Conserve stack in zfs_setattr()

Move 'tmpxvattr' from the stack to the heap to minimize stack
space usage.  This is enough to get us below the 1024 byte stack
frame warning.  That however is still a large stack frame and it
should be further reduced by moving the 'bulk' and 'xattr_bulk'
sa_bulk_attr_t variables to the heap in a future patch.

diff --git a/module/zfs/zfs_vnops.c b/module/zfs/zfs_vnops.c
index 2dcbfe0..7e8fd92 100644 (file)
--- a/module/zfs/zfs_vnops.c
+++ b/module/zfs/zfs_vnops.c
@@ -2248,7 +2248,7 @@ zfs_setattr(struct inode *ip, vattr_t *vap, int flags, cred_t *cr)
        zilog_t         *zilog;
        dmu_tx_t        *tx;
        vattr_t         oldva;
-       xvattr_t        tmpxvattr;
+       xvattr_t        *tmpxvattr;
        uint_t          mask = vap->va_mask;
        uint_t          saved_mask;
        int             trim_mask = 0;
@@ -2305,7 +2305,8 @@ zfs_setattr(struct inode *ip, vattr_t *vap, int flags, cred_t *cr)
         */
        xoap = xva_getxoptattr(xvap);
 
-       xva_init(&tmpxvattr);
+       tmpxvattr = kmem_alloc(sizeof(xvattr_t), KM_SLEEP);
+       xva_init(tmpxvattr);
 
        /*
         * Immutable files can only alter immutable bit and atime
@@ -2313,13 +2314,13 @@ zfs_setattr(struct inode *ip, vattr_t *vap, int flags, cred_t *cr)
        if ((zp->z_pflags & ZFS_IMMUTABLE) &&
            ((mask & (ATTR_SIZE|ATTR_UID|ATTR_GID|ATTR_MTIME|ATTR_MODE)) ||
            ((mask & ATTR_XVATTR) && XVA_ISSET_REQ(xvap, XAT_CREATETIME)))) {
-               ZFS_EXIT(zsb);
-               return (EPERM);
+               err = EPERM;
+               goto out3;
        }
 
        if ((mask & ATTR_SIZE) && (zp->z_pflags & ZFS_READONLY)) {
-               ZFS_EXIT(zsb);
-               return (EPERM);
+               err = EPERM;
+               goto out3;
        }
 
        /*
@@ -2331,8 +2332,8 @@ zfs_setattr(struct inode *ip, vattr_t *vap, int flags, cred_t *cr)
        if (mask & (ATTR_ATIME | ATTR_MTIME)) {
                if (((mask & ATTR_ATIME) && TIMESPEC_OVERFLOW(&vap->va_atime)) ||
                    ((mask & ATTR_MTIME) && TIMESPEC_OVERFLOW(&vap->va_mtime))) {
-                       ZFS_EXIT(zsb);
-                       return (EOVERFLOW);
+                       err = EOVERFLOW;
+                       goto out3;
                }
        }
 
@@ -2342,8 +2343,8 @@ top:
 
        /* Can this be moved to before the top label? */
        if (zsb->z_vfs->mnt_flags & MNT_READONLY) {
-               ZFS_EXIT(zsb);
-               return (EROFS);
+               err = EROFS;
+               goto out3;
        }
 
        /*
@@ -2352,10 +2353,9 @@ top:
 
        if (mask & ATTR_SIZE) {
                err = zfs_zaccess(zp, ACE_WRITE_DATA, 0, skipaclchk, cr);
-               if (err) {
-                       ZFS_EXIT(zsb);
-                       return (err);
-               }
+               if (err)
+                       goto out3;
+
                /*
                 * XXX - Note, we are not providing any open
                 * mode flags here (like FNDELAY), so we may
@@ -2364,17 +2364,13 @@ top:
                 */
                /* XXX - would it be OK to generate a log record here? */
                err = zfs_freesp(zp, vap->va_size, 0, 0, FALSE);
-               if (err) {
-                       ZFS_EXIT(zsb);
-                       return (err);
-               }
+               if (err)
+                       goto out3;
 
                /* Careful negative Linux return code here */
                err = -vmtruncate(ip, vap->va_size);
-               if (err) {
-                       ZFS_EXIT(zsb);
-                       return (err);
-               }
+               if (err)
+                       goto out3;
        }
 
        if (mask & (ATTR_ATIME|ATTR_MTIME) ||
@@ -2455,7 +2451,7 @@ top:
                                need_policy = TRUE;
                        } else {
                                XVA_CLR_REQ(xvap, XAT_APPENDONLY);
-                               XVA_SET_REQ(&tmpxvattr, XAT_APPENDONLY);
+                               XVA_SET_REQ(tmpxvattr, XAT_APPENDONLY);
                        }
                }
 
@@ -2465,7 +2461,7 @@ top:
                                need_policy = TRUE;
                        } else {
                                XVA_CLR_REQ(xvap, XAT_NOUNLINK);
-                               XVA_SET_REQ(&tmpxvattr, XAT_NOUNLINK);
+                               XVA_SET_REQ(tmpxvattr, XAT_NOUNLINK);
                        }
                }
 
@@ -2475,7 +2471,7 @@ top:
                                need_policy = TRUE;
                        } else {
                                XVA_CLR_REQ(xvap, XAT_IMMUTABLE);
-                               XVA_SET_REQ(&tmpxvattr, XAT_IMMUTABLE);
+                               XVA_SET_REQ(tmpxvattr, XAT_IMMUTABLE);
                        }
                }
 
@@ -2485,7 +2481,7 @@ top:
                                need_policy = TRUE;
                        } else {
                                XVA_CLR_REQ(xvap, XAT_NODUMP);
-                               XVA_SET_REQ(&tmpxvattr, XAT_NODUMP);
+                               XVA_SET_REQ(tmpxvattr, XAT_NODUMP);
                        }
                }
 
@@ -2495,7 +2491,7 @@ top:
                                need_policy = TRUE;
                        } else {
                                XVA_CLR_REQ(xvap, XAT_AV_MODIFIED);
-                               XVA_SET_REQ(&tmpxvattr, XAT_AV_MODIFIED);
+                               XVA_SET_REQ(tmpxvattr, XAT_AV_MODIFIED);
                        }
                }
 
@@ -2507,14 +2503,14 @@ top:
                                need_policy = TRUE;
                        } else {
                                XVA_CLR_REQ(xvap, XAT_AV_QUARANTINED);
-                               XVA_SET_REQ(&tmpxvattr, XAT_AV_QUARANTINED);
+                               XVA_SET_REQ(tmpxvattr, XAT_AV_QUARANTINED);
                        }
                }
 
                if (XVA_ISSET_REQ(xvap, XAT_REPARSE)) {
                        mutex_exit(&zp->z_lock);
-                       ZFS_EXIT(zsb);
-                       return (EPERM);
+                       err = EPERM;
+                       goto out3;
                }
 
                if (need_policy == FALSE &&
@@ -2530,10 +2526,9 @@ top:
                if (zfs_zaccess(zp, ACE_WRITE_ACL, 0, skipaclchk, cr) == 0) {
                        err = secpolicy_setid_setsticky_clear(ip, vap,
                            &oldva, cr);
-                       if (err) {
-                               ZFS_EXIT(zsb);
-                               return (err);
-                       }
+                       if (err)
+                               goto out3;
+
                        trim_mask |= ATTR_MODE;
                } else {
                        need_policy = TRUE;
@@ -2555,10 +2550,8 @@ top:
                }
                err = secpolicy_vnode_setattr(cr, ip, vap, &oldva, flags,
                    (int (*)(void *, int, cred_t *))zfs_zaccess_unix, zp);
-               if (err) {
-                       ZFS_EXIT(zsb);
-                       return (err);
-               }
+               if (err)
+                       goto out3;
 
                if (trim_mask)
                        vap->va_mask |= saved_mask;
@@ -2783,22 +2776,22 @@ top:
                 * so that return masks can be set for caller.
                 */
 
-               if (XVA_ISSET_REQ(&tmpxvattr, XAT_APPENDONLY)) {
+               if (XVA_ISSET_REQ(tmpxvattr, XAT_APPENDONLY)) {
                        XVA_SET_REQ(xvap, XAT_APPENDONLY);
                }
-               if (XVA_ISSET_REQ(&tmpxvattr, XAT_NOUNLINK)) {
+               if (XVA_ISSET_REQ(tmpxvattr, XAT_NOUNLINK)) {
                        XVA_SET_REQ(xvap, XAT_NOUNLINK);
                }
-               if (XVA_ISSET_REQ(&tmpxvattr, XAT_IMMUTABLE)) {
+               if (XVA_ISSET_REQ(tmpxvattr, XAT_IMMUTABLE)) {
                        XVA_SET_REQ(xvap, XAT_IMMUTABLE);
                }
-               if (XVA_ISSET_REQ(&tmpxvattr, XAT_NODUMP)) {
+               if (XVA_ISSET_REQ(tmpxvattr, XAT_NODUMP)) {
                        XVA_SET_REQ(xvap, XAT_NODUMP);
                }
-               if (XVA_ISSET_REQ(&tmpxvattr, XAT_AV_MODIFIED)) {
+               if (XVA_ISSET_REQ(tmpxvattr, XAT_AV_MODIFIED)) {
                        XVA_SET_REQ(xvap, XAT_AV_MODIFIED);
                }
-               if (XVA_ISSET_REQ(&tmpxvattr, XAT_AV_QUARANTINED)) {
+               if (XVA_ISSET_REQ(tmpxvattr, XAT_AV_QUARANTINED)) {
                        XVA_SET_REQ(xvap, XAT_AV_QUARANTINED);
                }
 
@@ -2854,6 +2847,8 @@ out2:
        if (zsb->z_os->os_sync == ZFS_SYNC_ALWAYS)
                zil_commit(zilog, 0);
 
+out3:
+       kmem_free(tmpxvattr, sizeof(xvattr_t));
        ZFS_EXIT(zsb);
        return (err);
 }