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Revision af5a30d8cfcfc561336f982b06345d6b815e0bb3 authored by Nick Piggin on 03 June 2010, 12:01:46 UTC, committed by Al Viro on 04 June 2010, 21:16:30 UTC 
fix truncate inode time modification breakage
 
mtime and ctime should be changed only if the file size has actually
changed. Patches changing ext2 and tmpfs from vmtruncate to new truncate
sequence has caused regressions where they always update timestamps.

There is some strange cases in POSIX where truncate(2) must not update
times unless the size has acutally changed, see 6e656be89.

This area is all still rather buggy in different ways in a lot of
filesystems and needs a cleanup and audit (ideally the vfs will provide
a simple attribute or call to direct all filesystems exactly which
attributes to change). But coming up with the best solution will take a
while and is not appropriate for rc anyway.

So fix recent regression for now.

Signed-off-by: Nick Piggin <npiggin@suse.de>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
1 parent 8718d36
Raw File
xattr_acl.c 
/*
 * linux/fs/xattr_acl.c
 *
 * Almost all from linux/fs/ext2/acl.c:
 * Copyright (C) 2001 by Andreas Gruenbacher, <a.gruenbacher@computer.org>
 */

#include <linux/module.h>
#include <linux/fs.h>
#include <linux/posix_acl_xattr.h>
#include <linux/gfp.h>


/*
 * Convert from extended attribute to in-memory representation.
 */
struct posix_acl *
posix_acl_from_xattr(const void *value, size_t size)
{
	posix_acl_xattr_header *header = (posix_acl_xattr_header *)value;
	posix_acl_xattr_entry *entry = (posix_acl_xattr_entry *)(header+1), *end;
	int count;
	struct posix_acl *acl;
	struct posix_acl_entry *acl_e;

	if (!value)
		return NULL;
	if (size < sizeof(posix_acl_xattr_header))
		 return ERR_PTR(-EINVAL);
	if (header->a_version != cpu_to_le32(POSIX_ACL_XATTR_VERSION))
		return ERR_PTR(-EOPNOTSUPP);

	count = posix_acl_xattr_count(size);
	if (count < 0)
		return ERR_PTR(-EINVAL);
	if (count == 0)
		return NULL;
	
	acl = posix_acl_alloc(count, GFP_NOFS);
	if (!acl)
		return ERR_PTR(-ENOMEM);
	acl_e = acl->a_entries;
	
	for (end = entry + count; entry != end; acl_e++, entry++) {
		acl_e->e_tag  = le16_to_cpu(entry->e_tag);
		acl_e->e_perm = le16_to_cpu(entry->e_perm);

		switch(acl_e->e_tag) {
			case ACL_USER_OBJ:
			case ACL_GROUP_OBJ:
			case ACL_MASK:
			case ACL_OTHER:
				acl_e->e_id = ACL_UNDEFINED_ID;
				break;

			case ACL_USER:
			case ACL_GROUP:
				acl_e->e_id = le32_to_cpu(entry->e_id);
				break;

			default:
				goto fail;
		}
	}
	return acl;

fail:
	posix_acl_release(acl);
	return ERR_PTR(-EINVAL);
}
EXPORT_SYMBOL (posix_acl_from_xattr);

/*
 * Convert from in-memory to extended attribute representation.
 */
int
posix_acl_to_xattr(const struct posix_acl *acl, void *buffer, size_t size)
{
	posix_acl_xattr_header *ext_acl = (posix_acl_xattr_header *)buffer;
	posix_acl_xattr_entry *ext_entry = ext_acl->a_entries;
	int real_size, n;

	real_size = posix_acl_xattr_size(acl->a_count);
	if (!buffer)
		return real_size;
	if (real_size > size)
		return -ERANGE;
	
	ext_acl->a_version = cpu_to_le32(POSIX_ACL_XATTR_VERSION);

	for (n=0; n < acl->a_count; n++, ext_entry++) {
		ext_entry->e_tag  = cpu_to_le16(acl->a_entries[n].e_tag);
		ext_entry->e_perm = cpu_to_le16(acl->a_entries[n].e_perm);
		ext_entry->e_id   = cpu_to_le32(acl->a_entries[n].e_id);
	}
	return real_size;
}
EXPORT_SYMBOL (posix_acl_to_xattr);
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