![Johannes Weiner](/assets/img/avatar_default.png)
Reclaim will be leaving shadow entries in the page cache radix tree upon evicting the real page. As those pages are found from the LRU, an iput() can lead to the inode being freed concurrently. At this point, reclaim must no longer install shadow pages because the inode freeing code needs to ensure the page tree is really empty. Add an address_space flag, AS_EXITING, that the inode freeing code sets under the tree lock before doing the final truncate. Reclaim will check for this flag before installing shadow pages. Signed-off-by: Johannes Weiner <hannes@cmpxchg.org> Reviewed-by: Rik van Riel <riel@redhat.com> Reviewed-by: Minchan Kim <minchan@kernel.org> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Bob Liu <bob.liu@oracle.com> Cc: Christoph Hellwig <hch@infradead.org> Cc: Dave Chinner <david@fromorbit.com> Cc: Greg Thelen <gthelen@google.com> Cc: Hugh Dickins <hughd@google.com> Cc: Jan Kara <jack@suse.cz> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Luigi Semenzato <semenzato@google.com> Cc: Mel Gorman <mgorman@suse.de> Cc: Metin Doslu <metin@citusdata.com> Cc: Michel Lespinasse <walken@google.com> Cc: Ozgun Erdogan <ozgun@citusdata.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Roman Gushchin <klamm@yandex-team.ru> Cc: Ryan Mallon <rmallon@gmail.com> Cc: Tejun Heo <tj@kernel.org> Cc: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
499 lines
12 KiB
C
499 lines
12 KiB
C
/*
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* Copyright (c) 2002 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/fs.h>
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#include <linux/pagemap.h>
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#include <linux/sched.h>
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#include <linux/mount.h>
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#include <linux/namei.h>
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#include "internal.h"
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struct afs_iget_data {
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struct afs_fid fid;
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struct afs_volume *volume; /* volume on which resides */
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};
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/*
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* map the AFS file status to the inode member variables
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*/
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static int afs_inode_map_status(struct afs_vnode *vnode, struct key *key)
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{
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struct inode *inode = AFS_VNODE_TO_I(vnode);
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_debug("FS: ft=%d lk=%d sz=%llu ver=%Lu mod=%hu",
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vnode->status.type,
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vnode->status.nlink,
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(unsigned long long) vnode->status.size,
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vnode->status.data_version,
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vnode->status.mode);
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switch (vnode->status.type) {
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case AFS_FTYPE_FILE:
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inode->i_mode = S_IFREG | vnode->status.mode;
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inode->i_op = &afs_file_inode_operations;
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inode->i_fop = &afs_file_operations;
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break;
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case AFS_FTYPE_DIR:
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inode->i_mode = S_IFDIR | vnode->status.mode;
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inode->i_op = &afs_dir_inode_operations;
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inode->i_fop = &afs_dir_file_operations;
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break;
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case AFS_FTYPE_SYMLINK:
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inode->i_mode = S_IFLNK | vnode->status.mode;
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inode->i_op = &page_symlink_inode_operations;
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break;
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default:
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printk("kAFS: AFS vnode with undefined type\n");
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return -EBADMSG;
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}
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#ifdef CONFIG_AFS_FSCACHE
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if (vnode->status.size != inode->i_size)
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fscache_attr_changed(vnode->cache);
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#endif
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set_nlink(inode, vnode->status.nlink);
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inode->i_uid = vnode->status.owner;
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inode->i_gid = GLOBAL_ROOT_GID;
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inode->i_size = vnode->status.size;
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inode->i_ctime.tv_sec = vnode->status.mtime_server;
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inode->i_ctime.tv_nsec = 0;
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inode->i_atime = inode->i_mtime = inode->i_ctime;
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inode->i_blocks = 0;
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inode->i_generation = vnode->fid.unique;
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inode->i_version = vnode->status.data_version;
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inode->i_mapping->a_ops = &afs_fs_aops;
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/* check to see whether a symbolic link is really a mountpoint */
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if (vnode->status.type == AFS_FTYPE_SYMLINK) {
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afs_mntpt_check_symlink(vnode, key);
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if (test_bit(AFS_VNODE_MOUNTPOINT, &vnode->flags)) {
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inode->i_mode = S_IFDIR | vnode->status.mode;
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inode->i_op = &afs_mntpt_inode_operations;
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inode->i_fop = &afs_mntpt_file_operations;
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}
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}
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return 0;
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}
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/*
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* iget5() comparator
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*/
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static int afs_iget5_test(struct inode *inode, void *opaque)
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{
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struct afs_iget_data *data = opaque;
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return inode->i_ino == data->fid.vnode &&
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inode->i_generation == data->fid.unique;
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}
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/*
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* iget5() comparator for inode created by autocell operations
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*
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* These pseudo inodes don't match anything.
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*/
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static int afs_iget5_autocell_test(struct inode *inode, void *opaque)
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{
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return 0;
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}
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/*
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* iget5() inode initialiser
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*/
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static int afs_iget5_set(struct inode *inode, void *opaque)
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{
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struct afs_iget_data *data = opaque;
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struct afs_vnode *vnode = AFS_FS_I(inode);
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inode->i_ino = data->fid.vnode;
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inode->i_generation = data->fid.unique;
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vnode->fid = data->fid;
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vnode->volume = data->volume;
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return 0;
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}
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/*
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* inode retrieval for autocell
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*/
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struct inode *afs_iget_autocell(struct inode *dir, const char *dev_name,
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int namesz, struct key *key)
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{
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struct afs_iget_data data;
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struct afs_super_info *as;
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struct afs_vnode *vnode;
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struct super_block *sb;
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struct inode *inode;
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static atomic_t afs_autocell_ino;
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_enter("{%x:%u},%*.*s,",
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AFS_FS_I(dir)->fid.vid, AFS_FS_I(dir)->fid.vnode,
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namesz, namesz, dev_name ?: "");
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sb = dir->i_sb;
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as = sb->s_fs_info;
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data.volume = as->volume;
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data.fid.vid = as->volume->vid;
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data.fid.unique = 0;
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data.fid.vnode = 0;
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inode = iget5_locked(sb, atomic_inc_return(&afs_autocell_ino),
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afs_iget5_autocell_test, afs_iget5_set,
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&data);
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if (!inode) {
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_leave(" = -ENOMEM");
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return ERR_PTR(-ENOMEM);
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}
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_debug("GOT INODE %p { ino=%lu, vl=%x, vn=%x, u=%x }",
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inode, inode->i_ino, data.fid.vid, data.fid.vnode,
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data.fid.unique);
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vnode = AFS_FS_I(inode);
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/* there shouldn't be an existing inode */
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BUG_ON(!(inode->i_state & I_NEW));
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inode->i_size = 0;
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inode->i_mode = S_IFDIR | S_IRUGO | S_IXUGO;
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inode->i_op = &afs_autocell_inode_operations;
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set_nlink(inode, 2);
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inode->i_uid = GLOBAL_ROOT_UID;
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inode->i_gid = GLOBAL_ROOT_GID;
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inode->i_ctime.tv_sec = get_seconds();
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inode->i_ctime.tv_nsec = 0;
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inode->i_atime = inode->i_mtime = inode->i_ctime;
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inode->i_blocks = 0;
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inode->i_version = 0;
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inode->i_generation = 0;
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set_bit(AFS_VNODE_PSEUDODIR, &vnode->flags);
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set_bit(AFS_VNODE_MOUNTPOINT, &vnode->flags);
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inode->i_flags |= S_AUTOMOUNT | S_NOATIME;
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unlock_new_inode(inode);
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_leave(" = %p", inode);
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return inode;
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}
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/*
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* inode retrieval
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*/
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struct inode *afs_iget(struct super_block *sb, struct key *key,
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struct afs_fid *fid, struct afs_file_status *status,
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struct afs_callback *cb)
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{
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struct afs_iget_data data = { .fid = *fid };
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struct afs_super_info *as;
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struct afs_vnode *vnode;
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struct inode *inode;
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int ret;
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_enter(",{%x:%u.%u},,", fid->vid, fid->vnode, fid->unique);
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as = sb->s_fs_info;
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data.volume = as->volume;
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inode = iget5_locked(sb, fid->vnode, afs_iget5_test, afs_iget5_set,
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&data);
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if (!inode) {
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_leave(" = -ENOMEM");
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return ERR_PTR(-ENOMEM);
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}
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_debug("GOT INODE %p { vl=%x vn=%x, u=%x }",
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inode, fid->vid, fid->vnode, fid->unique);
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vnode = AFS_FS_I(inode);
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/* deal with an existing inode */
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if (!(inode->i_state & I_NEW)) {
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_leave(" = %p", inode);
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return inode;
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}
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if (!status) {
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/* it's a remotely extant inode */
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set_bit(AFS_VNODE_CB_BROKEN, &vnode->flags);
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ret = afs_vnode_fetch_status(vnode, NULL, key);
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if (ret < 0)
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goto bad_inode;
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} else {
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/* it's an inode we just created */
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memcpy(&vnode->status, status, sizeof(vnode->status));
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if (!cb) {
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/* it's a symlink we just created (the fileserver
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* didn't give us a callback) */
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vnode->cb_version = 0;
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vnode->cb_expiry = 0;
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vnode->cb_type = 0;
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vnode->cb_expires = get_seconds();
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} else {
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vnode->cb_version = cb->version;
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vnode->cb_expiry = cb->expiry;
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vnode->cb_type = cb->type;
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vnode->cb_expires = vnode->cb_expiry + get_seconds();
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}
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}
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/* set up caching before mapping the status, as map-status reads the
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* first page of symlinks to see if they're really mountpoints */
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inode->i_size = vnode->status.size;
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#ifdef CONFIG_AFS_FSCACHE
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vnode->cache = fscache_acquire_cookie(vnode->volume->cache,
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&afs_vnode_cache_index_def,
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vnode, true);
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#endif
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ret = afs_inode_map_status(vnode, key);
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if (ret < 0)
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goto bad_inode;
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/* success */
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clear_bit(AFS_VNODE_UNSET, &vnode->flags);
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inode->i_flags |= S_NOATIME;
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unlock_new_inode(inode);
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_leave(" = %p [CB { v=%u t=%u }]", inode, vnode->cb_version, vnode->cb_type);
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return inode;
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/* failure */
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bad_inode:
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#ifdef CONFIG_AFS_FSCACHE
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fscache_relinquish_cookie(vnode->cache, 0);
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vnode->cache = NULL;
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#endif
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iget_failed(inode);
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_leave(" = %d [bad]", ret);
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return ERR_PTR(ret);
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}
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/*
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* mark the data attached to an inode as obsolete due to a write on the server
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* - might also want to ditch all the outstanding writes and dirty pages
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*/
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void afs_zap_data(struct afs_vnode *vnode)
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{
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_enter("{%x:%u}", vnode->fid.vid, vnode->fid.vnode);
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/* nuke all the non-dirty pages that aren't locked, mapped or being
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* written back in a regular file and completely discard the pages in a
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* directory or symlink */
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if (S_ISREG(vnode->vfs_inode.i_mode))
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invalidate_remote_inode(&vnode->vfs_inode);
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else
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invalidate_inode_pages2(vnode->vfs_inode.i_mapping);
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}
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/*
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* validate a vnode/inode
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* - there are several things we need to check
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* - parent dir data changes (rm, rmdir, rename, mkdir, create, link,
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* symlink)
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* - parent dir metadata changed (security changes)
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* - dentry data changed (write, truncate)
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* - dentry metadata changed (security changes)
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*/
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int afs_validate(struct afs_vnode *vnode, struct key *key)
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{
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int ret;
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_enter("{v={%x:%u} fl=%lx},%x",
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vnode->fid.vid, vnode->fid.vnode, vnode->flags,
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key_serial(key));
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if (vnode->cb_promised &&
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!test_bit(AFS_VNODE_CB_BROKEN, &vnode->flags) &&
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!test_bit(AFS_VNODE_MODIFIED, &vnode->flags) &&
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!test_bit(AFS_VNODE_ZAP_DATA, &vnode->flags)) {
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if (vnode->cb_expires < get_seconds() + 10) {
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_debug("callback expired");
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set_bit(AFS_VNODE_CB_BROKEN, &vnode->flags);
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} else {
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goto valid;
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}
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}
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if (test_bit(AFS_VNODE_DELETED, &vnode->flags))
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goto valid;
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mutex_lock(&vnode->validate_lock);
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/* if the promise has expired, we need to check the server again to get
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* a new promise - note that if the (parent) directory's metadata was
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* changed then the security may be different and we may no longer have
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* access */
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if (!vnode->cb_promised ||
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test_bit(AFS_VNODE_CB_BROKEN, &vnode->flags)) {
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_debug("not promised");
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ret = afs_vnode_fetch_status(vnode, NULL, key);
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if (ret < 0)
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goto error_unlock;
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_debug("new promise [fl=%lx]", vnode->flags);
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}
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if (test_bit(AFS_VNODE_DELETED, &vnode->flags)) {
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_debug("file already deleted");
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ret = -ESTALE;
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goto error_unlock;
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}
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/* if the vnode's data version number changed then its contents are
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* different */
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if (test_and_clear_bit(AFS_VNODE_ZAP_DATA, &vnode->flags))
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afs_zap_data(vnode);
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clear_bit(AFS_VNODE_MODIFIED, &vnode->flags);
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mutex_unlock(&vnode->validate_lock);
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valid:
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_leave(" = 0");
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return 0;
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error_unlock:
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mutex_unlock(&vnode->validate_lock);
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_leave(" = %d", ret);
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return ret;
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}
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/*
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* read the attributes of an inode
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*/
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int afs_getattr(struct vfsmount *mnt, struct dentry *dentry,
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struct kstat *stat)
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{
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struct inode *inode;
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inode = dentry->d_inode;
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_enter("{ ino=%lu v=%u }", inode->i_ino, inode->i_generation);
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generic_fillattr(inode, stat);
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return 0;
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}
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/*
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* discard an AFS inode
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*/
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int afs_drop_inode(struct inode *inode)
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{
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_enter("");
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if (test_bit(AFS_VNODE_PSEUDODIR, &AFS_FS_I(inode)->flags))
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return generic_delete_inode(inode);
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else
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return generic_drop_inode(inode);
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}
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/*
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* clear an AFS inode
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*/
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void afs_evict_inode(struct inode *inode)
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{
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struct afs_permits *permits;
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struct afs_vnode *vnode;
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vnode = AFS_FS_I(inode);
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_enter("{%x:%u.%d} v=%u x=%u t=%u }",
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vnode->fid.vid,
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vnode->fid.vnode,
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vnode->fid.unique,
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vnode->cb_version,
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vnode->cb_expiry,
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vnode->cb_type);
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_debug("CLEAR INODE %p", inode);
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ASSERTCMP(inode->i_ino, ==, vnode->fid.vnode);
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truncate_inode_pages_final(&inode->i_data);
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clear_inode(inode);
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afs_give_up_callback(vnode);
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if (vnode->server) {
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spin_lock(&vnode->server->fs_lock);
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rb_erase(&vnode->server_rb, &vnode->server->fs_vnodes);
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spin_unlock(&vnode->server->fs_lock);
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afs_put_server(vnode->server);
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vnode->server = NULL;
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}
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ASSERT(list_empty(&vnode->writebacks));
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ASSERT(!vnode->cb_promised);
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#ifdef CONFIG_AFS_FSCACHE
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fscache_relinquish_cookie(vnode->cache, 0);
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vnode->cache = NULL;
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#endif
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mutex_lock(&vnode->permits_lock);
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permits = vnode->permits;
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rcu_assign_pointer(vnode->permits, NULL);
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mutex_unlock(&vnode->permits_lock);
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if (permits)
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call_rcu(&permits->rcu, afs_zap_permits);
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_leave("");
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}
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/*
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* set the attributes of an inode
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*/
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int afs_setattr(struct dentry *dentry, struct iattr *attr)
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{
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struct afs_vnode *vnode = AFS_FS_I(dentry->d_inode);
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struct key *key;
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int ret;
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_enter("{%x:%u},{n=%s},%x",
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vnode->fid.vid, vnode->fid.vnode, dentry->d_name.name,
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|
attr->ia_valid);
|
|
|
|
if (!(attr->ia_valid & (ATTR_SIZE | ATTR_MODE | ATTR_UID | ATTR_GID |
|
|
ATTR_MTIME))) {
|
|
_leave(" = 0 [unsupported]");
|
|
return 0;
|
|
}
|
|
|
|
/* flush any dirty data outstanding on a regular file */
|
|
if (S_ISREG(vnode->vfs_inode.i_mode)) {
|
|
filemap_write_and_wait(vnode->vfs_inode.i_mapping);
|
|
afs_writeback_all(vnode);
|
|
}
|
|
|
|
if (attr->ia_valid & ATTR_FILE) {
|
|
key = attr->ia_file->private_data;
|
|
} else {
|
|
key = afs_request_key(vnode->volume->cell);
|
|
if (IS_ERR(key)) {
|
|
ret = PTR_ERR(key);
|
|
goto error;
|
|
}
|
|
}
|
|
|
|
ret = afs_vnode_setattr(vnode, key, attr);
|
|
if (!(attr->ia_valid & ATTR_FILE))
|
|
key_put(key);
|
|
|
|
error:
|
|
_leave(" = %d", ret);
|
|
return ret;
|
|
}
|