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-rw-r--r--fs/overlayfs/copy_up.c1108
1 files changed, 1108 insertions, 0 deletions
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 <linux/module.h>
+#include <linux/fs.h>
+#include <linux/slab.h>
+#include <linux/file.h>
+#include <linux/fileattr.h>
+#include <linux/splice.h>
+#include <linux/xattr.h>
+#include <linux/security.h>
+#include <linux/uaccess.h>
+#include <linux/sched/signal.h>
+#include <linux/cred.h>
+#include <linux/namei.h>
+#include <linux/fdtable.h>
+#include <linux/ratelimit.h>
+#include <linux/exportfs.h>
+#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+ pr_warn("\"check_copy_up\" module option is obsolete\n");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);
+}
generated by cgit v1.2.3 (git 2.39.1) at 2024-12-01 02:51:42 +0000