diff options
Diffstat (limited to 'fs/overlayfs')
| -rw-r--r-- | fs/overlayfs/Kconfig | 17 | ||||
| -rw-r--r-- | fs/overlayfs/copy_up.c | 6 | ||||
| -rw-r--r-- | fs/overlayfs/export.c | 75 | ||||
| -rw-r--r-- | fs/overlayfs/inode.c | 188 | ||||
| -rw-r--r-- | fs/overlayfs/namei.c | 67 | ||||
| -rw-r--r-- | fs/overlayfs/overlayfs.h | 19 | ||||
| -rw-r--r-- | fs/overlayfs/ovl_entry.h | 21 | ||||
| -rw-r--r-- | fs/overlayfs/readdir.c | 45 | ||||
| -rw-r--r-- | fs/overlayfs/super.c | 157 | ||||
| -rw-r--r-- | fs/overlayfs/util.c | 39 |
10 files changed, 468 insertions, 166 deletions
diff --git a/fs/overlayfs/Kconfig b/fs/overlayfs/Kconfig index ce6ff5a0a6e4..17032631c5cf 100644 --- a/fs/overlayfs/Kconfig +++ b/fs/overlayfs/Kconfig @@ -86,3 +86,20 @@ config OVERLAY_FS_NFS_EXPORT case basis with the "nfs_export=on" mount option. Say N unless you fully understand the consequences. + +config OVERLAY_FS_XINO_AUTO + bool "Overlayfs: auto enable inode number mapping" + default n + depends on OVERLAY_FS + help + If this config option is enabled then overlay filesystems will use + unused high bits in undelying filesystem inode numbers to map all + inodes to a unified address space. The mapped 64bit inode numbers + might not be compatible with applications that expect 32bit inodes. + + If compatibility with applications that expect 32bit inodes is not an + issue, then it is safe and recommended to say Y here. + + For more information, see Documentation/filesystems/overlayfs.txt + + If unsure, say N. diff --git a/fs/overlayfs/copy_up.c b/fs/overlayfs/copy_up.c index d855f508fa20..8bede0742619 100644 --- a/fs/overlayfs/copy_up.c +++ b/fs/overlayfs/copy_up.c @@ -232,7 +232,7 @@ int ovl_set_attr(struct dentry *upperdentry, struct kstat *stat) return err; } -struct ovl_fh *ovl_encode_fh(struct dentry *real, bool is_upper) +struct ovl_fh *ovl_encode_real_fh(struct dentry *real, bool is_upper) { struct ovl_fh *fh; int fh_type, fh_len, dwords; @@ -300,7 +300,7 @@ int ovl_set_origin(struct dentry *dentry, struct dentry *lower, * up and a pure upper inode. */ if (ovl_can_decode_fh(lower->d_sb)) { - fh = ovl_encode_fh(lower, false); + fh = ovl_encode_real_fh(lower, false); if (IS_ERR(fh)) return PTR_ERR(fh); } @@ -321,7 +321,7 @@ static int ovl_set_upper_fh(struct dentry *upper, struct dentry *index) const struct ovl_fh *fh; int err; - fh = ovl_encode_fh(upper, true); + fh = ovl_encode_real_fh(upper, true); if (IS_ERR(fh)) return PTR_ERR(fh); diff --git a/fs/overlayfs/export.c b/fs/overlayfs/export.c index 87bd4148f4fb..425a94672300 100644 --- a/fs/overlayfs/export.c +++ b/fs/overlayfs/export.c @@ -228,8 +228,8 @@ static int ovl_d_to_fh(struct dentry *dentry, char *buf, int buflen) goto fail; /* Encode an upper or lower file handle */ - fh = ovl_encode_fh(enc_lower ? ovl_dentry_lower(dentry) : - ovl_dentry_upper(dentry), !enc_lower); + fh = ovl_encode_real_fh(enc_lower ? ovl_dentry_lower(dentry) : + ovl_dentry_upper(dentry), !enc_lower); err = PTR_ERR(fh); if (IS_ERR(fh)) goto fail; @@ -267,8 +267,8 @@ static int ovl_dentry_to_fh(struct dentry *dentry, u32 *fid, int *max_len) return OVL_FILEID; } -static int ovl_encode_inode_fh(struct inode *inode, u32 *fid, int *max_len, - struct inode *parent) +static int ovl_encode_fh(struct inode *inode, u32 *fid, int *max_len, + struct inode *parent) { struct dentry *dentry; int type; @@ -305,15 +305,12 @@ static struct dentry *ovl_obtain_alias(struct super_block *sb, if (d_is_dir(upper ?: lower)) return ERR_PTR(-EIO); - inode = ovl_get_inode(sb, dget(upper), lower, index, !!lower); + inode = ovl_get_inode(sb, dget(upper), lowerpath, index, !!lower); if (IS_ERR(inode)) { dput(upper); return ERR_CAST(inode); } - if (index) - ovl_set_flag(OVL_INDEX, inode); - dentry = d_find_any_alias(inode); if (!dentry) { dentry = d_alloc_anon(inode->i_sb); @@ -685,7 +682,7 @@ static struct dentry *ovl_upper_fh_to_d(struct super_block *sb, if (!ofs->upper_mnt) return ERR_PTR(-EACCES); - upper = ovl_decode_fh(fh, ofs->upper_mnt); + upper = ovl_decode_real_fh(fh, ofs->upper_mnt, true); if (IS_ERR_OR_NULL(upper)) return upper; @@ -703,25 +700,39 @@ static struct dentry *ovl_lower_fh_to_d(struct super_block *sb, struct ovl_path *stack = &origin; struct dentry *dentry = NULL; struct dentry *index = NULL; - struct inode *inode = NULL; - bool is_deleted = false; + struct inode *inode; int err; - /* First lookup indexed upper by fh */ + /* First lookup overlay inode in inode cache by origin fh */ + err = ovl_check_origin_fh(ofs, fh, false, NULL, &stack); + if (err) + return ERR_PTR(err); + + if (!d_is_dir(origin.dentry) || + !(origin.dentry->d_flags & DCACHE_DISCONNECTED)) { + inode = ovl_lookup_inode(sb, origin.dentry, false); + err = PTR_ERR(inode); + if (IS_ERR(inode)) + goto out_err; + if (inode) { + dentry = d_find_any_alias(inode); + iput(inode); + if (dentry) + goto out; + } + } + + /* Then lookup indexed upper/whiteout by origin fh */ if (ofs->indexdir) { index = ovl_get_index_fh(ofs, fh); err = PTR_ERR(index); if (IS_ERR(index)) { - if (err != -ESTALE) - return ERR_PTR(err); - - /* Found a whiteout index - treat as deleted inode */ - is_deleted = true; index = NULL; + goto out_err; } } - /* Then try to get upper dir by index */ + /* Then try to get a connected upper dir by index */ if (index && d_is_dir(index)) { struct dentry *upper = ovl_index_upper(ofs, index); @@ -734,24 +745,19 @@ static struct dentry *ovl_lower_fh_to_d(struct super_block *sb, goto out; } - /* Then lookup origin by fh */ - err = ovl_check_origin_fh(ofs, fh, NULL, &stack); - if (err) { - goto out_err; - } else if (index) { - err = ovl_verify_origin(index, origin.dentry, false); + /* Otherwise, get a connected non-upper dir or disconnected non-dir */ + if (d_is_dir(origin.dentry) && + (origin.dentry->d_flags & DCACHE_DISCONNECTED)) { + dput(origin.dentry); + origin.dentry = NULL; + err = ovl_check_origin_fh(ofs, fh, true, NULL, &stack); if (err) goto out_err; - } else if (is_deleted) { - /* Lookup deleted non-dir by origin inode */ - if (!d_is_dir(origin.dentry)) - inode = ovl_lookup_inode(sb, origin.dentry, false); - err = -ESTALE; - if (!inode || atomic_read(&inode->i_count) == 1) + } + if (index) { + err = ovl_verify_origin(index, origin.dentry, false); + if (err) goto out_err; - - /* Deleted but still open? */ - index = dget(ovl_i_dentry_upper(inode)); } dentry = ovl_get_dentry(sb, NULL, &origin, index); @@ -759,7 +765,6 @@ static struct dentry *ovl_lower_fh_to_d(struct super_block *sb, out: dput(origin.dentry); dput(index); - iput(inode); return dentry; out_err: @@ -829,7 +834,7 @@ static struct dentry *ovl_get_parent(struct dentry *dentry) } const struct export_operations ovl_export_operations = { - .encode_fh = ovl_encode_inode_fh, + .encode_fh = ovl_encode_fh, .fh_to_dentry = ovl_fh_to_dentry, .fh_to_parent = ovl_fh_to_parent, .get_name = ovl_get_name, diff --git a/fs/overlayfs/inode.c b/fs/overlayfs/inode.c index 3b1bd469accd..6e3815fb006b 100644 --- a/fs/overlayfs/inode.c +++ b/fs/overlayfs/inode.c @@ -16,13 +16,6 @@ #include "overlayfs.h" -static dev_t ovl_get_pseudo_dev(struct dentry *dentry) -{ - struct ovl_entry *oe = dentry->d_fsdata; - - return oe->lowerstack[0].layer->pseudo_dev; -} - int ovl_setattr(struct dentry *dentry, struct iattr *attr) { int err; @@ -66,6 +59,69 @@ out: return err; } +static int ovl_map_dev_ino(struct dentry *dentry, struct kstat *stat, + struct ovl_layer *lower_layer) +{ + bool samefs = ovl_same_sb(dentry->d_sb); + unsigned int xinobits = ovl_xino_bits(dentry->d_sb); + + if (samefs) { + /* + * When all layers are on the same fs, all real inode + * number are unique, so we use the overlay st_dev, + * which is friendly to du -x. + */ + stat->dev = dentry->d_sb->s_dev; + return 0; + } else if (xinobits) { + unsigned int shift = 64 - xinobits; + /* + * All inode numbers of underlying fs should not be using the + * high xinobits, so we use high xinobits to partition the + * overlay st_ino address space. The high bits holds the fsid + * (upper fsid is 0). This way overlay inode numbers are unique + * and all inodes use overlay st_dev. Inode numbers are also + * persistent for a given layer configuration. + */ + if (stat->ino >> shift) { + pr_warn_ratelimited("overlayfs: inode number too big (%pd2, ino=%llu, xinobits=%d)\n", + dentry, stat->ino, xinobits); + } else { + if (lower_layer) + stat->ino |= ((u64)lower_layer->fsid) << shift; + + stat->dev = dentry->d_sb->s_dev; + return 0; + } + } + + /* The inode could not be mapped to a unified st_ino address space */ + if (S_ISDIR(dentry->d_inode->i_mode)) { + /* + * Always use the overlay st_dev for directories, so 'find + * -xdev' will scan the entire overlay mount and won't cross the + * overlay mount boundaries. + * + * If not all layers are on the same fs the pair {real st_ino; + * overlay st_dev} is not unique, so use the non persistent + * overlay st_ino for directories. + */ + stat->dev = dentry->d_sb->s_dev; + stat->ino = dentry->d_inode->i_ino; + } else if (lower_layer && lower_layer->fsid) { + /* + * For non-samefs setup, if we cannot map all layers st_ino + * to a unified address space, we need to make sure that st_dev + * is unique per lower fs. Upper layer uses real st_dev and + * lower layers use the unique anonymous bdev assigned to the + * lower fs. + */ + stat->dev = lower_layer->fs->pseudo_dev; + } + + return 0; +} + int ovl_getattr(const struct path *path, struct kstat *stat, u32 request_mask, unsigned int flags) { @@ -75,6 +131,7 @@ int ovl_getattr(const struct path *path, struct kstat *stat, const struct cred *old_cred; bool is_dir = S_ISDIR(dentry->d_inode->i_mode); bool samefs = ovl_same_sb(dentry->d_sb); + struct ovl_layer *lower_layer = NULL; int err; type = ovl_path_real(dentry, &realpath); @@ -84,14 +141,18 @@ int ovl_getattr(const struct path *path, struct kstat *stat, goto out; /* - * For non-dir or same fs, we use st_ino of the copy up origin, if we - * know it. This guaranties constant st_dev/st_ino across copy up. + * For non-dir or same fs, we use st_ino of the copy up origin. + * This guaranties constant st_dev/st_ino across copy up. + * With xino feature and non-samefs, we use st_ino of the copy up + * origin masked with high bits that represent the layer id. * - * If filesystem supports NFS export ops, this also guaranties + * If lower filesystem supports NFS file handles, this also guaranties * persistent st_ino across mount cycle. */ - if (!is_dir || samefs) { - if (OVL_TYPE_ORIGIN(type)) { + if (!is_dir || samefs || ovl_xino_bits(dentry->d_sb)) { + if (!OVL_TYPE_UPPER(type)) { + lower_layer = ovl_layer_lower(dentry); + } else if (OVL_TYPE_ORIGIN(type)) { struct kstat lowerstat; u32 lowermask = STATX_INO | (!is_dir ? STATX_NLINK : 0); @@ -118,43 +179,17 @@ int ovl_getattr(const struct path *path, struct kstat *stat, */ if (ovl_test_flag(OVL_INDEX, d_inode(dentry)) || (!ovl_verify_lower(dentry->d_sb) && - (is_dir || lowerstat.nlink == 1))) + (is_dir || lowerstat.nlink == 1))) { stat->ino = lowerstat.ino; - - if (samefs) - WARN_ON_ONCE(stat->dev != lowerstat.dev); - else - stat->dev = ovl_get_pseudo_dev(dentry); - } - if (samefs) { - /* - * When all layers are on the same fs, all real inode - * number are unique, so we use the overlay st_dev, - * which is friendly to du -x. - */ - stat->dev = dentry->d_sb->s_dev; - } else if (!OVL_TYPE_UPPER(type)) { - /* - * For non-samefs setup, to make sure that st_dev/st_ino - * pair is unique across the system, we use a unique - * anonymous st_dev for lower layer inode. - */ - stat->dev = ovl_get_pseudo_dev(dentry); + lower_layer = ovl_layer_lower(dentry); + } } - } else { - /* - * Always use the overlay st_dev for directories, so 'find - * -xdev' will scan the entire overlay mount and won't cross the - * overlay mount boundaries. - * - * If not all layers are on the same fs the pair {real st_ino; - * overlay st_dev} is not unique, so use the non persistent - * overlay st_ino for directories. - */ - stat->dev = dentry->d_sb->s_dev; - stat->ino = dentry->d_inode->i_ino; } + err = ovl_map_dev_ino(dentry, stat, lower_layer); + if (err) + goto out; + /* * It's probably not worth it to count subdirs to get the * correct link count. nlink=1 seems to pacify 'find' and @@ -383,24 +418,18 @@ int ovl_open_maybe_copy_up(struct dentry *dentry, unsigned int file_flags) int ovl_update_time(struct inode *inode, struct timespec *ts, int flags) { - struct dentry *alias; - struct path upperpath; - - if (!(flags & S_ATIME)) - return 0; - - alias = d_find_any_alias(inode); - if (!alias) - return 0; - - ovl_path_upper(alias, &upperpath); - if (upperpath.dentry) { - touch_atime(&upperpath); - inode->i_atime = d_inode(upperpath.dentry)->i_atime; + if (flags & S_ATIME) { + struct ovl_fs *ofs = inode->i_sb->s_fs_info; + struct path upperpath = { + .mnt = ofs->upper_mnt, + .dentry = ovl_upperdentry_dereference(OVL_I(inode)), + }; + + if (upperpath.dentry) { + touch_atime(&upperpath); + inode->i_atime = d_inode(upperpath.dentry)->i_atime; + } } - - dput(alias); - return 0; } @@ -459,9 +488,27 @@ static inline void ovl_lockdep_annotate_inode_mutex_key(struct inode *inode) #endif } -static void ovl_fill_inode(struct inode *inode, umode_t mode, dev_t rdev) +static void ovl_fill_inode(struct inode *inode, umode_t mode, dev_t rdev, + unsigned long ino, int fsid) { - inode->i_ino = get_next_ino(); + int xinobits = ovl_xino_bits(inode->i_sb); + + /* + * When NFS export is enabled and d_ino is consistent with st_ino + * (samefs or i_ino has enough bits to encode layer), set the same + * value used for d_ino to i_ino, because nfsd readdirplus compares + * d_ino values to i_ino values of child entries. When called from + * ovl_new_inode(), ino arg is 0, so i_ino will be updated to real + * upper inode i_ino on ovl_inode_init() or ovl_inode_update(). + */ + if (inode->i_sb->s_export_op && + (ovl_same_sb(inode->i_sb) || xinobits)) { + inode->i_ino = ino; + if (xinobits && fsid && !(ino >> (64 - xinobits))) + inode->i_ino |= (unsigned long)fsid << (64 - xinobits); + } else { + inode->i_ino = get_next_ino(); + } inode->i_mode = mode; inode->i_flags |= S_NOCMTIME; #ifdef CONFIG_FS_POSIX_ACL @@ -597,7 +644,7 @@ struct inode *ovl_new_inode(struct super_block *sb, umode_t mode, dev_t rdev) inode = new_inode(sb); if (inode) - ovl_fill_inode(inode, mode, rdev); + ovl_fill_inode(inode, mode, rdev, 0, 0); return inode; } @@ -703,13 +750,16 @@ static bool ovl_hash_bylower(struct super_block *sb, struct dentry *upper, } struct inode *ovl_get_inode(struct super_block *sb, struct dentry *upperdentry, - struct dentry *lowerdentry, struct dentry *index, + struct ovl_path *lowerpath, struct dentry *index, unsigned int numlower) { struct inode *realinode = upperdentry ? d_inode(upperdentry) : NULL; struct inode *inode; + struct dentry *lowerdentry = lowerpath ? lowerpath->dentry : NULL; bool bylower = ovl_hash_bylower(sb, upperdentry, lowerdentry, index); + int fsid = bylower ? lowerpath->layer->fsid : 0; bool is_dir; + unsigned long ino = 0; if (!realinode) realinode = d_inode(lowerdentry); @@ -748,18 +798,22 @@ struct inode *ovl_get_inode(struct super_block *sb, struct dentry *upperdentry, if (!is_dir) nlink = ovl_get_nlink(lowerdentry, upperdentry, nlink); set_nlink(inode, nlink); + ino = key->i_ino; } else { /* Lower hardlink that will be broken on copy up */ inode = new_inode(sb); if (!inode) goto out_nomem; } - ovl_fill_inode(inode, realinode->i_mode, realinode->i_rdev); + ovl_fill_inode(inode, realinode->i_mode, realinode->i_rdev, ino, fsid); ovl_inode_init(inode, upperdentry, lowerdentry); if (upperdentry && ovl_is_impuredir(upperdentry)) ovl_set_flag(OVL_IMPURE, inode); + if (index) + ovl_set_flag(OVL_INDEX, inode); + /* Check for non-merge dir that may have whiteouts */ if (is_dir) { if (((upperdentry && lowerdentry) || numlower > 1) || diff --git a/fs/overlayfs/namei.c b/fs/overlayfs/namei.c index 70fcfcc684cc..2dba29eadde6 100644 --- a/fs/overlayfs/namei.c +++ b/fs/overlayfs/namei.c @@ -56,6 +56,15 @@ static int ovl_check_redirect(struct dentry *dentry, struct ovl_lookup_data *d, if (s == next) goto invalid; } + /* + * One of the ancestor path elements in an absolute path + * lookup in ovl_lookup_layer() could have been opaque and + * that will stop further lookup in lower layers (d->stop=true) + * But we have found an absolute redirect in decendant path + * element and that should force continue lookup in lower + * layers (reset d->stop). + */ + d->stop = false; } else { if (strchr(buf, '/') != NULL) goto invalid; @@ -171,7 +180,8 @@ invalid: goto out; } -struct dentry *ovl_decode_fh(struct ovl_fh *fh, struct vfsmount *mnt) +struct dentry *ovl_decode_real_fh(struct ovl_fh *fh, struct vfsmount *mnt, + bool connected) { struct dentry *real; int bytes; @@ -186,7 +196,7 @@ struct dentry *ovl_decode_fh(struct ovl_fh *fh, struct vfsmount *mnt) bytes = (fh->len - offsetof(struct ovl_fh, fid)); real = exportfs_decode_fh(mnt, (struct fid *)fh->fid, bytes >> 2, (int)fh->type, - ovl_acceptable, mnt); + connected ? ovl_acceptable : NULL, mnt); if (IS_ERR(real)) { /* * Treat stale file handle to lower file as "origin unknown". @@ -220,6 +230,7 @@ static int ovl_lookup_single(struct dentry *base, struct ovl_lookup_data *d, { struct dentry *this; int err; + bool last_element = !post[0]; this = lookup_one_len_unlocked(name, base, namelen); if (IS_ERR(this)) { @@ -245,11 +256,23 @@ static int ovl_lookup_single(struct dentry *base, struct ovl_lookup_data *d, d->stop = true; if (d->is_dir) goto put_and_out; + + /* + * NB: handle failure to lookup non-last element when non-dir + * redirects become possible + */ + WARN_ON(!last_element); goto out; } - d->is_dir = true; - if (!d->last && ovl_is_opaquedir(this)) { - d->stop = d->opaque = true; + if (last_element) + d->is_dir = true; + if (d->last) + goto out; + + if (ovl_is_opaquedir(this)) { + d->stop = true; + if (last_element) + d->opaque = true; goto out; } err = ovl_check_redirect(this, d, prelen, post); @@ -310,14 +333,15 @@ static int ovl_lookup_layer(struct dentry *base, struct ovl_lookup_data *d, } -int ovl_check_origin_fh(struct ovl_fs *ofs, struct ovl_fh *fh, +int ovl_check_origin_fh(struct ovl_fs *ofs, struct ovl_fh *fh, bool connected, struct dentry *upperdentry, struct ovl_path **stackp) { struct dentry *origin = NULL; int i; for (i = 0; i < ofs->numlower; i++) { - origin = ovl_decode_fh(fh, ofs->lower_layers[i].mnt); + origin = ovl_decode_real_fh(fh, ofs->lower_layers[i].mnt, + connected); if (origin) break; } @@ -361,7 +385,7 @@ static int ovl_check_origin(struct ovl_fs *ofs, struct dentry *upperdentry, if (IS_ERR_OR_NULL(fh)) return PTR_ERR(fh); - err = ovl_check_origin_fh(ofs, fh, upperdentry, stackp); + err = ovl_check_origin_fh(ofs, fh, false, upperdentry, stackp); kfree(fh); if (err) { @@ -415,7 +439,7 @@ int ovl_verify_set_fh(struct dentry *dentry, const char *name, struct ovl_fh *fh; int err; - fh = ovl_encode_fh(real, is_upper); + fh = ovl_encode_real_fh(real, is_upper); err = PTR_ERR(fh); if (IS_ERR(fh)) goto fail; @@ -451,7 +475,7 @@ struct dentry *ovl_index_upper(struct ovl_fs *ofs, struct dentry *index) if (IS_ERR_OR_NULL(fh)) return ERR_CAST(fh); - upper = ovl_decode_fh(fh, ofs->upper_mnt); + upper = ovl_decode_real_fh(fh, ofs->upper_mnt, true); kfree(fh); if (IS_ERR_OR_NULL(upper)) @@ -558,7 +582,7 @@ int ovl_verify_index(struct ovl_fs *ofs, struct dentry *index) /* Check if non-dir index is orphan and don't warn before cleaning it */ if (!d_is_dir(index) && d_inode(index)->i_nlink == 1) { - err = ovl_check_origin_fh(ofs, fh, index, &stack); + err = ovl_check_origin_fh(ofs, fh, false, index, &stack); if (err) goto fail; @@ -619,7 +643,7 @@ int ovl_get_index_name(struct dentry *origin, struct qstr *name) struct ovl_fh *fh; int err; - fh = ovl_encode_fh(origin, false); + fh = ovl_encode_real_fh(origin, false); if (IS_ERR(fh)) return PTR_ERR(fh); @@ -815,7 +839,7 @@ struct dentry *ovl_lookup(struct inode *dir, struct dentry *dentry, .is_dir = false, .opaque = false, .stop = false, - .last = !poe->numlower, + .last = ofs->config.redirect_follow ? false : !poe->numlower, .redirect = NULL, }; @@ -873,7 +897,11 @@ struct dentry *ovl_lookup(struct inode *dir, struct dentry *dentry, for (i = 0; !d.stop && i < poe->numlower; i++) { struct ovl_path lower = poe->lowerstack[i]; - d.last = i == poe->numlower - 1; + if (!ofs->config.redirect_follow) + d.last = i == poe->numlower - 1; + else + d.last = lower.layer->idx == roe->numlower; + err = ovl_lookup_layer(lower.dentry, &d, &this); if (err) goto out_put; @@ -976,17 +1004,18 @@ struct dentry *ovl_lookup(struct inode *dir, struct dentry *dentry, upperdentry = dget(index); if (upperdentry || ctr) { - if (ctr) - origin = stack[0].dentry; - inode = ovl_get_inode(dentry->d_sb, upperdentry, origin, index, + inode = ovl_get_inode(dentry->d_sb, upperdentry, stack, index, ctr); err = PTR_ERR(inode); if (IS_ERR(inode)) goto out_free_oe; + /* + * NB: handle redirected hard links when non-dir redirects + * become possible + */ + WARN_ON(OVL_I(inode)->redirect); OVL_I(inode)->redirect = upperredirect; - if (index) - ovl_set_flag(OVL_INDEX, inode); } revert_creds(old_cred); diff --git a/fs/overlayfs/overlayfs.h b/fs/overlayfs/overlayfs.h index 225ff1171147..e0b7de799f6b 100644 --- a/fs/overlayfs/overlayfs.h +++ b/fs/overlayfs/overlayfs.h @@ -202,7 +202,7 @@ void ovl_drop_write(struct dentry *dentry); struct dentry *ovl_workdir(struct dentry *dentry); const struct cred *ovl_override_creds(struct super_block *sb); struct super_block *ovl_same_sb(struct super_block *sb); -bool ovl_can_decode_fh(struct super_block *sb); +int ovl_can_decode_fh(struct super_block *sb); struct dentry *ovl_indexdir(struct super_block *sb); bool ovl_index_all(struct super_block *sb); bool ovl_verify_lower(struct super_block *sb); @@ -215,6 +215,7 @@ void ovl_path_lower(struct dentry *dentry, struct path *path); enum ovl_path_type ovl_path_real(struct dentry *dentry, struct path *path); struct dentry *ovl_dentry_upper(struct dentry *dentry); struct dentry *ovl_dentry_lower(struct dentry *dentry); +struct ovl_layer *ovl_layer_lower(struct dentry *dentry); struct dentry *ovl_dentry_real(struct dentry *dentry); struct dentry *ovl_i_dentry_upper(struct inode *inode); struct inode *ovl_inode_upper(struct inode *inode); @@ -263,11 +264,19 @@ static inline bool ovl_is_impuredir(struct dentry *dentry) return ovl_check_dir_xattr(dentry, OVL_XATTR_IMPURE); } +static inline unsigned int ovl_xino_bits(struct super_block *sb) +{ + struct ovl_fs *ofs = sb->s_fs_info; + + return ofs->xino_bits; +} + /* namei.c */ int ovl_check_fh_len(struct ovl_fh *fh, int fh_len); -struct dentry *ovl_decode_fh(struct ovl_fh *fh, struct vfsmount *mnt); -int ovl_check_origin_fh(struct ovl_fs *ofs, struct ovl_fh *fh, +struct dentry *ovl_decode_real_fh(struct ovl_fh *fh, struct vfsmount *mnt, + bool connected); +int ovl_check_origin_fh(struct ovl_fs *ofs, struct ovl_fh *fh, bool connected, struct dentry *upperdentry, struct ovl_path **stackp); int ovl_verify_set_fh(struct dentry *dentry, const char *name, struct dentry *real, bool is_upper, bool set); @@ -329,7 +338,7 @@ struct inode *ovl_new_inode(struct super_block *sb, umode_t mode, dev_t rdev); struct inode *ovl_lookup_inode(struct super_block *sb, struct dentry *real, bool is_upper); struct inode *ovl_get_inode(struct super_block *sb, struct dentry *upperdentry, - struct dentry *lowerdentry, struct dentry *index, + struct ovl_path *lowerpath, struct dentry *index, unsigned int numlower); static inline void ovl_copyattr(struct inode *from, struct inode *to) { @@ -361,7 +370,7 @@ int ovl_copy_up(struct dentry *dentry); int ovl_copy_up_flags(struct dentry *dentry, int flags); int ovl_copy_xattr(struct dentry *old, struct dentry *new); int ovl_set_attr(struct dentry *upper, struct kstat *stat); -struct ovl_fh *ovl_encode_fh(struct dentry *real, bool is_upper); +struct ovl_fh *ovl_encode_real_fh(struct dentry *real, bool is_upper); int ovl_set_origin(struct dentry *dentry, struct dentry *lower, struct dentry *upper); diff --git a/fs/overlayfs/ovl_entry.h b/fs/overlayfs/ovl_entry.h index bfef6edcc111..41655a7d6894 100644 --- a/fs/overlayfs/ovl_entry.h +++ b/fs/overlayfs/ovl_entry.h @@ -18,13 +18,21 @@ struct ovl_config { const char *redirect_mode; bool index; bool nfs_export; + int xino; +}; + +struct ovl_sb { + struct super_block *sb; + dev_t pseudo_dev; }; struct ovl_layer { struct vfsmount *mnt; - dev_t pseudo_dev; - /* Index of this layer in fs root (upper == 0) */ + struct ovl_sb *fs; + /* Index of this layer in fs root (upper idx == 0) */ int idx; + /* One fsid per unique underlying sb (upper fsid == 0) */ + int fsid; }; struct ovl_path { @@ -35,8 +43,11 @@ struct ovl_path { /* private information held for overlayfs's superblock */ struct ovl_fs { struct vfsmount *upper_mnt; - unsigned numlower; + unsigned int numlower; + /* Number of unique lower sb that differ from upper sb */ + unsigned int numlowerfs; struct ovl_layer *lower_layers; + struct ovl_sb *lower_fs; /* workbasedir is the path at workdir= mount option */ struct dentry *workbasedir; /* workdir is the 'work' directory under workbasedir */ @@ -50,11 +61,11 @@ struct ovl_fs { const struct cred *creator_cred; bool tmpfile; bool noxattr; - /* sb common to all layers */ - struct super_block *same_sb; /* Did we take the inuse lock? */ bool upperdir_locked; bool workdir_locked; + /* Inode numbers in all layers do not use the high xino_bits */ + unsigned int xino_bits; }; /* private information held for every overlayfs dentry */ diff --git a/fs/overlayfs/readdir.c b/fs/overlayfs/readdir.c index c11f5c0906c3..ef1fe42ff7bb 100644 --- a/fs/overlayfs/readdir.c +++ b/fs/overlayfs/readdir.c @@ -120,6 +120,10 @@ static bool ovl_calc_d_ino(struct ovl_readdir_data *rdd, if (!rdd->dentry) return false; + /* Always recalc d_ino when remapping lower inode numbers */ + if (ovl_xino_bits(rdd->dentry->d_sb)) + return true; + /* Always recalc d_ino for parent */ if (strcmp(p->name, "..") == 0) return true; @@ -435,6 +439,19 @@ static struct ovl_dir_cache *ovl_cache_get(struct dentry *dentry) return cache; } +/* Map inode number to lower fs unique range */ +static u64 ovl_remap_lower_ino(u64 ino, int xinobits, int fsid, + const char *name, int namelen) +{ + if (ino >> (64 - xinobits)) { + pr_warn_ratelimited("overlayfs: d_ino too big (%.*s, ino=%llu, xinobits=%d)\n", + namelen, name, ino, xinobits); + return ino; + } + + return ino | ((u64)fsid) << (64 - xinobits); +} + /* * Set d_ino for upper entries. Non-upper entries should always report * the uppermost real inode ino and should not call this function. @@ -452,9 +469,10 @@ static int ovl_cache_update_ino(struct path *path, struct ovl_cache_entry *p) struct dentry *this = NULL; enum ovl_path_type type; u64 ino = p->real_ino; + int xinobits = ovl_xino_bits(dir->d_sb); int err = 0; - if (!ovl_same_sb(dir->d_sb)) + if (!ovl_same_sb(dir->d_sb) && !xinobits) goto out; if (p->name[0] == '.') { @@ -491,6 +509,10 @@ get: WARN_ON_ONCE(dir->d_sb->s_dev != stat.dev); ino = stat.ino; + } else if (xinobits && !OVL_TYPE_UPPER(type)) { + ino = ovl_remap_lower_ino(ino, xinobits, + ovl_layer_lower(this)->fsid, + p->name, p->len); } out: @@ -618,6 +640,8 @@ struct ovl_readdir_translate { struct ovl_dir_cache *cache; struct dir_context ctx; u64 parent_ino; + int fsid; + int xinobits; }; static int ovl_fill_real(struct dir_context *ctx, const char *name, @@ -628,14 +652,17 @@ static int ovl_fill_real(struct dir_context *ctx, const char *name, container_of(ctx, struct ovl_readdir_translate, ctx); struct dir_context *orig_ctx = rdt->orig_ctx; - if (rdt->parent_ino && strcmp(name, "..") == 0) + if (rdt->parent_ino && strcmp(name, "..") == 0) { ino = rdt->parent_ino; - else if (rdt->cache) { + } else if (rdt->cache) { struct ovl_cache_entry *p; p = ovl_cache_entry_find(&rdt->cache->root, name, namelen); if (p) ino = p->ino; + } else if (rdt->xinobits) { + ino = ovl_remap_lower_ino(ino, rdt->xinobits, rdt->fsid, + name, namelen); } return orig_ctx->actor(orig_ctx, name, namelen, offset, ino, d_type); @@ -646,11 +673,16 @@ static int ovl_iterate_real(struct file *file, struct dir_context *ctx) int err; struct ovl_dir_file *od = file->private_data; struct dentry *dir = file->f_path.dentry; + struct ovl_layer *lower_layer = ovl_layer_lower(dir); struct ovl_readdir_translate rdt = { .ctx.actor = ovl_fill_real, .orig_ctx = ctx, + .xinobits = ovl_xino_bits(dir->d_sb), }; + if (rdt.xinobits && lower_layer) + rdt.fsid = lower_layer->fsid; + if (OVL_TYPE_MERGE(ovl_path_type(dir->d_parent))) { struct kstat stat; struct path statpath = file->f_path; @@ -693,9 +725,10 @@ static int ovl_iterate(struct file *file, struct dir_context *ctx) * dir is impure then need to adjust d_ino for copied up * entries. */ - if (ovl_same_sb(dentry->d_sb) && - (ovl_test_flag(OVL_IMPURE, d_inode(dentry)) || - OVL_TYPE_MERGE(ovl_path_type(dentry->d_parent)))) { + if (ovl_xino_bits(dentry->d_sb) || + (ovl_same_sb(dentry->d_sb) && + (ovl_test_flag(OVL_IMPURE, d_inode(dentry)) || + OVL_TYPE_MERGE(ovl_path_type(dentry->d_parent))))) { return ovl_iterate_real(file, ctx); } return iterate_dir(od->realfile, ctx); diff --git a/fs/overlayfs/super.c b/fs/overlayfs/super.c index 7c24619ae7fc..e8551c97de51 100644 --- a/fs/overlayfs/super.c +++ b/fs/overlayfs/super.c @@ -17,6 +17,7 @@ #include <linux/statfs.h> #include <linux/seq_file.h> #include <linux/posix_acl_xattr.h> +#include <linux/exportfs.h> #include "overlayfs.h" MODULE_AUTHOR("Miklos Szeredi <miklos@szeredi.hu>"); @@ -50,6 +51,11 @@ module_param_named(nfs_export, ovl_nfs_export_def, bool, 0644); MODULE_PARM_DESC(ovl_nfs_export_def, "Default to on or off for the NFS export feature"); +static bool ovl_xino_auto_def = IS_ENABLED(CONFIG_OVERLAY_FS_XINO_AUTO); +module_param_named(xino_auto, ovl_xino_auto_def, bool, 0644); +MODULE_PARM_DESC(ovl_xino_auto_def, + "Auto enable xino feature"); + static void ovl_entry_stack_free(struct ovl_entry *oe) { unsigned int i; @@ -236,11 +242,12 @@ static void ovl_free_fs(struct ovl_fs *ofs) if (ofs->upperdir_locked) ovl_inuse_unlock(ofs->upper_mnt->mnt_root); mntput(ofs->upper_mnt); - for (i = 0; i < ofs->numlower; i++) { + for (i = 0; i < ofs->numlower; i++) mntput(ofs->lower_layers[i].mnt); - free_anon_bdev(ofs->lower_layers[i].pseudo_dev); - } + for (i = 0; i < ofs->numlowerfs; i++) + free_anon_bdev(ofs->lower_fs[i].pseudo_dev); kfree(ofs->lower_layers); + kfree(ofs->lower_fs); kfree(ofs->config.lowerdir); kfree(ofs->config.upperdir); @@ -325,6 +332,23 @@ static const char *ovl_redirect_mode_def(void) return ovl_redirect_dir_def ? "on" : "off"; } +enum { + OVL_XINO_OFF, + OVL_XINO_AUTO, + OVL_XINO_ON, +}; + +static const char * const ovl_xino_str[] = { + "off", + "auto", + "on", +}; + +static inline int ovl_xino_def(void) +{ + return ovl_xino_auto_def ? OVL_XINO_AUTO : OVL_XINO_OFF; +} + /** * ovl_show_options * @@ -350,6 +374,8 @@ static int ovl_show_options(struct seq_file *m, struct dentry *dentry) if (ofs->config.nfs_export != ovl_nfs_export_def) seq_printf(m, ",nfs_export=%s", ofs->config.nfs_export ? "on" : "off"); + if (ofs->config.xino != ovl_xino_def()) + seq_printf(m, ",xino=%s", ovl_xino_str[ofs->config.xino]); return 0; } @@ -384,6 +410,9 @@ enum { OPT_INDEX_OFF, OPT_NFS_EXPORT_ON, OPT_NFS_EXPORT_OFF, + OPT_XINO_ON, + OPT_XINO_OFF, + OPT_XINO_AUTO, OPT_ERR, }; @@ -397,6 +426,9 @@ static const match_table_t ovl_tokens = { {OPT_INDEX_OFF, "index=off"}, {OPT_NFS_EXPORT_ON, "nfs_export=on"}, {OPT_NFS_EXPORT_OFF, "nfs_export=off"}, + {OPT_XINO_ON, "xino=on"}, + {OPT_XINO_OFF, "xino=off"}, + {OPT_XINO_AUTO, "xino=auto"}, {OPT_ERR, NULL} }; @@ -511,6 +543,18 @@ static int ovl_parse_opt(char *opt, struct ovl_config *config) config->nfs_export = false; break; + case OPT_XINO_ON: + config->xino = OVL_XINO_ON; + break; + + case OPT_XINO_OFF: + config->xino = OVL_XINO_OFF; + break; + + case OPT_XINO_AUTO: + config->xino = OVL_XINO_AUTO; + break; + default: pr_err("overlayfs: unrecognized mount option \"%s\" or missing value\n", p); return -EINVAL; @@ -700,6 +744,7 @@ static int ovl_check_namelen(struct path *path, struct ovl_fs *ofs, static int ovl_lower_dir(const char *name, struct path *path, struct ovl_fs *ofs, int *stack_depth, bool *remote) { + int fh_type; int err; err = ovl_mount_dir_noesc(name, path); @@ -719,15 +764,19 @@ static int ovl_lower_dir(const char *name, struct path *path, * The inodes index feature and NFS export need to encode and decode * file handles, so they require that all layers support them. */ + fh_type = ovl_can_decode_fh(path->dentry->d_sb); if ((ofs->config.nfs_export || - (ofs->config.index && ofs->config.upperdir)) && - !ovl_can_decode_fh(path->dentry->d_sb)) { + (ofs->config.index && ofs->config.upperdir)) && !fh_type) { ofs->config.index = false; ofs->config.nfs_export = false; pr_warn("overlayfs: fs on '%s' does not support file handles, falling back to index=off,nfs_export=off.\n", name); } + /* Check if lower fs has 32bit inode numbers */ + if (fh_type != FILEID_INO32_GEN) + ofs->xino_bits = 0; + return 0; out_put: @@ -951,6 +1000,7 @@ static int ovl_make_workdir(struct ovl_fs *ofs, struct path *workpath) { struct vfsmount *mnt = ofs->upper_mnt; struct dentry *temp; + int fh_type; int err; err = mnt_want_write(mnt); @@ -1000,12 +1050,16 @@ static int ovl_make_workdir(struct ovl_fs *ofs, struct path *workpath) } /* Check if upper/work fs supports file handles */ - if (ofs->config.index && - !ovl_can_decode_fh(ofs->workdir->d_sb)) { + fh_type = ovl_can_decode_fh(ofs->workdir->d_sb); + if (ofs->config.index && !fh_type) { ofs->config.index = false; pr_warn("overlayfs: upper fs does not support file handles, falling back to index=off.\n"); } + /* Check if upper fs has 32bit inode numbers */ + if (fh_type != FILEID_INO32_GEN) + ofs->xino_bits = 0; + /* NFS export of r/w mount depends on index */ if (ofs->config.nfs_export && !ofs->config.index) { pr_warn("overlayfs: NFS export requires \"index=on\", falling back to nfs_export=off.\n"); @@ -1108,6 +1162,35 @@ out: return err; } +/* Get a unique fsid for the layer */ +static int ovl_get_fsid(struct ovl_fs *ofs, struct super_block *sb) +{ + unsigned int i; + dev_t dev; + int err; + + /* fsid 0 is reserved for upper fs even with non upper overlay */ + if (ofs->upper_mnt && ofs->upper_mnt->mnt_sb == sb) + return 0; + + for (i = 0; i < ofs->numlowerfs; i++) { + if (ofs->lower_fs[i].sb == sb) + return i + 1; + } + + err = get_anon_bdev(&dev); + if (err) { + pr_err("overlayfs: failed to get anonymous bdev for lowerpath\n"); + return err; + } + + ofs->lower_fs[ofs->numlowerfs].sb = sb; + ofs->lower_fs[ofs->numlowerfs].pseudo_dev = dev; + ofs->numlowerfs++; + + return ofs->numlowerfs; +} + static int ovl_get_lower_layers(struct ovl_fs *ofs, struct path *stack, unsigned int numlower) { @@ -1119,23 +1202,27 @@ static int ovl_get_lower_layers(struct ovl_fs *ofs, struct path *stack, GFP_KERNEL); if (ofs->lower_layers == NULL) goto out; + + ofs->lower_fs = kcalloc(numlower, sizeof(struct ovl_sb), + GFP_KERNEL); + if (ofs->lower_fs == NULL) + goto out; + for (i = 0; i < numlower; i++) { struct vfsmount *mnt; - dev_t dev; + int fsid; - err = get_anon_bdev(&dev); - if (err) { - pr_err("overlayfs: failed to get anonymous bdev for lowerpath\n"); + err = fsid = ovl_get_fsid(ofs, stack[i].mnt->mnt_sb); + if (err < 0) goto out; - } mnt = clone_private_mount(&stack[i]); err = PTR_ERR(mnt); if (IS_ERR(mnt)) { pr_err("overlayfs: failed to clone lowerpath\n"); - free_anon_bdev(dev); goto out; } + /* * Make lower layers R/O. That way fchmod/fchown on lower file * will fail instead of modifying lower fs. @@ -1143,16 +1230,41 @@ static int ovl_get_lower_layers(struct ovl_fs *ofs, struct path *stack, mnt->mnt_flags |= MNT_READONLY | MNT_NOATIME; ofs->lower_layers[ofs->numlower].mnt = mnt; - ofs->lower_layers[ofs->numlower].pseudo_dev = dev; ofs->lower_layers[ofs->numlower].idx = i + 1; + ofs->lower_layers[ofs->numlower].fsid = fsid; + if (fsid) { + ofs->lower_layers[ofs->numlower].fs = + &ofs->lower_fs[fsid - 1]; + } ofs->numlower++; + } + + /* + * When all layers on same fs, overlay can use real inode numbers. + * With mount option "xino=on", mounter declares that there are enough + * free high bits in underlying fs to hold the unique fsid. + * If overlayfs does encounter underlying inodes using the high xino + * bits reserved for fsid, it emits a warning and uses the original + * inode number. + */ + if (!ofs->numlowerfs || (ofs->numlowerfs == 1 && !ofs->upper_mnt)) { + ofs->xino_bits = 0; + ofs->config.xino = OVL_XINO_OFF; + } else if (ofs->config.xino == OVL_XINO_ON && !ofs->xino_bits) { + /* + * This is a roundup of number of bits needed for numlowerfs+1 + * (i.e. ilog2(numlowerfs+1 - 1) + 1). fsid 0 is reserved for + * upper fs even with non upper overlay. + */ + BUILD_BUG_ON(ilog2(OVL_MAX_STACK) > 31); + ofs->xino_bits = ilog2(ofs->numlowerfs) + 1; + } - /* Check if all lower layers are on same sb */ - if (i == 0) - ofs->same_sb = mnt->mnt_sb; - else if (ofs->same_sb != mnt->mnt_sb) - ofs->same_sb = NULL; + if (ofs->xino_bits) { + pr_info("overlayfs: \"xino\" feature enabled using %d upper inode bits.\n", + ofs->xino_bits); } + err = 0; out: return err; @@ -1263,6 +1375,7 @@ static int ovl_fill_super(struct super_block *sb, void *data, int silent) ofs->config.index = ovl_index_def; ofs->config.nfs_export = ovl_nfs_export_def; + ofs->config.xino = ovl_xino_def(); err = ovl_parse_opt((char *) data, &ofs->config); if (err) goto out_err; @@ -1276,6 +1389,10 @@ static int ovl_fill_super(struct super_block *sb, void *data, int silent) sb->s_stack_depth = 0; sb->s_maxbytes = MAX_LFS_FILESIZE; + /* Assume underlaying fs uses 32bit inodes unless proven otherwise */ + if (ofs->config.xino != OVL_XINO_OFF) + ofs->xino_bits = BITS_PER_LONG - 32; + if (ofs->config.upperdir) { if (!ofs->config.workdir) { pr_err("overlayfs: missing 'workdir'\n"); @@ -1305,8 +1422,6 @@ static int ovl_fill_super(struct super_block *sb, void *data, int silent) /* If the upper fs is nonexistent, we mark overlayfs r/o too */ if (!ofs->upper_mnt) sb->s_flags |= SB_RDONLY; - else if (ofs->upper_mnt->mnt_sb != ofs->same_sb) - ofs->same_sb = NULL; if (!(ovl_force_readonly(ofs)) && ofs->config.index) { err = ovl_get_indexdir(ofs, oe, &upperpath); diff --git a/fs/overlayfs/util.c b/fs/overlayfs/util.c index 930784a26623..6f1078028c66 100644 --- a/fs/overlayfs/util.c +++ b/fs/overlayfs/util.c @@ -47,13 +47,29 @@ struct super_block *ovl_same_sb(struct super_block *sb) { struct ovl_fs *ofs = sb->s_fs_info; - return ofs->same_sb; + if (!ofs->numlowerfs) + return ofs->upper_mnt->mnt_sb; + else if (ofs->numlowerfs == 1 && !ofs->upper_mnt) + return ofs->lower_fs[0].sb; + else + return NULL; } -bool ovl_can_decode_fh(struct super_block *sb) +/* + * Check if underlying fs supports file handles and try to determine encoding + * type, in order to deduce maximum inode number used by fs. + * + * Return 0 if file handles are not supported. + * Return 1 (FILEID_INO32_GEN) if fs uses the default 32bit inode encoding. + * Return -1 if fs uses a non default encoding with unknown inode size. + */ +int ovl_can_decode_fh(struct super_block *sb) { - return (sb->s_export_op && sb->s_export_op->fh_to_dentry && - !uuid_is_null(&sb->s_uuid)); + if (!sb->s_export_op || !sb->s_export_op->fh_to_dentry || + uuid_is_null(&sb->s_uuid)) + return 0; + + return sb->s_export_op->encode_fh ? -1 : FILEID_INO32_GEN; } struct dentry *ovl_indexdir(struct super_block *sb) @@ -172,6 +188,13 @@ struct dentry *ovl_dentry_lower(struct dentry *dentry) return oe->numlower ? oe->lowerstack[0].dentry : NULL; } +struct ovl_layer *ovl_layer_lower(struct dentry *dentry) +{ + struct ovl_entry *oe = dentry->d_fsdata; + + return oe->numlower ? oe->lowerstack[0].layer : NULL; +} + struct dentry *ovl_dentry_real(struct dentry *dentry) { return ovl_dentry_upper(dentry) ?: ovl_dentry_lower(dentry); @@ -279,12 +302,16 @@ void ovl_dentry_set_redirect(struct dentry *dentry, const char *redirect) void ovl_inode_init(struct inode *inode, struct dentry *upperdentry, struct dentry *lowerdentry) { + struct inode *realinode = d_inode(upperdentry ?: lowerdentry); + if (upperdentry) OVL_I(inode)->__upperdentry = upperdentry; if (lowerdentry) OVL_I(inode)->lower = igrab(d_inode(lowerdentry)); - ovl_copyattr(d_inode(upperdentry ?: lowerdentry), inode); + ovl_copyattr(realinode, inode); + if (!inode->i_ino) + inode->i_ino = realinode->i_ino; } void ovl_inode_update(struct inode *inode, struct dentry *upperdentry) @@ -299,6 +326,8 @@ void ovl_inode_update(struct inode *inode, struct dentry *upperdentry) smp_wmb(); OVL_I(inode)->__upperdentry = upperdentry; if (inode_unhashed(inode)) { + if (!inode->i_ino) + inode->i_ino = upperinode->i_ino; inode->i_private = upperinode; __insert_inode_hash(inode, (unsigned long) upperinode); } |