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Commit 42e49608 authored by Wu Fengguang's avatar Wu Fengguang Committed by Linus Torvalds
Browse files

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: default avatarWu 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: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 85f1fb72

fs/file_table.c

+2 −0
Original line number Original line Diff line number Diff line
@@ -393,7 +393,9 @@ void mark_files_ro(struct super_block *sb) 
			continue;

			continue;

		if (!(f->f_mode & FMODE_WRITE))

		if (!(f->f_mode & FMODE_WRITE))

			continue;

			continue;

		spin_lock(&f->f_lock);

		f->f_mode &= ~FMODE_WRITE;

		f->f_mode &= ~FMODE_WRITE;

		spin_unlock(&f->f_lock);

		if (file_check_writeable(f) != 0)

		if (file_check_writeable(f) != 0)

			continue;

			continue;

		file_release_write(f);

		file_release_write(f);

fs/nfsd/nfs4state.c

+2 −0
Original line number Original line Diff line number Diff line
@@ -1998,7 +1998,9 @@ nfs4_file_downgrade(struct file *filp, unsigned int share_access) 
{

{

	if (share_access & NFS4_SHARE_ACCESS_WRITE) {

	if (share_access & NFS4_SHARE_ACCESS_WRITE) {

		drop_file_write_access(filp);

		drop_file_write_access(filp);

		spin_lock(&filp->f_lock);

		filp->f_mode = (filp->f_mode | FMODE_READ) & ~FMODE_WRITE;

		filp->f_mode = (filp->f_mode | FMODE_READ) & ~FMODE_WRITE;

		spin_unlock(&filp->f_lock);

	}

	}

}

}