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path: root/fs/xfs/xfs_fsops.c
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Diffstat (limited to 'fs/xfs/xfs_fsops.c')
-rw-r--r--fs/xfs/xfs_fsops.c105
1 files changed, 60 insertions, 45 deletions
diff --git a/fs/xfs/xfs_fsops.c b/fs/xfs/xfs_fsops.c
index b4d75825ae37..7191c3878b4a 100644
--- a/fs/xfs/xfs_fsops.c
+++ b/fs/xfs/xfs_fsops.c
@@ -667,8 +667,11 @@ xfs_reserve_blocks(
__uint64_t *inval,
xfs_fsop_resblks_t *outval)
{
- __int64_t lcounter, delta, fdblks_delta;
+ __int64_t lcounter, delta;
+ __int64_t fdblks_delta = 0;
__uint64_t request;
+ __int64_t free;
+ int error = 0;
/* If inval is null, report current values and return */
if (inval == (__uint64_t *)NULL) {
@@ -682,24 +685,23 @@ xfs_reserve_blocks(
request = *inval;
/*
- * With per-cpu counters, this becomes an interesting
- * problem. we needto work out if we are freeing or allocation
- * blocks first, then we can do the modification as necessary.
+ * With per-cpu counters, this becomes an interesting problem. we need
+ * to work out if we are freeing or allocation blocks first, then we can
+ * do the modification as necessary.
*
- * We do this under the m_sb_lock so that if we are near
- * ENOSPC, we will hold out any changes while we work out
- * what to do. This means that the amount of free space can
- * change while we do this, so we need to retry if we end up
- * trying to reserve more space than is available.
+ * We do this under the m_sb_lock so that if we are near ENOSPC, we will
+ * hold out any changes while we work out what to do. This means that
+ * the amount of free space can change while we do this, so we need to
+ * retry if we end up trying to reserve more space than is available.
*/
-retry:
spin_lock(&mp->m_sb_lock);
/*
* If our previous reservation was larger than the current value,
- * then move any unused blocks back to the free pool.
+ * then move any unused blocks back to the free pool. Modify the resblks
+ * counters directly since we shouldn't have any problems unreserving
+ * space.
*/
- fdblks_delta = 0;
if (mp->m_resblks > request) {
lcounter = mp->m_resblks_avail - request;
if (lcounter > 0) { /* release unused blocks */
@@ -707,54 +709,67 @@ retry:
mp->m_resblks_avail -= lcounter;
}
mp->m_resblks = request;
- } else {
- __int64_t free;
+ if (fdblks_delta) {
+ spin_unlock(&mp->m_sb_lock);
+ error = xfs_mod_fdblocks(mp, fdblks_delta, 0);
+ spin_lock(&mp->m_sb_lock);
+ }
+
+ goto out;
+ }
+ /*
+ * If the request is larger than the current reservation, reserve the
+ * blocks before we update the reserve counters. Sample m_fdblocks and
+ * perform a partial reservation if the request exceeds free space.
+ */
+ error = -ENOSPC;
+ do {
free = percpu_counter_sum(&mp->m_fdblocks) -
XFS_ALLOC_SET_ASIDE(mp);
if (!free)
- goto out; /* ENOSPC and fdblks_delta = 0 */
+ break;
delta = request - mp->m_resblks;
lcounter = free - delta;
- if (lcounter < 0) {
+ if (lcounter < 0)
/* We can't satisfy the request, just get what we can */
- mp->m_resblks += free;
- mp->m_resblks_avail += free;
- fdblks_delta = -free;
- } else {
- fdblks_delta = -delta;
- mp->m_resblks = request;
- mp->m_resblks_avail += delta;
- }
- }
-out:
- if (outval) {
- outval->resblks = mp->m_resblks;
- outval->resblks_avail = mp->m_resblks_avail;
- }
- spin_unlock(&mp->m_sb_lock);
+ fdblks_delta = free;
+ else
+ fdblks_delta = delta;
- if (fdblks_delta) {
/*
- * If we are putting blocks back here, m_resblks_avail is
- * already at its max so this will put it in the free pool.
- *
- * If we need space, we'll either succeed in getting it
- * from the free block count or we'll get an enospc. If
- * we get a ENOSPC, it means things changed while we were
- * calculating fdblks_delta and so we should try again to
- * see if there is anything left to reserve.
+ * We'll either succeed in getting space from the free block
+ * count or we'll get an ENOSPC. If we get a ENOSPC, it means
+ * things changed while we were calculating fdblks_delta and so
+ * we should try again to see if there is anything left to
+ * reserve.
*
* Don't set the reserved flag here - we don't want to reserve
* the extra reserve blocks from the reserve.....
*/
- int error;
- error = xfs_mod_fdblocks(mp, fdblks_delta, 0);
- if (error == -ENOSPC)
- goto retry;
+ spin_unlock(&mp->m_sb_lock);
+ error = xfs_mod_fdblocks(mp, -fdblks_delta, 0);
+ spin_lock(&mp->m_sb_lock);
+ } while (error == -ENOSPC);
+
+ /*
+ * Update the reserve counters if blocks have been successfully
+ * allocated.
+ */
+ if (!error && fdblks_delta) {
+ mp->m_resblks += fdblks_delta;
+ mp->m_resblks_avail += fdblks_delta;
}
- return 0;
+
+out:
+ if (outval) {
+ outval->resblks = mp->m_resblks;
+ outval->resblks_avail = mp->m_resblks_avail;
+ }
+
+ spin_unlock(&mp->m_sb_lock);
+ return error;
}
int