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Commit | Line | Data |
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cb8b711e GKH |
1 | From 42e49608683ab25fbbbf9c40edb944601e543882 Mon Sep 17 00:00:00 2001 |
2 | From: Wu Fengguang <fengguang.wu@intel.com> | |
3 | Date: Fri, 5 Mar 2010 13:42:01 -0800 | |
4 | Subject: vfs: take f_lock on modifying f_mode after open time | |
5 | ||
6 | From: Wu Fengguang <fengguang.wu@intel.com> | |
7 | ||
8 | commit 42e49608683ab25fbbbf9c40edb944601e543882 upstream. | |
9 | ||
10 | We'll introduce FMODE_RANDOM which will be runtime modified. So protect | |
11 | all runtime modification to f_mode with f_lock to avoid races. | |
12 | ||
13 | Signed-off-by: Wu Fengguang <fengguang.wu@intel.com> | |
14 | Cc: Al Viro <viro@zeniv.linux.org.uk> | |
15 | Cc: Christoph Hellwig <hch@infradead.org> | |
16 | Cc: Trond Myklebust <Trond.Myklebust@netapp.com> | |
17 | Cc: Chuck Lever <chuck.lever@oracle.com> | |
18 | Signed-off-by: Andrew Morton <akpm@linux-foundation.org> | |
19 | Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> | |
20 | Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de> | |
21 | ||
22 | --- | |
23 | fs/file_table.c | 2 ++ | |
24 | fs/nfsd/nfs4state.c | 2 ++ | |
25 | 2 files changed, 4 insertions(+) | |
26 | ||
27 | --- a/fs/file_table.c | |
28 | +++ b/fs/file_table.c | |
29 | @@ -420,7 +420,9 @@ retry: | |
30 | continue; | |
31 | if (!(f->f_mode & FMODE_WRITE)) | |
32 | continue; | |
33 | + spin_lock(&f->f_lock); | |
34 | f->f_mode &= ~FMODE_WRITE; | |
35 | + spin_unlock(&f->f_lock); | |
36 | if (file_check_writeable(f) != 0) | |
37 | continue; | |
38 | file_release_write(f); | |
39 | --- a/fs/nfsd/nfs4state.c | |
40 | +++ b/fs/nfsd/nfs4state.c | |
41 | @@ -2002,7 +2002,9 @@ nfs4_file_downgrade(struct file *filp, u | |
42 | { | |
43 | if (share_access & NFS4_SHARE_ACCESS_WRITE) { | |
44 | drop_file_write_access(filp); | |
45 | + spin_lock(&filp->f_lock); | |
46 | filp->f_mode = (filp->f_mode | FMODE_READ) & ~FMODE_WRITE; | |
47 | + spin_unlock(&filp->f_lock); | |
48 | } | |
49 | } | |
50 |