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1065 lines
24 KiB
1065 lines
24 KiB
// SPDX-License-Identifier: GPL-2.0-only |
|
/* |
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* |
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* Copyright (C) 2011 Novell Inc. |
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*/ |
|
|
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#include <linux/module.h> |
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#include <linux/fs.h> |
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#include <linux/slab.h> |
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#include <linux/file.h> |
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#include <linux/fileattr.h> |
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#include <linux/splice.h> |
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#include <linux/xattr.h> |
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#include <linux/security.h> |
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#include <linux/uaccess.h> |
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#include <linux/sched/signal.h> |
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#include <linux/cred.h> |
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#include <linux/namei.h> |
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#include <linux/fdtable.h> |
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#include <linux/ratelimit.h> |
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#include <linux/exportfs.h> |
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#include "overlayfs.h" |
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|
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#define OVL_COPY_UP_CHUNK_SIZE (1 << 20) |
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|
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static int ovl_ccup_set(const char *buf, const struct kernel_param *param) |
|
{ |
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pr_warn("\"check_copy_up\" module option is obsolete\n"); |
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return 0; |
|
} |
|
|
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static int ovl_ccup_get(char *buf, const struct kernel_param *param) |
|
{ |
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return sprintf(buf, "N\n"); |
|
} |
|
|
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module_param_call(check_copy_up, ovl_ccup_set, ovl_ccup_get, NULL, 0644); |
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MODULE_PARM_DESC(check_copy_up, "Obsolete; does nothing"); |
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|
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static bool ovl_must_copy_xattr(const char *name) |
|
{ |
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return !strcmp(name, XATTR_POSIX_ACL_ACCESS) || |
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!strcmp(name, XATTR_POSIX_ACL_DEFAULT) || |
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!strncmp(name, XATTR_SECURITY_PREFIX, XATTR_SECURITY_PREFIX_LEN); |
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} |
|
|
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int ovl_copy_xattr(struct super_block *sb, struct dentry *old, |
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struct dentry *new) |
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{ |
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ssize_t list_size, size, value_size = 0; |
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char *buf, *name, *value = NULL; |
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int error = 0; |
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size_t slen; |
|
|
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if (!(old->d_inode->i_opflags & IOP_XATTR) || |
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!(new->d_inode->i_opflags & IOP_XATTR)) |
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return 0; |
|
|
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list_size = vfs_listxattr(old, NULL, 0); |
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if (list_size <= 0) { |
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if (list_size == -EOPNOTSUPP) |
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return 0; |
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return list_size; |
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} |
|
|
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buf = kvzalloc(list_size, GFP_KERNEL); |
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if (!buf) |
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return -ENOMEM; |
|
|
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list_size = vfs_listxattr(old, buf, list_size); |
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if (list_size <= 0) { |
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error = list_size; |
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goto out; |
|
} |
|
|
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for (name = buf; list_size; name += slen) { |
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slen = strnlen(name, list_size) + 1; |
|
|
|
/* underlying fs providing us with an broken xattr list? */ |
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if (WARN_ON(slen > list_size)) { |
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error = -EIO; |
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break; |
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} |
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list_size -= slen; |
|
|
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if (ovl_is_private_xattr(sb, name)) |
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continue; |
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|
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error = security_inode_copy_up_xattr(name); |
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if (error < 0 && error != -EOPNOTSUPP) |
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break; |
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if (error == 1) { |
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error = 0; |
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continue; /* Discard */ |
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} |
|
retry: |
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size = vfs_getxattr(&init_user_ns, old, name, value, value_size); |
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if (size == -ERANGE) |
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size = vfs_getxattr(&init_user_ns, old, name, NULL, 0); |
|
|
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if (size < 0) { |
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error = size; |
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break; |
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} |
|
|
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if (size > value_size) { |
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void *new; |
|
|
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new = kvmalloc(size, GFP_KERNEL); |
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if (!new) { |
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error = -ENOMEM; |
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break; |
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} |
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kvfree(value); |
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value = new; |
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value_size = size; |
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goto retry; |
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} |
|
|
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error = vfs_setxattr(&init_user_ns, new, name, value, size, 0); |
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if (error) { |
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if (error != -EOPNOTSUPP || ovl_must_copy_xattr(name)) |
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break; |
|
|
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/* Ignore failure to copy unknown xattrs */ |
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error = 0; |
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} |
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} |
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kvfree(value); |
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out: |
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kvfree(buf); |
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return error; |
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} |
|
|
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static int ovl_copy_fileattr(struct inode *inode, struct path *old, |
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struct path *new) |
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{ |
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struct fileattr oldfa = { .flags_valid = true }; |
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struct fileattr newfa = { .flags_valid = true }; |
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int err; |
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|
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err = ovl_real_fileattr_get(old, &oldfa); |
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if (err) |
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return err; |
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|
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err = ovl_real_fileattr_get(new, &newfa); |
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if (err) |
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return err; |
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|
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/* |
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* We cannot set immutable and append-only flags on upper inode, |
|
* because we would not be able to link upper inode to upper dir |
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* not set overlay private xattr on upper inode. |
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* Store these flags in overlay.protattr xattr instead. |
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*/ |
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if (oldfa.flags & OVL_PROT_FS_FLAGS_MASK) { |
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err = ovl_set_protattr(inode, new->dentry, &oldfa); |
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if (err) |
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return err; |
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} |
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|
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BUILD_BUG_ON(OVL_COPY_FS_FLAGS_MASK & ~FS_COMMON_FL); |
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newfa.flags &= ~OVL_COPY_FS_FLAGS_MASK; |
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newfa.flags |= (oldfa.flags & OVL_COPY_FS_FLAGS_MASK); |
|
|
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BUILD_BUG_ON(OVL_COPY_FSX_FLAGS_MASK & ~FS_XFLAG_COMMON); |
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newfa.fsx_xflags &= ~OVL_COPY_FSX_FLAGS_MASK; |
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newfa.fsx_xflags |= (oldfa.fsx_xflags & OVL_COPY_FSX_FLAGS_MASK); |
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|
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return ovl_real_fileattr_set(new, &newfa); |
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} |
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|
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static int ovl_copy_up_data(struct ovl_fs *ofs, struct path *old, |
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struct path *new, loff_t len) |
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{ |
|
struct file *old_file; |
|
struct file *new_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; |
|
|
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if (len == 0) |
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return 0; |
|
|
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old_file = ovl_path_open(old, O_LARGEFILE | O_RDONLY); |
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if (IS_ERR(old_file)) |
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return PTR_ERR(old_file); |
|
|
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new_file = ovl_path_open(new, O_LARGEFILE | O_WRONLY); |
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if (IS_ERR(new_file)) { |
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error = PTR_ERR(new_file); |
|
goto out_fput; |
|
} |
|
|
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/* Try to use clone_file_range to clone up within the same fs */ |
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cloned = do_clone_file_range(old_file, 0, new_file, 0, len, 0); |
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if (cloned == len) |
|
goto out; |
|
/* Couldn't clone, so now we try to copy the data */ |
|
|
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/* Check if lower fs supports seek operation */ |
|
if (old_file->f_mode & FMODE_LSEEK && |
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old_file->f_op->llseek) |
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skip_hole = true; |
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|
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while (len) { |
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size_t this_len = OVL_COPY_UP_CHUNK_SIZE; |
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long bytes; |
|
|
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if (len < this_len) |
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this_len = len; |
|
|
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if (signal_pending_state(TASK_KILLABLE, current)) { |
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error = -EINTR; |
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break; |
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} |
|
|
|
/* |
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* Fill zero for hole will cost unnecessary disk space |
|
* and meanwhile slow down the copy-up speed, so we do |
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* an optimization for hole during copy-up, it relies |
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* on SEEK_DATA implementation in lower fs so if lower |
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* fs does not support it, copy-up will behave as before. |
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* |
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* Detail logic of hole detection as below: |
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* When we detect next data position is larger than current |
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* position we will skip that hole, otherwise we copy |
|
* data in the size of OVL_COPY_UP_CHUNK_SIZE. Actually, |
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* 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. |
|
*/ |
|
|
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if (skip_hole && data_pos < old_pos) { |
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data_pos = vfs_llseek(old_file, old_pos, SEEK_DATA); |
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if (data_pos > old_pos) { |
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hole_len = data_pos - old_pos; |
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len -= hole_len; |
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old_pos = new_pos = data_pos; |
|
continue; |
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} else if (data_pos == -ENXIO) { |
|
break; |
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} else if (data_pos < 0) { |
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skip_hole = false; |
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} |
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} |
|
|
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bytes = do_splice_direct(old_file, &old_pos, |
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new_file, &new_pos, |
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this_len, SPLICE_F_MOVE); |
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if (bytes <= 0) { |
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error = bytes; |
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break; |
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} |
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WARN_ON(old_pos != new_pos); |
|
|
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len -= bytes; |
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} |
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out: |
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if (!error && ovl_should_sync(ofs)) |
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error = vfs_fsync(new_file, 0); |
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fput(new_file); |
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out_fput: |
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fput(old_file); |
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return error; |
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} |
|
|
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static int ovl_set_size(struct dentry *upperdentry, struct kstat *stat) |
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{ |
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struct iattr attr = { |
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.ia_valid = ATTR_SIZE, |
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.ia_size = stat->size, |
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}; |
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|
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return notify_change(&init_user_ns, upperdentry, &attr, NULL); |
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} |
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|
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static int ovl_set_timestamps(struct dentry *upperdentry, struct kstat *stat) |
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{ |
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struct iattr attr = { |
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.ia_valid = |
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ATTR_ATIME | ATTR_MTIME | ATTR_ATIME_SET | ATTR_MTIME_SET, |
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.ia_atime = stat->atime, |
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.ia_mtime = stat->mtime, |
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}; |
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|
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return notify_change(&init_user_ns, upperdentry, &attr, NULL); |
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} |
|
|
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int ovl_set_attr(struct dentry *upperdentry, struct kstat *stat) |
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{ |
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int err = 0; |
|
|
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if (!S_ISLNK(stat->mode)) { |
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struct iattr attr = { |
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.ia_valid = ATTR_MODE, |
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.ia_mode = stat->mode, |
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}; |
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err = notify_change(&init_user_ns, upperdentry, &attr, NULL); |
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} |
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if (!err) { |
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struct iattr attr = { |
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.ia_valid = ATTR_UID | ATTR_GID, |
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.ia_uid = stat->uid, |
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.ia_gid = stat->gid, |
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}; |
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err = notify_change(&init_user_ns, upperdentry, &attr, NULL); |
|
} |
|
if (!err) |
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ovl_set_timestamps(upperdentry, stat); |
|
|
|
return err; |
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} |
|
|
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struct ovl_fh *ovl_encode_real_fh(struct ovl_fs *ofs, struct dentry *real, |
|
bool is_upper) |
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{ |
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struct ovl_fh *fh; |
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int fh_type, dwords; |
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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); |
|
|
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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. |
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*/ |
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dwords = buflen >> 2; |
|
fh_type = exportfs_encode_fh(real, (void *)fh->fb.fid, &dwords, 0); |
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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; |
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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_do_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(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 = 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 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_copy_up_inode(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, datapath; |
|
int err; |
|
|
|
ovl_path_upper(c->dentry, &upperpath); |
|
if (WARN_ON(upperpath.dentry != NULL)) |
|
return -EIO; |
|
|
|
upperpath.dentry = temp; |
|
|
|
/* |
|
* 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) { |
|
ovl_path_lowerdata(c->dentry, &datapath); |
|
err = ovl_copy_up_data(ofs, &datapath, &upperpath, |
|
c->stat.size); |
|
if (err) |
|
return err; |
|
} |
|
|
|
err = ovl_copy_xattr(c->dentry->d_sb, c->lowerpath.dentry, temp); |
|
if (err) |
|
return err; |
|
|
|
if (inode->i_flags & OVL_COPY_I_FLAGS_MASK) { |
|
/* |
|
* 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(temp, &c->stat); |
|
if (!err) |
|
err = ovl_set_attr(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 inode *inode; |
|
struct inode *udir = d_inode(c->destdir), *wdir = d_inode(c->workdir); |
|
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(c->workdir, &cattr); |
|
ovl_revert_cu_creds(&cc); |
|
|
|
err = PTR_ERR(temp); |
|
if (IS_ERR(temp)) |
|
goto unlock; |
|
|
|
err = ovl_copy_up_inode(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 = lookup_one_len(c->destname.name, c->destdir, c->destname.len); |
|
err = PTR_ERR(upper); |
|
if (IS_ERR(upper)) |
|
goto cleanup; |
|
|
|
err = ovl_do_rename(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(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 inode *udir = d_inode(c->destdir); |
|
struct dentry *temp, *upper; |
|
struct ovl_cu_creds cc; |
|
int err; |
|
|
|
err = ovl_prep_cu_creds(c->dentry, &cc); |
|
if (err) |
|
return err; |
|
|
|
temp = ovl_do_tmpfile(c->workdir, c->stat.mode); |
|
ovl_revert_cu_creds(&cc); |
|
|
|
if (IS_ERR(temp)) |
|
return PTR_ERR(temp); |
|
|
|
err = ovl_copy_up_inode(c, temp); |
|
if (err) |
|
goto out_dput; |
|
|
|
inode_lock_nested(udir, I_MUTEX_PARENT); |
|
|
|
upper = lookup_one_len(c->destname.name, c->destdir, c->destname.len); |
|
err = PTR_ERR(upper); |
|
if (!IS_ERR(upper)) { |
|
err = ovl_do_link(temp, udir, upper); |
|
dput(upper); |
|
} |
|
inode_unlock(udir); |
|
|
|
if (err) |
|
goto out_dput; |
|
|
|
if (!c->metacopy) |
|
ovl_set_upperdata(d_inode(c->dentry)); |
|
ovl_inode_update(d_inode(c->dentry), temp); |
|
|
|
return 0; |
|
|
|
out_dput: |
|
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 = 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(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; |
|
} |
|
|
|
static ssize_t ovl_getxattr(struct dentry *dentry, char *name, char **value) |
|
{ |
|
ssize_t res; |
|
char *buf; |
|
|
|
res = vfs_getxattr(&init_user_ns, dentry, name, NULL, 0); |
|
if (res == -ENODATA || res == -EOPNOTSUPP) |
|
res = 0; |
|
|
|
if (res > 0) { |
|
buf = kzalloc(res, GFP_KERNEL); |
|
if (!buf) |
|
return -ENOMEM; |
|
|
|
res = vfs_getxattr(&init_user_ns, dentry, 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, datapath; |
|
int err; |
|
char *capability = NULL; |
|
ssize_t 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); |
|
if (cap_size < 0) |
|
goto out; |
|
} |
|
|
|
err = ovl_copy_up_data(ofs, &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 = vfs_setxattr(&init_user_ns, upperpath.dentry, |
|
XATTR_NAME_CAPS, capability, cap_size, 0); |
|
if (err) |
|
goto out_free; |
|
} |
|
|
|
|
|
err = ovl_do_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; |
|
|
|
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); |
|
}
|
|
|