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Diffstat (limited to 'fs/xfs/xfs_mount.c')
-rw-r--r--fs/xfs/xfs_mount.c15
1 files changed, 14 insertions, 1 deletions
diff --git a/fs/xfs/xfs_mount.c b/fs/xfs/xfs_mount.c
index cb1e2c4702c3..bdfee1943796 100644
--- a/fs/xfs/xfs_mount.c
+++ b/fs/xfs/xfs_mount.c
@@ -1188,6 +1188,7 @@ xfs_mod_fdblocks(
int64_t lcounter;
long long res_used;
s32 batch;
+ uint64_t set_aside;
if (delta > 0) {
/*
@@ -1227,8 +1228,20 @@ xfs_mod_fdblocks(
else
batch = XFS_FDBLOCKS_BATCH;
+ /*
+ * Set aside allocbt blocks because these blocks are tracked as free
+ * space but not available for allocation. Technically this means that a
+ * single reservation cannot consume all remaining free space, but the
+ * ratio of allocbt blocks to usable free blocks should be rather small.
+ * The tradeoff without this is that filesystems that maintain high
+ * perag block reservations can over reserve physical block availability
+ * and fail physical allocation, which leads to much more serious
+ * problems (i.e. transaction abort, pagecache discards, etc.) than
+ * slightly premature -ENOSPC.
+ */
+ set_aside = mp->m_alloc_set_aside + atomic64_read(&mp->m_allocbt_blks);
percpu_counter_add_batch(&mp->m_fdblocks, delta, batch);
- if (__percpu_counter_compare(&mp->m_fdblocks, mp->m_alloc_set_aside,
+ if (__percpu_counter_compare(&mp->m_fdblocks, set_aside,
XFS_FDBLOCKS_BATCH) >= 0) {
/* we had space! */
return 0;