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>

1 files changed, 84 insertions, 60 deletions

diff --git a/fs/nfsd/vfs.c b/fs/nfsd/vfs.c
index 94b5f5d2bfed..c3f57cf14a63 100644
--- 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;