^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) * Overlayfs NFS export support.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 4) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 5) * Amir Goldstein <amir73il@gmail.com>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 6) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 7) * Copyright (C) 2017-2018 CTERA Networks. All Rights Reserved.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 8) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 9)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 10) #include <linux/fs.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 11) #include <linux/cred.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 12) #include <linux/mount.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 13) #include <linux/namei.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 14) #include <linux/xattr.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 15) #include <linux/exportfs.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 16) #include <linux/ratelimit.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 17) #include "overlayfs.h"
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 18)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 19) static int ovl_encode_maybe_copy_up(struct dentry *dentry)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 20) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 21) int err;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 22)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 23) if (ovl_dentry_upper(dentry))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 24) return 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 25)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 26) err = ovl_want_write(dentry);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 27) if (!err) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 28) err = ovl_copy_up(dentry);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 29) ovl_drop_write(dentry);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 30) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 31)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 32) if (err) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 33) pr_warn_ratelimited("failed to copy up on encode (%pd2, err=%i)\n",
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 34) dentry, err);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 35) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 36)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 37) return err;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 38) }
^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) * Before encoding a non-upper directory file handle from real layer N, we need
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 42) * to check if it will be possible to reconnect an overlay dentry from the real
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 43) * lower decoded dentry. This is done by following the overlay ancestry up to a
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 44) * "layer N connected" ancestor and verifying that all parents along the way are
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 45) * "layer N connectable". If an ancestor that is NOT "layer N connectable" is
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 46) * found, we need to copy up an ancestor, which is "layer N connectable", thus
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 47) * making that ancestor "layer N connected". For example:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 48) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 49) * layer 1: /a
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 50) * layer 2: /a/b/c
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 51) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 52) * The overlay dentry /a is NOT "layer 2 connectable", because if dir /a is
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 53) * copied up and renamed, upper dir /a will be indexed by lower dir /a from
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 54) * layer 1. The dir /a from layer 2 will never be indexed, so the algorithm (*)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 55) * in ovl_lookup_real_ancestor() will not be able to lookup a connected overlay
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 56) * dentry from the connected lower dentry /a/b/c.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 57) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 58) * To avoid this problem on decode time, we need to copy up an ancestor of
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 59) * /a/b/c, which is "layer 2 connectable", on encode time. That ancestor is
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 60) * /a/b. After copy up (and index) of /a/b, it will become "layer 2 connected"
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 61) * and when the time comes to decode the file handle from lower dentry /a/b/c,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 62) * ovl_lookup_real_ancestor() will find the indexed ancestor /a/b and decoding
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 63) * a connected overlay dentry will be accomplished.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 64) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 65) * (*) the algorithm in ovl_lookup_real_ancestor() can be improved to lookup an
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 66) * entry /a in the lower layers above layer N and find the indexed dir /a from
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 67) * layer 1. If that improvement is made, then the check for "layer N connected"
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 68) * will need to verify there are no redirects in lower layers above N. In the
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 69) * example above, /a will be "layer 2 connectable". However, if layer 2 dir /a
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 70) * is a target of a layer 1 redirect, then /a will NOT be "layer 2 connectable":
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 71) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 72) * layer 1: /A (redirect = /a)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 73) * layer 2: /a/b/c
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 74) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 75)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 76) /* Return the lowest layer for encoding a connectable file handle */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 77) static int ovl_connectable_layer(struct dentry *dentry)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 78) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 79) struct ovl_entry *oe = OVL_E(dentry);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 80)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 81) /* We can get overlay root from root of any layer */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 82) if (dentry == dentry->d_sb->s_root)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 83) return oe->numlower;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 84)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 85) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 86) * If it's an unindexed merge dir, then it's not connectable with any
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 87) * lower layer
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 88) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 89) if (ovl_dentry_upper(dentry) &&
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 90) !ovl_test_flag(OVL_INDEX, d_inode(dentry)))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 91) return 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 92)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 93) /* We can get upper/overlay path from indexed/lower dentry */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 94) return oe->lowerstack[0].layer->idx;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 95) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 96)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 97) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 98) * @dentry is "connected" if all ancestors up to root or a "connected" ancestor
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 99) * have the same uppermost lower layer as the origin's layer. We may need to
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 100) * copy up a "connectable" ancestor to make it "connected". A "connected" dentry
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 101) * cannot become non "connected", so cache positive result in dentry flags.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 102) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 103) * Return the connected origin layer or < 0 on error.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 104) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 105) static int ovl_connect_layer(struct dentry *dentry)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 106) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 107) struct dentry *next, *parent = NULL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 108) int origin_layer;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 109) int err = 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 110)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 111) if (WARN_ON(dentry == dentry->d_sb->s_root) ||
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 112) WARN_ON(!ovl_dentry_lower(dentry)))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 113) return -EIO;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 114)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 115) origin_layer = OVL_E(dentry)->lowerstack[0].layer->idx;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 116) if (ovl_dentry_test_flag(OVL_E_CONNECTED, dentry))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 117) return origin_layer;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 118)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 119) /* Find the topmost origin layer connectable ancestor of @dentry */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 120) next = dget(dentry);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 121) for (;;) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 122) parent = dget_parent(next);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 123) if (WARN_ON(parent == next)) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 124) err = -EIO;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 125) break;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 126) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 127)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 128) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 129) * If @parent is not origin layer connectable, then copy up
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 130) * @next which is origin layer connectable and we are done.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 131) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 132) if (ovl_connectable_layer(parent) < origin_layer) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 133) err = ovl_encode_maybe_copy_up(next);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 134) break;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 135) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 136)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 137) /* If @parent is connected or indexed we are done */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 138) if (ovl_dentry_test_flag(OVL_E_CONNECTED, parent) ||
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 139) ovl_test_flag(OVL_INDEX, d_inode(parent)))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 140) break;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 141)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 142) dput(next);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 143) next = parent;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 144) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 145)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 146) dput(parent);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 147) dput(next);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 148)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 149) if (!err)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 150) ovl_dentry_set_flag(OVL_E_CONNECTED, dentry);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 151)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 152) return err ?: origin_layer;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 153) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 154)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 155) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 156) * We only need to encode origin if there is a chance that the same object was
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 157) * encoded pre copy up and then we need to stay consistent with the same
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 158) * encoding also after copy up. If non-pure upper is not indexed, then it was
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 159) * copied up before NFS export was enabled. In that case we don't need to worry
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 160) * about staying consistent with pre copy up encoding and we encode an upper
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 161) * file handle. Overlay root dentry is a private case of non-indexed upper.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 162) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 163) * The following table summarizes the different file handle encodings used for
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 164) * different overlay object types:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 165) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 166) * Object type | Encoding
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 167) * --------------------------------
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 168) * Pure upper | U
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 169) * Non-indexed upper | U
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 170) * Indexed upper | L (*)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 171) * Non-upper | L (*)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 172) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 173) * U = upper file handle
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 174) * L = lower file handle
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 175) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 176) * (*) Connecting an overlay dir from real lower dentry is not always
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 177) * possible when there are redirects in lower layers and non-indexed merge dirs.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 178) * To mitigate those case, we may copy up the lower dir ancestor before encode
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 179) * a lower dir file handle.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 180) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 181) * Return 0 for upper file handle, > 0 for lower file handle or < 0 on error.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 182) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 183) static int ovl_check_encode_origin(struct dentry *dentry)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 184) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 185) struct ovl_fs *ofs = dentry->d_sb->s_fs_info;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 186)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 187) /* Upper file handle for pure upper */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 188) if (!ovl_dentry_lower(dentry))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 189) return 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 190)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 191) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 192) * Upper file handle for non-indexed upper.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 193) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 194) * Root is never indexed, so if there's an upper layer, encode upper for
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 195) * root.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 196) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 197) if (ovl_dentry_upper(dentry) &&
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 198) !ovl_test_flag(OVL_INDEX, d_inode(dentry)))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 199) return 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 200)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 201) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 202) * Decoding a merge dir, whose origin's ancestor is under a redirected
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 203) * lower dir or under a non-indexed upper is not always possible.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 204) * ovl_connect_layer() will try to make origin's layer "connected" by
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 205) * copying up a "connectable" ancestor.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 206) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 207) if (d_is_dir(dentry) && ovl_upper_mnt(ofs))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 208) return ovl_connect_layer(dentry);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 209)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 210) /* Lower file handle for indexed and non-upper dir/non-dir */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 211) return 1;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 212) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 213)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 214) static int ovl_dentry_to_fid(struct dentry *dentry, u32 *fid, int buflen)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 215) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 216) struct ovl_fh *fh = NULL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 217) int err, enc_lower;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 218) int len;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 219)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 220) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 221) * Check if we should encode a lower or upper file handle and maybe
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 222) * copy up an ancestor to make lower file handle connectable.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 223) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 224) err = enc_lower = ovl_check_encode_origin(dentry);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 225) if (enc_lower < 0)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 226) goto fail;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 227)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 228) /* Encode an upper or lower file handle */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 229) fh = ovl_encode_real_fh(enc_lower ? ovl_dentry_lower(dentry) :
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 230) ovl_dentry_upper(dentry), !enc_lower);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 231) if (IS_ERR(fh))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 232) return PTR_ERR(fh);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 233)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 234) len = OVL_FH_LEN(fh);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 235) if (len <= buflen)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 236) memcpy(fid, fh, len);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 237) err = len;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 238)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 239) out:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 240) kfree(fh);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 241) return err;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 242)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 243) fail:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 244) pr_warn_ratelimited("failed to encode file handle (%pd2, err=%i)\n",
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 245) dentry, err);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 246) goto out;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 247) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 248)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 249) static int ovl_encode_fh(struct inode *inode, u32 *fid, int *max_len,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 250) struct inode *parent)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 251) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 252) struct dentry *dentry;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 253) int bytes, buflen = *max_len << 2;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 254)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 255) /* TODO: encode connectable file handles */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 256) if (parent)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 257) return FILEID_INVALID;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 258)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 259) dentry = d_find_any_alias(inode);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 260) if (WARN_ON(!dentry))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 261) return FILEID_INVALID;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 262)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 263) bytes = ovl_dentry_to_fid(dentry, fid, buflen);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 264) dput(dentry);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 265) if (bytes <= 0)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 266) return FILEID_INVALID;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 267)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 268) *max_len = bytes >> 2;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 269) if (bytes > buflen)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 270) return FILEID_INVALID;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 271)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 272) return OVL_FILEID_V1;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 273) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 274)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 275) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 276) * Find or instantiate an overlay dentry from real dentries and index.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 277) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 278) static struct dentry *ovl_obtain_alias(struct super_block *sb,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 279) struct dentry *upper_alias,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 280) struct ovl_path *lowerpath,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 281) struct dentry *index)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 282) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 283) struct dentry *lower = lowerpath ? lowerpath->dentry : NULL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 284) struct dentry *upper = upper_alias ?: index;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 285) struct dentry *dentry;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 286) struct inode *inode;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 287) struct ovl_entry *oe;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 288) struct ovl_inode_params oip = {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 289) .lowerpath = lowerpath,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 290) .index = index,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 291) .numlower = !!lower
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 292) };
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 293)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 294) /* We get overlay directory dentries with ovl_lookup_real() */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 295) if (d_is_dir(upper ?: lower))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 296) return ERR_PTR(-EIO);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 297)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 298) oip.upperdentry = dget(upper);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 299) inode = ovl_get_inode(sb, &oip);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 300) if (IS_ERR(inode)) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 301) dput(upper);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 302) return ERR_CAST(inode);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 303) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 304)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 305) if (upper)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 306) ovl_set_flag(OVL_UPPERDATA, inode);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 307)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 308) dentry = d_find_any_alias(inode);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 309) if (dentry)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 310) goto out_iput;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 311)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 312) dentry = d_alloc_anon(inode->i_sb);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 313) if (unlikely(!dentry))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 314) goto nomem;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 315) oe = ovl_alloc_entry(lower ? 1 : 0);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 316) if (!oe)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 317) goto nomem;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 318)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 319) if (lower) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 320) oe->lowerstack->dentry = dget(lower);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 321) oe->lowerstack->layer = lowerpath->layer;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 322) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 323) dentry->d_fsdata = oe;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 324) if (upper_alias)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 325) ovl_dentry_set_upper_alias(dentry);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 326)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 327) ovl_dentry_update_reval(dentry, upper,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 328) DCACHE_OP_REVALIDATE | DCACHE_OP_WEAK_REVALIDATE);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 329)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 330) return d_instantiate_anon(dentry, inode);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 331)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 332) nomem:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 333) dput(dentry);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 334) dentry = ERR_PTR(-ENOMEM);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 335) out_iput:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 336) iput(inode);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 337) return dentry;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 338) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 339)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 340) /* Get the upper or lower dentry in stach whose on layer @idx */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 341) static struct dentry *ovl_dentry_real_at(struct dentry *dentry, int idx)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 342) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 343) struct ovl_entry *oe = dentry->d_fsdata;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 344) int i;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 345)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 346) if (!idx)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 347) return ovl_dentry_upper(dentry);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 348)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 349) for (i = 0; i < oe->numlower; i++) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 350) if (oe->lowerstack[i].layer->idx == idx)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 351) return oe->lowerstack[i].dentry;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 352) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 353)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 354) return NULL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 355) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 356)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 357) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 358) * Lookup a child overlay dentry to get a connected overlay dentry whose real
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 359) * dentry is @real. If @real is on upper layer, we lookup a child overlay
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 360) * dentry with the same name as the real dentry. Otherwise, we need to consult
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 361) * index for lookup.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 362) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 363) static struct dentry *ovl_lookup_real_one(struct dentry *connected,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 364) struct dentry *real,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 365) const struct ovl_layer *layer)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 366) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 367) struct inode *dir = d_inode(connected);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 368) struct dentry *this, *parent = NULL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 369) struct name_snapshot name;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 370) int err;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 371)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 372) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 373) * Lookup child overlay dentry by real name. The dir mutex protects us
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 374) * from racing with overlay rename. If the overlay dentry that is above
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 375) * real has already been moved to a parent that is not under the
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 376) * connected overlay dir, we return -ECHILD and restart the lookup of
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 377) * connected real path from the top.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 378) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 379) inode_lock_nested(dir, I_MUTEX_PARENT);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 380) err = -ECHILD;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 381) parent = dget_parent(real);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 382) if (ovl_dentry_real_at(connected, layer->idx) != parent)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 383) goto fail;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 384)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 385) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 386) * We also need to take a snapshot of real dentry name to protect us
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 387) * from racing with underlying layer rename. In this case, we don't
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 388) * care about returning ESTALE, only from dereferencing a free name
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 389) * pointer because we hold no lock on the real dentry.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 390) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 391) take_dentry_name_snapshot(&name, real);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 392) this = lookup_one_len(name.name.name, connected, name.name.len);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 393) release_dentry_name_snapshot(&name);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 394) err = PTR_ERR(this);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 395) if (IS_ERR(this)) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 396) goto fail;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 397) } else if (!this || !this->d_inode) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 398) dput(this);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 399) err = -ENOENT;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 400) goto fail;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 401) } else if (ovl_dentry_real_at(this, layer->idx) != real) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 402) dput(this);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 403) err = -ESTALE;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 404) goto fail;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 405) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 406)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 407) out:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 408) dput(parent);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 409) inode_unlock(dir);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 410) return this;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 411)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 412) fail:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 413) pr_warn_ratelimited("failed to lookup one by real (%pd2, layer=%d, connected=%pd2, err=%i)\n",
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 414) real, layer->idx, connected, err);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 415) this = ERR_PTR(err);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 416) goto out;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 417) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 418)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 419) static struct dentry *ovl_lookup_real(struct super_block *sb,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 420) struct dentry *real,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 421) const struct ovl_layer *layer);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 422)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 423) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 424) * Lookup an indexed or hashed overlay dentry by real inode.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 425) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 426) static struct dentry *ovl_lookup_real_inode(struct super_block *sb,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 427) struct dentry *real,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 428) const struct ovl_layer *layer)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 429) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 430) struct ovl_fs *ofs = sb->s_fs_info;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 431) struct dentry *index = NULL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 432) struct dentry *this = NULL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 433) struct inode *inode;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 434)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 435) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 436) * Decoding upper dir from index is expensive, so first try to lookup
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 437) * overlay dentry in inode/dcache.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 438) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 439) inode = ovl_lookup_inode(sb, real, !layer->idx);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 440) if (IS_ERR(inode))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 441) return ERR_CAST(inode);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 442) if (inode) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 443) this = d_find_any_alias(inode);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 444) iput(inode);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 445) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 446)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 447) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 448) * For decoded lower dir file handle, lookup index by origin to check
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 449) * if lower dir was copied up and and/or removed.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 450) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 451) if (!this && layer->idx && ofs->indexdir && !WARN_ON(!d_is_dir(real))) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 452) index = ovl_lookup_index(ofs, NULL, real, false);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 453) if (IS_ERR(index))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 454) return index;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 455) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 456)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 457) /* Get connected upper overlay dir from index */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 458) if (index) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 459) struct dentry *upper = ovl_index_upper(ofs, index);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 460)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 461) dput(index);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 462) if (IS_ERR_OR_NULL(upper))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 463) return upper;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 464)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 465) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 466) * ovl_lookup_real() in lower layer may call recursively once to
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 467) * ovl_lookup_real() in upper layer. The first level call walks
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 468) * back lower parents to the topmost indexed parent. The second
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 469) * recursive call walks back from indexed upper to the topmost
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 470) * connected/hashed upper parent (or up to root).
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 471) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 472) this = ovl_lookup_real(sb, upper, &ofs->layers[0]);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 473) dput(upper);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 474) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 475)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 476) if (IS_ERR_OR_NULL(this))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 477) return this;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 478)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 479) if (ovl_dentry_real_at(this, layer->idx) != real) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 480) dput(this);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 481) this = ERR_PTR(-EIO);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 482) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 483)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 484) return this;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 485) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 486)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 487) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 488) * Lookup an indexed or hashed overlay dentry, whose real dentry is an
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 489) * ancestor of @real.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 490) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 491) static struct dentry *ovl_lookup_real_ancestor(struct super_block *sb,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 492) struct dentry *real,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 493) const struct ovl_layer *layer)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 494) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 495) struct dentry *next, *parent = NULL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 496) struct dentry *ancestor = ERR_PTR(-EIO);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 497)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 498) if (real == layer->mnt->mnt_root)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 499) return dget(sb->s_root);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 500)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 501) /* Find the topmost indexed or hashed ancestor */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 502) next = dget(real);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 503) for (;;) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 504) parent = dget_parent(next);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 505)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 506) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 507) * Lookup a matching overlay dentry in inode/dentry
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 508) * cache or in index by real inode.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 509) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 510) ancestor = ovl_lookup_real_inode(sb, next, layer);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 511) if (ancestor)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 512) break;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 513)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 514) if (parent == layer->mnt->mnt_root) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 515) ancestor = dget(sb->s_root);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 516) break;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 517) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 518)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 519) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 520) * If @real has been moved out of the layer root directory,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 521) * we will eventully hit the real fs root. This cannot happen
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 522) * by legit overlay rename, so we return error in that case.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 523) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 524) if (parent == next) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 525) ancestor = ERR_PTR(-EXDEV);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 526) break;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 527) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 528)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 529) dput(next);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 530) next = parent;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 531) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 532)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 533) dput(parent);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 534) dput(next);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 535)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 536) return ancestor;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 537) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 538)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 539) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 540) * Lookup a connected overlay dentry whose real dentry is @real.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 541) * If @real is on upper layer, we lookup a child overlay dentry with the same
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 542) * path the real dentry. Otherwise, we need to consult index for lookup.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 543) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 544) static struct dentry *ovl_lookup_real(struct super_block *sb,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 545) struct dentry *real,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 546) const struct ovl_layer *layer)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 547) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 548) struct dentry *connected;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 549) int err = 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 550)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 551) connected = ovl_lookup_real_ancestor(sb, real, layer);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 552) if (IS_ERR(connected))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 553) return connected;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 554)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 555) while (!err) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 556) struct dentry *next, *this;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 557) struct dentry *parent = NULL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 558) struct dentry *real_connected = ovl_dentry_real_at(connected,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 559) layer->idx);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 560)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 561) if (real_connected == real)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 562) break;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 563)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 564) /* Find the topmost dentry not yet connected */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 565) next = dget(real);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 566) for (;;) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 567) parent = dget_parent(next);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 568)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 569) if (parent == real_connected)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 570) break;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 571)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 572) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 573) * If real has been moved out of 'real_connected',
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 574) * we will not find 'real_connected' and hit the layer
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 575) * root. In that case, we need to restart connecting.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 576) * This game can go on forever in the worst case. We
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 577) * may want to consider taking s_vfs_rename_mutex if
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 578) * this happens more than once.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 579) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 580) if (parent == layer->mnt->mnt_root) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 581) dput(connected);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 582) connected = dget(sb->s_root);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 583) break;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 584) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 585)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 586) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 587) * If real file has been moved out of the layer root
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 588) * directory, we will eventully hit the real fs root.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 589) * This cannot happen by legit overlay rename, so we
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 590) * return error in that case.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 591) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 592) if (parent == next) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 593) err = -EXDEV;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 594) break;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 595) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 596)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 597) dput(next);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 598) next = parent;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 599) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 600)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 601) if (!err) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 602) this = ovl_lookup_real_one(connected, next, layer);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 603) if (IS_ERR(this))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 604) err = PTR_ERR(this);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 605)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 606) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 607) * Lookup of child in overlay can fail when racing with
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 608) * overlay rename of child away from 'connected' parent.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 609) * In this case, we need to restart the lookup from the
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 610) * top, because we cannot trust that 'real_connected' is
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 611) * still an ancestor of 'real'. There is a good chance
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 612) * that the renamed overlay ancestor is now in cache, so
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 613) * ovl_lookup_real_ancestor() will find it and we can
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 614) * continue to connect exactly from where lookup failed.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 615) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 616) if (err == -ECHILD) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 617) this = ovl_lookup_real_ancestor(sb, real,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 618) layer);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 619) err = PTR_ERR_OR_ZERO(this);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 620) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 621) if (!err) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 622) dput(connected);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 623) connected = this;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 624) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 625) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 626)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 627) dput(parent);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 628) dput(next);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 629) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 630)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 631) if (err)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 632) goto fail;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 633)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 634) return connected;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 635)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 636) fail:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 637) pr_warn_ratelimited("failed to lookup by real (%pd2, layer=%d, connected=%pd2, err=%i)\n",
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 638) real, layer->idx, connected, err);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 639) dput(connected);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 640) return ERR_PTR(err);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 641) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 642)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 643) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 644) * Get an overlay dentry from upper/lower real dentries and index.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 645) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 646) static struct dentry *ovl_get_dentry(struct super_block *sb,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 647) struct dentry *upper,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 648) struct ovl_path *lowerpath,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 649) struct dentry *index)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 650) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 651) struct ovl_fs *ofs = sb->s_fs_info;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 652) const struct ovl_layer *layer = upper ? &ofs->layers[0] : lowerpath->layer;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 653) struct dentry *real = upper ?: (index ?: lowerpath->dentry);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 654)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 655) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 656) * Obtain a disconnected overlay dentry from a non-dir real dentry
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 657) * and index.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 658) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 659) if (!d_is_dir(real))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 660) return ovl_obtain_alias(sb, upper, lowerpath, index);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 661)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 662) /* Removed empty directory? */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 663) if ((real->d_flags & DCACHE_DISCONNECTED) || d_unhashed(real))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 664) return ERR_PTR(-ENOENT);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 665)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 666) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 667) * If real dentry is connected and hashed, get a connected overlay
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 668) * dentry whose real dentry is @real.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 669) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 670) return ovl_lookup_real(sb, real, layer);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 671) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 672)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 673) static struct dentry *ovl_upper_fh_to_d(struct super_block *sb,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 674) struct ovl_fh *fh)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 675) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 676) struct ovl_fs *ofs = sb->s_fs_info;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 677) struct dentry *dentry;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 678) struct dentry *upper;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 679)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 680) if (!ovl_upper_mnt(ofs))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 681) return ERR_PTR(-EACCES);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 682)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 683) upper = ovl_decode_real_fh(fh, ovl_upper_mnt(ofs), true);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 684) if (IS_ERR_OR_NULL(upper))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 685) return upper;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 686)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 687) dentry = ovl_get_dentry(sb, upper, NULL, NULL);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 688) dput(upper);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 689)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 690) return dentry;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 691) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 692)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 693) static struct dentry *ovl_lower_fh_to_d(struct super_block *sb,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 694) struct ovl_fh *fh)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 695) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 696) struct ovl_fs *ofs = sb->s_fs_info;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 697) struct ovl_path origin = { };
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 698) struct ovl_path *stack = &origin;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 699) struct dentry *dentry = NULL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 700) struct dentry *index = NULL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 701) struct inode *inode;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 702) int err;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 703)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 704) /* First lookup overlay inode in inode cache by origin fh */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 705) err = ovl_check_origin_fh(ofs, fh, false, NULL, &stack);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 706) if (err)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 707) return ERR_PTR(err);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 708)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 709) if (!d_is_dir(origin.dentry) ||
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 710) !(origin.dentry->d_flags & DCACHE_DISCONNECTED)) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 711) inode = ovl_lookup_inode(sb, origin.dentry, false);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 712) err = PTR_ERR(inode);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 713) if (IS_ERR(inode))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 714) goto out_err;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 715) if (inode) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 716) dentry = d_find_any_alias(inode);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 717) iput(inode);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 718) if (dentry)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 719) goto out;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 720) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 721) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 722)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 723) /* Then lookup indexed upper/whiteout by origin fh */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 724) if (ofs->indexdir) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 725) index = ovl_get_index_fh(ofs, fh);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 726) err = PTR_ERR(index);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 727) if (IS_ERR(index)) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 728) index = NULL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 729) goto out_err;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 730) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 731) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 732)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 733) /* Then try to get a connected upper dir by index */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 734) if (index && d_is_dir(index)) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 735) struct dentry *upper = ovl_index_upper(ofs, index);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 736)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 737) err = PTR_ERR(upper);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 738) if (IS_ERR_OR_NULL(upper))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 739) goto out_err;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 740)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 741) dentry = ovl_get_dentry(sb, upper, NULL, NULL);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 742) dput(upper);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 743) goto out;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 744) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 745)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 746) /* Find origin.dentry again with ovl_acceptable() layer check */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 747) if (d_is_dir(origin.dentry)) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 748) dput(origin.dentry);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 749) origin.dentry = NULL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 750) err = ovl_check_origin_fh(ofs, fh, true, NULL, &stack);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 751) if (err)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 752) goto out_err;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 753) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 754) if (index) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 755) err = ovl_verify_origin(ofs, index, origin.dentry, false);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 756) if (err)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 757) goto out_err;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 758) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 759)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 760) /* Get a connected non-upper dir or disconnected non-dir */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 761) dentry = ovl_get_dentry(sb, NULL, &origin, index);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 762)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 763) out:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 764) dput(origin.dentry);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 765) dput(index);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 766) return dentry;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 767)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 768) out_err:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 769) dentry = ERR_PTR(err);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 770) goto out;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 771) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 772)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 773) static struct ovl_fh *ovl_fid_to_fh(struct fid *fid, int buflen, int fh_type)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 774) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 775) struct ovl_fh *fh;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 776)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 777) /* If on-wire inner fid is aligned - nothing to do */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 778) if (fh_type == OVL_FILEID_V1)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 779) return (struct ovl_fh *)fid;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 780)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 781) if (fh_type != OVL_FILEID_V0)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 782) return ERR_PTR(-EINVAL);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 783)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 784) if (buflen <= OVL_FH_WIRE_OFFSET)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 785) return ERR_PTR(-EINVAL);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 786)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 787) fh = kzalloc(buflen, GFP_KERNEL);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 788) if (!fh)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 789) return ERR_PTR(-ENOMEM);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 790)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 791) /* Copy unaligned inner fh into aligned buffer */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 792) memcpy(&fh->fb, fid, buflen - OVL_FH_WIRE_OFFSET);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 793) return fh;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 794) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 795)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 796) static struct dentry *ovl_fh_to_dentry(struct super_block *sb, struct fid *fid,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 797) int fh_len, int fh_type)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 798) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 799) struct dentry *dentry = NULL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 800) struct ovl_fh *fh = NULL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 801) int len = fh_len << 2;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 802) unsigned int flags = 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 803) int err;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 804)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 805) fh = ovl_fid_to_fh(fid, len, fh_type);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 806) err = PTR_ERR(fh);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 807) if (IS_ERR(fh))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 808) goto out_err;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 809)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 810) err = ovl_check_fh_len(fh, len);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 811) if (err)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 812) goto out_err;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 813)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 814) flags = fh->fb.flags;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 815) dentry = (flags & OVL_FH_FLAG_PATH_UPPER) ?
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 816) ovl_upper_fh_to_d(sb, fh) :
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 817) ovl_lower_fh_to_d(sb, fh);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 818) err = PTR_ERR(dentry);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 819) if (IS_ERR(dentry) && err != -ESTALE)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 820) goto out_err;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 821)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 822) out:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 823) /* We may have needed to re-align OVL_FILEID_V0 */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 824) if (!IS_ERR_OR_NULL(fh) && fh != (void *)fid)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 825) kfree(fh);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 826)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 827) return dentry;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 828)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 829) out_err:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 830) pr_warn_ratelimited("failed to decode file handle (len=%d, type=%d, flags=%x, err=%i)\n",
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 831) fh_len, fh_type, flags, err);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 832) dentry = ERR_PTR(err);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 833) goto out;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 834) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 835)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 836) static struct dentry *ovl_fh_to_parent(struct super_block *sb, struct fid *fid,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 837) int fh_len, int fh_type)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 838) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 839) pr_warn_ratelimited("connectable file handles not supported; use 'no_subtree_check' exportfs option.\n");
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 840) return ERR_PTR(-EACCES);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 841) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 842)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 843) static int ovl_get_name(struct dentry *parent, char *name,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 844) struct dentry *child)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 845) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 846) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 847) * ovl_fh_to_dentry() returns connected dir overlay dentries and
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 848) * ovl_fh_to_parent() is not implemented, so we should not get here.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 849) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 850) WARN_ON_ONCE(1);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 851) return -EIO;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 852) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 853)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 854) static struct dentry *ovl_get_parent(struct dentry *dentry)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 855) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 856) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 857) * ovl_fh_to_dentry() returns connected dir overlay dentries, so we
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 858) * should not get here.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 859) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 860) WARN_ON_ONCE(1);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 861) return ERR_PTR(-EIO);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 862) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 863)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 864) const struct export_operations ovl_export_operations = {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 865) .encode_fh = ovl_encode_fh,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 866) .fh_to_dentry = ovl_fh_to_dentry,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 867) .fh_to_parent = ovl_fh_to_parent,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 868) .get_name = ovl_get_name,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 869) .get_parent = ovl_get_parent,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 870) };
Orange Pi5 kernel
Deprecated Linux kernel 5.10.110 for OrangePi 5/5B/5+ boards
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