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  1. 01 4月, 2009 3 次提交
  3. 28 3月, 2009 1 次提交
  5. 27 3月, 2009 2 次提交
  7. 18 2月, 2009 1 次提交
    • A
      Fix incomplete __mntput locking · 1a88b536
      由 Al Viro 提交于 
      Getting this wrong caused

	WARNING: at fs/namespace.c:636 mntput_no_expire+0xac/0xf2()

due to optimistically checking cpu_writer->mnt outside the spinlock.

Here's what we really want:
 * we know that nobody will set cpu_writer->mnt to mnt from now on
 * all changes to that sucker are done under cpu_writer->lock
 * we want the laziest equivalent of
	spin_lock(&cpu_writer->lock);
	if (likely(cpu_writer->mnt != mnt)) {
		spin_unlock(&cpu_writer->lock);
		continue;
	}
	/* do stuff */
  that would make sure we won't miss earlier setting of ->mnt done by
  another CPU.

Anyway, for now we just move the spin_lock() earlier and move the test
into the properly locked region.
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
Reported-and-tested-by: NLi Zefan <lizf@cn.fujitsu.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      1a88b536
  9. 14 1月, 2009 2 次提交
  11. 01 1月, 2009 1 次提交
  13. 14 11月, 2008 1 次提交
  15. 13 11月, 2008 1 次提交
  17. 23 10月, 2008 3 次提交
  19. 01 8月, 2008 1 次提交
  21. 27 7月, 2008 4 次提交
  23. 14 7月, 2008 1 次提交
  25. 30 4月, 2008 1 次提交
  27. 29 4月, 2008 1 次提交
  29. 28 4月, 2008 1 次提交
  31. 25 4月, 2008 1 次提交
  33. 23 4月, 2008 5 次提交
    • M
      [patch 7/7] vfs: mountinfo: show dominating group id · 97e7e0f7
      由 Miklos Szeredi 提交于 
      Show peer group ID of nearest dominating group that has intersection
with the mount's namespace.
Signed-off-by: NMiklos Szeredi <mszeredi@suse.cz>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
      97e7e0f7
    • R
      [patch 6/7] vfs: mountinfo: add /proc/<pid>/mountinfo · 2d4d4864
      由 Ram Pai 提交于 
      [mszeredi@suse.cz] rewrite and split big patch into managable chunks

/proc/mounts in its current form lacks important information:

 - propagation state
 - root of mount for bind mounts
 - the st_dev value used within the filesystem
 - identifier for each mount and it's parent

It also suffers from the following problems:

 - not easily extendable
 - ambiguity of mountpoints within a chrooted environment
 - doesn't distinguish between filesystem dependent and independent options
 - doesn't distinguish between per mount and per super block options

This patch introduces /proc/<pid>/mountinfo which attempts to address
all these deficiencies.

Code shared between /proc/<pid>/mounts and /proc/<pid>/mountinfo is
extracted into separate functions.

Thanks to Al Viro for the help in getting the design right.
Signed-off-by: NRam Pai <linuxram@us.ibm.com>
Signed-off-by: NMiklos Szeredi <mszeredi@suse.cz>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
      2d4d4864
    • M
      [patch 5/7] vfs: mountinfo: allow using process root · a1a2c409
      由 Miklos Szeredi 提交于 
      Allow /proc/<pid>/mountinfo to use the root of <pid> to calculate
mountpoints.

 - move definition of 'struct proc_mounts' to <linux/mnt_namespace.h>
 - add the process's namespace and root to this structure
 - pass a pointer to 'struct proc_mounts' into seq_operations

In addition the following cleanups are made:

 - use a common open function for /proc/<pid>/{mounts,mountstat}
 - surround namespace.c part of these proc files with #ifdef CONFIG_PROC_FS
 - make the seq_operations structures const
Signed-off-by: NMiklos Szeredi <mszeredi@suse.cz>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
      a1a2c409
    • M
      [patch 4/7] vfs: mountinfo: add mount peer group ID · 719f5d7f
      由 Miklos Szeredi 提交于 
      Add a unique ID to each peer group using the IDR infrastructure.  The
identifiers are reused after the peer group dissolves.

The IDR structures are protected by holding namepspace_sem for write
while allocating or deallocating IDs.

IDs are allocated when a previously unshared vfsmount becomes the
first member of a peer group.  When a new member is added to an
existing group, the ID is copied from one of the old members.

IDs are freed when the last member of a peer group is unshared.

Setting the MNT_SHARED flag on members of a subtree is done as a
separate step, after all the IDs have been allocated.  This way an
allocation failure can be cleaned up easilty, without affecting the
propagation state.

Based on design sketch by Al Viro.
Signed-off-by: NMiklos Szeredi <mszeredi@suse.cz>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
      719f5d7f
    • M
      [patch 3/7] vfs: mountinfo: add mount ID · 73cd49ec
      由 Miklos Szeredi 提交于 
      Add a unique ID to each vfsmount using the IDR infrastructure.  The
identifiers are reused after the vfsmount is freed.
Signed-off-by: NMiklos Szeredi <mszeredi@suse.cz>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
      73cd49ec
  35. 22 4月, 2008 3 次提交
  37. 19 4月, 2008 3 次提交
    • D
      [PATCH] r/o bind mounts: honor mount writer counts at remount · 2e4b7fcd
      由 Dave Hansen 提交于 
      Originally from: Herbert Poetzl <herbert@13thfloor.at>

This is the core of the read-only bind mount patch set.

Note that this does _not_ add a "ro" option directly to the bind mount
operation.  If you require such a mount, you must first do the bind, then
follow it up with a 'mount -o remount,ro' operation:

If you wish to have a r/o bind mount of /foo on bar:

	mount --bind /foo /bar
	mount -o remount,ro /bar
Acked-by: NAl Viro <viro@ZenIV.linux.org.uk>
Signed-off-by: NChristoph Hellwig <hch@infradead.org>
Signed-off-by: NDave Hansen <haveblue@us.ibm.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
      2e4b7fcd
    • D
      [PATCH] r/o bind mounts: track numbers of writers to mounts · 3d733633
      由 Dave Hansen 提交于 
      This is the real meat of the entire series.  It actually
implements the tracking of the number of writers to a mount.
However, it causes scalability problems because there can be
hundreds of cpus doing open()/close() on files on the same mnt at
the same time.  Even an atomic_t in the mnt has massive scalaing
problems because the cacheline gets so terribly contended.

This uses a statically-allocated percpu variable.  All want/drop
operations are local to a cpu as long that cpu operates on the same
mount, and there are no writer count imbalances.  Writer count
imbalances happen when a write is taken on one cpu, and released
on another, like when an open/close pair is performed on two

Upon a remount,ro request, all of the data from the percpu
variables is collected (expensive, but very rare) and we determine
if there are any outstanding writers to the mount.

I've written a little benchmark to sit in a loop for a couple of
seconds in several cpus in parallel doing open/write/close loops.

http://sr71.net/~dave/linux/openbench.c

The code in here is a a worst-possible case for this patch.  It
does opens on a _pair_ of files in two different mounts in parallel.
This should cause my code to lose its "operate on the same mount"
optimization completely.  This worst-case scenario causes a 3%
degredation in the benchmark.

I could probably get rid of even this 3%, but it would be more
complex than what I have here, and I think this is getting into
acceptable territory.  In practice, I expect writing more than 3
bytes to a file, as well as disk I/O to mask any effects that this
has.

(To get rid of that 3%, we could have an #defined number of mounts
in the percpu variable.  So, instead of a CPU getting operate only
on percpu data when it accesses only one mount, it could stay on
percpu data when it only accesses N or fewer mounts.)

[AV] merged fix for __clear_mnt_mount() stepping on freed vfsmount
Acked-by: NAl Viro <viro@ZenIV.linux.org.uk>
Signed-off-by: NChristoph Hellwig <hch@infradead.org>
Signed-off-by: NDave Hansen <haveblue@us.ibm.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
      3d733633
    • D
      [PATCH] r/o bind mounts: stub functions · 8366025e
      由 Dave Hansen 提交于 
      This patch adds two function mnt_want_write() and mnt_drop_write().  These are
used like a lock pair around and fs operations that might cause a write to the
filesystem.

Before these can become useful, we must first cover each place in the VFS
where writes are performed with a want/drop pair.  When that is complete, we
can actually introduce code that will safely check the counts before allowing
r/w<->r/o transitions to occur.
Acked-by: NSerge Hallyn <serue@us.ibm.com>
Acked-by: NAl Viro <viro@ZenIV.linux.org.uk>
Signed-off-by: NChristoph Hellwig <hch@infradead.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NDave Hansen <haveblue@us.ibm.com>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
      8366025e
  39. 28 3月, 2008 4 次提交