bcachefs: Use memalloc_nofs_save() in bch2_read_endio()

This solves a problematic memory allocation in bch2_bio_uncompress() ->
vmap().

Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>

diff --git a/fs/bcachefs/io.c b/fs/bcachefs/io.c
index e13382fc5b01809fc4b792aedf0c8a0928b2138e..f80b3ce4c7d77f6bd63655bc40eb99c8f475b7f6 100644 (file)
--- a/fs/bcachefs/io.c
+++ b/fs/bcachefs/io.c
@@ -1808,8 +1808,11 @@ static void __bch2_read_endio(struct work_struct *work)
        struct bvec_iter dst_iter = rbio->bvec_iter;
        struct bch_extent_crc_unpacked crc = rbio->pick.crc;
        struct nonce nonce = extent_nonce(rbio->version, crc);
+       unsigned nofs_flags;
        struct bch_csum csum;
 
+       nofs_flags = memalloc_nofs_save();
+
        /* Reset iterator for checksumming and copying bounced data: */
        if (rbio->bounce) {
                src->bi_iter.bi_size            = crc.compressed_size << 9;
@@ -1874,6 +1877,8 @@ nodecode:
                rbio = bch2_rbio_free(rbio);
                bch2_rbio_done(rbio);
        }
+out:
+       memalloc_nofs_restore(nofs_flags);
        return;
 csum_err:
        /*
@@ -1884,7 +1889,7 @@ csum_err:
        if (!rbio->bounce && (rbio->flags & BCH_READ_USER_MAPPED)) {
                rbio->flags |= BCH_READ_MUST_BOUNCE;
                bch2_rbio_error(rbio, READ_RETRY, BLK_STS_IOERR);
-               return;
+               goto out;
        }
 
        bch2_dev_inum_io_error(ca, rbio->read_pos.inode, (u64) rbio->bvec_iter.bi_sector,
@@ -1892,12 +1897,12 @@ csum_err:
                rbio->pick.crc.csum.hi, rbio->pick.crc.csum.lo,
                csum.hi, csum.lo, crc.csum_type);
        bch2_rbio_error(rbio, READ_RETRY_AVOID, BLK_STS_IOERR);
-       return;
+       goto out;
 decompression_err:
        bch_err_inum_ratelimited(c, rbio->read_pos.inode,
                                 "decompression error");
        bch2_rbio_error(rbio, READ_ERR, BLK_STS_IOERR);
-       return;
+       goto out;
 }
 
 static void bch2_read_endio(struct bio *bio)