al Viro <viro@zeniv.linux.org.uk >
2012-01-03 22:57:12 -05:00
c63181e6b6
vfs: move fsnotify junk to struct mount
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Signed-off-by: Al Viro <viro@zeniv.linux.org.uk >
2012-01-03 22:57:12 -05:00
52ba1621de
vfs: move mnt_devname
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Signed-off-by: Al Viro <viro@zeniv.linux.org.uk >
2012-01-03 22:57:11 -05:00
1a4eeaf2a8
vfs: move mnt_list to struct mount
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Signed-off-by: Al Viro <viro@zeniv.linux.org.uk >
2012-01-03 22:57:11 -05:00
fc7be130c7
vfs: switch pnode.h macros to struct mount *
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Signed-off-by: Al Viro <viro@zeniv.linux.org.uk >
2012-01-03 22:57:11 -05:00
863d684f94
vfs: move the rest of int fields to struct mount
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Signed-off-by: Al Viro <viro@zeniv.linux.org.uk >
2012-01-03 22:57:10 -05:00
15169fe784
vfs: mnt_id/mnt_group_id moved
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Signed-off-by: Al Viro <viro@zeniv.linux.org.uk >
2012-01-03 22:57:10 -05:00
143c8c91ce
vfs: mnt_ns moved to struct mount
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Signed-off-by: Al Viro <viro@zeniv.linux.org.uk >
2012-01-03 22:57:09 -05:00
900148dcac
vfs: spread struct mount - mntput_no_expire
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Signed-off-by: Al Viro <viro@zeniv.linux.org.uk >
2012-01-03 22:57:09 -05:00
95bc5f25c1
vfs: spread struct mount - do_add_mount and graft_tree
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Signed-off-by: Al Viro <viro@zeniv.linux.org.uk >
2012-01-03 22:57:09 -05:00
6776db3d32
vfs: take mnt_share/mnt_slave/mnt_slave_list and mnt_expire to struct mount
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Signed-off-by: Al Viro <viro@zeniv.linux.org.uk >
2012-01-03 22:57:08 -05:00
32301920f4
vfs: and now we can make ->mnt_master point to struct mount
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Signed-off-by: Al Viro <viro@zeniv.linux.org.uk >
2012-01-03 22:57:08 -05:00
Miklos Szeredi
Al Viro