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