518 lines
13 KiB
C
518 lines
13 KiB
C
/*
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* Copyright 2012 Xyratex Technology Limited
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*
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* Copyright (c) 2013, 2015, Intel Corporation.
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*
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* Author: Andrew Perepechko <Andrew_Perepechko@xyratex.com>
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*
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*/
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#define DEBUG_SUBSYSTEM S_LLITE
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#include <linux/fs.h>
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#include <linux/sched.h>
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#include <linux/mm.h>
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#include "../include/obd_support.h"
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#include "../include/lustre_lite.h"
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#include "../include/lustre_dlm.h"
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#include "../include/lustre_ver.h"
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#include "llite_internal.h"
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/* If we ever have hundreds of extended attributes, we might want to consider
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* using a hash or a tree structure instead of list for faster lookups.
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*/
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struct ll_xattr_entry {
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struct list_head xe_list; /* protected with
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* lli_xattrs_list_rwsem
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*/
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char *xe_name; /* xattr name, \0-terminated */
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char *xe_value; /* xattr value */
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unsigned xe_namelen; /* strlen(xe_name) + 1 */
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unsigned xe_vallen; /* xattr value length */
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};
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static struct kmem_cache *xattr_kmem;
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static struct lu_kmem_descr xattr_caches[] = {
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{
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.ckd_cache = &xattr_kmem,
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.ckd_name = "xattr_kmem",
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.ckd_size = sizeof(struct ll_xattr_entry)
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},
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{
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.ckd_cache = NULL
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}
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};
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int ll_xattr_init(void)
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{
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return lu_kmem_init(xattr_caches);
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}
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void ll_xattr_fini(void)
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{
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lu_kmem_fini(xattr_caches);
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}
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/**
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* Initializes xattr cache for an inode.
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*
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* This initializes the xattr list and marks cache presence.
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*/
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static void ll_xattr_cache_init(struct ll_inode_info *lli)
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{
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INIT_LIST_HEAD(&lli->lli_xattrs);
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lli->lli_flags |= LLIF_XATTR_CACHE;
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}
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/**
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* This looks for a specific extended attribute.
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*
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* Find in @cache and return @xattr_name attribute in @xattr,
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* for the NULL @xattr_name return the first cached @xattr.
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*
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* \retval 0 success
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* \retval -ENODATA if not found
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*/
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static int ll_xattr_cache_find(struct list_head *cache,
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const char *xattr_name,
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struct ll_xattr_entry **xattr)
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{
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struct ll_xattr_entry *entry;
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list_for_each_entry(entry, cache, xe_list) {
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/* xattr_name == NULL means look for any entry */
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if (!xattr_name || strcmp(xattr_name, entry->xe_name) == 0) {
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*xattr = entry;
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CDEBUG(D_CACHE, "find: [%s]=%.*s\n",
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entry->xe_name, entry->xe_vallen,
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entry->xe_value);
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return 0;
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}
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}
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return -ENODATA;
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}
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/**
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* This adds an xattr.
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*
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* Add @xattr_name attr with @xattr_val value and @xattr_val_len length,
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*
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* \retval 0 success
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* \retval -ENOMEM if no memory could be allocated for the cached attr
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* \retval -EPROTO if duplicate xattr is being added
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*/
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static int ll_xattr_cache_add(struct list_head *cache,
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const char *xattr_name,
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const char *xattr_val,
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unsigned xattr_val_len)
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{
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struct ll_xattr_entry *xattr;
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if (ll_xattr_cache_find(cache, xattr_name, &xattr) == 0) {
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CDEBUG(D_CACHE, "duplicate xattr: [%s]\n", xattr_name);
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return -EPROTO;
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}
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xattr = kmem_cache_zalloc(xattr_kmem, GFP_NOFS);
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if (!xattr) {
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CDEBUG(D_CACHE, "failed to allocate xattr\n");
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return -ENOMEM;
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}
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xattr->xe_name = kstrdup(xattr_name, GFP_NOFS);
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if (!xattr->xe_name) {
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CDEBUG(D_CACHE, "failed to alloc xattr name %u\n",
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xattr->xe_namelen);
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goto err_name;
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}
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xattr->xe_value = kmemdup(xattr_val, xattr_val_len, GFP_NOFS);
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if (!xattr->xe_value)
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goto err_value;
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xattr->xe_vallen = xattr_val_len;
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list_add(&xattr->xe_list, cache);
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CDEBUG(D_CACHE, "set: [%s]=%.*s\n", xattr_name, xattr_val_len,
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xattr_val);
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return 0;
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err_value:
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kfree(xattr->xe_name);
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err_name:
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kmem_cache_free(xattr_kmem, xattr);
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return -ENOMEM;
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}
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/**
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* This removes an extended attribute from cache.
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*
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* Remove @xattr_name attribute from @cache.
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*
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* \retval 0 success
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* \retval -ENODATA if @xattr_name is not cached
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*/
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static int ll_xattr_cache_del(struct list_head *cache,
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const char *xattr_name)
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{
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struct ll_xattr_entry *xattr;
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CDEBUG(D_CACHE, "del xattr: %s\n", xattr_name);
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if (ll_xattr_cache_find(cache, xattr_name, &xattr) == 0) {
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list_del(&xattr->xe_list);
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kfree(xattr->xe_name);
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kfree(xattr->xe_value);
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kmem_cache_free(xattr_kmem, xattr);
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return 0;
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}
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return -ENODATA;
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}
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/**
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* This iterates cached extended attributes.
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*
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* Walk over cached attributes in @cache and
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* fill in @xld_buffer or only calculate buffer
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* size if @xld_buffer is NULL.
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*
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* \retval >= 0 buffer list size
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* \retval -ENODATA if the list cannot fit @xld_size buffer
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*/
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static int ll_xattr_cache_list(struct list_head *cache,
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char *xld_buffer,
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int xld_size)
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{
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struct ll_xattr_entry *xattr, *tmp;
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int xld_tail = 0;
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list_for_each_entry_safe(xattr, tmp, cache, xe_list) {
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CDEBUG(D_CACHE, "list: buffer=%p[%d] name=%s\n",
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xld_buffer, xld_tail, xattr->xe_name);
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if (xld_buffer) {
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xld_size -= xattr->xe_namelen;
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if (xld_size < 0)
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break;
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memcpy(&xld_buffer[xld_tail],
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xattr->xe_name, xattr->xe_namelen);
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}
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xld_tail += xattr->xe_namelen;
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}
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if (xld_size < 0)
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return -ERANGE;
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return xld_tail;
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}
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/**
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* Check if the xattr cache is initialized (filled).
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*
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* \retval 0 @cache is not initialized
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* \retval 1 @cache is initialized
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*/
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static int ll_xattr_cache_valid(struct ll_inode_info *lli)
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{
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return !!(lli->lli_flags & LLIF_XATTR_CACHE);
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}
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/**
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* This finalizes the xattr cache.
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*
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* Free all xattr memory. @lli is the inode info pointer.
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*
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* \retval 0 no error occurred
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*/
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static int ll_xattr_cache_destroy_locked(struct ll_inode_info *lli)
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{
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if (!ll_xattr_cache_valid(lli))
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return 0;
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while (ll_xattr_cache_del(&lli->lli_xattrs, NULL) == 0)
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; /* empty loop */
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lli->lli_flags &= ~LLIF_XATTR_CACHE;
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return 0;
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}
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int ll_xattr_cache_destroy(struct inode *inode)
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{
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struct ll_inode_info *lli = ll_i2info(inode);
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int rc;
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down_write(&lli->lli_xattrs_list_rwsem);
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rc = ll_xattr_cache_destroy_locked(lli);
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up_write(&lli->lli_xattrs_list_rwsem);
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return rc;
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}
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/**
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* Match or enqueue a PR lock.
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*
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* Find or request an LDLM lock with xattr data.
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* Since LDLM does not provide API for atomic match_or_enqueue,
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* the function handles it with a separate enq lock.
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* If successful, the function exits with the list lock held.
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*
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* \retval 0 no error occurred
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* \retval -ENOMEM not enough memory
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*/
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static int ll_xattr_find_get_lock(struct inode *inode,
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struct lookup_intent *oit,
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struct ptlrpc_request **req)
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{
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enum ldlm_mode mode;
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struct lustre_handle lockh = { 0 };
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struct md_op_data *op_data;
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struct ll_inode_info *lli = ll_i2info(inode);
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struct ldlm_enqueue_info einfo = { .ei_type = LDLM_IBITS,
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.ei_mode = it_to_lock_mode(oit),
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.ei_cb_bl = ll_md_blocking_ast,
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.ei_cb_cp = ldlm_completion_ast };
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struct ll_sb_info *sbi = ll_i2sbi(inode);
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struct obd_export *exp = sbi->ll_md_exp;
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int rc;
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mutex_lock(&lli->lli_xattrs_enq_lock);
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/* inode may have been shrunk and recreated, so data is gone, match lock
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* only when data exists.
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*/
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if (ll_xattr_cache_valid(lli)) {
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/* Try matching first. */
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mode = ll_take_md_lock(inode, MDS_INODELOCK_XATTR, &lockh, 0,
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LCK_PR);
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if (mode != 0) {
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/* fake oit in mdc_revalidate_lock() manner */
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oit->d.lustre.it_lock_handle = lockh.cookie;
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oit->d.lustre.it_lock_mode = mode;
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goto out;
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}
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}
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/* Enqueue if the lock isn't cached locally. */
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op_data = ll_prep_md_op_data(NULL, inode, NULL, NULL, 0, 0,
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LUSTRE_OPC_ANY, NULL);
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if (IS_ERR(op_data)) {
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mutex_unlock(&lli->lli_xattrs_enq_lock);
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return PTR_ERR(op_data);
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}
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op_data->op_valid = OBD_MD_FLXATTR | OBD_MD_FLXATTRLS;
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rc = md_enqueue(exp, &einfo, oit, op_data, &lockh, NULL, 0, NULL, 0);
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ll_finish_md_op_data(op_data);
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if (rc < 0) {
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CDEBUG(D_CACHE,
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"md_intent_lock failed with %d for fid "DFID"\n",
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rc, PFID(ll_inode2fid(inode)));
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mutex_unlock(&lli->lli_xattrs_enq_lock);
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return rc;
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}
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*req = (struct ptlrpc_request *)oit->d.lustre.it_data;
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out:
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down_write(&lli->lli_xattrs_list_rwsem);
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mutex_unlock(&lli->lli_xattrs_enq_lock);
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return 0;
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}
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/**
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* Refill the xattr cache.
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*
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* Fetch and cache the whole of xattrs for @inode, acquiring
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* a read or a write xattr lock depending on operation in @oit.
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* Intent is dropped on exit unless the operation is setxattr.
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*
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* \retval 0 no error occurred
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* \retval -EPROTO network protocol error
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* \retval -ENOMEM not enough memory for the cache
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*/
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static int ll_xattr_cache_refill(struct inode *inode, struct lookup_intent *oit)
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{
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struct ll_sb_info *sbi = ll_i2sbi(inode);
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struct ptlrpc_request *req = NULL;
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const char *xdata, *xval, *xtail, *xvtail;
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struct ll_inode_info *lli = ll_i2info(inode);
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struct mdt_body *body;
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__u32 *xsizes;
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int rc, i;
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rc = ll_xattr_find_get_lock(inode, oit, &req);
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if (rc)
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goto out_no_unlock;
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/* Do we have the data at this point? */
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if (ll_xattr_cache_valid(lli)) {
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ll_stats_ops_tally(sbi, LPROC_LL_GETXATTR_HITS, 1);
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rc = 0;
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goto out_maybe_drop;
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}
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/* Matched but no cache? Cancelled on error by a parallel refill. */
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if (unlikely(!req)) {
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CDEBUG(D_CACHE, "cancelled by a parallel getxattr\n");
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rc = -EIO;
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goto out_maybe_drop;
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}
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if (oit->d.lustre.it_status < 0) {
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CDEBUG(D_CACHE, "getxattr intent returned %d for fid "DFID"\n",
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oit->d.lustre.it_status, PFID(ll_inode2fid(inode)));
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rc = oit->d.lustre.it_status;
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/* xattr data is so large that we don't want to cache it */
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if (rc == -ERANGE)
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rc = -EAGAIN;
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goto out_destroy;
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}
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body = req_capsule_server_get(&req->rq_pill, &RMF_MDT_BODY);
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if (!body) {
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CERROR("no MDT BODY in the refill xattr reply\n");
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rc = -EPROTO;
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goto out_destroy;
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}
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/* do not need swab xattr data */
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xdata = req_capsule_server_sized_get(&req->rq_pill, &RMF_EADATA,
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body->eadatasize);
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xval = req_capsule_server_sized_get(&req->rq_pill, &RMF_EAVALS,
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body->aclsize);
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xsizes = req_capsule_server_sized_get(&req->rq_pill, &RMF_EAVALS_LENS,
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body->max_mdsize * sizeof(__u32));
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if (!xdata || !xval || !xsizes) {
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CERROR("wrong setxattr reply\n");
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rc = -EPROTO;
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goto out_destroy;
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}
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xtail = xdata + body->eadatasize;
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xvtail = xval + body->aclsize;
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CDEBUG(D_CACHE, "caching: xdata=%p xtail=%p\n", xdata, xtail);
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ll_xattr_cache_init(lli);
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for (i = 0; i < body->max_mdsize; i++) {
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CDEBUG(D_CACHE, "caching [%s]=%.*s\n", xdata, *xsizes, xval);
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/* Perform consistency checks: attr names and vals in pill */
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if (!memchr(xdata, 0, xtail - xdata)) {
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CERROR("xattr protocol violation (names are broken)\n");
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rc = -EPROTO;
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} else if (xval + *xsizes > xvtail) {
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CERROR("xattr protocol violation (vals are broken)\n");
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rc = -EPROTO;
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} else if (OBD_FAIL_CHECK(OBD_FAIL_LLITE_XATTR_ENOMEM)) {
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rc = -ENOMEM;
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} else if (!strcmp(xdata, XATTR_NAME_ACL_ACCESS)) {
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/* Filter out ACL ACCESS since it's cached separately */
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CDEBUG(D_CACHE, "not caching %s\n",
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XATTR_NAME_ACL_ACCESS);
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rc = 0;
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} else {
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rc = ll_xattr_cache_add(&lli->lli_xattrs, xdata, xval,
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*xsizes);
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}
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if (rc < 0) {
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ll_xattr_cache_destroy_locked(lli);
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goto out_destroy;
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}
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xdata += strlen(xdata) + 1;
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xval += *xsizes;
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xsizes++;
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}
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if (xdata != xtail || xval != xvtail)
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CERROR("a hole in xattr data\n");
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ll_set_lock_data(sbi->ll_md_exp, inode, oit, NULL);
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goto out_maybe_drop;
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out_maybe_drop:
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ll_intent_drop_lock(oit);
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if (rc != 0)
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up_write(&lli->lli_xattrs_list_rwsem);
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out_no_unlock:
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ptlrpc_req_finished(req);
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return rc;
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out_destroy:
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up_write(&lli->lli_xattrs_list_rwsem);
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ldlm_lock_decref_and_cancel((struct lustre_handle *)
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&oit->d.lustre.it_lock_handle,
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oit->d.lustre.it_lock_mode);
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goto out_no_unlock;
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}
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/**
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* Get an xattr value or list xattrs using the write-through cache.
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*
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* Get the xattr value (@valid has OBD_MD_FLXATTR set) of @name or
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* list xattr names (@valid has OBD_MD_FLXATTRLS set) for @inode.
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* The resulting value/list is stored in @buffer if the former
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* is not larger than @size.
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*
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* \retval 0 no error occurred
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* \retval -EPROTO network protocol error
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* \retval -ENOMEM not enough memory for the cache
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* \retval -ERANGE the buffer is not large enough
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* \retval -ENODATA no such attr or the list is empty
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*/
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int ll_xattr_cache_get(struct inode *inode, const char *name, char *buffer,
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size_t size, __u64 valid)
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{
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struct lookup_intent oit = { .it_op = IT_GETXATTR };
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struct ll_inode_info *lli = ll_i2info(inode);
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int rc = 0;
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LASSERT(!!(valid & OBD_MD_FLXATTR) ^ !!(valid & OBD_MD_FLXATTRLS));
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down_read(&lli->lli_xattrs_list_rwsem);
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if (!ll_xattr_cache_valid(lli)) {
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up_read(&lli->lli_xattrs_list_rwsem);
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rc = ll_xattr_cache_refill(inode, &oit);
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if (rc)
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return rc;
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downgrade_write(&lli->lli_xattrs_list_rwsem);
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} else {
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ll_stats_ops_tally(ll_i2sbi(inode), LPROC_LL_GETXATTR_HITS, 1);
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}
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if (valid & OBD_MD_FLXATTR) {
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struct ll_xattr_entry *xattr;
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rc = ll_xattr_cache_find(&lli->lli_xattrs, name, &xattr);
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if (rc == 0) {
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rc = xattr->xe_vallen;
|
|
/* zero size means we are only requested size in rc */
|
|
if (size != 0) {
|
|
if (size >= xattr->xe_vallen)
|
|
memcpy(buffer, xattr->xe_value,
|
|
xattr->xe_vallen);
|
|
else
|
|
rc = -ERANGE;
|
|
}
|
|
}
|
|
} else if (valid & OBD_MD_FLXATTRLS) {
|
|
rc = ll_xattr_cache_list(&lli->lli_xattrs,
|
|
size ? buffer : NULL, size);
|
|
}
|
|
|
|
goto out;
|
|
out:
|
|
up_read(&lli->lli_xattrs_list_rwsem);
|
|
|
|
return rc;
|
|
}
|