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![David Howells](/assets/img/avatar_default.png)
While randstruct was satisfied with using an open-coded "void *" offset cast for the netfs_i_context <-> inode casting, __builtin_object_size() as used by FORTIFY_SOURCE was not as easily fooled. This was causing the following complaint[1] from gcc v12: In file included from include/linux/string.h:253, from include/linux/ceph/ceph_debug.h:7, from fs/ceph/inode.c:2: In function 'fortify_memset_chk', inlined from 'netfs_i_context_init' at include/linux/netfs.h:326:2, inlined from 'ceph_alloc_inode' at fs/ceph/inode.c:463:2: include/linux/fortify-string.h:242:25: warning: call to '__write_overflow_field' declared with attribute warning: detected write beyond size of field (1st parameter); maybe use struct_group()? [-Wattribute-warning] 242 | __write_overflow_field(p_size_field, size); | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Fix this by embedding a struct inode into struct netfs_i_context (which should perhaps be renamed to struct netfs_inode). The struct inode vfs_inode fields are then removed from the 9p, afs, ceph and cifs inode structs and vfs_inode is then simply changed to "netfs.inode" in those filesystems. Further, rename netfs_i_context to netfs_inode, get rid of the netfs_inode() function that converted a netfs_i_context pointer to an inode pointer (that can now be done with &ctx->inode) and rename the netfs_i_context() function to netfs_inode() (which is now a wrapper around container_of()). Most of the changes were done with: perl -p -i -e 's/vfs_inode/netfs.inode/'g \ `git grep -l 'vfs_inode' -- fs/{9p,afs,ceph,cifs}/*.[ch]` Kees suggested doing it with a pair structure[2] and a special declarator to insert that into the network filesystem's inode wrapper[3], but I think it's cleaner to embed it - and then it doesn't matter if struct randomisation reorders things. Dave Chinner suggested using a filesystem-specific VFS_I() function in each filesystem to convert that filesystem's own inode wrapper struct into the VFS inode struct[4]. Version #2: - Fix a couple of missed name changes due to a disabled cifs option. - Rename nfs_i_context to nfs_inode - Use "netfs" instead of "nic" as the member name in per-fs inode wrapper structs. [ This also undoes commit507160f46c
("netfs: gcc-12: temporarily disable '-Wattribute-warning' for now") that is no longer needed ] Fixes:bc899ee1c8
("netfs: Add a netfs inode context") Reported-by: Jeff Layton <jlayton@kernel.org> Signed-off-by: David Howells <dhowells@redhat.com> Reviewed-by: Jeff Layton <jlayton@kernel.org> Reviewed-by: Kees Cook <keescook@chromium.org> Reviewed-by: Xiubo Li <xiubli@redhat.com> cc: Jonathan Corbet <corbet@lwn.net> cc: Eric Van Hensbergen <ericvh@gmail.com> cc: Latchesar Ionkov <lucho@ionkov.net> cc: Dominique Martinet <asmadeus@codewreck.org> cc: Christian Schoenebeck <linux_oss@crudebyte.com> cc: Marc Dionne <marc.dionne@auristor.com> cc: Ilya Dryomov <idryomov@gmail.com> cc: Steve French <smfrench@gmail.com> cc: William Kucharski <william.kucharski@oracle.com> cc: "Matthew Wilcox (Oracle)" <willy@infradead.org> cc: Dave Chinner <david@fromorbit.com> cc: linux-doc@vger.kernel.org cc: v9fs-developer@lists.sourceforge.net cc: linux-afs@lists.infradead.org cc: ceph-devel@vger.kernel.org cc: linux-cifs@vger.kernel.org cc: samba-technical@lists.samba.org cc: linux-fsdevel@vger.kernel.org cc: linux-hardening@vger.kernel.org Link: https://lore.kernel.org/r/d2ad3a3d7bdd794c6efb562d2f2b655fb67756b9.camel@kernel.org/ [1] Link: https://lore.kernel.org/r/20220517210230.864239-1-keescook@chromium.org/ [2] Link: https://lore.kernel.org/r/20220518202212.2322058-1-keescook@chromium.org/ [3] Link: https://lore.kernel.org/r/20220524101205.GI2306852@dread.disaster.area/ [4] Link: https://lore.kernel.org/r/165296786831.3591209.12111293034669289733.stgit@warthog.procyon.org.uk/ # v1 Link: https://lore.kernel.org/r/165305805651.4094995.7763502506786714216.stgit@warthog.procyon.org.uk # v2 Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
228 lines
5.9 KiB
C
228 lines
5.9 KiB
C
/*
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* Copyright (c) 2002, 2007 Red Hat, Inc. All rights reserved.
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*
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* This software may be freely redistributed under the terms of the
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* GNU General Public License.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
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*
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* Authors: David Woodhouse <dwmw2@infradead.org>
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* David Howells <dhowells@redhat.com>
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*
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*/
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/init.h>
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#include <linux/circ_buf.h>
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#include <linux/sched.h>
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#include "internal.h"
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/*
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* Handle invalidation of an mmap'd file. We invalidate all the PTEs referring
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* to the pages in this file's pagecache, forcing the kernel to go through
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* ->fault() or ->page_mkwrite() - at which point we can handle invalidation
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* more fully.
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*/
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void afs_invalidate_mmap_work(struct work_struct *work)
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{
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struct afs_vnode *vnode = container_of(work, struct afs_vnode, cb_work);
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unmap_mapping_pages(vnode->netfs.inode.i_mapping, 0, 0, false);
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}
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void afs_server_init_callback_work(struct work_struct *work)
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{
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struct afs_server *server = container_of(work, struct afs_server, initcb_work);
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struct afs_vnode *vnode;
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struct afs_cell *cell = server->cell;
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down_read(&cell->fs_open_mmaps_lock);
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list_for_each_entry(vnode, &cell->fs_open_mmaps, cb_mmap_link) {
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if (vnode->cb_server == server) {
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clear_bit(AFS_VNODE_CB_PROMISED, &vnode->flags);
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queue_work(system_unbound_wq, &vnode->cb_work);
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}
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}
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up_read(&cell->fs_open_mmaps_lock);
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}
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/*
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* Allow the fileserver to request callback state (re-)initialisation.
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* Unfortunately, UUIDs are not guaranteed unique.
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*/
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void afs_init_callback_state(struct afs_server *server)
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{
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rcu_read_lock();
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do {
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server->cb_s_break++;
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atomic_inc(&server->cell->fs_s_break);
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if (!list_empty(&server->cell->fs_open_mmaps))
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queue_work(system_unbound_wq, &server->initcb_work);
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} while ((server = rcu_dereference(server->uuid_next)));
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rcu_read_unlock();
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}
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/*
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* actually break a callback
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*/
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void __afs_break_callback(struct afs_vnode *vnode, enum afs_cb_break_reason reason)
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{
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_enter("");
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clear_bit(AFS_VNODE_NEW_CONTENT, &vnode->flags);
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if (test_and_clear_bit(AFS_VNODE_CB_PROMISED, &vnode->flags)) {
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vnode->cb_break++;
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vnode->cb_v_break = vnode->volume->cb_v_break;
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afs_clear_permits(vnode);
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if (vnode->lock_state == AFS_VNODE_LOCK_WAITING_FOR_CB)
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afs_lock_may_be_available(vnode);
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if (reason != afs_cb_break_for_deleted &&
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vnode->status.type == AFS_FTYPE_FILE &&
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atomic_read(&vnode->cb_nr_mmap))
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queue_work(system_unbound_wq, &vnode->cb_work);
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trace_afs_cb_break(&vnode->fid, vnode->cb_break, reason, true);
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} else {
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trace_afs_cb_break(&vnode->fid, vnode->cb_break, reason, false);
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}
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}
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void afs_break_callback(struct afs_vnode *vnode, enum afs_cb_break_reason reason)
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{
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write_seqlock(&vnode->cb_lock);
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__afs_break_callback(vnode, reason);
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write_sequnlock(&vnode->cb_lock);
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}
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/*
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* Look up a volume by volume ID under RCU conditions.
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*/
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static struct afs_volume *afs_lookup_volume_rcu(struct afs_cell *cell,
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afs_volid_t vid)
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{
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struct afs_volume *volume = NULL;
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struct rb_node *p;
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int seq = 0;
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do {
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/* Unfortunately, rbtree walking doesn't give reliable results
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* under just the RCU read lock, so we have to check for
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* changes.
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*/
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read_seqbegin_or_lock(&cell->volume_lock, &seq);
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p = rcu_dereference_raw(cell->volumes.rb_node);
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while (p) {
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volume = rb_entry(p, struct afs_volume, cell_node);
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if (volume->vid < vid)
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p = rcu_dereference_raw(p->rb_left);
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else if (volume->vid > vid)
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p = rcu_dereference_raw(p->rb_right);
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else
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break;
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volume = NULL;
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}
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} while (need_seqretry(&cell->volume_lock, seq));
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done_seqretry(&cell->volume_lock, seq);
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return volume;
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}
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/*
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* allow the fileserver to explicitly break one callback
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* - happens when
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* - the backing file is changed
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* - a lock is released
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*/
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static void afs_break_one_callback(struct afs_volume *volume,
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struct afs_fid *fid)
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{
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struct super_block *sb;
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struct afs_vnode *vnode;
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struct inode *inode;
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if (fid->vnode == 0 && fid->unique == 0) {
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/* The callback break applies to an entire volume. */
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write_lock(&volume->cb_v_break_lock);
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volume->cb_v_break++;
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trace_afs_cb_break(fid, volume->cb_v_break,
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afs_cb_break_for_volume_callback, false);
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write_unlock(&volume->cb_v_break_lock);
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return;
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}
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/* See if we can find a matching inode - even an I_NEW inode needs to
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* be marked as it can have its callback broken before we finish
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* setting up the local inode.
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*/
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sb = rcu_dereference(volume->sb);
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if (!sb)
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return;
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inode = find_inode_rcu(sb, fid->vnode, afs_ilookup5_test_by_fid, fid);
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if (inode) {
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vnode = AFS_FS_I(inode);
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afs_break_callback(vnode, afs_cb_break_for_callback);
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} else {
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trace_afs_cb_miss(fid, afs_cb_break_for_callback);
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}
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}
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static void afs_break_some_callbacks(struct afs_server *server,
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struct afs_callback_break *cbb,
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size_t *_count)
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{
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struct afs_callback_break *residue = cbb;
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struct afs_volume *volume;
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afs_volid_t vid = cbb->fid.vid;
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size_t i;
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volume = afs_lookup_volume_rcu(server->cell, vid);
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/* TODO: Find all matching volumes if we couldn't match the server and
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* break them anyway.
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*/
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for (i = *_count; i > 0; cbb++, i--) {
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if (cbb->fid.vid == vid) {
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_debug("- Fid { vl=%08llx n=%llu u=%u }",
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cbb->fid.vid,
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cbb->fid.vnode,
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cbb->fid.unique);
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--*_count;
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if (volume)
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afs_break_one_callback(volume, &cbb->fid);
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} else {
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*residue++ = *cbb;
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}
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}
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}
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/*
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* allow the fileserver to break callback promises
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*/
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void afs_break_callbacks(struct afs_server *server, size_t count,
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struct afs_callback_break *callbacks)
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{
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_enter("%p,%zu,", server, count);
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ASSERT(server != NULL);
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rcu_read_lock();
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while (count > 0)
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afs_break_some_callbacks(server, callbacks, &count);
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rcu_read_unlock();
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return;
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}
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