[PATCH 12/30] r/o bind mounts: elevate mnt_writers for unlink callers

Dave Hansen
2008-02-15T22:43:55Z

linux-2.6.git-dave/fs/namei.c | 4 ++++
linux-2.6.git-dave/ipc/mqueue.c | 5 ++++-
2 files changed, 8 insertions(+), 1 deletion(-)

diff -puN fs/namei.c~r-o-bind-mounts-elevate-mnt-writers-for-vfs_unlink-callers fs/namei.c
--- linux-2.6.git/fs/namei.c~r-o-bind-mounts-elevate-mnt-writers-for-vfs_unlink-callers 2008-02-15 13:25:48.000000000 -0800
+++ linux-2.6.git-dave/fs/namei.c 2008-02-15 13:25:48.000000000 -0800
@@ -2280,7 +2280,11 @@ static long do_unlinkat(int dfd, const c
inode = dentry->d_inode;
if (inode)
atomic_inc(&inode->i_count);
+ error = mnt_want_write(nd.path.mnt);
+ if (error)
+ goto exit2;
error = vfs_unlink(nd.path.dentry->d_inode, dentry);
+ mnt_drop_write(nd.path.mnt);
exit2:
dput(dentry);
}
diff -puN ipc/mqueue.c~r-o-bind-mounts-elevate-mnt-writers-for-vfs_unlink-callers ipc/mqueue.c
--- linux-2.6.git/ipc/mqueue.c~r-o-bind-mounts-elevate-mnt-writers-for-vfs_unlink-callers 2008-02-15 13:25:48.000000000 -0800
+++ linux-2.6.git-dave/ipc/mqueue.c 2008-02-15 13:25:48.000000000 -0800
@@ -742,8 +742,11 @@ asmlinkage long sys_mq_unlink(const char
inode = dentry->d_inode;
if (inode)
atomic_inc(&inode->i_count);
-
+ err = mnt_want_write(mqueue_mnt);
+ if (err)
+ goto out_err;
err = vfs_unlink(dentry->d_parent->d_inode, dentry);
+ mnt_drop_write(mqueue_mnt);
out_err:
dput(dentry);

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