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bcachefs: Wrap write path in memalloc_nofs_save()

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This fixes a lockdep splat where we're allocating memory with vmalloc in
the compression bounce path, which doesn't always obey GFP_NOFS.

Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
This commit is contained in:
Kent Overstreet 2020-07-20 13:00:15 -04:00 committed by Kent Overstreet
parent f621e1521c
commit e8306e3b4c
2 changed files with 10 additions and 8 deletions
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6
fs/bcachefs/compress.c
View File

@ -7,7 +7,6 @@
#include "super-io.h"
#include <linux/lz4.h>
#include <linux/sched/mm.h>
#include <linux/zlib.h>
#include <linux/zstd.h>
@ -64,7 +63,7 @@ static struct bbuf __bio_map_or_bounce(struct bch_fs *c, struct bio *bio,
struct bbuf ret;
struct bio_vec bv;
struct bvec_iter iter;
unsigned nr_pages = 0, flags;
unsigned nr_pages = 0;
struct page *stack_pages[16];
struct page **pages = NULL;
void *data;
@ -104,10 +103,7 @@ static struct bbuf __bio_map_or_bounce(struct bch_fs *c, struct bio *bio,
__bio_for_each_segment(bv, bio, iter, start)
pages[nr_pages++] = bv.bv_page;
flags = memalloc_nofs_save();
data = vmap(pages, nr_pages, VM_MAP, PAGE_KERNEL);
memalloc_nofs_restore(flags);
if (pages != stack_pages)
kfree(pages);

12
fs/bcachefs/io.c
View File

@ -32,6 +32,7 @@
#include <linux/blkdev.h>
#include <linux/random.h>
#include <linux/sched/mm.h>
#ifndef CONFIG_BCACHEFS_NO_LATENCY_ACCT
@ -1052,7 +1053,10 @@ static void __bch2_write(struct closure *cl)
struct write_point *wp;
struct bio *bio;
bool skip_put = true;
unsigned nofs_flags;
int ret;
nofs_flags = memalloc_nofs_save();
again:
memset(&op->failed, 0, sizeof(op->failed));
@ -1134,13 +1138,15 @@ again:
if (!skip_put)
continue_at(cl, bch2_write_index, index_update_wq(op));
out:
memalloc_nofs_restore(nofs_flags);
return;
err:
op->error = ret;
op->flags |= BCH_WRITE_DONE;
continue_at(cl, bch2_write_index, index_update_wq(op));
return;
goto out;
flush_io:
/*
* If the write can't all be submitted at once, we generally want to
@ -1151,7 +1157,7 @@ flush_io:
*/
if (current->flags & PF_WQ_WORKER) {
continue_at(cl, bch2_write_index, index_update_wq(op));
return;
goto out;
}
closure_sync(cl);
@ -1162,7 +1168,7 @@ flush_io:
if (op->error) {
op->flags |= BCH_WRITE_DONE;
continue_at_nobarrier(cl, bch2_write_done, NULL);
return;
goto out;
}
}