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Diffstat (limited to 'fs/ext4/mballoc.c')
-rw-r--r--fs/ext4/mballoc.c26
1 files changed, 25 insertions, 1 deletions
diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c
index 9f12f29bc346..9e06334771a3 100644
--- a/fs/ext4/mballoc.c
+++ b/fs/ext4/mballoc.c
@@ -4104,6 +4104,15 @@ ext4_mb_normalize_request(struct ext4_allocation_context *ac,
size = size >> bsbits;
start = start_off >> bsbits;
+ /*
+ * For tiny groups (smaller than 8MB) the chosen allocation
+ * alignment may be larger than group size. Make sure the
+ * alignment does not move allocation to a different group which
+ * makes mballoc fail assertions later.
+ */
+ start = max(start, rounddown(ac->ac_o_ex.fe_logical,
+ (ext4_lblk_t)EXT4_BLOCKS_PER_GROUP(ac->ac_sb)));
+
/* don't cover already allocated blocks in selected range */
if (ar->pleft && start <= ar->lleft) {
size -= ar->lleft + 1 - start;
@@ -4176,7 +4185,22 @@ ext4_mb_normalize_request(struct ext4_allocation_context *ac,
}
rcu_read_unlock();
- if (start + size <= ac->ac_o_ex.fe_logical &&
+ /*
+ * In this function "start" and "size" are normalized for better
+ * alignment and length such that we could preallocate more blocks.
+ * This normalization is done such that original request of
+ * ac->ac_o_ex.fe_logical & fe_len should always lie within "start" and
+ * "size" boundaries.
+ * (Note fe_len can be relaxed since FS block allocation API does not
+ * provide gurantee on number of contiguous blocks allocation since that
+ * depends upon free space left, etc).
+ * In case of inode pa, later we use the allocated blocks
+ * [pa_start + fe_logical - pa_lstart, fe_len/size] from the preallocated
+ * range of goal/best blocks [start, size] to put it at the
+ * ac_o_ex.fe_logical extent of this inode.
+ * (See ext4_mb_use_inode_pa() for more details)
+ */
+ if (start + size <= ac->ac_o_ex.fe_logical ||
start > ac->ac_o_ex.fe_logical) {
ext4_msg(ac->ac_sb, KERN_ERR,
"start %lu, size %lu, fe_logical %lu",