diff options
Diffstat (limited to 'fs/overlayfs/util.c')
| -rw-r--r-- | fs/overlayfs/util.c | 1012 |
1 files changed, 819 insertions, 193 deletions
diff --git a/fs/overlayfs/util.c b/fs/overlayfs/util.c index 7c01327b1852..94986d11a166 100644 --- a/fs/overlayfs/util.c +++ b/fs/overlayfs/util.c @@ -1,10 +1,7 @@ +// SPDX-License-Identifier: GPL-2.0-only /* * Copyright (C) 2011 Novell Inc. * Copyright (C) 2016 Red Hat, Inc. - * - * This program is free software; you can redistribute it and/or modify it - * under the terms of the GNU General Public License version 2 as published by - * the Free Software Foundation. */ #include <linux/fs.h> @@ -13,48 +10,65 @@ #include <linux/cred.h> #include <linux/xattr.h> #include <linux/exportfs.h> +#include <linux/file.h> +#include <linux/fileattr.h> #include <linux/uuid.h> #include <linux/namei.h> #include <linux/ratelimit.h> +#include <linux/overflow.h> #include "overlayfs.h" +/* Get write access to upper mnt - may fail if upper sb was remounted ro */ +int ovl_get_write_access(struct dentry *dentry) +{ + struct ovl_fs *ofs = OVL_FS(dentry->d_sb); + return mnt_get_write_access(ovl_upper_mnt(ofs)); +} + +/* Get write access to upper sb - may block if upper sb is frozen */ +void ovl_start_write(struct dentry *dentry) +{ + struct ovl_fs *ofs = OVL_FS(dentry->d_sb); + sb_start_write(ovl_upper_mnt(ofs)->mnt_sb); +} + int ovl_want_write(struct dentry *dentry) { - struct ovl_fs *ofs = dentry->d_sb->s_fs_info; - return mnt_want_write(ofs->upper_mnt); + struct ovl_fs *ofs = OVL_FS(dentry->d_sb); + return mnt_want_write(ovl_upper_mnt(ofs)); +} + +void ovl_put_write_access(struct dentry *dentry) +{ + struct ovl_fs *ofs = OVL_FS(dentry->d_sb); + mnt_put_write_access(ovl_upper_mnt(ofs)); +} + +void ovl_end_write(struct dentry *dentry) +{ + struct ovl_fs *ofs = OVL_FS(dentry->d_sb); + sb_end_write(ovl_upper_mnt(ofs)->mnt_sb); } void ovl_drop_write(struct dentry *dentry) { - struct ovl_fs *ofs = dentry->d_sb->s_fs_info; - mnt_drop_write(ofs->upper_mnt); + struct ovl_fs *ofs = OVL_FS(dentry->d_sb); + mnt_drop_write(ovl_upper_mnt(ofs)); } struct dentry *ovl_workdir(struct dentry *dentry) { - struct ovl_fs *ofs = dentry->d_sb->s_fs_info; + struct ovl_fs *ofs = OVL_FS(dentry->d_sb); return ofs->workdir; } const struct cred *ovl_override_creds(struct super_block *sb) { - struct ovl_fs *ofs = sb->s_fs_info; + struct ovl_fs *ofs = OVL_FS(sb); return override_creds(ofs->creator_cred); } -struct super_block *ovl_same_sb(struct super_block *sb) -{ - struct ovl_fs *ofs = sb->s_fs_info; - - 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; -} - /* * Check if underlying fs supports file handles and try to determine encoding * type, in order to deduce maximum inode number used by fs. @@ -65,7 +79,10 @@ struct super_block *ovl_same_sb(struct super_block *sb) */ int ovl_can_decode_fh(struct super_block *sb) { - if (!sb->s_export_op || !sb->s_export_op->fh_to_dentry) + if (!capable(CAP_DAC_READ_SEARCH)) + return 0; + + if (!exportfs_can_decode_fh(sb->s_export_op)) return 0; return sb->s_export_op->encode_fh ? -1 : FILEID_INO32_GEN; @@ -73,15 +90,15 @@ int ovl_can_decode_fh(struct super_block *sb) struct dentry *ovl_indexdir(struct super_block *sb) { - struct ovl_fs *ofs = sb->s_fs_info; + struct ovl_fs *ofs = OVL_FS(sb); - return ofs->indexdir; + return ofs->config.index ? ofs->workdir : NULL; } /* Index all files on copy up. For now only enabled for NFS export */ bool ovl_index_all(struct super_block *sb) { - struct ovl_fs *ofs = sb->s_fs_info; + struct ovl_fs *ofs = OVL_FS(sb); return ofs->config.nfs_export && ofs->config.index; } @@ -89,40 +106,117 @@ bool ovl_index_all(struct super_block *sb) /* Verify lower origin on lookup. For now only enabled for NFS export */ bool ovl_verify_lower(struct super_block *sb) { - struct ovl_fs *ofs = sb->s_fs_info; + struct ovl_fs *ofs = OVL_FS(sb); return ofs->config.nfs_export && ofs->config.index; } +struct ovl_path *ovl_stack_alloc(unsigned int n) +{ + return kcalloc(n, sizeof(struct ovl_path), GFP_KERNEL); +} + +void ovl_stack_cpy(struct ovl_path *dst, struct ovl_path *src, unsigned int n) +{ + unsigned int i; + + memcpy(dst, src, sizeof(struct ovl_path) * n); + for (i = 0; i < n; i++) + dget(src[i].dentry); +} + +void ovl_stack_put(struct ovl_path *stack, unsigned int n) +{ + unsigned int i; + + for (i = 0; stack && i < n; i++) + dput(stack[i].dentry); +} + +void ovl_stack_free(struct ovl_path *stack, unsigned int n) +{ + ovl_stack_put(stack, n); + kfree(stack); +} + struct ovl_entry *ovl_alloc_entry(unsigned int numlower) { - size_t size = offsetof(struct ovl_entry, lowerstack[numlower]); - struct ovl_entry *oe = kzalloc(size, GFP_KERNEL); + struct ovl_entry *oe; + oe = kzalloc(struct_size(oe, __lowerstack, numlower), GFP_KERNEL); if (oe) - oe->numlower = numlower; + oe->__numlower = numlower; return oe; } +void ovl_free_entry(struct ovl_entry *oe) +{ + ovl_stack_put(ovl_lowerstack(oe), ovl_numlower(oe)); + kfree(oe); +} + +#define OVL_D_REVALIDATE (DCACHE_OP_REVALIDATE | DCACHE_OP_WEAK_REVALIDATE) + bool ovl_dentry_remote(struct dentry *dentry) { - return dentry->d_flags & - (DCACHE_OP_REVALIDATE | DCACHE_OP_WEAK_REVALIDATE | - DCACHE_OP_REAL); + return dentry->d_flags & OVL_D_REVALIDATE; +} + +void ovl_dentry_update_reval(struct dentry *dentry, struct dentry *realdentry) +{ + if (!ovl_dentry_remote(realdentry)) + return; + + spin_lock(&dentry->d_lock); + dentry->d_flags |= realdentry->d_flags & OVL_D_REVALIDATE; + spin_unlock(&dentry->d_lock); +} + +void ovl_dentry_init_reval(struct dentry *dentry, struct dentry *upperdentry, + struct ovl_entry *oe) +{ + return ovl_dentry_init_flags(dentry, upperdentry, oe, OVL_D_REVALIDATE); +} + +void ovl_dentry_init_flags(struct dentry *dentry, struct dentry *upperdentry, + struct ovl_entry *oe, unsigned int mask) +{ + struct ovl_path *lowerstack = ovl_lowerstack(oe); + unsigned int i, flags = 0; + + if (upperdentry) + flags |= upperdentry->d_flags; + for (i = 0; i < ovl_numlower(oe) && lowerstack[i].dentry; i++) + flags |= lowerstack[i].dentry->d_flags; + + spin_lock(&dentry->d_lock); + dentry->d_flags &= ~mask; + dentry->d_flags |= flags & mask; + spin_unlock(&dentry->d_lock); } bool ovl_dentry_weird(struct dentry *dentry) { - return dentry->d_flags & (DCACHE_NEED_AUTOMOUNT | - DCACHE_MANAGE_TRANSIT | - DCACHE_OP_HASH | - DCACHE_OP_COMPARE); + if (!d_can_lookup(dentry) && !d_is_file(dentry) && !d_is_symlink(dentry)) + return true; + + if (dentry->d_flags & (DCACHE_NEED_AUTOMOUNT | DCACHE_MANAGE_TRANSIT)) + return true; + + /* + * Exceptionally for layers with casefold, we accept that they have + * their own hash and compare operations + */ + if (sb_has_encoding(dentry->d_sb)) + return false; + + return dentry->d_flags & (DCACHE_OP_HASH | DCACHE_OP_COMPARE); } enum ovl_path_type ovl_path_type(struct dentry *dentry) { - struct ovl_entry *oe = dentry->d_fsdata; + struct ovl_entry *oe = OVL_E(dentry); enum ovl_path_type type = 0; if (ovl_dentry_upper(dentry)) { @@ -131,7 +225,7 @@ enum ovl_path_type ovl_path_type(struct dentry *dentry) /* * Non-dir dentry can hold lower dentry of its copy up origin. */ - if (oe->numlower) { + if (ovl_numlower(oe)) { if (ovl_test_flag(OVL_CONST_INO, d_inode(dentry))) type |= __OVL_PATH_ORIGIN; if (d_is_dir(dentry) || @@ -139,7 +233,7 @@ enum ovl_path_type ovl_path_type(struct dentry *dentry) type |= __OVL_PATH_MERGE; } } else { - if (oe->numlower > 1) + if (ovl_numlower(oe) > 1) type |= __OVL_PATH_MERGE; } return type; @@ -147,19 +241,20 @@ enum ovl_path_type ovl_path_type(struct dentry *dentry) void ovl_path_upper(struct dentry *dentry, struct path *path) { - struct ovl_fs *ofs = dentry->d_sb->s_fs_info; + struct ovl_fs *ofs = OVL_FS(dentry->d_sb); - path->mnt = ofs->upper_mnt; + path->mnt = ovl_upper_mnt(ofs); path->dentry = ovl_dentry_upper(dentry); } void ovl_path_lower(struct dentry *dentry, struct path *path) { - struct ovl_entry *oe = dentry->d_fsdata; + struct ovl_entry *oe = OVL_E(dentry); + struct ovl_path *lowerpath = ovl_lowerstack(oe); - if (oe->numlower) { - path->mnt = oe->lowerstack[0].layer->mnt; - path->dentry = oe->lowerstack[0].dentry; + if (ovl_numlower(oe)) { + path->mnt = lowerpath->layer->mnt; + path->dentry = lowerpath->dentry; } else { *path = (struct path) { }; } @@ -167,11 +262,19 @@ void ovl_path_lower(struct dentry *dentry, struct path *path) void ovl_path_lowerdata(struct dentry *dentry, struct path *path) { - struct ovl_entry *oe = dentry->d_fsdata; + struct ovl_entry *oe = OVL_E(dentry); + struct ovl_path *lowerdata = ovl_lowerdata(oe); + struct dentry *lowerdata_dentry = ovl_lowerdata_dentry(oe); - if (oe->numlower) { - path->mnt = oe->lowerstack[oe->numlower - 1].layer->mnt; - path->dentry = oe->lowerstack[oe->numlower - 1].dentry; + if (lowerdata_dentry) { + path->dentry = lowerdata_dentry; + /* + * Pairs with smp_wmb() in ovl_dentry_set_lowerdata(). + * Make sure that if lowerdata->dentry is visible, then + * datapath->layer is visible as well. + */ + smp_rmb(); + path->mnt = READ_ONCE(lowerdata->layer)->mnt; } else { *path = (struct path) { }; } @@ -189,36 +292,73 @@ enum ovl_path_type ovl_path_real(struct dentry *dentry, struct path *path) return type; } +enum ovl_path_type ovl_path_realdata(struct dentry *dentry, struct path *path) +{ + enum ovl_path_type type = ovl_path_type(dentry); + + WARN_ON_ONCE(d_is_dir(dentry)); + + if (!OVL_TYPE_UPPER(type) || OVL_TYPE_MERGE(type)) + ovl_path_lowerdata(dentry, path); + else + ovl_path_upper(dentry, path); + + return type; +} + struct dentry *ovl_dentry_upper(struct dentry *dentry) { - return ovl_upperdentry_dereference(OVL_I(d_inode(dentry))); + struct inode *inode = d_inode(dentry); + + return inode ? ovl_upperdentry_dereference(OVL_I(inode)) : NULL; } struct dentry *ovl_dentry_lower(struct dentry *dentry) { - struct ovl_entry *oe = dentry->d_fsdata; + struct ovl_entry *oe = OVL_E(dentry); - return oe->numlower ? oe->lowerstack[0].dentry : NULL; + return ovl_numlower(oe) ? ovl_lowerstack(oe)->dentry : NULL; } -struct ovl_layer *ovl_layer_lower(struct dentry *dentry) +const struct ovl_layer *ovl_layer_lower(struct dentry *dentry) { - struct ovl_entry *oe = dentry->d_fsdata; + struct ovl_entry *oe = OVL_E(dentry); - return oe->numlower ? oe->lowerstack[0].layer : NULL; + return ovl_numlower(oe) ? ovl_lowerstack(oe)->layer : NULL; } /* * ovl_dentry_lower() could return either a data dentry or metacopy dentry - * dependig on what is stored in lowerstack[0]. At times we need to find + * depending on what is stored in lowerstack[0]. At times we need to find * lower dentry which has data (and not metacopy dentry). This helper * returns the lower data dentry. */ struct dentry *ovl_dentry_lowerdata(struct dentry *dentry) { - struct ovl_entry *oe = dentry->d_fsdata; + return ovl_lowerdata_dentry(OVL_E(dentry)); +} + +int ovl_dentry_set_lowerdata(struct dentry *dentry, struct ovl_path *datapath) +{ + struct ovl_entry *oe = OVL_E(dentry); + struct ovl_path *lowerdata = ovl_lowerdata(oe); + struct dentry *datadentry = datapath->dentry; + + if (WARN_ON_ONCE(ovl_numlower(oe) <= 1)) + return -EIO; + + WRITE_ONCE(lowerdata->layer, datapath->layer); + /* + * Pairs with smp_rmb() in ovl_path_lowerdata(). + * Make sure that if lowerdata->dentry is visible, then + * lowerdata->layer is visible as well. + */ + smp_wmb(); + WRITE_ONCE(lowerdata->dentry, dget(datadentry)); - return oe->numlower ? oe->lowerstack[oe->numlower - 1].dentry : NULL; + ovl_dentry_update_reval(dentry, datadentry); + + return 0; } struct dentry *ovl_dentry_real(struct dentry *dentry) @@ -231,6 +371,21 @@ struct dentry *ovl_i_dentry_upper(struct inode *inode) return ovl_upperdentry_dereference(OVL_I(inode)); } +struct inode *ovl_i_path_real(struct inode *inode, struct path *path) +{ + struct ovl_path *lowerpath = ovl_lowerpath(OVL_I_E(inode)); + + path->dentry = ovl_i_dentry_upper(inode); + if (!path->dentry) { + path->dentry = lowerpath->dentry; + path->mnt = lowerpath->layer->mnt; + } else { + path->mnt = ovl_upper_mnt(OVL_FS(inode->i_sb)); + } + + return path->dentry ? d_inode_rcu(path->dentry) : NULL; +} + struct inode *ovl_inode_upper(struct inode *inode) { struct dentry *upperdentry = ovl_i_dentry_upper(inode); @@ -240,7 +395,9 @@ struct inode *ovl_inode_upper(struct inode *inode) struct inode *ovl_inode_lower(struct inode *inode) { - return OVL_I(inode)->lower; + struct ovl_path *lowerpath = ovl_lowerpath(OVL_I_E(inode)); + + return lowerpath ? d_inode(lowerpath->dentry) : NULL; } struct inode *ovl_inode_real(struct inode *inode) @@ -251,10 +408,12 @@ struct inode *ovl_inode_real(struct inode *inode) /* Return inode which contains lower data. Do not return metacopy */ struct inode *ovl_inode_lowerdata(struct inode *inode) { + struct dentry *lowerdata = ovl_lowerdata_dentry(OVL_I_E(inode)); + if (WARN_ON(!S_ISREG(inode->i_mode))) return NULL; - return OVL_I(inode)->lowerdata ?: ovl_inode_lower(inode); + return lowerdata ? d_inode(lowerdata) : NULL; } /* Return real inode which contains data. Does not return metacopy inode */ @@ -269,9 +428,15 @@ struct inode *ovl_inode_realdata(struct inode *inode) return ovl_inode_lowerdata(inode); } +const char *ovl_lowerdata_redirect(struct inode *inode) +{ + return inode && S_ISREG(inode->i_mode) ? + OVL_I(inode)->lowerdata_redirect : NULL; +} + struct ovl_dir_cache *ovl_dir_cache(struct inode *inode) { - return OVL_I(inode)->cache; + return inode && S_ISDIR(inode->i_mode) ? OVL_I(inode)->cache : NULL; } void ovl_set_dir_cache(struct inode *inode, struct ovl_dir_cache *cache) @@ -281,17 +446,17 @@ void ovl_set_dir_cache(struct inode *inode, struct ovl_dir_cache *cache) void ovl_dentry_set_flag(unsigned long flag, struct dentry *dentry) { - set_bit(flag, &OVL_E(dentry)->flags); + set_bit(flag, OVL_E_FLAGS(dentry)); } void ovl_dentry_clear_flag(unsigned long flag, struct dentry *dentry) { - clear_bit(flag, &OVL_E(dentry)->flags); + clear_bit(flag, OVL_E_FLAGS(dentry)); } bool ovl_dentry_test_flag(unsigned long flag, struct dentry *dentry) { - return test_bit(flag, &OVL_E(dentry)->flags); + return test_bit(flag, OVL_E_FLAGS(dentry)); } bool ovl_dentry_is_opaque(struct dentry *dentry) @@ -309,6 +474,33 @@ void ovl_dentry_set_opaque(struct dentry *dentry) ovl_dentry_set_flag(OVL_E_OPAQUE, dentry); } +bool ovl_dentry_has_xwhiteouts(struct dentry *dentry) +{ + return ovl_dentry_test_flag(OVL_E_XWHITEOUTS, dentry); +} + +void ovl_dentry_set_xwhiteouts(struct dentry *dentry) +{ + ovl_dentry_set_flag(OVL_E_XWHITEOUTS, dentry); +} + +/* + * ovl_layer_set_xwhiteouts() is called before adding the overlay dir + * dentry to dcache, while readdir of that same directory happens after + * the overlay dir dentry is in dcache, so if some cpu observes that + * ovl_dentry_is_xwhiteouts(), it will also observe layer->has_xwhiteouts + * for the layers where xwhiteouts marker was found in that merge dir. + */ +void ovl_layer_set_xwhiteouts(struct ovl_fs *ofs, + const struct ovl_layer *layer) +{ + if (layer->has_xwhiteouts) + return; + + /* Write once to read-mostly layer properties */ + ofs->layers[layer->idx].has_xwhiteouts = true; +} + /* * For hard links and decoded file handles, it's possible for ovl_dentry_upper() * to return positive, while there's no actual upper alias for the inode. @@ -381,13 +573,6 @@ bool ovl_dentry_needs_data_copy_up(struct dentry *dentry, int flags) return !ovl_has_upperdata(d_inode(dentry)); } -bool ovl_redirect_dir(struct super_block *sb) -{ - struct ovl_fs *ofs = sb->s_fs_info; - - return ofs->config.redirect_dir && !ofs->noxattr; -} - const char *ovl_dentry_get_redirect(struct dentry *dentry) { return OVL_I(d_inode(dentry))->redirect; @@ -401,24 +586,6 @@ void ovl_dentry_set_redirect(struct dentry *dentry, const char *redirect) oi->redirect = redirect; } -void ovl_inode_init(struct inode *inode, struct dentry *upperdentry, - struct dentry *lowerdentry, struct dentry *lowerdata) -{ - struct inode *realinode = d_inode(upperdentry ?: lowerdentry); - - if (upperdentry) - OVL_I(inode)->__upperdentry = upperdentry; - if (lowerdentry) - OVL_I(inode)->lower = igrab(d_inode(lowerdentry)); - if (lowerdata) - OVL_I(inode)->lowerdata = igrab(d_inode(lowerdata)); - - ovl_copyattr(realinode, inode); - ovl_copyflags(realinode, inode); - if (!inode->i_ino) - inode->i_ino = realinode->i_ino; -} - void ovl_inode_update(struct inode *inode, struct dentry *upperdentry) { struct inode *upperinode = d_inode(upperdentry); @@ -431,40 +598,38 @@ 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); } } -static void ovl_dentry_version_inc(struct dentry *dentry, bool impurity) +static void ovl_dir_version_inc(struct dentry *dentry, bool impurity) { struct inode *inode = d_inode(dentry); WARN_ON(!inode_is_locked(inode)); + WARN_ON(!d_is_dir(dentry)); /* - * Version is used by readdir code to keep cache consistent. For merge - * dirs all changes need to be noted. For non-merge dirs, cache only - * contains impure (ones which have been copied up and have origins) - * entries, so only need to note changes to impure entries. + * Version is used by readdir code to keep cache consistent. + * For merge dirs (or dirs with origin) all changes need to be noted. + * For non-merge dirs, cache contains only impure entries (i.e. ones + * which have been copied up and have origins), so only need to note + * changes to impure entries. */ - if (OVL_TYPE_MERGE(ovl_path_type(dentry)) || impurity) + if (!ovl_dir_is_real(inode) || impurity) OVL_I(inode)->version++; } void ovl_dir_modified(struct dentry *dentry, bool impurity) { /* Copy mtime/ctime */ - ovl_copyattr(d_inode(ovl_dentry_upper(dentry)), d_inode(dentry)); + ovl_copyattr(d_inode(dentry)); - ovl_dentry_version_inc(dentry, impurity); + ovl_dir_version_inc(dentry, impurity); } -u64 ovl_dentry_version_get(struct dentry *dentry) +u64 ovl_inode_version_get(struct inode *inode) { - struct inode *inode = d_inode(dentry); - WARN_ON(!inode_is_locked(inode)); return OVL_I(inode)->version; } @@ -476,9 +641,45 @@ bool ovl_is_whiteout(struct dentry *dentry) return inode && IS_WHITEOUT(inode); } -struct file *ovl_path_open(struct path *path, int flags) +/* + * Use this over ovl_is_whiteout for upper and lower files, as it also + * handles overlay.whiteout xattr whiteout files. + */ +bool ovl_path_is_whiteout(struct ovl_fs *ofs, const struct path *path) +{ + return ovl_is_whiteout(path->dentry) || + ovl_path_check_xwhiteout_xattr(ofs, path); +} + +struct file *ovl_path_open(const struct path *path, int flags) { - return dentry_open(path, flags | O_NOATIME, current_cred()); + struct inode *inode = d_inode(path->dentry); + struct mnt_idmap *real_idmap = mnt_idmap(path->mnt); + int err, acc_mode; + + if (flags & ~(O_ACCMODE | O_LARGEFILE)) + BUG(); + + switch (flags & O_ACCMODE) { + case O_RDONLY: + acc_mode = MAY_READ; + break; + case O_WRONLY: + acc_mode = MAY_WRITE; + break; + default: + BUG(); + } + + err = inode_permission(real_idmap, inode, acc_mode | MAY_OPEN); + if (err) + return ERR_PTR(err); + + /* O_NOATIME is an optimization, don't fail if not permitted */ + if (inode_owner_or_capable(real_idmap, inode)) + flags |= O_NOATIME; + + return dentry_open(path, flags, current_cred()); } /* Caller should hold ovl_inode->lock */ @@ -519,30 +720,44 @@ bool ovl_already_copied_up(struct dentry *dentry, int flags) return false; } +/* + * The copy up "transaction" keeps an elevated mnt write count on upper mnt, + * but leaves taking freeze protection on upper sb to lower level helpers. + */ int ovl_copy_up_start(struct dentry *dentry, int flags) { struct inode *inode = d_inode(dentry); int err; - err = ovl_inode_lock(inode); - if (!err && ovl_already_copied_up_locked(dentry, flags)) { + err = ovl_inode_lock_interruptible(inode); + if (err) + return err; + + if (ovl_already_copied_up_locked(dentry, flags)) err = 1; /* Already copied up */ - ovl_inode_unlock(inode); - } + else + err = ovl_get_write_access(dentry); + if (err) + goto out_unlock; + + return 0; +out_unlock: + ovl_inode_unlock(inode); return err; } void ovl_copy_up_end(struct dentry *dentry) { + ovl_put_write_access(dentry); ovl_inode_unlock(d_inode(dentry)); } -bool ovl_check_origin_xattr(struct dentry *dentry) +bool ovl_path_check_origin_xattr(struct ovl_fs *ofs, const struct path *path) { int res; - res = vfs_getxattr(dentry, OVL_XATTR_ORIGIN, NULL, 0); + res = ovl_path_getxattr(ofs, path, OVL_XATTR_ORIGIN, NULL, 0); /* Zero size value means "copied up but origin unknown" */ if (res >= 0) @@ -551,35 +766,136 @@ bool ovl_check_origin_xattr(struct dentry *dentry) return false; } -bool ovl_check_dir_xattr(struct dentry *dentry, const char *name) +bool ovl_path_check_xwhiteout_xattr(struct ovl_fs *ofs, const struct path *path) { + struct dentry *dentry = path->dentry; int res; - char val; - if (!d_is_dir(dentry)) + /* xattr.whiteout must be a zero size regular file */ + if (!d_is_reg(dentry) || i_size_read(d_inode(dentry)) != 0) return false; - res = vfs_getxattr(dentry, name, &val, 1); - if (res == 1 && val == 'y') - return true; + res = ovl_path_getxattr(ofs, path, OVL_XATTR_XWHITEOUT, NULL, 0); + return res >= 0; +} + +/* + * Load persistent uuid from xattr into s_uuid if found, or store a new + * random generated value in s_uuid and in xattr. + */ +bool ovl_init_uuid_xattr(struct super_block *sb, struct ovl_fs *ofs, + const struct path *upperpath) +{ + bool set = false; + uuid_t uuid; + int res; + + /* Try to load existing persistent uuid */ + res = ovl_path_getxattr(ofs, upperpath, OVL_XATTR_UUID, uuid.b, + UUID_SIZE); + if (res == UUID_SIZE) + goto set_uuid; + + if (res != -ENODATA) + goto fail; + + /* + * With uuid=auto, if uuid xattr is found, it will be used. + * If uuid xattrs is not found, generate a persistent uuid only on mount + * of new overlays where upper root dir is not yet marked as impure. + * An upper dir is marked as impure on copy up or lookup of its subdirs. + */ + if (ofs->config.uuid == OVL_UUID_AUTO) { + res = ovl_path_getxattr(ofs, upperpath, OVL_XATTR_IMPURE, NULL, + 0); + if (res > 0) { + /* Any mount of old overlay - downgrade to uuid=null */ + ofs->config.uuid = OVL_UUID_NULL; + return true; + } else if (res == -ENODATA) { + /* First mount of new overlay - upgrade to uuid=on */ + ofs->config.uuid = OVL_UUID_ON; + } else if (res < 0) { + goto fail; + } + + } + + /* Generate overlay instance uuid */ + uuid_gen(&uuid); + + /* Try to store persistent uuid */ + set = true; + res = ovl_setxattr(ofs, upperpath->dentry, OVL_XATTR_UUID, uuid.b, + UUID_SIZE); + if (res) + goto fail; +set_uuid: + super_set_uuid(sb, uuid.b, sizeof(uuid)); + return true; + +fail: + ofs->config.uuid = OVL_UUID_NULL; + pr_warn("failed to %s uuid (%pd2, err=%i); falling back to uuid=null.\n", + set ? "set" : "get", upperpath->dentry, res); return false; } -int ovl_check_setxattr(struct dentry *dentry, struct dentry *upperdentry, - const char *name, const void *value, size_t size, +char ovl_get_dir_xattr_val(struct ovl_fs *ofs, const struct path *path, + enum ovl_xattr ox) +{ + int res; + char val; + + if (!d_is_dir(path->dentry)) + return 0; + + res = ovl_path_getxattr(ofs, path, ox, &val, 1); + return res == 1 ? val : 0; +} + +#define OVL_XATTR_OPAQUE_POSTFIX "opaque" +#define OVL_XATTR_REDIRECT_POSTFIX "redirect" +#define OVL_XATTR_ORIGIN_POSTFIX "origin" +#define OVL_XATTR_IMPURE_POSTFIX "impure" +#define OVL_XATTR_NLINK_POSTFIX "nlink" +#define OVL_XATTR_UPPER_POSTFIX "upper" +#define OVL_XATTR_UUID_POSTFIX "uuid" +#define OVL_XATTR_METACOPY_POSTFIX "metacopy" +#define OVL_XATTR_PROTATTR_POSTFIX "protattr" +#define OVL_XATTR_XWHITEOUT_POSTFIX "whiteout" + +#define OVL_XATTR_TAB_ENTRY(x) \ + [x] = { [false] = OVL_XATTR_TRUSTED_PREFIX x ## _POSTFIX, \ + [true] = OVL_XATTR_USER_PREFIX x ## _POSTFIX } + +const char *const ovl_xattr_table[][2] = { + OVL_XATTR_TAB_ENTRY(OVL_XATTR_OPAQUE), + OVL_XATTR_TAB_ENTRY(OVL_XATTR_REDIRECT), + OVL_XATTR_TAB_ENTRY(OVL_XATTR_ORIGIN), + OVL_XATTR_TAB_ENTRY(OVL_XATTR_IMPURE), + OVL_XATTR_TAB_ENTRY(OVL_XATTR_NLINK), + OVL_XATTR_TAB_ENTRY(OVL_XATTR_UPPER), + OVL_XATTR_TAB_ENTRY(OVL_XATTR_UUID), + OVL_XATTR_TAB_ENTRY(OVL_XATTR_METACOPY), + OVL_XATTR_TAB_ENTRY(OVL_XATTR_PROTATTR), + OVL_XATTR_TAB_ENTRY(OVL_XATTR_XWHITEOUT), +}; + +int ovl_check_setxattr(struct ovl_fs *ofs, struct dentry *upperdentry, + enum ovl_xattr ox, const void *value, size_t size, int xerr) { int err; - struct ovl_fs *ofs = dentry->d_sb->s_fs_info; if (ofs->noxattr) return xerr; - err = ovl_do_setxattr(upperdentry, name, value, size, 0); + err = ovl_setxattr(ofs, upperdentry, ox, value, size); if (err == -EOPNOTSUPP) { - pr_warn("overlayfs: cannot set %s xattr on upper\n", name); + pr_warn("cannot set %s xattr on upper\n", ovl_xattr(ofs, ox)); ofs->noxattr = true; return xerr; } @@ -589,6 +905,7 @@ int ovl_check_setxattr(struct dentry *dentry, struct dentry *upperdentry, int ovl_set_impure(struct dentry *dentry, struct dentry *upperdentry) { + struct ovl_fs *ofs = OVL_FS(dentry->d_sb); int err; if (ovl_test_flag(OVL_IMPURE, d_inode(dentry))) @@ -598,30 +915,96 @@ int ovl_set_impure(struct dentry *dentry, struct dentry *upperdentry) * Do not fail when upper doesn't support xattrs. * Upper inodes won't have origin nor redirect xattr anyway. */ - err = ovl_check_setxattr(dentry, upperdentry, OVL_XATTR_IMPURE, - "y", 1, 0); + err = ovl_check_setxattr(ofs, upperdentry, OVL_XATTR_IMPURE, "y", 1, 0); if (!err) ovl_set_flag(OVL_IMPURE, d_inode(dentry)); return err; } -void ovl_set_flag(unsigned long flag, struct inode *inode) -{ - set_bit(flag, &OVL_I(inode)->flags); -} -void ovl_clear_flag(unsigned long flag, struct inode *inode) +#define OVL_PROTATTR_MAX 32 /* Reserved for future flags */ + +void ovl_check_protattr(struct inode *inode, struct dentry *upper) { - clear_bit(flag, &OVL_I(inode)->flags); + struct ovl_fs *ofs = OVL_FS(inode->i_sb); + u32 iflags = inode->i_flags & OVL_PROT_I_FLAGS_MASK; + char buf[OVL_PROTATTR_MAX+1]; + int res, n; + + res = ovl_getxattr_upper(ofs, upper, OVL_XATTR_PROTATTR, buf, + OVL_PROTATTR_MAX); + if (res < 0) + return; + + /* + * Initialize inode flags from overlay.protattr xattr and upper inode + * flags. If upper inode has those fileattr flags set (i.e. from old + * kernel), we do not clear them on ovl_get_inode(), but we will clear + * them on next fileattr_set(). + */ + for (n = 0; n < res; n++) { + if (buf[n] == 'a') + iflags |= S_APPEND; + else if (buf[n] == 'i') + iflags |= S_IMMUTABLE; + else + break; + } + + if (!res || n < res) { + pr_warn_ratelimited("incompatible overlay.protattr format (%pd2, len=%d)\n", + upper, res); + } else { + inode_set_flags(inode, iflags, OVL_PROT_I_FLAGS_MASK); + } } -bool ovl_test_flag(unsigned long flag, struct inode *inode) +int ovl_set_protattr(struct inode *inode, struct dentry *upper, + struct file_kattr *fa) { - return test_bit(flag, &OVL_I(inode)->flags); + struct ovl_fs *ofs = OVL_FS(inode->i_sb); + char buf[OVL_PROTATTR_MAX]; + int len = 0, err = 0; + u32 iflags = 0; + + BUILD_BUG_ON(HWEIGHT32(OVL_PROT_FS_FLAGS_MASK) > OVL_PROTATTR_MAX); + + if (fa->flags & FS_APPEND_FL) { + buf[len++] = 'a'; + iflags |= S_APPEND; + } + if (fa->flags & FS_IMMUTABLE_FL) { + buf[len++] = 'i'; + iflags |= S_IMMUTABLE; + } + + /* + * Do not allow to set protection flags when upper doesn't support + * xattrs, because we do not set those fileattr flags on upper inode. + * Remove xattr if it exist and all protection flags are cleared. + */ + if (len) { + err = ovl_check_setxattr(ofs, upper, OVL_XATTR_PROTATTR, + buf, len, -EPERM); + } else if (inode->i_flags & OVL_PROT_I_FLAGS_MASK) { + err = ovl_removexattr(ofs, upper, OVL_XATTR_PROTATTR); + if (err == -EOPNOTSUPP || err == -ENODATA) + err = 0; + } + if (err) + return err; + + inode_set_flags(inode, iflags, OVL_PROT_I_FLAGS_MASK); + + /* Mask out the fileattr flags that should not be set in upper inode */ + fa->flags &= ~OVL_PROT_FS_FLAGS_MASK; + fa->fsx_xflags &= ~OVL_PROT_FSX_FLAGS_MASK; + + return 0; } -/** +/* * Caller must hold a reference to inode to prevent it from being freed while * it is marked inuse. */ @@ -631,8 +1014,8 @@ bool ovl_inuse_trylock(struct dentry *dentry) bool locked = false; spin_lock(&inode->i_lock); - if (!(inode->i_state & I_OVL_INUSE)) { - inode->i_state |= I_OVL_INUSE; + if (!(inode_state_read(inode) & I_OVL_INUSE)) { + inode_state_set(inode, I_OVL_INUSE); locked = true; } spin_unlock(&inode->i_lock); @@ -646,12 +1029,24 @@ void ovl_inuse_unlock(struct dentry *dentry) struct inode *inode = d_inode(dentry); spin_lock(&inode->i_lock); - WARN_ON(!(inode->i_state & I_OVL_INUSE)); - inode->i_state &= ~I_OVL_INUSE; + WARN_ON(!(inode_state_read(inode) & I_OVL_INUSE)); + inode_state_clear(inode, I_OVL_INUSE); spin_unlock(&inode->i_lock); } } +bool ovl_is_inuse(struct dentry *dentry) +{ + struct inode *inode = d_inode(dentry); + bool inuse; + + spin_lock(&inode->i_lock); + inuse = (inode_state_read(inode) & I_OVL_INUSE); + spin_unlock(&inode->i_lock); + + return inuse; +} + /* * Does this overlay dentry need to be indexed on copy up? */ @@ -676,22 +1071,28 @@ bool ovl_need_index(struct dentry *dentry) /* Caller must hold OVL_I(inode)->lock */ static void ovl_cleanup_index(struct dentry *dentry) { + struct ovl_fs *ofs = OVL_FS(dentry->d_sb); struct dentry *indexdir = ovl_indexdir(dentry->d_sb); - struct inode *dir = indexdir->d_inode; struct dentry *lowerdentry = ovl_dentry_lower(dentry); struct dentry *upperdentry = ovl_dentry_upper(dentry); struct dentry *index = NULL; struct inode *inode; struct qstr name = { }; + bool got_write = false; int err; - err = ovl_get_index_name(lowerdentry, &name); + err = ovl_get_index_name(ofs, lowerdentry, &name); + if (err) + goto fail; + + err = ovl_want_write(dentry); if (err) goto fail; + got_write = true; inode = d_inode(upperdentry); if (!S_ISDIR(inode->i_mode) && inode->i_nlink != 1) { - pr_warn_ratelimited("overlayfs: cleanup linked index (%pd2, ino=%lu, nlink=%u)\n", + pr_warn_ratelimited("cleanup linked index (%pd2, ino=%lu, nlink=%u)\n", upperdentry, inode->i_ino, inode->i_nlink); /* * We either have a bug with persistent union nlink or a lower @@ -707,30 +1108,30 @@ static void ovl_cleanup_index(struct dentry *dentry) goto out; } - inode_lock_nested(dir, I_MUTEX_PARENT); - index = lookup_one_len(name.name, indexdir, name.len); + index = ovl_lookup_upper_unlocked(ofs, name.name, indexdir, name.len); err = PTR_ERR(index); if (IS_ERR(index)) { index = NULL; } else if (ovl_index_all(dentry->d_sb)) { /* Whiteout orphan index to block future open by handle */ - err = ovl_cleanup_and_whiteout(indexdir, dir, index); + err = ovl_cleanup_and_whiteout(OVL_FS(dentry->d_sb), + indexdir, index); } else { /* Cleanup orphan index entries */ - err = ovl_cleanup(dir, index); + err = ovl_cleanup(ofs, indexdir, index); } - - inode_unlock(dir); if (err) goto fail; out: + if (got_write) + ovl_drop_write(dentry); kfree(name.name); dput(index); return; fail: - pr_err("overlayfs: cleanup index of '%pd2' failed (%i)\n", dentry, err); + pr_err("cleanup index of '%pd2' failed (%i)\n", dentry, err); goto out; } @@ -741,7 +1142,6 @@ fail: int ovl_nlink_start(struct dentry *dentry) { struct inode *inode = d_inode(dentry); - const struct cred *old_cred; int err; if (WARN_ON(!inode)) @@ -767,26 +1167,34 @@ int ovl_nlink_start(struct dentry *dentry) return err; } - err = ovl_inode_lock(inode); + err = ovl_inode_lock_interruptible(inode); if (err) return err; + err = ovl_want_write(dentry); + if (err) + goto out_unlock; + if (d_is_dir(dentry) || !ovl_test_flag(OVL_INDEX, inode)) - goto out; + return 0; - old_cred = ovl_override_creds(dentry->d_sb); /* * The overlay inode nlink should be incremented/decremented IFF the * upper operation succeeds, along with nlink change of upper inode. * Therefore, before link/unlink/rename, we store the union nlink * value relative to the upper inode nlink in an upper inode xattr. */ - err = ovl_set_nlink_upper(dentry); - revert_creds(old_cred); - -out: + with_ovl_creds(dentry->d_sb) + err = ovl_set_nlink_upper(dentry); if (err) - ovl_inode_unlock(inode); + goto out_drop_write; + + return 0; + +out_drop_write: + ovl_drop_write(dentry); +out_unlock: + ovl_inode_unlock(inode); return err; } @@ -795,25 +1203,30 @@ void ovl_nlink_end(struct dentry *dentry) { struct inode *inode = d_inode(dentry); - if (ovl_test_flag(OVL_INDEX, inode) && inode->i_nlink == 0) { - const struct cred *old_cred; + ovl_drop_write(dentry); - old_cred = ovl_override_creds(dentry->d_sb); - ovl_cleanup_index(dentry); - revert_creds(old_cred); + if (ovl_test_flag(OVL_INDEX, inode) && inode->i_nlink == 0) { + with_ovl_creds(dentry->d_sb) + ovl_cleanup_index(dentry); } ovl_inode_unlock(inode); } -int ovl_lock_rename_workdir(struct dentry *workdir, struct dentry *upperdir) +int ovl_lock_rename_workdir(struct dentry *workdir, struct dentry *work, + struct dentry *upperdir, struct dentry *upper) { - /* Workdir should not be the same as upperdir */ - if (workdir == upperdir) - goto err; + struct dentry *trap; /* Workdir should not be subdir of upperdir and vice versa */ - if (lock_rename(workdir, upperdir) != NULL) + trap = lock_rename(workdir, upperdir); + if (IS_ERR(trap)) + goto err; + if (trap) + goto err_unlock; + if (work && (work->d_parent != workdir || d_unhashed(work))) + goto err_unlock; + if (upper && (upper->d_parent != upperdir || d_unhashed(upper))) goto err_unlock; return 0; @@ -821,35 +1234,83 @@ int ovl_lock_rename_workdir(struct dentry *workdir, struct dentry *upperdir) err_unlock: unlock_rename(workdir, upperdir); err: - pr_err("overlayfs: failed to lock workdir+upperdir\n"); + pr_err("failed to lock workdir+upperdir\n"); return -EIO; } -/* err < 0, 0 if no metacopy xattr, 1 if metacopy xattr found */ -int ovl_check_metacopy_xattr(struct dentry *dentry) +/* + * err < 0, 0 if no metacopy xattr, metacopy data size if xattr found. + * an empty xattr returns OVL_METACOPY_MIN_SIZE to distinguish from no xattr value. + */ +int ovl_check_metacopy_xattr(struct ovl_fs *ofs, const struct path *path, + struct ovl_metacopy *data) { int res; /* Only regular files can have metacopy xattr */ - if (!S_ISREG(d_inode(dentry)->i_mode)) + if (!S_ISREG(d_inode(path->dentry)->i_mode)) return 0; - res = vfs_getxattr(dentry, OVL_XATTR_METACOPY, NULL, 0); + res = ovl_path_getxattr(ofs, path, OVL_XATTR_METACOPY, + data, data ? OVL_METACOPY_MAX_SIZE : 0); if (res < 0) { if (res == -ENODATA || res == -EOPNOTSUPP) return 0; + /* + * getxattr on user.* may fail with EACCES in case there's no + * read permission on the inode. Not much we can do, other than + * tell the caller that this is not a metacopy inode. + */ + if (ofs->config.userxattr && res == -EACCES) + return 0; goto out; } - return 1; + if (res == 0) { + /* Emulate empty data for zero size metacopy xattr */ + res = OVL_METACOPY_MIN_SIZE; + if (data) { + memset(data, 0, res); + data->len = res; + } + } else if (res < OVL_METACOPY_MIN_SIZE) { + pr_warn_ratelimited("metacopy file '%pd' has too small xattr\n", + path->dentry); + return -EIO; + } else if (data) { + if (data->version != 0) { + pr_warn_ratelimited("metacopy file '%pd' has unsupported version\n", + path->dentry); + return -EIO; + } + if (res != data->len) { + pr_warn_ratelimited("metacopy file '%pd' has invalid xattr size\n", + path->dentry); + return -EIO; + } + } + + return res; out: - pr_warn_ratelimited("overlayfs: failed to get metacopy (%i)\n", res); + pr_warn_ratelimited("failed to get metacopy (%i)\n", res); return res; } +int ovl_set_metacopy_xattr(struct ovl_fs *ofs, struct dentry *d, struct ovl_metacopy *metacopy) +{ + size_t len = metacopy->len; + + /* If no flags or digest fall back to empty metacopy file */ + if (metacopy->version == 0 && metacopy->flags == 0 && metacopy->digest_algo == 0) + len = 0; + + return ovl_check_setxattr(ofs, d, OVL_XATTR_METACOPY, + metacopy, len, -EOPNOTSUPP); +} + bool ovl_is_metacopy_dentry(struct dentry *dentry) { - struct ovl_entry *oe = dentry->d_fsdata; + struct ovl_entry *oe = OVL_E(dentry); if (!d_is_reg(dentry)) return false; @@ -860,29 +1321,27 @@ bool ovl_is_metacopy_dentry(struct dentry *dentry) return false; } - return (oe->numlower > 1); + return (ovl_numlower(oe) > 1); } -char *ovl_get_redirect_xattr(struct dentry *dentry, int padding) +char *ovl_get_redirect_xattr(struct ovl_fs *ofs, const struct path *path, int padding) { int res; char *s, *next, *buf = NULL; - res = vfs_getxattr(dentry, OVL_XATTR_REDIRECT, NULL, 0); - if (res < 0) { - if (res == -ENODATA || res == -EOPNOTSUPP) - return NULL; + res = ovl_path_getxattr(ofs, path, OVL_XATTR_REDIRECT, NULL, 0); + if (res == -ENODATA || res == -EOPNOTSUPP) + return NULL; + if (res < 0) goto fail; - } + if (res == 0) + goto invalid; buf = kzalloc(res + padding + 1, GFP_KERNEL); if (!buf) return ERR_PTR(-ENOMEM); - if (res == 0) - goto invalid; - - res = vfs_getxattr(dentry, OVL_XATTR_REDIRECT, buf, res); + res = ovl_path_getxattr(ofs, path, OVL_XATTR_REDIRECT, buf, res); if (res < 0) goto fail; if (res == 0) @@ -900,15 +1359,182 @@ char *ovl_get_redirect_xattr(struct dentry *dentry, int padding) } return buf; - -err_free: - kfree(buf); - return ERR_PTR(res); -fail: - pr_warn_ratelimited("overlayfs: failed to get redirect (%i)\n", res); - goto err_free; invalid: - pr_warn_ratelimited("overlayfs: invalid redirect (%s)\n", buf); + pr_warn_ratelimited("invalid redirect (%s)\n", buf); res = -EINVAL; goto err_free; +fail: + pr_warn_ratelimited("failed to get redirect (%i)\n", res); +err_free: + kfree(buf); + return ERR_PTR(res); +} + +/* Call with mounter creds as it may open the file */ +int ovl_ensure_verity_loaded(const struct path *datapath) +{ + struct inode *inode = d_inode(datapath->dentry); + struct file *filp; + + if (!fsverity_active(inode) && IS_VERITY(inode)) { + /* + * If this inode was not yet opened, the verity info hasn't been + * loaded yet, so we need to do that here to force it into memory. + */ + filp = kernel_file_open(datapath, O_RDONLY, current_cred()); + if (IS_ERR(filp)) + return PTR_ERR(filp); + fput(filp); + } + + return 0; +} + +int ovl_validate_verity(struct ovl_fs *ofs, + const struct path *metapath, + const struct path *datapath) +{ + struct ovl_metacopy metacopy_data; + u8 actual_digest[FS_VERITY_MAX_DIGEST_SIZE]; + int xattr_digest_size, digest_size; + int xattr_size, err; + u8 verity_algo; + + if (!ofs->config.verity_mode || + /* Verity only works on regular files */ + !S_ISREG(d_inode(metapath->dentry)->i_mode)) + return 0; + + xattr_size = ovl_check_metacopy_xattr(ofs, metapath, &metacopy_data); + if (xattr_size < 0) + return xattr_size; + + if (!xattr_size || !metacopy_data.digest_algo) { + if (ofs->config.verity_mode == OVL_VERITY_REQUIRE) { + pr_warn_ratelimited("metacopy file '%pd' has no digest specified\n", + metapath->dentry); + return -EIO; + } + return 0; + } + + xattr_digest_size = ovl_metadata_digest_size(&metacopy_data); + + err = ovl_ensure_verity_loaded(datapath); + if (err < 0) { + pr_warn_ratelimited("lower file '%pd' failed to load fs-verity info\n", + datapath->dentry); + return -EIO; + } + + digest_size = fsverity_get_digest(d_inode(datapath->dentry), actual_digest, + &verity_algo, NULL); + if (digest_size == 0) { + pr_warn_ratelimited("lower file '%pd' has no fs-verity digest\n", datapath->dentry); + return -EIO; + } + + if (xattr_digest_size != digest_size || + metacopy_data.digest_algo != verity_algo || + memcmp(metacopy_data.digest, actual_digest, xattr_digest_size) != 0) { + pr_warn_ratelimited("lower file '%pd' has the wrong fs-verity digest\n", + datapath->dentry); + return -EIO; + } + + return 0; +} + +int ovl_get_verity_digest(struct ovl_fs *ofs, const struct path *src, + struct ovl_metacopy *metacopy) +{ + int err, digest_size; + + if (!ofs->config.verity_mode || !S_ISREG(d_inode(src->dentry)->i_mode)) + return 0; + + err = ovl_ensure_verity_loaded(src); + if (err < 0) { + pr_warn_ratelimited("lower file '%pd' failed to load fs-verity info\n", + src->dentry); + return -EIO; + } + + digest_size = fsverity_get_digest(d_inode(src->dentry), + metacopy->digest, &metacopy->digest_algo, NULL); + if (digest_size == 0 || + WARN_ON_ONCE(digest_size > FS_VERITY_MAX_DIGEST_SIZE)) { + if (ofs->config.verity_mode == OVL_VERITY_REQUIRE) { + pr_warn_ratelimited("lower file '%pd' has no fs-verity digest\n", + src->dentry); + return -EIO; + } + return 0; + } + + metacopy->len += digest_size; + return 0; +} + +/* + * ovl_sync_status() - Check fs sync status for volatile mounts + * + * Returns 1 if this is not a volatile mount and a real sync is required. + * + * Returns 0 if syncing can be skipped because mount is volatile, and no errors + * have occurred on the upperdir since the mount. + * + * Returns -errno if it is a volatile mount, and the error that occurred since + * the last mount. If the error code changes, it'll return the latest error + * code. + */ + +int ovl_sync_status(struct ovl_fs *ofs) +{ + struct vfsmount *mnt; + + if (ovl_should_sync(ofs)) + return 1; + + mnt = ovl_upper_mnt(ofs); + if (!mnt) + return 0; + + return errseq_check(&mnt->mnt_sb->s_wb_err, ofs->errseq); +} + +/* + * ovl_copyattr() - copy inode attributes from layer to ovl inode + * + * When overlay copies inode information from an upper or lower layer to the + * relevant overlay inode it will apply the idmapping of the upper or lower + * layer when doing so ensuring that the ovl inode ownership will correctly + * reflect the ownership of the idmapped upper or lower layer. For example, an + * idmapped upper or lower layer mapping id 1001 to id 1000 will take care to + * map any lower or upper inode owned by id 1001 to id 1000. These mapping + * helpers are nops when the relevant layer isn't idmapped. + */ +void ovl_copyattr(struct inode *inode) +{ + struct path realpath; + struct inode *realinode; + struct mnt_idmap *real_idmap; + vfsuid_t vfsuid; + vfsgid_t vfsgid; + + realinode = ovl_i_path_real(inode, &realpath); + real_idmap = mnt_idmap(realpath.mnt); + + spin_lock(&inode->i_lock); + vfsuid = i_uid_into_vfsuid(real_idmap, realinode); + vfsgid = i_gid_into_vfsgid(real_idmap, realinode); + + inode->i_uid = vfsuid_into_kuid(vfsuid); + inode->i_gid = vfsgid_into_kgid(vfsgid); + inode->i_mode = realinode->i_mode; + inode_set_atime_to_ts(inode, inode_get_atime(realinode)); + inode_set_mtime_to_ts(inode, inode_get_mtime(realinode)); + inode_set_ctime_to_ts(inode, inode_get_ctime(realinode)); + i_size_write(inode, i_size_read(realinode)); + spin_unlock(&inode->i_lock); } |