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-rw-r--r--fs/overlayfs/copy_up.c906
1 files changed, 906 insertions, 0 deletions
diff --git a/fs/overlayfs/copy_up.c b/fs/overlayfs/copy_up.c
new file mode 100644
index 000000000..30abafcd4
--- /dev/null
+++ b/fs/overlayfs/copy_up.c
@@ -0,0 +1,906 @@
+/*
+ *
+ * Copyright (C) 2011 Novell 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/module.h>
+#include <linux/fs.h>
+#include <linux/slab.h>
+#include <linux/file.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+ pr_warn("overlayfs: \"check_copy_up\" module option is obsolete\n");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(ovl_check_copy_up, "Obsolete; does nothing");
+
+int ovl_copy_xattr(struct dentry *old, struct dentry *new)
+{
+ 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 = kzalloc(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(name))
+ continue;
+
+ error = security_inode_copy_up_xattr(name);
+ if (error < 0 && error != -EOPNOTSUPP)
+ break;
+ if (error == 1) {
+ error = 0;
+ continue; /* Discard */
+ }
+retry:
+ size = vfs_getxattr(old, name, value, value_size);
+ if (size == -ERANGE)
+ size = vfs_getxattr(old, name, NULL, 0);
+
+ if (size < 0) {
+ error = size;
+ break;
+ }
+
+ if (size > value_size) {
+ void *new;
+
+ new = krealloc(value, size, GFP_KERNEL);
+ if (!new) {
+ error = -ENOMEM;
+ break;
+ }
+ value = new;
+ value_size = size;
+ goto retry;
+ }
+
+ error = vfs_setxattr(new, name, value, size, 0);
+ if (error)
+ break;
+ }
+ kfree(value);
+out:
+ kfree(buf);
+ return error;
+}
+
+static int ovl_copy_up_data(struct path *old, struct path *new, loff_t len)
+{
+ struct file *old_file;
+ struct file *new_file;
+ loff_t old_pos = 0;
+ loff_t new_pos = 0;
+ int error = 0;
+
+ if (len == 0)
+ return 0;
+
+ old_file = ovl_path_open(old, O_LARGEFILE | O_RDONLY);
+ if (IS_ERR(old_file))
+ return PTR_ERR(old_file);
+
+ new_file = ovl_path_open(new, O_LARGEFILE | O_WRONLY);
+ if (IS_ERR(new_file)) {
+ error = PTR_ERR(new_file);
+ goto out_fput;
+ }
+
+ /* Try to use clone_file_range to clone up within the same fs */
+ error = do_clone_file_range(old_file, 0, new_file, 0, len);
+ if (!error)
+ goto out;
+ /* Couldn't clone, so now we try to copy the data */
+ error = 0;
+
+ /* FIXME: copy up sparse files efficiently */
+ 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;
+ }
+
+ 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;
+ }
+out:
+ if (!error)
+ error = vfs_fsync(new_file, 0);
+ fput(new_file);
+out_fput:
+ fput(old_file);
+ return error;
+}
+
+static int ovl_set_size(struct dentry *upperdentry, struct kstat *stat)
+{
+ struct iattr attr = {
+ .ia_valid = ATTR_SIZE,
+ .ia_size = stat->size,
+ };
+
+ return notify_change(upperdentry, &attr, NULL);
+}
+
+static int ovl_set_timestamps(struct dentry *upperdentry, struct kstat *stat)
+{
+ struct iattr attr = {
+ .ia_valid =
+ ATTR_ATIME | ATTR_MTIME | ATTR_ATIME_SET | ATTR_MTIME_SET,
+ .ia_atime = stat->atime,
+ .ia_mtime = stat->mtime,
+ };
+
+ return notify_change(upperdentry, &attr, NULL);
+}
+
+int ovl_set_attr(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 = notify_change(upperdentry, &attr, NULL);
+ }
+ if (!err) {
+ struct iattr attr = {
+ .ia_valid = ATTR_UID | ATTR_GID,
+ .ia_uid = stat->uid,
+ .ia_gid = stat->gid,
+ };
+ err = notify_change(upperdentry, &attr, NULL);
+ }
+ if (!err)
+ ovl_set_timestamps(upperdentry, stat);
+
+ return err;
+}
+
+struct ovl_fh *ovl_encode_real_fh(struct dentry *real, bool is_upper)
+{
+ struct ovl_fh *fh;
+ int fh_type, fh_len, dwords;
+ void *buf;
+ int buflen = MAX_HANDLE_SZ;
+ uuid_t *uuid = &real->d_sb->s_uuid;
+
+ buf = kmalloc(buflen, GFP_KERNEL);
+ if (!buf)
+ 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, buf, &dwords, 0);
+ buflen = (dwords << 2);
+
+ fh = ERR_PTR(-EIO);
+ if (WARN_ON(fh_type < 0) ||
+ WARN_ON(buflen > MAX_HANDLE_SZ) ||
+ WARN_ON(fh_type == FILEID_INVALID))
+ goto out;
+
+ BUILD_BUG_ON(MAX_HANDLE_SZ + offsetof(struct ovl_fh, fid) > 255);
+ fh_len = offsetof(struct ovl_fh, fid) + buflen;
+ fh = kmalloc(fh_len, GFP_KERNEL);
+ if (!fh) {
+ fh = ERR_PTR(-ENOMEM);
+ goto out;
+ }
+
+ fh->version = OVL_FH_VERSION;
+ fh->magic = OVL_FH_MAGIC;
+ fh->type = fh_type;
+ fh->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->flags |= OVL_FH_FLAG_PATH_UPPER;
+ fh->len = fh_len;
+ fh->uuid = *uuid;
+ memcpy(fh->fid, buf, buflen);
+
+out:
+ kfree(buf);
+ return fh;
+}
+
+int ovl_set_origin(struct dentry *dentry, 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(lower, false);
+ if (IS_ERR(fh))
+ return PTR_ERR(fh);
+ }
+
+ /*
+ * Do not fail when upper doesn't support xattrs.
+ */
+ err = ovl_check_setxattr(dentry, upper, OVL_XATTR_ORIGIN, fh,
+ fh ? fh->len : 0, 0);
+ kfree(fh);
+
+ return err;
+}
+
+/* Store file handle of @upper dir in @index dir entry */
+static int ovl_set_upper_fh(struct dentry *upper, struct dentry *index)
+{
+ const struct ovl_fh *fh;
+ int err;
+
+ fh = ovl_encode_real_fh(upper, true);
+ if (IS_ERR(fh))
+ return PTR_ERR(fh);
+
+ err = ovl_do_setxattr(index, OVL_XATTR_UPPER, fh, fh->len, 0);
+
+ 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 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(origin, &name);
+ if (err)
+ return err;
+
+ temp = ovl_create_temp(indexdir, OVL_CATTR(S_IFDIR | 0));
+ err = PTR_ERR(temp);
+ if (IS_ERR(temp))
+ goto free_name;
+
+ err = ovl_set_upper_fh(upper, temp);
+ if (err)
+ goto out;
+
+ index = lookup_one_len(name.name, indexdir, name.len);
+ if (IS_ERR(index)) {
+ err = PTR_ERR(index);
+ } else {
+ err = ovl_do_rename(dir, temp, dir, index, 0);
+ dput(index);
+ }
+out:
+ if (err)
+ ovl_cleanup(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 tmpfile;
+ 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 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 = lookup_one_len(c->dentry->d_name.name, upperdir,
+ c->dentry->d_name.len);
+ err = PTR_ERR(upper);
+ if (!IS_ERR(upper)) {
+ err = ovl_do_link(ovl_dentry_upper(c->dentry), udir, upper);
+ dput(upper);
+
+ if (!err) {
+ /* Restore timestamps on parent (best effort) */
+ ovl_set_timestamps(upperdir, &c->pstat);
+ ovl_dentry_set_upper_alias(c->dentry);
+ }
+ }
+ inode_unlock(udir);
+ if (err)
+ return err;
+
+ err = ovl_set_nlink_upper(c->dentry);
+
+ return err;
+}
+
+static int ovl_install_temp(struct ovl_copy_up_ctx *c, struct dentry *temp,
+ struct dentry **newdentry)
+{
+ int err;
+ struct dentry *upper;
+ struct inode *udir = d_inode(c->destdir);
+
+ upper = lookup_one_len(c->destname.name, c->destdir, c->destname.len);
+ if (IS_ERR(upper))
+ return PTR_ERR(upper);
+
+ if (c->tmpfile)
+ err = ovl_do_link(temp, udir, upper);
+ else
+ err = ovl_do_rename(d_inode(c->workdir), temp, udir, upper, 0);
+
+ if (!err)
+ *newdentry = dget(c->tmpfile ? upper : temp);
+ dput(upper);
+
+ return err;
+}
+
+static struct dentry *ovl_get_tmpfile(struct ovl_copy_up_ctx *c)
+{
+ int err;
+ struct dentry *temp;
+ const struct cred *old_creds = NULL;
+ struct cred *new_creds = NULL;
+ 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
+ };
+
+ err = security_inode_copy_up(c->dentry, &new_creds);
+ temp = ERR_PTR(err);
+ if (err < 0)
+ goto out;
+
+ if (new_creds)
+ old_creds = override_creds(new_creds);
+
+ if (c->tmpfile)
+ temp = ovl_do_tmpfile(c->workdir, c->stat.mode);
+ else
+ temp = ovl_create_temp(c->workdir, &cattr);
+out:
+ if (new_creds) {
+ revert_creds(old_creds);
+ put_cred(new_creds);
+ }
+
+ return temp;
+}
+
+static int ovl_copy_up_inode(struct ovl_copy_up_ctx *c, struct dentry *temp)
+{
+ int err;
+
+ /*
+ * Copy up data first and then xattrs. Writing data after
+ * xattrs will remove security.capability xattr automatically.
+ */
+ if (S_ISREG(c->stat.mode) && !c->metacopy) {
+ struct path upperpath, datapath;
+
+ ovl_path_upper(c->dentry, &upperpath);
+ if (WARN_ON(upperpath.dentry != NULL))
+ return -EIO;
+ upperpath.dentry = temp;
+
+ ovl_path_lowerdata(c->dentry, &datapath);
+ err = ovl_copy_up_data(&datapath, &upperpath, c->stat.size);
+ if (err)
+ return err;
+ }
+
+ err = ovl_copy_xattr(c->lowerpath.dentry, temp);
+ 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(c->dentry, c->lowerpath.dentry, temp);
+ if (err)
+ return err;
+ }
+
+ if (c->metacopy) {
+ err = ovl_check_setxattr(c->dentry, temp, OVL_XATTR_METACOPY,
+ NULL, 0, -EOPNOTSUPP);
+ if (err)
+ return err;
+ }
+
+ inode_lock(temp->d_inode);
+ if (c->metacopy)
+ err = ovl_set_size(temp, &c->stat);
+ if (!err)
+ err = ovl_set_attr(temp, &c->stat);
+ inode_unlock(temp->d_inode);
+
+ return err;
+}
+
+static int ovl_copy_up_locked(struct ovl_copy_up_ctx *c)
+{
+ struct inode *udir = c->destdir->d_inode;
+ struct inode *inode;
+ struct dentry *newdentry = NULL;
+ struct dentry *temp;
+ int err;
+
+ temp = ovl_get_tmpfile(c);
+ if (IS_ERR(temp))
+ return PTR_ERR(temp);
+
+ err = ovl_copy_up_inode(c, temp);
+ if (err)
+ goto out;
+
+ if (S_ISDIR(c->stat.mode) && c->indexed) {
+ err = ovl_create_index(c->dentry, c->lowerpath.dentry, temp);
+ if (err)
+ goto out;
+ }
+
+ if (c->tmpfile) {
+ inode_lock_nested(udir, I_MUTEX_PARENT);
+ err = ovl_install_temp(c, temp, &newdentry);
+ inode_unlock(udir);
+ } else {
+ err = ovl_install_temp(c, temp, &newdentry);
+ }
+ if (err)
+ goto out;
+
+ if (!c->metacopy)
+ ovl_set_upperdata(d_inode(c->dentry));
+ inode = d_inode(c->dentry);
+ ovl_inode_update(inode, newdentry);
+ if (S_ISDIR(inode->i_mode))
+ ovl_set_flag(OVL_WHITEOUTS, inode);
+
+out:
+ if (err && !c->tmpfile)
+ ovl_cleanup(d_inode(c->workdir), temp);
+ dput(temp);
+ 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 = c->dentry->d_sb->s_fs_info;
+ 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(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) {
+ c->tmpfile = true;
+ err = ovl_copy_up_locked(c);
+ } else {
+ err = ovl_lock_rename_workdir(c->workdir, c->destdir);
+ if (!err) {
+ err = ovl_copy_up_locked(c);
+ unlock_rename(c->workdir, c->destdir);
+ }
+ }
+
+
+ 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(c->destdir, &c->pstat);
+ inode_unlock(udir);
+
+ ovl_dentry_set_upper_alias(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;
+}
+
+/* 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 path upperpath, datapath;
+ int err;
+ char *capability = NULL;
+ ssize_t uninitialized_var(cap_size);
+
+ ovl_path_upper(c->dentry, &upperpath);
+ if (WARN_ON(upperpath.dentry == NULL))
+ return -EIO;
+
+ ovl_path_lowerdata(c->dentry, &datapath);
+ if (WARN_ON(datapath.dentry == NULL))
+ return -EIO;
+
+ if (c->stat.size) {
+ err = cap_size = ovl_getxattr(upperpath.dentry, XATTR_NAME_CAPS,
+ &capability, 0);
+ if (err < 0 && err != -ENODATA)
+ goto out;
+ }
+
+ err = ovl_copy_up_data(&datapath, &upperpath, c->stat.size);
+ 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(upperpath.dentry, XATTR_NAME_CAPS,
+ capability, cap_size, 0);
+ if (err)
+ goto out_free;
+ }
+
+
+ err = vfs_removexattr(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;
+
+ 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;
+}
+
+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 2024-11-30 01:55:53 +0000