From 0622753b800e4cc6cb9319b36b27658c72dd7cdc Mon Sep 17 00:00:00 2001 From: Dave Hansen Date: Fri, 15 Feb 2008 14:37:34 -0800 Subject: [PATCH] [PATCH] r/o bind mounts: elevate write count for rmdir and unlink. Elevate the write count during the vfs_rmdir() and vfs_unlink(). [AV: merged rmdir and unlink parts, added missing pieces in nfsd] Acked-by: Serge Hallyn Acked-by: Al Viro Signed-off-by: Christoph Hellwig Signed-off-by: Dave Hansen Signed-off-by: Andrew Morton Signed-off-by: Al Viro --- fs/namei.c | 9 +++++++++ fs/nfsd/nfs4recover.c | 12 +++++++++++- fs/nfsd/vfs.c | 8 +++++++- ipc/mqueue.c | 5 ++++- 4 files changed, 31 insertions(+), 3 deletions(-) diff --git a/fs/namei.c b/fs/namei.c index a1f8bbb..89ef317 100644 --- a/fs/namei.c +++ b/fs/namei.c @@ -2190,7 +2190,12 @@ static long do_rmdir(int dfd, const char __user *pathname) error = PTR_ERR(dentry); if (IS_ERR(dentry)) goto exit2; + error = mnt_want_write(nd.path.mnt); + if (error) + goto exit3; error = vfs_rmdir(nd.path.dentry->d_inode, dentry); + mnt_drop_write(nd.path.mnt); +exit3: dput(dentry); exit2: mutex_unlock(&nd.path.dentry->d_inode->i_mutex); @@ -2271,7 +2276,11 @@ static long do_unlinkat(int dfd, const char __user *pathname) 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 --git a/fs/nfsd/nfs4recover.c b/fs/nfsd/nfs4recover.c index 1ff9062..4e77a1a 100644 --- a/fs/nfsd/nfs4recover.c +++ b/fs/nfsd/nfs4recover.c @@ -46,6 +46,7 @@ #include #include #include +#include #define NFSDDBG_FACILITY NFSDDBG_PROC @@ -313,12 +314,17 @@ nfsd4_remove_clid_dir(struct nfs4_client *clp) if (!rec_dir_init || !clp->cl_firststate) return; + status = mnt_want_write(rec_dir.path.mnt); + if (status) + goto out; clp->cl_firststate = 0; nfs4_save_user(&uid, &gid); status = nfsd4_unlink_clid_dir(clp->cl_recdir, HEXDIR_LEN-1); nfs4_reset_user(uid, gid); if (status == 0) nfsd4_sync_rec_dir(); + mnt_drop_write(rec_dir.path.mnt); +out: if (status) printk("NFSD: Failed to remove expired client state directory" " %.*s\n", HEXDIR_LEN, clp->cl_recdir); @@ -347,13 +353,17 @@ nfsd4_recdir_purge_old(void) { if (!rec_dir_init) return; + status = mnt_want_write(rec_dir.path.mnt); + if (status) + goto out; status = nfsd4_list_rec_dir(rec_dir.path.dentry, purge_old); if (status == 0) nfsd4_sync_rec_dir(); + mnt_drop_write(rec_dir.path.mnt); +out: if (status) printk("nfsd4: failed to purge old clients from recovery" " directory %s\n", rec_dir.path.dentry->d_name.name); - return; } static int diff --git a/fs/nfsd/vfs.c b/fs/nfsd/vfs.c index 46f59d5..efff58a 100644 --- a/fs/nfsd/vfs.c +++ b/fs/nfsd/vfs.c @@ -1750,6 +1750,10 @@ nfsd_unlink(struct svc_rqst *rqstp, struct svc_fh *fhp, int type, if (!type) type = rdentry->d_inode->i_mode & S_IFMT; + host_err = mnt_want_write(fhp->fh_export->ex_path.mnt); + if (host_err) + goto out_nfserr; + if (type != S_IFDIR) { /* It's UNLINK */ #ifdef MSNFS if ((fhp->fh_export->ex_flags & NFSEXP_MSNFS) && @@ -1765,10 +1769,12 @@ nfsd_unlink(struct svc_rqst *rqstp, struct svc_fh *fhp, int type, dput(rdentry); if (host_err) - goto out_nfserr; + goto out_drop; if (EX_ISSYNC(fhp->fh_export)) host_err = nfsd_sync_dir(dentry); +out_drop: + mnt_drop_write(fhp->fh_export->ex_path.mnt); out_nfserr: err = nfserrno(host_err); out: diff --git a/ipc/mqueue.c b/ipc/mqueue.c index 60f7a27..34262c1 100644 --- a/ipc/mqueue.c +++ b/ipc/mqueue.c @@ -742,8 +742,11 @@ asmlinkage long sys_mq_unlink(const char __user *u_name) 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); -- 1.8.2.3