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authorWu Fengguang <fengguang.wu@intel.com>2010-03-05 13:42:01 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2010-03-06 11:26:25 -0800
commit42e49608683ab25fbbbf9c40edb944601e543882 (patch)
tree5cc8beee91f235cdaf6be986f90275e04137c2bc
parent85f1fb72fa76eabc4481dc79f42d2b011df54762 (diff)
vfs: take f_lock on modifying f_mode after open time
We'll introduce FMODE_RANDOM which will be runtime modified. So protect all runtime modification to f_mode with f_lock to avoid races. Signed-off-by: Wu Fengguang <fengguang.wu@intel.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Christoph Hellwig <hch@infradead.org> Cc: Trond Myklebust <Trond.Myklebust@netapp.com> Cc: Chuck Lever <chuck.lever@oracle.com> Cc: <stable@kernel.org> [2.6.33.x] Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--fs/file_table.c2
-rw-r--r--fs/nfsd/nfs4state.c2
2 files changed, 4 insertions, 0 deletions
diff --git a/fs/file_table.c b/fs/file_table.c
index b98404b5438..32d12b78bac 100644
--- a/fs/file_table.c
+++ b/fs/file_table.c
@@ -393,7 +393,9 @@ retry:
continue;
if (!(f->f_mode & FMODE_WRITE))
continue;
+ spin_lock(&f->f_lock);
f->f_mode &= ~FMODE_WRITE;
+ spin_unlock(&f->f_lock);
if (file_check_writeable(f) != 0)
continue;
file_release_write(f);
diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
index f19ed866c95..fcafe6087f6 100644
--- a/fs/nfsd/nfs4state.c
+++ b/fs/nfsd/nfs4state.c
@@ -1998,7 +1998,9 @@ nfs4_file_downgrade(struct file *filp, unsigned int share_access)
{
if (share_access & NFS4_SHARE_ACCESS_WRITE) {
drop_file_write_access(filp);
+ spin_lock(&filp->f_lock);
filp->f_mode = (filp->f_mode | FMODE_READ) & ~FMODE_WRITE;
+ spin_unlock(&filp->f_lock);
}
}