We'll introduce FMODE_RANDOM which will be runtime modified.
So protect all runtime modification to f_mode with f_lock to
avoid races.
CC: Al Viro <viro@xxxxxxxxxxxxxxxxxx>
CC: Christoph Hellwig <hch@xxxxxxxxxxxxx>
Signed-off-by: Wu Fengguang <fengguang.wu@xxxxxxxxx>
---
fs/file_table.c | 2 ++
fs/nfsd/nfs4state.c | 2 ++
2 files changed, 4 insertions(+)
--- linux.orig/fs/file_table.c 2010-01-15 09:11:07.000000000 +0800
+++ linux/fs/file_table.c 2010-01-15 09:11:15.000000000 +0800
@@ -392,7 +392,9 @@ 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);
--- linux.orig/fs/nfsd/nfs4state.c 2010-01-15 09:08:22.000000000 +0800
+++ linux/fs/nfsd/nfs4state.c 2010-01-15 09:11:15.000000000 +0800
@@ -1998,7 +1998,9 @@ nfs4_file_downgrade(struct file *filp, u
{
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);
}
}
--
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