From 2c3c1048746a4622d8c89a29670120dc8fab93c4 Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Sun, 7 Apr 2024 20:49:45 +0200 Subject: Adding upstream version 6.1.76. Signed-off-by: Daniel Baumann --- fs/overlayfs/copy_up.c | 1108 ++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 1108 insertions(+) create mode 100644 fs/overlayfs/copy_up.c (limited to 'fs/overlayfs/copy_up.c') diff --git a/fs/overlayfs/copy_up.c b/fs/overlayfs/copy_up.c new file mode 100644 index 000000000..86d4b6975 --- /dev/null +++ b/fs/overlayfs/copy_up.c @@ -0,0 +1,1108 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * + * Copyright (C) 2011 Novell Inc. + */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include "overlayfs.h" + +#define OVL_COPY_UP_CHUNK_SIZE (1 << 20) + +static int ovl_ccup_set(const char *buf, const struct kernel_param *param) +{ + pr_warn("\"check_copy_up\" module option is obsolete\n"); + return 0; +} + +static int ovl_ccup_get(char *buf, const struct kernel_param *param) +{ + return sprintf(buf, "N\n"); +} + +module_param_call(check_copy_up, ovl_ccup_set, ovl_ccup_get, NULL, 0644); +MODULE_PARM_DESC(check_copy_up, "Obsolete; does nothing"); + +static bool ovl_must_copy_xattr(const char *name) +{ + return !strcmp(name, XATTR_POSIX_ACL_ACCESS) || + !strcmp(name, XATTR_POSIX_ACL_DEFAULT) || + !strncmp(name, XATTR_SECURITY_PREFIX, XATTR_SECURITY_PREFIX_LEN); +} + +int ovl_copy_xattr(struct super_block *sb, const struct path *oldpath, struct dentry *new) +{ + struct dentry *old = oldpath->dentry; + ssize_t list_size, size, value_size = 0; + char *buf, *name, *value = NULL; + int error = 0; + size_t slen; + + if (!(old->d_inode->i_opflags & IOP_XATTR) || + !(new->d_inode->i_opflags & IOP_XATTR)) + return 0; + + list_size = vfs_listxattr(old, NULL, 0); + if (list_size <= 0) { + if (list_size == -EOPNOTSUPP) + return 0; + return list_size; + } + + buf = kvzalloc(list_size, GFP_KERNEL); + if (!buf) + return -ENOMEM; + + list_size = vfs_listxattr(old, buf, list_size); + if (list_size <= 0) { + error = list_size; + goto out; + } + + for (name = buf; list_size; name += slen) { + slen = strnlen(name, list_size) + 1; + + /* underlying fs providing us with an broken xattr list? */ + if (WARN_ON(slen > list_size)) { + error = -EIO; + break; + } + list_size -= slen; + + if (ovl_is_private_xattr(sb, name)) + continue; + + error = security_inode_copy_up_xattr(name); + if (error < 0 && error != -EOPNOTSUPP) + break; + if (error == 1) { + error = 0; + continue; /* Discard */ + } +retry: + size = ovl_do_getxattr(oldpath, name, value, value_size); + if (size == -ERANGE) + size = ovl_do_getxattr(oldpath, name, NULL, 0); + + if (size < 0) { + error = size; + break; + } + + if (size > value_size) { + void *new; + + new = kvmalloc(size, GFP_KERNEL); + if (!new) { + error = -ENOMEM; + break; + } + kvfree(value); + value = new; + value_size = size; + goto retry; + } + + error = ovl_do_setxattr(OVL_FS(sb), new, name, value, size, 0); + if (error) { + if (error != -EOPNOTSUPP || ovl_must_copy_xattr(name)) + break; + + /* Ignore failure to copy unknown xattrs */ + error = 0; + } + } + kvfree(value); +out: + kvfree(buf); + return error; +} + +static int ovl_copy_fileattr(struct inode *inode, const struct path *old, + const struct path *new) +{ + struct fileattr oldfa = { .flags_valid = true }; + struct fileattr newfa = { .flags_valid = true }; + int err; + + err = ovl_real_fileattr_get(old, &oldfa); + if (err) { + /* Ntfs-3g returns -EINVAL for "no fileattr support" */ + if (err == -ENOTTY || err == -EINVAL) + return 0; + pr_warn("failed to retrieve lower fileattr (%pd2, err=%i)\n", + old->dentry, err); + return err; + } + + /* + * We cannot set immutable and append-only flags on upper inode, + * because we would not be able to link upper inode to upper dir + * not set overlay private xattr on upper inode. + * Store these flags in overlay.protattr xattr instead. + */ + if (oldfa.flags & OVL_PROT_FS_FLAGS_MASK) { + err = ovl_set_protattr(inode, new->dentry, &oldfa); + if (err == -EPERM) + pr_warn_once("copying fileattr: no xattr on upper\n"); + else if (err) + return err; + } + + /* Don't bother copying flags if none are set */ + if (!(oldfa.flags & OVL_COPY_FS_FLAGS_MASK)) + return 0; + + err = ovl_real_fileattr_get(new, &newfa); + if (err) { + /* + * Returning an error if upper doesn't support fileattr will + * result in a regression, so revert to the old behavior. + */ + if (err == -ENOTTY || err == -EINVAL) { + pr_warn_once("copying fileattr: no support on upper\n"); + return 0; + } + pr_warn("failed to retrieve upper fileattr (%pd2, err=%i)\n", + new->dentry, err); + return err; + } + + BUILD_BUG_ON(OVL_COPY_FS_FLAGS_MASK & ~FS_COMMON_FL); + newfa.flags &= ~OVL_COPY_FS_FLAGS_MASK; + newfa.flags |= (oldfa.flags & OVL_COPY_FS_FLAGS_MASK); + + BUILD_BUG_ON(OVL_COPY_FSX_FLAGS_MASK & ~FS_XFLAG_COMMON); + newfa.fsx_xflags &= ~OVL_COPY_FSX_FLAGS_MASK; + newfa.fsx_xflags |= (oldfa.fsx_xflags & OVL_COPY_FSX_FLAGS_MASK); + + return ovl_real_fileattr_set(new, &newfa); +} + +static int ovl_copy_up_file(struct ovl_fs *ofs, struct dentry *dentry, + struct file *new_file, loff_t len) +{ + struct path datapath; + struct file *old_file; + loff_t old_pos = 0; + loff_t new_pos = 0; + loff_t cloned; + loff_t data_pos = -1; + loff_t hole_len; + bool skip_hole = false; + int error = 0; + + ovl_path_lowerdata(dentry, &datapath); + if (WARN_ON(datapath.dentry == NULL)) + return -EIO; + + old_file = ovl_path_open(&datapath, O_LARGEFILE | O_RDONLY); + if (IS_ERR(old_file)) + return PTR_ERR(old_file); + + /* Try to use clone_file_range to clone up within the same fs */ + cloned = do_clone_file_range(old_file, 0, new_file, 0, len, 0); + if (cloned == len) + goto out_fput; + /* Couldn't clone, so now we try to copy the data */ + + /* Check if lower fs supports seek operation */ + if (old_file->f_mode & FMODE_LSEEK) + skip_hole = true; + + while (len) { + size_t this_len = OVL_COPY_UP_CHUNK_SIZE; + long bytes; + + if (len < this_len) + this_len = len; + + if (signal_pending_state(TASK_KILLABLE, current)) { + error = -EINTR; + break; + } + + /* + * Fill zero for hole will cost unnecessary disk space + * and meanwhile slow down the copy-up speed, so we do + * an optimization for hole during copy-up, it relies + * on SEEK_DATA implementation in lower fs so if lower + * fs does not support it, copy-up will behave as before. + * + * Detail logic of hole detection as below: + * When we detect next data position is larger than current + * position we will skip that hole, otherwise we copy + * data in the size of OVL_COPY_UP_CHUNK_SIZE. Actually, + * it may not recognize all kind of holes and sometimes + * only skips partial of hole area. However, it will be + * enough for most of the use cases. + */ + + if (skip_hole && data_pos < old_pos) { + data_pos = vfs_llseek(old_file, old_pos, SEEK_DATA); + if (data_pos > old_pos) { + hole_len = data_pos - old_pos; + len -= hole_len; + old_pos = new_pos = data_pos; + continue; + } else if (data_pos == -ENXIO) { + break; + } else if (data_pos < 0) { + skip_hole = false; + } + } + + bytes = do_splice_direct(old_file, &old_pos, + new_file, &new_pos, + this_len, SPLICE_F_MOVE); + if (bytes <= 0) { + error = bytes; + break; + } + WARN_ON(old_pos != new_pos); + + len -= bytes; + } + if (!error && ovl_should_sync(ofs)) + error = vfs_fsync(new_file, 0); +out_fput: + fput(old_file); + return error; +} + +static int ovl_set_size(struct ovl_fs *ofs, + struct dentry *upperdentry, struct kstat *stat) +{ + struct iattr attr = { + .ia_valid = ATTR_SIZE, + .ia_size = stat->size, + }; + + return ovl_do_notify_change(ofs, upperdentry, &attr); +} + +static int ovl_set_timestamps(struct ovl_fs *ofs, struct dentry *upperdentry, + struct kstat *stat) +{ + struct iattr attr = { + .ia_valid = + ATTR_ATIME | ATTR_MTIME | ATTR_ATIME_SET | ATTR_MTIME_SET | ATTR_CTIME, + .ia_atime = stat->atime, + .ia_mtime = stat->mtime, + }; + + return ovl_do_notify_change(ofs, upperdentry, &attr); +} + +int ovl_set_attr(struct ovl_fs *ofs, struct dentry *upperdentry, + struct kstat *stat) +{ + int err = 0; + + if (!S_ISLNK(stat->mode)) { + struct iattr attr = { + .ia_valid = ATTR_MODE, + .ia_mode = stat->mode, + }; + err = ovl_do_notify_change(ofs, upperdentry, &attr); + } + if (!err) { + struct iattr attr = { + .ia_valid = ATTR_UID | ATTR_GID, + .ia_vfsuid = VFSUIDT_INIT(stat->uid), + .ia_vfsgid = VFSGIDT_INIT(stat->gid), + }; + err = ovl_do_notify_change(ofs, upperdentry, &attr); + } + if (!err) + ovl_set_timestamps(ofs, upperdentry, stat); + + return err; +} + +struct ovl_fh *ovl_encode_real_fh(struct ovl_fs *ofs, struct dentry *real, + bool is_upper) +{ + struct ovl_fh *fh; + int fh_type, dwords; + int buflen = MAX_HANDLE_SZ; + uuid_t *uuid = &real->d_sb->s_uuid; + int err; + + /* Make sure the real fid stays 32bit aligned */ + BUILD_BUG_ON(OVL_FH_FID_OFFSET % 4); + BUILD_BUG_ON(MAX_HANDLE_SZ + OVL_FH_FID_OFFSET > 255); + + fh = kzalloc(buflen + OVL_FH_FID_OFFSET, GFP_KERNEL); + if (!fh) + return ERR_PTR(-ENOMEM); + + /* + * We encode a non-connectable file handle for non-dir, because we + * only need to find the lower inode number and we don't want to pay + * the price or reconnecting the dentry. + */ + dwords = buflen >> 2; + fh_type = exportfs_encode_fh(real, (void *)fh->fb.fid, &dwords, 0); + buflen = (dwords << 2); + + err = -EIO; + if (WARN_ON(fh_type < 0) || + WARN_ON(buflen > MAX_HANDLE_SZ) || + WARN_ON(fh_type == FILEID_INVALID)) + goto out_err; + + fh->fb.version = OVL_FH_VERSION; + fh->fb.magic = OVL_FH_MAGIC; + fh->fb.type = fh_type; + fh->fb.flags = OVL_FH_FLAG_CPU_ENDIAN; + /* + * When we will want to decode an overlay dentry from this handle + * and all layers are on the same fs, if we get a disconncted real + * dentry when we decode fid, the only way to tell if we should assign + * it to upperdentry or to lowerstack is by checking this flag. + */ + if (is_upper) + fh->fb.flags |= OVL_FH_FLAG_PATH_UPPER; + fh->fb.len = sizeof(fh->fb) + buflen; + if (ofs->config.uuid) + fh->fb.uuid = *uuid; + + return fh; + +out_err: + kfree(fh); + return ERR_PTR(err); +} + +int ovl_set_origin(struct ovl_fs *ofs, struct dentry *lower, + struct dentry *upper) +{ + const struct ovl_fh *fh = NULL; + int err; + + /* + * When lower layer doesn't support export operations store a 'null' fh, + * so we can use the overlay.origin xattr to distignuish between a copy + * up and a pure upper inode. + */ + if (ovl_can_decode_fh(lower->d_sb)) { + fh = ovl_encode_real_fh(ofs, lower, false); + if (IS_ERR(fh)) + return PTR_ERR(fh); + } + + /* + * Do not fail when upper doesn't support xattrs. + */ + err = ovl_check_setxattr(ofs, upper, OVL_XATTR_ORIGIN, fh->buf, + fh ? fh->fb.len : 0, 0); + kfree(fh); + + /* Ignore -EPERM from setting "user.*" on symlink/special */ + return err == -EPERM ? 0 : err; +} + +/* Store file handle of @upper dir in @index dir entry */ +static int ovl_set_upper_fh(struct ovl_fs *ofs, struct dentry *upper, + struct dentry *index) +{ + const struct ovl_fh *fh; + int err; + + fh = ovl_encode_real_fh(ofs, upper, true); + if (IS_ERR(fh)) + return PTR_ERR(fh); + + err = ovl_setxattr(ofs, index, OVL_XATTR_UPPER, fh->buf, fh->fb.len); + + kfree(fh); + return err; +} + +/* + * Create and install index entry. + * + * Caller must hold i_mutex on indexdir. + */ +static int ovl_create_index(struct dentry *dentry, struct dentry *origin, + struct dentry *upper) +{ + struct ovl_fs *ofs = OVL_FS(dentry->d_sb); + struct dentry *indexdir = ovl_indexdir(dentry->d_sb); + struct inode *dir = d_inode(indexdir); + struct dentry *index = NULL; + struct dentry *temp = NULL; + struct qstr name = { }; + int err; + + /* + * For now this is only used for creating index entry for directories, + * because non-dir are copied up directly to index and then hardlinked + * to upper dir. + * + * TODO: implement create index for non-dir, so we can call it when + * encoding file handle for non-dir in case index does not exist. + */ + if (WARN_ON(!d_is_dir(dentry))) + return -EIO; + + /* Directory not expected to be indexed before copy up */ + if (WARN_ON(ovl_test_flag(OVL_INDEX, d_inode(dentry)))) + return -EIO; + + err = ovl_get_index_name(ofs, origin, &name); + if (err) + return err; + + temp = ovl_create_temp(ofs, indexdir, OVL_CATTR(S_IFDIR | 0)); + err = PTR_ERR(temp); + if (IS_ERR(temp)) + goto free_name; + + err = ovl_set_upper_fh(ofs, upper, temp); + if (err) + goto out; + + index = ovl_lookup_upper(ofs, name.name, indexdir, name.len); + if (IS_ERR(index)) { + err = PTR_ERR(index); + } else { + err = ovl_do_rename(ofs, dir, temp, dir, index, 0); + dput(index); + } +out: + if (err) + ovl_cleanup(ofs, dir, temp); + dput(temp); +free_name: + kfree(name.name); + return err; +} + +struct ovl_copy_up_ctx { + struct dentry *parent; + struct dentry *dentry; + struct path lowerpath; + struct kstat stat; + struct kstat pstat; + const char *link; + struct dentry *destdir; + struct qstr destname; + struct dentry *workdir; + bool origin; + bool indexed; + bool metacopy; +}; + +static int ovl_link_up(struct ovl_copy_up_ctx *c) +{ + int err; + struct dentry *upper; + struct dentry *upperdir = ovl_dentry_upper(c->parent); + struct ovl_fs *ofs = OVL_FS(c->dentry->d_sb); + struct inode *udir = d_inode(upperdir); + + /* Mark parent "impure" because it may now contain non-pure upper */ + err = ovl_set_impure(c->parent, upperdir); + if (err) + return err; + + err = ovl_set_nlink_lower(c->dentry); + if (err) + return err; + + inode_lock_nested(udir, I_MUTEX_PARENT); + upper = ovl_lookup_upper(ofs, c->dentry->d_name.name, upperdir, + c->dentry->d_name.len); + err = PTR_ERR(upper); + if (!IS_ERR(upper)) { + err = ovl_do_link(ofs, ovl_dentry_upper(c->dentry), udir, upper); + dput(upper); + + if (!err) { + /* Restore timestamps on parent (best effort) */ + ovl_set_timestamps(ofs, upperdir, &c->pstat); + ovl_dentry_set_upper_alias(c->dentry); + ovl_dentry_update_reval(c->dentry, upper); + } + } + inode_unlock(udir); + if (err) + return err; + + err = ovl_set_nlink_upper(c->dentry); + + return err; +} + +static int ovl_copy_up_data(struct ovl_copy_up_ctx *c, const struct path *temp) +{ + struct ovl_fs *ofs = OVL_FS(c->dentry->d_sb); + struct file *new_file; + int err; + + if (!S_ISREG(c->stat.mode) || c->metacopy || !c->stat.size) + return 0; + + new_file = ovl_path_open(temp, O_LARGEFILE | O_WRONLY); + if (IS_ERR(new_file)) + return PTR_ERR(new_file); + + err = ovl_copy_up_file(ofs, c->dentry, new_file, c->stat.size); + fput(new_file); + + return err; +} + +static int ovl_copy_up_metadata(struct ovl_copy_up_ctx *c, struct dentry *temp) +{ + struct ovl_fs *ofs = OVL_FS(c->dentry->d_sb); + struct inode *inode = d_inode(c->dentry); + struct path upperpath = { .mnt = ovl_upper_mnt(ofs), .dentry = temp }; + int err; + + err = ovl_copy_xattr(c->dentry->d_sb, &c->lowerpath, temp); + if (err) + return err; + + if (inode->i_flags & OVL_COPY_I_FLAGS_MASK && + (S_ISREG(c->stat.mode) || S_ISDIR(c->stat.mode))) { + /* + * Copy the fileattr inode flags that are the source of already + * copied i_flags + */ + err = ovl_copy_fileattr(inode, &c->lowerpath, &upperpath); + if (err) + return err; + } + + /* + * Store identifier of lower inode in upper inode xattr to + * allow lookup of the copy up origin inode. + * + * Don't set origin when we are breaking the association with a lower + * hard link. + */ + if (c->origin) { + err = ovl_set_origin(ofs, c->lowerpath.dentry, temp); + if (err) + return err; + } + + if (c->metacopy) { + err = ovl_check_setxattr(ofs, temp, OVL_XATTR_METACOPY, + NULL, 0, -EOPNOTSUPP); + if (err) + return err; + } + + inode_lock(temp->d_inode); + if (S_ISREG(c->stat.mode)) + err = ovl_set_size(ofs, temp, &c->stat); + if (!err) + err = ovl_set_attr(ofs, temp, &c->stat); + inode_unlock(temp->d_inode); + + return err; +} + +struct ovl_cu_creds { + const struct cred *old; + struct cred *new; +}; + +static int ovl_prep_cu_creds(struct dentry *dentry, struct ovl_cu_creds *cc) +{ + int err; + + cc->old = cc->new = NULL; + err = security_inode_copy_up(dentry, &cc->new); + if (err < 0) + return err; + + if (cc->new) + cc->old = override_creds(cc->new); + + return 0; +} + +static void ovl_revert_cu_creds(struct ovl_cu_creds *cc) +{ + if (cc->new) { + revert_creds(cc->old); + put_cred(cc->new); + } +} + +/* + * Copyup using workdir to prepare temp file. Used when copying up directories, + * special files or when upper fs doesn't support O_TMPFILE. + */ +static int ovl_copy_up_workdir(struct ovl_copy_up_ctx *c) +{ + struct ovl_fs *ofs = OVL_FS(c->dentry->d_sb); + struct inode *inode; + struct inode *udir = d_inode(c->destdir), *wdir = d_inode(c->workdir); + struct path path = { .mnt = ovl_upper_mnt(ofs) }; + struct dentry *temp, *upper; + struct ovl_cu_creds cc; + int err; + struct ovl_cattr cattr = { + /* Can't properly set mode on creation because of the umask */ + .mode = c->stat.mode & S_IFMT, + .rdev = c->stat.rdev, + .link = c->link + }; + + /* workdir and destdir could be the same when copying up to indexdir */ + err = -EIO; + if (lock_rename(c->workdir, c->destdir) != NULL) + goto unlock; + + err = ovl_prep_cu_creds(c->dentry, &cc); + if (err) + goto unlock; + + temp = ovl_create_temp(ofs, c->workdir, &cattr); + ovl_revert_cu_creds(&cc); + + err = PTR_ERR(temp); + if (IS_ERR(temp)) + goto unlock; + + /* + * Copy up data first and then xattrs. Writing data after + * xattrs will remove security.capability xattr automatically. + */ + path.dentry = temp; + err = ovl_copy_up_data(c, &path); + if (err) + goto cleanup; + + err = ovl_copy_up_metadata(c, temp); + if (err) + goto cleanup; + + if (S_ISDIR(c->stat.mode) && c->indexed) { + err = ovl_create_index(c->dentry, c->lowerpath.dentry, temp); + if (err) + goto cleanup; + } + + upper = ovl_lookup_upper(ofs, c->destname.name, c->destdir, + c->destname.len); + err = PTR_ERR(upper); + if (IS_ERR(upper)) + goto cleanup; + + err = ovl_do_rename(ofs, wdir, temp, udir, upper, 0); + dput(upper); + if (err) + goto cleanup; + + if (!c->metacopy) + ovl_set_upperdata(d_inode(c->dentry)); + inode = d_inode(c->dentry); + ovl_inode_update(inode, temp); + if (S_ISDIR(inode->i_mode)) + ovl_set_flag(OVL_WHITEOUTS, inode); +unlock: + unlock_rename(c->workdir, c->destdir); + + return err; + +cleanup: + ovl_cleanup(ofs, wdir, temp); + dput(temp); + goto unlock; +} + +/* Copyup using O_TMPFILE which does not require cross dir locking */ +static int ovl_copy_up_tmpfile(struct ovl_copy_up_ctx *c) +{ + struct ovl_fs *ofs = OVL_FS(c->dentry->d_sb); + struct inode *udir = d_inode(c->destdir); + struct dentry *temp, *upper; + struct file *tmpfile; + struct ovl_cu_creds cc; + int err; + + err = ovl_prep_cu_creds(c->dentry, &cc); + if (err) + return err; + + tmpfile = ovl_do_tmpfile(ofs, c->workdir, c->stat.mode); + ovl_revert_cu_creds(&cc); + + if (IS_ERR(tmpfile)) + return PTR_ERR(tmpfile); + + temp = tmpfile->f_path.dentry; + if (!c->metacopy && c->stat.size) { + err = ovl_copy_up_file(ofs, c->dentry, tmpfile, c->stat.size); + if (err) + goto out_fput; + } + + err = ovl_copy_up_metadata(c, temp); + if (err) + goto out_fput; + + inode_lock_nested(udir, I_MUTEX_PARENT); + + upper = ovl_lookup_upper(ofs, c->destname.name, c->destdir, + c->destname.len); + err = PTR_ERR(upper); + if (!IS_ERR(upper)) { + err = ovl_do_link(ofs, temp, udir, upper); + dput(upper); + } + inode_unlock(udir); + + if (err) + goto out_fput; + + if (!c->metacopy) + ovl_set_upperdata(d_inode(c->dentry)); + ovl_inode_update(d_inode(c->dentry), dget(temp)); + +out_fput: + fput(tmpfile); + return err; +} + +/* + * Copy up a single dentry + * + * All renames start with copy up of source if necessary. The actual + * rename will only proceed once the copy up was successful. Copy up uses + * upper parent i_mutex for exclusion. Since rename can change d_parent it + * is possible that the copy up will lock the old parent. At that point + * the file will have already been copied up anyway. + */ +static int ovl_do_copy_up(struct ovl_copy_up_ctx *c) +{ + int err; + struct ovl_fs *ofs = OVL_FS(c->dentry->d_sb); + bool to_index = false; + + /* + * Indexed non-dir is copied up directly to the index entry and then + * hardlinked to upper dir. Indexed dir is copied up to indexdir, + * then index entry is created and then copied up dir installed. + * Copying dir up to indexdir instead of workdir simplifies locking. + */ + if (ovl_need_index(c->dentry)) { + c->indexed = true; + if (S_ISDIR(c->stat.mode)) + c->workdir = ovl_indexdir(c->dentry->d_sb); + else + to_index = true; + } + + if (S_ISDIR(c->stat.mode) || c->stat.nlink == 1 || to_index) + c->origin = true; + + if (to_index) { + c->destdir = ovl_indexdir(c->dentry->d_sb); + err = ovl_get_index_name(ofs, c->lowerpath.dentry, &c->destname); + if (err) + return err; + } else if (WARN_ON(!c->parent)) { + /* Disconnected dentry must be copied up to index dir */ + return -EIO; + } else { + /* + * Mark parent "impure" because it may now contain non-pure + * upper + */ + err = ovl_set_impure(c->parent, c->destdir); + if (err) + return err; + } + + /* Should we copyup with O_TMPFILE or with workdir? */ + if (S_ISREG(c->stat.mode) && ofs->tmpfile) + err = ovl_copy_up_tmpfile(c); + else + err = ovl_copy_up_workdir(c); + if (err) + goto out; + + if (c->indexed) + ovl_set_flag(OVL_INDEX, d_inode(c->dentry)); + + if (to_index) { + /* Initialize nlink for copy up of disconnected dentry */ + err = ovl_set_nlink_upper(c->dentry); + } else { + struct inode *udir = d_inode(c->destdir); + + /* Restore timestamps on parent (best effort) */ + inode_lock(udir); + ovl_set_timestamps(ofs, c->destdir, &c->pstat); + inode_unlock(udir); + + ovl_dentry_set_upper_alias(c->dentry); + ovl_dentry_update_reval(c->dentry, ovl_dentry_upper(c->dentry)); + } + +out: + if (to_index) + kfree(c->destname.name); + return err; +} + +static bool ovl_need_meta_copy_up(struct dentry *dentry, umode_t mode, + int flags) +{ + struct ovl_fs *ofs = dentry->d_sb->s_fs_info; + + if (!ofs->config.metacopy) + return false; + + if (!S_ISREG(mode)) + return false; + + if (flags && ((OPEN_FMODE(flags) & FMODE_WRITE) || (flags & O_TRUNC))) + return false; + + return true; +} + +static ssize_t ovl_getxattr_value(const struct path *path, char *name, char **value) +{ + ssize_t res; + char *buf; + + res = ovl_do_getxattr(path, name, NULL, 0); + if (res == -ENODATA || res == -EOPNOTSUPP) + res = 0; + + if (res > 0) { + buf = kzalloc(res, GFP_KERNEL); + if (!buf) + return -ENOMEM; + + res = ovl_do_getxattr(path, name, buf, res); + if (res < 0) + kfree(buf); + else + *value = buf; + } + return res; +} + +/* Copy up data of an inode which was copied up metadata only in the past. */ +static int ovl_copy_up_meta_inode_data(struct ovl_copy_up_ctx *c) +{ + struct ovl_fs *ofs = OVL_FS(c->dentry->d_sb); + struct path upperpath; + int err; + char *capability = NULL; + ssize_t cap_size; + + ovl_path_upper(c->dentry, &upperpath); + if (WARN_ON(upperpath.dentry == NULL)) + return -EIO; + + if (c->stat.size) { + err = cap_size = ovl_getxattr_value(&upperpath, XATTR_NAME_CAPS, + &capability); + if (cap_size < 0) + goto out; + } + + err = ovl_copy_up_data(c, &upperpath); + if (err) + goto out_free; + + /* + * Writing to upper file will clear security.capability xattr. We + * don't want that to happen for normal copy-up operation. + */ + if (capability) { + err = ovl_do_setxattr(ofs, upperpath.dentry, XATTR_NAME_CAPS, + capability, cap_size, 0); + if (err) + goto out_free; + } + + + err = ovl_removexattr(ofs, upperpath.dentry, OVL_XATTR_METACOPY); + if (err) + goto out_free; + + ovl_set_upperdata(d_inode(c->dentry)); +out_free: + kfree(capability); +out: + return err; +} + +static int ovl_copy_up_one(struct dentry *parent, struct dentry *dentry, + int flags) +{ + int err; + DEFINE_DELAYED_CALL(done); + struct path parentpath; + struct ovl_copy_up_ctx ctx = { + .parent = parent, + .dentry = dentry, + .workdir = ovl_workdir(dentry), + }; + + if (WARN_ON(!ctx.workdir)) + return -EROFS; + + ovl_path_lower(dentry, &ctx.lowerpath); + err = vfs_getattr(&ctx.lowerpath, &ctx.stat, + STATX_BASIC_STATS, AT_STATX_SYNC_AS_STAT); + if (err) + return err; + + if (!kuid_has_mapping(current_user_ns(), ctx.stat.uid) || + !kgid_has_mapping(current_user_ns(), ctx.stat.gid)) + return -EOVERFLOW; + + ctx.metacopy = ovl_need_meta_copy_up(dentry, ctx.stat.mode, flags); + + if (parent) { + ovl_path_upper(parent, &parentpath); + ctx.destdir = parentpath.dentry; + ctx.destname = dentry->d_name; + + err = vfs_getattr(&parentpath, &ctx.pstat, + STATX_ATIME | STATX_MTIME, + AT_STATX_SYNC_AS_STAT); + if (err) + return err; + } + + /* maybe truncate regular file. this has no effect on dirs */ + if (flags & O_TRUNC) + ctx.stat.size = 0; + + if (S_ISLNK(ctx.stat.mode)) { + ctx.link = vfs_get_link(ctx.lowerpath.dentry, &done); + if (IS_ERR(ctx.link)) + return PTR_ERR(ctx.link); + } + + err = ovl_copy_up_start(dentry, flags); + /* err < 0: interrupted, err > 0: raced with another copy-up */ + if (unlikely(err)) { + if (err > 0) + err = 0; + } else { + if (!ovl_dentry_upper(dentry)) + err = ovl_do_copy_up(&ctx); + if (!err && parent && !ovl_dentry_has_upper_alias(dentry)) + err = ovl_link_up(&ctx); + if (!err && ovl_dentry_needs_data_copy_up_locked(dentry, flags)) + err = ovl_copy_up_meta_inode_data(&ctx); + ovl_copy_up_end(dentry); + } + do_delayed_call(&done); + + return err; +} + +static int ovl_copy_up_flags(struct dentry *dentry, int flags) +{ + int err = 0; + const struct cred *old_cred; + bool disconnected = (dentry->d_flags & DCACHE_DISCONNECTED); + + /* + * With NFS export, copy up can get called for a disconnected non-dir. + * In this case, we will copy up lower inode to index dir without + * linking it to upper dir. + */ + if (WARN_ON(disconnected && d_is_dir(dentry))) + return -EIO; + + old_cred = ovl_override_creds(dentry->d_sb); + while (!err) { + struct dentry *next; + struct dentry *parent = NULL; + + if (ovl_already_copied_up(dentry, flags)) + break; + + next = dget(dentry); + /* find the topmost dentry not yet copied up */ + for (; !disconnected;) { + parent = dget_parent(next); + + if (ovl_dentry_upper(parent)) + break; + + dput(next); + next = parent; + } + + err = ovl_copy_up_one(parent, next, flags); + + dput(parent); + dput(next); + } + revert_creds(old_cred); + + return err; +} + +static bool ovl_open_need_copy_up(struct dentry *dentry, int flags) +{ + /* Copy up of disconnected dentry does not set upper alias */ + if (ovl_already_copied_up(dentry, flags)) + return false; + + if (special_file(d_inode(dentry)->i_mode)) + return false; + + if (!ovl_open_flags_need_copy_up(flags)) + return false; + + return true; +} + +int ovl_maybe_copy_up(struct dentry *dentry, int flags) +{ + int err = 0; + + if (ovl_open_need_copy_up(dentry, flags)) { + err = ovl_want_write(dentry); + if (!err) { + err = ovl_copy_up_flags(dentry, flags); + ovl_drop_write(dentry); + } + } + + return err; +} + +int ovl_copy_up_with_data(struct dentry *dentry) +{ + return ovl_copy_up_flags(dentry, O_WRONLY); +} + +int ovl_copy_up(struct dentry *dentry) +{ + return ovl_copy_up_flags(dentry, 0); +} -- cgit v1.2.3