From cc7992b8b63a24ab676ac0b86f31547fa66dfa7b Mon Sep 17 00:00:00 2001 From: Niels de Vos Date: Tue, 1 Aug 2017 10:42:11 +0200 Subject: [PATCH 583/587] libglusterfs: the global_xlator should have valid cbks There is a case where Gluster/NFS needs to resolve a path outside of the nfs-xlator itself. While resolving the path to fetch the GFID for creating the NFS-filehandle, gfapi may set an inode-ctx through glfs_resolve_at(). This inode-ctx is linked with the global_xlator. Because the global_xlator does not have any cbks, loc_wipe() will cause a segfault when it calls inode_unref() and xl->cbks->forget(). It is assumed that all xlators have a cbks symbol, otherwise loading of the xlator will fail. The global_xlator is not loaded in the same way, so there is no failure noticed when the instance is created. By adding an empty `struct xlator_cbks`, the global_xlator behaves similat to other xlators that do not implement all callbacks. I would have preferred to keep the inode-ctx setting through glfs_resolve_at() contained within Gluster/NFS. Unfortunately Gluster/NFS also uses the inode-ctx, and is not prepared to see the values that glfs_resolve_at() stores there. This problem is not easily reproducible because it involves mounting over WebNFS (like Solaris 10 can do). The segfault will also not be immediate, unless the following is done: 1. create a subdir on a volume 2. mount the volume/subdir over WebNFS 3. unmount the volume/subdir 4. mount the root of the volume 5. delete the subdir on the volume -> segfault of Gluster/NFS Cherry picked from commit cec5036f7e99ae265bb5e0e7f3df30166466eb2c: > Change-Id: I2bd71d033e97edc07ba93b2d4ada558f65d68999 > BUG: 1468291 > Signed-off-by: Niels de Vos > Reviewed-on: https://review.gluster.org/17897 > Smoke: Gluster Build System > Reviewed-by: Amar Tumballi > Reviewed-by: jiffin tony Thottan > CentOS-regression: Gluster Build System > Reviewed-by: Jeff Darcy Change-Id: I2bd71d033e97edc07ba93b2d4ada558f65d68999 BUG: 1472773 Signed-off-by: Niels de Vos Reviewed-on: https://code.engineering.redhat.com/gerrit/113997 Reviewed-by: Jiffin Thottan Reviewed-by: Atin Mukherjee --- libglusterfs/src/globals.c | 12 ++++++++++++ 1 file changed, 12 insertions(+) diff --git a/libglusterfs/src/globals.c b/libglusterfs/src/globals.c index c537971..0ac1ab9 100644 --- a/libglusterfs/src/globals.c +++ b/libglusterfs/src/globals.c @@ -125,6 +125,17 @@ glusterfs_this_destroy (void *ptr) FREE (ptr); } +static struct xlator_cbks global_cbks = { + .forget = NULL, + .release = NULL, + .releasedir = NULL, + .invalidate = NULL, + .client_destroy = NULL, + .client_disconnect = NULL, + .ictxmerge = NULL, + .ictxsize = NULL, + .fdctxsize = NULL, +}; int glusterfs_this_init () @@ -141,6 +152,7 @@ glusterfs_this_init () global_xlator.name = "glusterfs"; global_xlator.type = "global"; + global_xlator.cbks = &global_cbks; INIT_LIST_HEAD (&global_xlator.volume_options); -- 1.8.3.1