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![Jingbo Xu](/assets/img/avatar_default.png)
Optimise the negative xattr lookup with bloom filter. The bit value for the bloom filter map has a reverse semantics for compatibility. That is, the bit value of 0 indicates existence, while the bit value of 1 indicates the absence of corresponding xattr. The initial version is _only_ enabled when xattr_filter_reserved is zero. The filter map internals may change in the future, in which case the reserved flag will be set non-zero and we don't need bothering the compatible bits again at that time. For now disable the optimization if this reserved flag is non-zero. Signed-off-by: Jingbo Xu <jefflexu@linux.alibaba.com> Reviewed-by: Gao Xiang <hsiangkao@linux.alibaba.com> Reviewed-by: Chao Yu <chao@kernel.org> Link: https://lore.kernel.org/r/20230722094538.11754-3-jefflexu@linux.alibaba.com Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
560 lines
14 KiB
C
560 lines
14 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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/*
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* Copyright (C) 2017-2018 HUAWEI, Inc.
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* https://www.huawei.com/
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* Copyright (C) 2021-2022, Alibaba Cloud
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*/
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#include <linux/security.h>
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#include <linux/xxhash.h>
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#include "xattr.h"
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struct erofs_xattr_iter {
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struct super_block *sb;
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struct erofs_buf buf;
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erofs_off_t pos;
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void *kaddr;
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char *buffer;
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int buffer_size, buffer_ofs;
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/* getxattr */
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int index, infix_len;
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struct qstr name;
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/* listxattr */
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struct dentry *dentry;
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};
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static int erofs_init_inode_xattrs(struct inode *inode)
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{
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struct erofs_inode *const vi = EROFS_I(inode);
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struct erofs_xattr_iter it;
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unsigned int i;
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struct erofs_xattr_ibody_header *ih;
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struct super_block *sb = inode->i_sb;
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int ret = 0;
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/* the most case is that xattrs of this inode are initialized. */
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if (test_bit(EROFS_I_EA_INITED_BIT, &vi->flags)) {
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/*
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* paired with smp_mb() at the end of the function to ensure
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* fields will only be observed after the bit is set.
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*/
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smp_mb();
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return 0;
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}
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if (wait_on_bit_lock(&vi->flags, EROFS_I_BL_XATTR_BIT, TASK_KILLABLE))
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return -ERESTARTSYS;
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/* someone has initialized xattrs for us? */
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if (test_bit(EROFS_I_EA_INITED_BIT, &vi->flags))
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goto out_unlock;
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/*
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* bypass all xattr operations if ->xattr_isize is not greater than
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* sizeof(struct erofs_xattr_ibody_header), in detail:
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* 1) it is not enough to contain erofs_xattr_ibody_header then
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* ->xattr_isize should be 0 (it means no xattr);
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* 2) it is just to contain erofs_xattr_ibody_header, which is on-disk
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* undefined right now (maybe use later with some new sb feature).
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*/
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if (vi->xattr_isize == sizeof(struct erofs_xattr_ibody_header)) {
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erofs_err(sb,
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"xattr_isize %d of nid %llu is not supported yet",
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vi->xattr_isize, vi->nid);
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ret = -EOPNOTSUPP;
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goto out_unlock;
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} else if (vi->xattr_isize < sizeof(struct erofs_xattr_ibody_header)) {
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if (vi->xattr_isize) {
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erofs_err(sb, "bogus xattr ibody @ nid %llu", vi->nid);
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DBG_BUGON(1);
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ret = -EFSCORRUPTED;
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goto out_unlock; /* xattr ondisk layout error */
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}
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ret = -ENOATTR;
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goto out_unlock;
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}
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it.buf = __EROFS_BUF_INITIALIZER;
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erofs_init_metabuf(&it.buf, sb);
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it.pos = erofs_iloc(inode) + vi->inode_isize;
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/* read in shared xattr array (non-atomic, see kmalloc below) */
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it.kaddr = erofs_bread(&it.buf, erofs_blknr(sb, it.pos), EROFS_KMAP);
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if (IS_ERR(it.kaddr)) {
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ret = PTR_ERR(it.kaddr);
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goto out_unlock;
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}
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ih = it.kaddr + erofs_blkoff(sb, it.pos);
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vi->xattr_name_filter = le32_to_cpu(ih->h_name_filter);
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vi->xattr_shared_count = ih->h_shared_count;
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vi->xattr_shared_xattrs = kmalloc_array(vi->xattr_shared_count,
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sizeof(uint), GFP_KERNEL);
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if (!vi->xattr_shared_xattrs) {
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erofs_put_metabuf(&it.buf);
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ret = -ENOMEM;
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goto out_unlock;
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}
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/* let's skip ibody header */
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it.pos += sizeof(struct erofs_xattr_ibody_header);
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for (i = 0; i < vi->xattr_shared_count; ++i) {
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it.kaddr = erofs_bread(&it.buf, erofs_blknr(sb, it.pos),
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EROFS_KMAP);
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if (IS_ERR(it.kaddr)) {
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kfree(vi->xattr_shared_xattrs);
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vi->xattr_shared_xattrs = NULL;
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ret = PTR_ERR(it.kaddr);
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goto out_unlock;
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}
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vi->xattr_shared_xattrs[i] = le32_to_cpu(*(__le32 *)
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(it.kaddr + erofs_blkoff(sb, it.pos)));
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it.pos += sizeof(__le32);
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}
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erofs_put_metabuf(&it.buf);
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/* paired with smp_mb() at the beginning of the function. */
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smp_mb();
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set_bit(EROFS_I_EA_INITED_BIT, &vi->flags);
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out_unlock:
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clear_and_wake_up_bit(EROFS_I_BL_XATTR_BIT, &vi->flags);
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return ret;
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}
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static bool erofs_xattr_user_list(struct dentry *dentry)
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{
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return test_opt(&EROFS_SB(dentry->d_sb)->opt, XATTR_USER);
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}
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static bool erofs_xattr_trusted_list(struct dentry *dentry)
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{
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return capable(CAP_SYS_ADMIN);
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}
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static int erofs_xattr_generic_get(const struct xattr_handler *handler,
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struct dentry *unused, struct inode *inode,
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const char *name, void *buffer, size_t size)
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{
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if (handler->flags == EROFS_XATTR_INDEX_USER &&
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!test_opt(&EROFS_I_SB(inode)->opt, XATTR_USER))
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return -EOPNOTSUPP;
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return erofs_getxattr(inode, handler->flags, name, buffer, size);
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}
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const struct xattr_handler erofs_xattr_user_handler = {
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.prefix = XATTR_USER_PREFIX,
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.flags = EROFS_XATTR_INDEX_USER,
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.list = erofs_xattr_user_list,
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.get = erofs_xattr_generic_get,
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};
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const struct xattr_handler erofs_xattr_trusted_handler = {
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.prefix = XATTR_TRUSTED_PREFIX,
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.flags = EROFS_XATTR_INDEX_TRUSTED,
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.list = erofs_xattr_trusted_list,
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.get = erofs_xattr_generic_get,
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};
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#ifdef CONFIG_EROFS_FS_SECURITY
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const struct xattr_handler __maybe_unused erofs_xattr_security_handler = {
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.prefix = XATTR_SECURITY_PREFIX,
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.flags = EROFS_XATTR_INDEX_SECURITY,
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.get = erofs_xattr_generic_get,
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};
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#endif
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const struct xattr_handler *erofs_xattr_handlers[] = {
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&erofs_xattr_user_handler,
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&erofs_xattr_trusted_handler,
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#ifdef CONFIG_EROFS_FS_SECURITY
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&erofs_xattr_security_handler,
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#endif
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NULL,
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};
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static int erofs_xattr_copy_to_buffer(struct erofs_xattr_iter *it,
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unsigned int len)
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{
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unsigned int slice, processed;
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struct super_block *sb = it->sb;
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void *src;
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for (processed = 0; processed < len; processed += slice) {
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it->kaddr = erofs_bread(&it->buf, erofs_blknr(sb, it->pos),
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EROFS_KMAP);
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if (IS_ERR(it->kaddr))
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return PTR_ERR(it->kaddr);
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src = it->kaddr + erofs_blkoff(sb, it->pos);
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slice = min_t(unsigned int, sb->s_blocksize -
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erofs_blkoff(sb, it->pos), len - processed);
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memcpy(it->buffer + it->buffer_ofs, src, slice);
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it->buffer_ofs += slice;
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it->pos += slice;
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}
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return 0;
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}
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static int erofs_listxattr_foreach(struct erofs_xattr_iter *it)
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{
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struct erofs_xattr_entry entry;
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unsigned int base_index, name_total, prefix_len, infix_len = 0;
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const char *prefix, *infix = NULL;
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int err;
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/* 1. handle xattr entry */
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entry = *(struct erofs_xattr_entry *)
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(it->kaddr + erofs_blkoff(it->sb, it->pos));
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it->pos += sizeof(struct erofs_xattr_entry);
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base_index = entry.e_name_index;
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if (entry.e_name_index & EROFS_XATTR_LONG_PREFIX) {
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struct erofs_sb_info *sbi = EROFS_SB(it->sb);
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struct erofs_xattr_prefix_item *pf = sbi->xattr_prefixes +
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(entry.e_name_index & EROFS_XATTR_LONG_PREFIX_MASK);
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if (pf >= sbi->xattr_prefixes + sbi->xattr_prefix_count)
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return 0;
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infix = pf->prefix->infix;
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infix_len = pf->infix_len;
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base_index = pf->prefix->base_index;
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}
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prefix = erofs_xattr_prefix(base_index, it->dentry);
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if (!prefix)
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return 0;
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prefix_len = strlen(prefix);
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name_total = prefix_len + infix_len + entry.e_name_len + 1;
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if (!it->buffer) {
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it->buffer_ofs += name_total;
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return 0;
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}
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if (it->buffer_ofs + name_total > it->buffer_size)
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return -ERANGE;
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memcpy(it->buffer + it->buffer_ofs, prefix, prefix_len);
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memcpy(it->buffer + it->buffer_ofs + prefix_len, infix, infix_len);
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it->buffer_ofs += prefix_len + infix_len;
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/* 2. handle xattr name */
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err = erofs_xattr_copy_to_buffer(it, entry.e_name_len);
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if (err)
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return err;
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it->buffer[it->buffer_ofs++] = '\0';
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return 0;
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}
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static int erofs_getxattr_foreach(struct erofs_xattr_iter *it)
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{
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struct super_block *sb = it->sb;
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struct erofs_xattr_entry entry;
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unsigned int slice, processed, value_sz;
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/* 1. handle xattr entry */
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entry = *(struct erofs_xattr_entry *)
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(it->kaddr + erofs_blkoff(sb, it->pos));
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it->pos += sizeof(struct erofs_xattr_entry);
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value_sz = le16_to_cpu(entry.e_value_size);
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/* should also match the infix for long name prefixes */
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if (entry.e_name_index & EROFS_XATTR_LONG_PREFIX) {
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struct erofs_sb_info *sbi = EROFS_SB(sb);
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struct erofs_xattr_prefix_item *pf = sbi->xattr_prefixes +
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(entry.e_name_index & EROFS_XATTR_LONG_PREFIX_MASK);
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if (pf >= sbi->xattr_prefixes + sbi->xattr_prefix_count)
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return -ENOATTR;
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if (it->index != pf->prefix->base_index ||
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it->name.len != entry.e_name_len + pf->infix_len)
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return -ENOATTR;
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if (memcmp(it->name.name, pf->prefix->infix, pf->infix_len))
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return -ENOATTR;
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it->infix_len = pf->infix_len;
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} else {
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if (it->index != entry.e_name_index ||
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it->name.len != entry.e_name_len)
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return -ENOATTR;
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it->infix_len = 0;
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}
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/* 2. handle xattr name */
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for (processed = 0; processed < entry.e_name_len; processed += slice) {
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it->kaddr = erofs_bread(&it->buf, erofs_blknr(sb, it->pos),
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EROFS_KMAP);
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if (IS_ERR(it->kaddr))
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return PTR_ERR(it->kaddr);
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slice = min_t(unsigned int,
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sb->s_blocksize - erofs_blkoff(sb, it->pos),
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entry.e_name_len - processed);
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if (memcmp(it->name.name + it->infix_len + processed,
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it->kaddr + erofs_blkoff(sb, it->pos), slice))
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return -ENOATTR;
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it->pos += slice;
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}
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/* 3. handle xattr value */
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if (!it->buffer) {
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it->buffer_ofs = value_sz;
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return 0;
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}
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if (it->buffer_size < value_sz)
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return -ERANGE;
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return erofs_xattr_copy_to_buffer(it, value_sz);
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}
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static int erofs_xattr_iter_inline(struct erofs_xattr_iter *it,
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struct inode *inode, bool getxattr)
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{
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struct erofs_inode *const vi = EROFS_I(inode);
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unsigned int xattr_header_sz, remaining, entry_sz;
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erofs_off_t next_pos;
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int ret;
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xattr_header_sz = sizeof(struct erofs_xattr_ibody_header) +
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sizeof(u32) * vi->xattr_shared_count;
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if (xattr_header_sz >= vi->xattr_isize) {
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DBG_BUGON(xattr_header_sz > vi->xattr_isize);
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return -ENOATTR;
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}
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remaining = vi->xattr_isize - xattr_header_sz;
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it->pos = erofs_iloc(inode) + vi->inode_isize + xattr_header_sz;
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while (remaining) {
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it->kaddr = erofs_bread(&it->buf, erofs_blknr(it->sb, it->pos),
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EROFS_KMAP);
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if (IS_ERR(it->kaddr))
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return PTR_ERR(it->kaddr);
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entry_sz = erofs_xattr_entry_size(it->kaddr +
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erofs_blkoff(it->sb, it->pos));
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/* xattr on-disk corruption: xattr entry beyond xattr_isize */
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if (remaining < entry_sz) {
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DBG_BUGON(1);
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return -EFSCORRUPTED;
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}
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remaining -= entry_sz;
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next_pos = it->pos + entry_sz;
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if (getxattr)
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ret = erofs_getxattr_foreach(it);
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else
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ret = erofs_listxattr_foreach(it);
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if ((getxattr && ret != -ENOATTR) || (!getxattr && ret))
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break;
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it->pos = next_pos;
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}
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return ret;
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}
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static int erofs_xattr_iter_shared(struct erofs_xattr_iter *it,
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struct inode *inode, bool getxattr)
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{
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struct erofs_inode *const vi = EROFS_I(inode);
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struct super_block *const sb = it->sb;
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struct erofs_sb_info *sbi = EROFS_SB(sb);
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unsigned int i;
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int ret = -ENOATTR;
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for (i = 0; i < vi->xattr_shared_count; ++i) {
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it->pos = erofs_pos(sb, sbi->xattr_blkaddr) +
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vi->xattr_shared_xattrs[i] * sizeof(__le32);
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it->kaddr = erofs_bread(&it->buf, erofs_blknr(sb, it->pos),
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EROFS_KMAP);
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if (IS_ERR(it->kaddr))
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return PTR_ERR(it->kaddr);
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if (getxattr)
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ret = erofs_getxattr_foreach(it);
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else
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ret = erofs_listxattr_foreach(it);
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if ((getxattr && ret != -ENOATTR) || (!getxattr && ret))
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break;
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}
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return ret;
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}
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int erofs_getxattr(struct inode *inode, int index, const char *name,
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void *buffer, size_t buffer_size)
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{
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int ret;
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unsigned int hashbit;
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struct erofs_xattr_iter it;
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struct erofs_inode *vi = EROFS_I(inode);
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struct erofs_sb_info *sbi = EROFS_SB(inode->i_sb);
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if (!name)
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return -EINVAL;
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ret = erofs_init_inode_xattrs(inode);
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if (ret)
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return ret;
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/* reserved flag is non-zero if there's any change of on-disk format */
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if (erofs_sb_has_xattr_filter(sbi) && !sbi->xattr_filter_reserved) {
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hashbit = xxh32(name, strlen(name),
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EROFS_XATTR_FILTER_SEED + index);
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hashbit &= EROFS_XATTR_FILTER_BITS - 1;
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if (vi->xattr_name_filter & (1U << hashbit))
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return -ENOATTR;
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}
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it.index = index;
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it.name = (struct qstr)QSTR_INIT(name, strlen(name));
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if (it.name.len > EROFS_NAME_LEN)
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return -ERANGE;
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it.sb = inode->i_sb;
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it.buf = __EROFS_BUF_INITIALIZER;
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erofs_init_metabuf(&it.buf, it.sb);
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it.buffer = buffer;
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it.buffer_size = buffer_size;
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it.buffer_ofs = 0;
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ret = erofs_xattr_iter_inline(&it, inode, true);
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if (ret == -ENOATTR)
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ret = erofs_xattr_iter_shared(&it, inode, true);
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erofs_put_metabuf(&it.buf);
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return ret ? ret : it.buffer_ofs;
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}
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ssize_t erofs_listxattr(struct dentry *dentry, char *buffer, size_t buffer_size)
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{
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int ret;
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struct erofs_xattr_iter it;
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struct inode *inode = d_inode(dentry);
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ret = erofs_init_inode_xattrs(inode);
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if (ret == -ENOATTR)
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return 0;
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if (ret)
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return ret;
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it.sb = dentry->d_sb;
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it.buf = __EROFS_BUF_INITIALIZER;
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erofs_init_metabuf(&it.buf, it.sb);
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it.dentry = dentry;
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it.buffer = buffer;
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it.buffer_size = buffer_size;
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it.buffer_ofs = 0;
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ret = erofs_xattr_iter_inline(&it, inode, false);
|
|
if (!ret || ret == -ENOATTR)
|
|
ret = erofs_xattr_iter_shared(&it, inode, false);
|
|
if (ret == -ENOATTR)
|
|
ret = 0;
|
|
erofs_put_metabuf(&it.buf);
|
|
return ret ? ret : it.buffer_ofs;
|
|
}
|
|
|
|
void erofs_xattr_prefixes_cleanup(struct super_block *sb)
|
|
{
|
|
struct erofs_sb_info *sbi = EROFS_SB(sb);
|
|
int i;
|
|
|
|
if (sbi->xattr_prefixes) {
|
|
for (i = 0; i < sbi->xattr_prefix_count; i++)
|
|
kfree(sbi->xattr_prefixes[i].prefix);
|
|
kfree(sbi->xattr_prefixes);
|
|
sbi->xattr_prefixes = NULL;
|
|
}
|
|
}
|
|
|
|
int erofs_xattr_prefixes_init(struct super_block *sb)
|
|
{
|
|
struct erofs_sb_info *sbi = EROFS_SB(sb);
|
|
struct erofs_buf buf = __EROFS_BUF_INITIALIZER;
|
|
erofs_off_t pos = (erofs_off_t)sbi->xattr_prefix_start << 2;
|
|
struct erofs_xattr_prefix_item *pfs;
|
|
int ret = 0, i, len;
|
|
|
|
if (!sbi->xattr_prefix_count)
|
|
return 0;
|
|
|
|
pfs = kzalloc(sbi->xattr_prefix_count * sizeof(*pfs), GFP_KERNEL);
|
|
if (!pfs)
|
|
return -ENOMEM;
|
|
|
|
if (sbi->packed_inode)
|
|
buf.inode = sbi->packed_inode;
|
|
else
|
|
erofs_init_metabuf(&buf, sb);
|
|
|
|
for (i = 0; i < sbi->xattr_prefix_count; i++) {
|
|
void *ptr = erofs_read_metadata(sb, &buf, &pos, &len);
|
|
|
|
if (IS_ERR(ptr)) {
|
|
ret = PTR_ERR(ptr);
|
|
break;
|
|
} else if (len < sizeof(*pfs->prefix) ||
|
|
len > EROFS_NAME_LEN + sizeof(*pfs->prefix)) {
|
|
kfree(ptr);
|
|
ret = -EFSCORRUPTED;
|
|
break;
|
|
}
|
|
pfs[i].prefix = ptr;
|
|
pfs[i].infix_len = len - sizeof(struct erofs_xattr_long_prefix);
|
|
}
|
|
|
|
erofs_put_metabuf(&buf);
|
|
sbi->xattr_prefixes = pfs;
|
|
if (ret)
|
|
erofs_xattr_prefixes_cleanup(sb);
|
|
return ret;
|
|
}
|
|
|
|
#ifdef CONFIG_EROFS_FS_POSIX_ACL
|
|
struct posix_acl *erofs_get_acl(struct inode *inode, int type, bool rcu)
|
|
{
|
|
struct posix_acl *acl;
|
|
int prefix, rc;
|
|
char *value = NULL;
|
|
|
|
if (rcu)
|
|
return ERR_PTR(-ECHILD);
|
|
|
|
switch (type) {
|
|
case ACL_TYPE_ACCESS:
|
|
prefix = EROFS_XATTR_INDEX_POSIX_ACL_ACCESS;
|
|
break;
|
|
case ACL_TYPE_DEFAULT:
|
|
prefix = EROFS_XATTR_INDEX_POSIX_ACL_DEFAULT;
|
|
break;
|
|
default:
|
|
return ERR_PTR(-EINVAL);
|
|
}
|
|
|
|
rc = erofs_getxattr(inode, prefix, "", NULL, 0);
|
|
if (rc > 0) {
|
|
value = kmalloc(rc, GFP_KERNEL);
|
|
if (!value)
|
|
return ERR_PTR(-ENOMEM);
|
|
rc = erofs_getxattr(inode, prefix, "", value, rc);
|
|
}
|
|
|
|
if (rc == -ENOATTR)
|
|
acl = NULL;
|
|
else if (rc < 0)
|
|
acl = ERR_PTR(rc);
|
|
else
|
|
acl = posix_acl_from_xattr(&init_user_ns, value, rc);
|
|
kfree(value);
|
|
return acl;
|
|
}
|
|
#endif
|