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authorJan Kara <jack@suse.cz>2017-02-10 08:50:56 +0300
committerTheodore Ts'o <tytso@mit.edu>2017-02-10 08:50:56 +0300
commitd9b22cf9f5466a057f2a4f1e642b469fa9d73117 (patch)
tree61fb0bf8028df1bd79ea44c4376b213dcd70249a /fs/ext4
parent168316db3583253b9e5d46392e5b9d03d531406f (diff)
downloadlinux-d9b22cf9f5466a057f2a4f1e642b469fa9d73117.tar.xz
ext4: fix stripe-unaligned allocations
When a filesystem is created using: mkfs.ext4 -b 4096 -E stride=512 <dev> and we try to allocate 64MB extent, we will end up directly in ext4_mb_complex_scan_group(). This is because the request is detected as power-of-two allocation (so we start in ext4_mb_regular_allocator() with ac_criteria == 0) however the check before ext4_mb_simple_scan_group() refuses the direct buddy scan because the allocation request is too large. Since cr == 0, the check whether we should use ext4_mb_scan_aligned() fails as well and we fall back to ext4_mb_complex_scan_group(). Fix the problem by checking for upper limit on power-of-two requests directly when detecting them. Reported-by: Ross Zwisler <ross.zwisler@linux.intel.com> Signed-off-by: Jan Kara <jack@suse.cz> Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Diffstat (limited to 'fs/ext4')
-rw-r--r--fs/ext4/mballoc.c6
1 files changed, 4 insertions, 2 deletions
diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c
index f513f273ff89..10c62de642c6 100644
--- a/fs/ext4/mballoc.c
+++ b/fs/ext4/mballoc.c
@@ -2146,8 +2146,10 @@ ext4_mb_regular_allocator(struct ext4_allocation_context *ac)
* We search using buddy data only if the order of the request
* is greater than equal to the sbi_s_mb_order2_reqs
* You can tune it via /sys/fs/ext4/<partition>/mb_order2_req
+ * We also support searching for power-of-two requests only for
+ * requests upto maximum buddy size we have constructed.
*/
- if (i >= sbi->s_mb_order2_reqs) {
+ if (i >= sbi->s_mb_order2_reqs && i <= sb->s_blocksize_bits + 2) {
/*
* This should tell if fe_len is exactly power of 2
*/
@@ -2217,7 +2219,7 @@ repeat:
}
ac->ac_groups_scanned++;
- if (cr == 0 && ac->ac_2order < sb->s_blocksize_bits+2)
+ if (cr == 0)
ext4_mb_simple_scan_group(ac, &e4b);
else if (cr == 1 && sbi->s_stripe &&
!(ac->ac_g_ex.fe_len % sbi->s_stripe))