nfsd: split up nfsd_setattr

Split out two helpers to make the code more readable and easier to verify
for correctness.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Cc: stable@vger.kernel.org
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

diff --git a/fs/nfsd/vfs.c b/fs/nfsd/vfs.c
index 94b5f5d..c3f57cf 100644 (file)
--- a/fs/nfsd/vfs.c
+++ b/fs/nfsd/vfs.c
@@ -298,41 +298,12 @@ commit_metadata(struct svc_fh *fhp)
 }
 
 /*
- * Set various file attributes.
- * N.B. After this call fhp needs an fh_put
+ * Go over the attributes and take care of the small differences between
+ * NFS semantics and what Linux expects.
  */
-__be32
-nfsd_setattr(struct svc_rqst *rqstp, struct svc_fh *fhp, struct iattr *iap,
-            int check_guard, time_t guardtime)
+static void
+nfsd_sanitize_attrs(struct inode *inode, struct iattr *iap)
 {
-       struct dentry   *dentry;
-       struct inode    *inode;
-       int             accmode = NFSD_MAY_SATTR;
-       umode_t         ftype = 0;
-       __be32          err;
-       int             host_err;
-       int             size_change = 0;
-
-       if (iap->ia_valid & (ATTR_ATIME | ATTR_MTIME | ATTR_SIZE))
-               accmode |= NFSD_MAY_WRITE|NFSD_MAY_OWNER_OVERRIDE;
-       if (iap->ia_valid & ATTR_SIZE)
-               ftype = S_IFREG;
-
-       /* Get inode */
-       err = fh_verify(rqstp, fhp, ftype, accmode);
-       if (err)
-               goto out;
-
-       dentry = fhp->fh_dentry;
-       inode = dentry->d_inode;
-
-       /* Ignore any mode updates on symlinks */
-       if (S_ISLNK(inode->i_mode))
-               iap->ia_valid &= ~ATTR_MODE;
-
-       if (!iap->ia_valid)
-               goto out;
-
        /*
         * NFSv2 does not differentiate between "set-[ac]time-to-now"
         * which only requires access, and "set-[ac]time-to-X" which
@@ -342,8 +313,7 @@ nfsd_setattr(struct svc_rqst *rqstp, struct svc_fh *fhp, struct iattr *iap,
         * convert to "set to now" instead of "set to explicit time"
         *
         * We only call inode_change_ok as the last test as technically
-        * it is not an interface that we should be using.  It is only
-        * valid if the filesystem does not define it's own i_op->setattr.
+        * it is not an interface that we should be using.
         */
 #define BOTH_TIME_SET (ATTR_ATIME_SET | ATTR_MTIME_SET)
 #define        MAX_TOUCH_TIME_ERROR (30*60)
@@ -369,30 +339,6 @@ nfsd_setattr(struct svc_rqst *rqstp, struct svc_fh *fhp, struct iattr *iap,
                        iap->ia_valid &= ~BOTH_TIME_SET;
                }
        }
-           
-       /*
-        * The size case is special.
-        * It changes the file as well as the attributes.
-        */
-       if (iap->ia_valid & ATTR_SIZE) {
-               if (iap->ia_size < inode->i_size) {
-                       err = nfsd_permission(rqstp, fhp->fh_export, dentry,
-                                       NFSD_MAY_TRUNC|NFSD_MAY_OWNER_OVERRIDE);
-                       if (err)
-                               goto out;
-               }
-
-               host_err = get_write_access(inode);
-               if (host_err)
-                       goto out_nfserr;
-
-               size_change = 1;
-               host_err = locks_verify_truncate(inode, NULL, iap->ia_size);
-               if (host_err) {
-                       put_write_access(inode);
-                       goto out_nfserr;
-               }
-       }
 
        /* sanitize the mode change */
        if (iap->ia_valid & ATTR_MODE) {
@@ -415,8 +361,86 @@ nfsd_setattr(struct svc_rqst *rqstp, struct svc_fh *fhp, struct iattr *iap,
                        iap->ia_valid |= (ATTR_KILL_SUID | ATTR_KILL_SGID);
                }
        }
+}
 
-       /* Change the attributes. */
+static __be32
+nfsd_get_write_access(struct svc_rqst *rqstp, struct svc_fh *fhp,
+               struct iattr *iap)
+{
+       struct inode *inode = fhp->fh_dentry->d_inode;
+       int host_err;
+
+       if (iap->ia_size < inode->i_size) {
+               __be32 err;
+
+               err = nfsd_permission(rqstp, fhp->fh_export, fhp->fh_dentry,
+                               NFSD_MAY_TRUNC | NFSD_MAY_OWNER_OVERRIDE);
+               if (err)
+                       return err;
+       }
+
+       host_err = get_write_access(inode);
+       if (host_err)
+               goto out_nfserrno;
+
+       host_err = locks_verify_truncate(inode, NULL, iap->ia_size);
+       if (host_err)
+               goto out_put_write_access;
+       return 0;
+
+out_put_write_access:
+       put_write_access(inode);
+out_nfserrno:
+       return nfserrno(host_err);
+}
+
+/*
+ * Set various file attributes.  After this call fhp needs an fh_put.
+ */
+__be32
+nfsd_setattr(struct svc_rqst *rqstp, struct svc_fh *fhp, struct iattr *iap,
+            int check_guard, time_t guardtime)
+{
+       struct dentry   *dentry;
+       struct inode    *inode;
+       int             accmode = NFSD_MAY_SATTR;
+       umode_t         ftype = 0;
+       __be32          err;
+       int             host_err;
+       int             size_change = 0;
+
+       if (iap->ia_valid & (ATTR_ATIME | ATTR_MTIME | ATTR_SIZE))
+               accmode |= NFSD_MAY_WRITE|NFSD_MAY_OWNER_OVERRIDE;
+       if (iap->ia_valid & ATTR_SIZE)
+               ftype = S_IFREG;
+
+       /* Get inode */
+       err = fh_verify(rqstp, fhp, ftype, accmode);
+       if (err)
+               goto out;
+
+       dentry = fhp->fh_dentry;
+       inode = dentry->d_inode;
+
+       /* Ignore any mode updates on symlinks */
+       if (S_ISLNK(inode->i_mode))
+               iap->ia_valid &= ~ATTR_MODE;
+
+       if (!iap->ia_valid)
+               goto out;
+
+       nfsd_sanitize_attrs(inode, iap);
+
+       /*
+        * The size case is special, it changes the file in addition to the
+        * attributes.
+        */
+       if (iap->ia_valid & ATTR_SIZE) {
+               err = nfsd_get_write_access(rqstp, fhp, iap);
+               if (err)
+                       goto out;
+               size_change = 1;
+       }
 
        iap->ia_valid |= ATTR_CTIME;