ext4: convert EXT4_B2C(sbi->s_stripe) users to EXT4_NUM_B2C

Although we have checks to make sure s_stripe is a multiple of cluster
size, in case we accidentally end up with a scenario where this is not
the case, use EXT4_NUM_B2C() so that we don't end up with unexpected
cases where EXT4_B2C(stripe) becomes 0.

Also make the is_stripe_aligned check in regular_allocator a bit more
robust while we are at it. This should ideally have no functional change
unless we have a bug somewhere causing (stripe % cluster_size != 0)

Reviewed-by: Kemeng Shi <shikemeng@huaweicloud.com>
Signed-off-by: Ojaswin Mujoo <ojaswin@linux.ibm.com>
Reviewed-by: Ritesh Harjani (IBM) <ritesh.list@gmail.com>
Link: https://patch.msgid.link/e0c0a3b58a40935a1361f668851d041575861411.1725002410.git.ojaswin@linux.ibm.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>

diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c
index bf9ba7effbd59dbb29c4e4deb3733afd4cdb50f5..d73e38323879ce217ba650e37197e7408666d877 100644 (file)
--- a/fs/ext4/mballoc.c
+++ b/fs/ext4/mballoc.c
@@ -2356,7 +2356,7 @@ int ext4_mb_find_by_goal(struct ext4_allocation_context *ac,
        ex.fe_logical = 0xDEADFA11; /* debug value */
 
        if (max >= ac->ac_g_ex.fe_len &&
-           ac->ac_g_ex.fe_len == EXT4_B2C(sbi, sbi->s_stripe)) {
+           ac->ac_g_ex.fe_len == EXT4_NUM_B2C(sbi, sbi->s_stripe)) {
                ext4_fsblk_t start;
 
                start = ext4_grp_offs_to_block(ac->ac_sb, &ex);
@@ -2553,7 +2553,7 @@ void ext4_mb_scan_aligned(struct ext4_allocation_context *ac,
        do_div(a, sbi->s_stripe);
        i = (a * sbi->s_stripe) - first_group_block;
 
-       stripe = EXT4_B2C(sbi, sbi->s_stripe);
+       stripe = EXT4_NUM_B2C(sbi, sbi->s_stripe);
        i = EXT4_B2C(sbi, i);
        while (i < EXT4_CLUSTERS_PER_GROUP(sb)) {
                if (!mb_test_bit(i, bitmap)) {
@@ -2928,9 +2928,11 @@ repeat:
                        if (cr == CR_POWER2_ALIGNED)
                                ext4_mb_simple_scan_group(ac, &e4b);
                        else {
-                               bool is_stripe_aligned = sbi->s_stripe &&
+                               bool is_stripe_aligned =
+                                       (sbi->s_stripe >=
+                                        sbi->s_cluster_ratio) &&
                                        !(ac->ac_g_ex.fe_len %
-                                         EXT4_B2C(sbi, sbi->s_stripe));
+                                         EXT4_NUM_B2C(sbi, sbi->s_stripe));
 
                                if ((cr == CR_GOAL_LEN_FAST ||
                                     cr == CR_BEST_AVAIL_LEN) &&
@@ -3706,7 +3708,7 @@ int ext4_mb_init(struct super_block *sb)
         */
        if (sbi->s_stripe > 1) {
                sbi->s_mb_group_prealloc = roundup(
-                       sbi->s_mb_group_prealloc, EXT4_B2C(sbi, sbi->s_stripe));
+                       sbi->s_mb_group_prealloc, EXT4_NUM_B2C(sbi, sbi->s_stripe));
        }
 
        sbi->s_locality_groups = alloc_percpu(struct ext4_locality_group);