Orange Pi5 kernel

^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   1) // SPDX-License-Identifier: GPL-2.0-only
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   2) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   3)  * V9FS FID Management
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   4)  *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   5)  *  Copyright (C) 2007 by Latchesar Ionkov <lucho@ionkov.net>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   6)  *  Copyright (C) 2005, 2006 by Eric Van Hensbergen <ericvh@gmail.com>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   7)  */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   8) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   9) #include <linux/module.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  10) #include <linux/errno.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  11) #include <linux/fs.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  12) #include <linux/slab.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  13) #include <linux/sched.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  14) #include <linux/idr.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  15) #include <net/9p/9p.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  16) #include <net/9p/client.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  17) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  18) #include "v9fs.h"
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  19) #include "v9fs_vfs.h"
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  20) #include "fid.h"
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  21) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  22) /**
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  23)  * v9fs_fid_add - add a fid to a dentry
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  24)  * @dentry: dentry that the fid is being added to
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  25)  * @fid: fid to add
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  26)  *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  27)  */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  28) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  29) static inline void __add_fid(struct dentry *dentry, struct p9_fid *fid)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  30) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  31) 	hlist_add_head(&fid->dlist, (struct hlist_head *)&dentry->d_fsdata);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  32) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  33) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  34) void v9fs_fid_add(struct dentry *dentry, struct p9_fid *fid)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  35) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  36) 	spin_lock(&dentry->d_lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  37) 	__add_fid(dentry, fid);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  38) 	spin_unlock(&dentry->d_lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  39) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  40) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  41) /**
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  42)  * v9fs_fid_find - retrieve a fid that belongs to the specified uid
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  43)  * @dentry: dentry to look for fid in
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  44)  * @uid: return fid that belongs to the specified user
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  45)  * @any: if non-zero, return any fid associated with the dentry
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  46)  *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  47)  */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  48) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  49) static struct p9_fid *v9fs_fid_find(struct dentry *dentry, kuid_t uid, int any)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  50) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  51) 	struct p9_fid *fid, *ret;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  52) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  53) 	p9_debug(P9_DEBUG_VFS, " dentry: %pd (%p) uid %d any %d\n",
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  54) 		 dentry, dentry, from_kuid(&init_user_ns, uid),
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  55) 		 any);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  56) 	ret = NULL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  57) 	/* we'll recheck under lock if there's anything to look in */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  58) 	if (dentry->d_fsdata) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  59) 		struct hlist_head *h = (struct hlist_head *)&dentry->d_fsdata;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  60) 		spin_lock(&dentry->d_lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  61) 		hlist_for_each_entry(fid, h, dlist) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  62) 			if (any || uid_eq(fid->uid, uid)) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  63) 				ret = fid;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  64) 				break;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  65) 			}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  66) 		}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  67) 		spin_unlock(&dentry->d_lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  68) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  69) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  70) 	return ret;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  71) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  72) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  73) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  74)  * We need to hold v9ses->rename_sem as long as we hold references
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  75)  * to returned path array. Array element contain pointers to
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  76)  * dentry names.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  77)  */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  78) static int build_path_from_dentry(struct v9fs_session_info *v9ses,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  79) 				  struct dentry *dentry, const unsigned char ***names)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  80) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  81) 	int n = 0, i;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  82) 	const unsigned char **wnames;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  83) 	struct dentry *ds;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  84) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  85) 	for (ds = dentry; !IS_ROOT(ds); ds = ds->d_parent)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  86) 		n++;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  87) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  88) 	wnames = kmalloc_array(n, sizeof(char *), GFP_KERNEL);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  89) 	if (!wnames)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  90) 		goto err_out;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  91) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  92) 	for (ds = dentry, i = (n-1); i >= 0; i--, ds = ds->d_parent)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  93) 		wnames[i] = ds->d_name.name;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  94) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  95) 	*names = wnames;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  96) 	return n;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  97) err_out:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  98) 	return -ENOMEM;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  99) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 100) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 101) static struct p9_fid *v9fs_fid_lookup_with_uid(struct dentry *dentry,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 102) 					       kuid_t uid, int any)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 103) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 104) 	struct dentry *ds;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 105) 	const unsigned char **wnames, *uname;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 106) 	int i, n, l, clone, access;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 107) 	struct v9fs_session_info *v9ses;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 108) 	struct p9_fid *fid, *old_fid = NULL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 109) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 110) 	v9ses = v9fs_dentry2v9ses(dentry);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 111) 	access = v9ses->flags & V9FS_ACCESS_MASK;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 112) 	fid = v9fs_fid_find(dentry, uid, any);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 113) 	if (fid)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 114) 		return fid;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 115) 	/*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 116) 	 * we don't have a matching fid. To do a TWALK we need
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 117) 	 * parent fid. We need to prevent rename when we want to
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 118) 	 * look at the parent.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 119) 	 */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 120) 	down_read(&v9ses->rename_sem);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 121) 	ds = dentry->d_parent;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 122) 	fid = v9fs_fid_find(ds, uid, any);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 123) 	if (fid) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 124) 		/* Found the parent fid do a lookup with that */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 125) 		fid = p9_client_walk(fid, 1, &dentry->d_name.name, 1);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 126) 		goto fid_out;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 127) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 128) 	up_read(&v9ses->rename_sem);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 129) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 130) 	/* start from the root and try to do a lookup */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 131) 	fid = v9fs_fid_find(dentry->d_sb->s_root, uid, any);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 132) 	if (!fid) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 133) 		/* the user is not attached to the fs yet */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 134) 		if (access == V9FS_ACCESS_SINGLE)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 135) 			return ERR_PTR(-EPERM);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 136) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 137) 		if (v9fs_proto_dotu(v9ses) || v9fs_proto_dotl(v9ses))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 138) 				uname = NULL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 139) 		else
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 140) 			uname = v9ses->uname;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 141) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 142) 		fid = p9_client_attach(v9ses->clnt, NULL, uname, uid,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 143) 				       v9ses->aname);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 144) 		if (IS_ERR(fid))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 145) 			return fid;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 146) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 147) 		v9fs_fid_add(dentry->d_sb->s_root, fid);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 148) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 149) 	/* If we are root ourself just return that */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 150) 	if (dentry->d_sb->s_root == dentry)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 151) 		return fid;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 152) 	/*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 153) 	 * Do a multipath walk with attached root.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 154) 	 * When walking parent we need to make sure we
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 155) 	 * don't have a parallel rename happening
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 156) 	 */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 157) 	down_read(&v9ses->rename_sem);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 158) 	n  = build_path_from_dentry(v9ses, dentry, &wnames);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 159) 	if (n < 0) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 160) 		fid = ERR_PTR(n);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 161) 		goto err_out;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 162) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 163) 	clone = 1;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 164) 	i = 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 165) 	while (i < n) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 166) 		l = min(n - i, P9_MAXWELEM);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 167) 		/*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 168) 		 * We need to hold rename lock when doing a multipath
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 169) 		 * walk to ensure none of the patch component change
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 170) 		 */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 171) 		fid = p9_client_walk(fid, l, &wnames[i], clone);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 172) 		if (IS_ERR(fid)) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 173) 			if (old_fid) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 174) 				/*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 175) 				 * If we fail, clunk fid which are mapping
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 176) 				 * to path component and not the last component
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 177) 				 * of the path.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 178) 				 */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 179) 				p9_client_clunk(old_fid);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 180) 			}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 181) 			kfree(wnames);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 182) 			goto err_out;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 183) 		}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 184) 		old_fid = fid;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 185) 		i += l;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 186) 		clone = 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 187) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 188) 	kfree(wnames);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 189) fid_out:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 190) 	if (!IS_ERR(fid)) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 191) 		spin_lock(&dentry->d_lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 192) 		if (d_unhashed(dentry)) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 193) 			spin_unlock(&dentry->d_lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 194) 			p9_client_clunk(fid);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 195) 			fid = ERR_PTR(-ENOENT);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 196) 		} else {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 197) 			__add_fid(dentry, fid);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 198) 			spin_unlock(&dentry->d_lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 199) 		}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 200) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 201) err_out:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 202) 	up_read(&v9ses->rename_sem);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 203) 	return fid;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 204) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 205) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 206) /**
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 207)  * v9fs_fid_lookup - lookup for a fid, try to walk if not found
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 208)  * @dentry: dentry to look for fid in
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 209)  *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 210)  * Look for a fid in the specified dentry for the current user.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 211)  * If no fid is found, try to create one walking from a fid from the parent
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 212)  * dentry (if it has one), or the root dentry. If the user haven't accessed
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 213)  * the fs yet, attach now and walk from the root.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 214)  */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 215) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 216) struct p9_fid *v9fs_fid_lookup(struct dentry *dentry)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 217) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 218) 	kuid_t uid;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 219) 	int  any, access;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 220) 	struct v9fs_session_info *v9ses;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 221) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 222) 	v9ses = v9fs_dentry2v9ses(dentry);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 223) 	access = v9ses->flags & V9FS_ACCESS_MASK;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 224) 	switch (access) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 225) 	case V9FS_ACCESS_SINGLE:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 226) 	case V9FS_ACCESS_USER:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 227) 	case V9FS_ACCESS_CLIENT:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 228) 		uid = current_fsuid();
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 229) 		any = 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 230) 		break;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 231) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 232) 	case V9FS_ACCESS_ANY:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 233) 		uid = v9ses->uid;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 234) 		any = 1;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 235) 		break;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 236) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 237) 	default:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 238) 		uid = INVALID_UID;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 239) 		any = 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 240) 		break;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 241) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 242) 	return v9fs_fid_lookup_with_uid(dentry, uid, any);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 243) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 244) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 245) struct p9_fid *v9fs_writeback_fid(struct dentry *dentry)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 246) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 247) 	int err;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 248) 	struct p9_fid *fid;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 249) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 250) 	fid = clone_fid(v9fs_fid_lookup_with_uid(dentry, GLOBAL_ROOT_UID, 0));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 251) 	if (IS_ERR(fid))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 252) 		goto error_out;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 253) 	/*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 254) 	 * writeback fid will only be used to write back the
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 255) 	 * dirty pages. We always request for the open fid in read-write
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 256) 	 * mode so that a partial page write which result in page
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 257) 	 * read can work.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 258) 	 */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 259) 	err = p9_client_open(fid, O_RDWR);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 260) 	if (err < 0) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 261) 		p9_client_clunk(fid);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 262) 		fid = ERR_PTR(err);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 263) 		goto error_out;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 264) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 265) error_out:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 266) 	return fid;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 267) }