qemu

qed-table.c (5683B)

---

 /*
  * QEMU Enhanced Disk Format Table I/O
  *
  * Copyright IBM, Corp. 2010
  *
  * Authors:
  *  Stefan Hajnoczi   <stefanha@linux.vnet.ibm.com>
  *  Anthony Liguori   <aliguori@us.ibm.com>
  *
  * This work is licensed under the terms of the GNU LGPL, version 2 or later.
  * See the COPYING.LIB file in the top-level directory.
  *
  */
 
 #include "qemu/osdep.h"
 #include "trace.h"
 #include "qemu/sockets.h" /* for EINPROGRESS on Windows */
 #include "qed.h"
 #include "qemu/bswap.h"
 #include "qemu/memalign.h"
 
 /* Called with table_lock held.  */
 static int coroutine_fn qed_read_table(BDRVQEDState *s, uint64_t offset,
                                        QEDTable *table)
 {
     unsigned int bytes = s->header.cluster_size * s->header.table_size;
 
     int noffsets;
     int i, ret;
 
     trace_qed_read_table(s, offset, table);
 
     qemu_co_mutex_unlock(&s->table_lock);
     ret = bdrv_co_pread(s->bs->file, offset, bytes, table->offsets, 0);
     qemu_co_mutex_lock(&s->table_lock);
     if (ret < 0) {
         goto out;
     }
 
     /* Byteswap offsets */
     noffsets = bytes / sizeof(uint64_t);
     for (i = 0; i < noffsets; i++) {
         table->offsets[i] = le64_to_cpu(table->offsets[i]);
     }
 
     ret = 0;
 out:
     /* Completion */
     trace_qed_read_table_cb(s, table, ret);
     return ret;
 }
 
 /**
  * Write out an updated part or all of a table
  *
  * @s:          QED state
  * @offset:     Offset of table in image file, in bytes
  * @table:      Table
  * @index:      Index of first element
  * @n:          Number of elements
  * @flush:      Whether or not to sync to disk
  *
  * Called with table_lock held.
  */
 static int coroutine_fn qed_write_table(BDRVQEDState *s, uint64_t offset,
                                         QEDTable *table, unsigned int index,
                                         unsigned int n, bool flush)
 {
     unsigned int sector_mask = BDRV_SECTOR_SIZE / sizeof(uint64_t) - 1;
     unsigned int start, end, i;
     QEDTable *new_table;
     size_t len_bytes;
     int ret;
 
     trace_qed_write_table(s, offset, table, index, n);
 
     /* Calculate indices of the first and one after last elements */
     start = index & ~sector_mask;
     end = (index + n + sector_mask) & ~sector_mask;
 
     len_bytes = (end - start) * sizeof(uint64_t);
 
     new_table = qemu_blockalign(s->bs, len_bytes);
 
     /* Byteswap table */
     for (i = start; i < end; i++) {
         uint64_t le_offset = cpu_to_le64(table->offsets[i]);
         new_table->offsets[i - start] = le_offset;
     }
 
     /* Adjust for offset into table */
     offset += start * sizeof(uint64_t);
 
     qemu_co_mutex_unlock(&s->table_lock);
     ret = bdrv_co_pwrite(s->bs->file, offset, len_bytes, new_table->offsets, 0);
     qemu_co_mutex_lock(&s->table_lock);
     trace_qed_write_table_cb(s, table, flush, ret);
     if (ret < 0) {
         goto out;
     }
 
     if (flush) {
         ret = bdrv_co_flush(s->bs);
         if (ret < 0) {
             goto out;
         }
     }
 
     ret = 0;
 out:
     qemu_vfree(new_table);
     return ret;
 }
 
 int coroutine_fn qed_read_l1_table_sync(BDRVQEDState *s)
 {
     return qed_read_table(s, s->header.l1_table_offset, s->l1_table);
 }
 
 /* Called with table_lock held.  */
 int coroutine_fn qed_write_l1_table(BDRVQEDState *s, unsigned int index,
                                     unsigned int n)
 {
     BLKDBG_EVENT(s->bs->file, BLKDBG_L1_UPDATE);
     return qed_write_table(s, s->header.l1_table_offset,
                            s->l1_table, index, n, false);
 }
 
 int coroutine_fn qed_write_l1_table_sync(BDRVQEDState *s, unsigned int index,
                                          unsigned int n)
 {
     return qed_write_l1_table(s, index, n);
 }
 
 /* Called with table_lock held.  */
 int coroutine_fn qed_read_l2_table(BDRVQEDState *s, QEDRequest *request,
                                    uint64_t offset)
 {
     int ret;
 
     qed_unref_l2_cache_entry(request->l2_table);
 
     /* Check for cached L2 entry */
     request->l2_table = qed_find_l2_cache_entry(&s->l2_cache, offset);
     if (request->l2_table) {
         return 0;
     }
 
     request->l2_table = qed_alloc_l2_cache_entry(&s->l2_cache);
     request->l2_table->table = qed_alloc_table(s);
 
     BLKDBG_EVENT(s->bs->file, BLKDBG_L2_LOAD);
     ret = qed_read_table(s, offset, request->l2_table->table);
 
     if (ret) {
         /* can't trust loaded L2 table anymore */
         qed_unref_l2_cache_entry(request->l2_table);
         request->l2_table = NULL;
     } else {
         request->l2_table->offset = offset;
 
         qed_commit_l2_cache_entry(&s->l2_cache, request->l2_table);
 
         /* This is guaranteed to succeed because we just committed the entry
          * to the cache.
          */
         request->l2_table = qed_find_l2_cache_entry(&s->l2_cache, offset);
         assert(request->l2_table != NULL);
     }
 
     return ret;
 }
 
 int coroutine_fn qed_read_l2_table_sync(BDRVQEDState *s, QEDRequest *request,
                                         uint64_t offset)
 {
     return qed_read_l2_table(s, request, offset);
 }
 
 /* Called with table_lock held.  */
 int coroutine_fn qed_write_l2_table(BDRVQEDState *s, QEDRequest *request,
                                     unsigned int index, unsigned int n,
                                     bool flush)
 {
     BLKDBG_EVENT(s->bs->file, BLKDBG_L2_UPDATE);
     return qed_write_table(s, request->l2_table->offset,
                            request->l2_table->table, index, n, flush);
 }
 
 int coroutine_fn qed_write_l2_table_sync(BDRVQEDState *s, QEDRequest *request,
                                          unsigned int index, unsigned int n,
                                          bool flush)
 {
     return qed_write_l2_table(s, request, index, n, flush);
 }