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authorJens Axboe <axboe@kernel.dk>2019-02-15 08:43:59 -0700
committerJens Axboe <axboe@kernel.dk>2019-02-15 08:43:59 -0700
commit6fb845f0e78de19eaaf6a2d351702474e44b6a9e (patch)
tree94c6474b38d8f59d8f0de0151053283812e456c6 /fs/iomap.c
parent56d18f62f556b80105e38e7975975cf7465aae3e (diff)
parentd13937116f1e82bf508a6325111b322c30c85eb9 (diff)
Merge tag 'v5.0-rc6' into for-5.1/block
Pull in 5.0-rc6 to avoid a dumb merge conflict with fs/iomap.c. This is needed since io_uring is now based on the block branch, to avoid a conflict between the multi-page bvecs and the bits of io_uring that touch the core block parts. * tag 'v5.0-rc6': (525 commits) Linux 5.0-rc6 x86/mm: Make set_pmd_at() paravirt aware MAINTAINERS: Update the ocores i2c bus driver maintainer, etc blk-mq: remove duplicated definition of blk_mq_freeze_queue Blk-iolatency: warn on negative inflight IO counter blk-iolatency: fix IO hang due to negative inflight counter MAINTAINERS: unify reference to xen-devel list x86/mm/cpa: Fix set_mce_nospec() futex: Handle early deadlock return correctly futex: Fix barrier comment net: dsa: b53: Fix for failure when irq is not defined in dt blktrace: Show requests without sector mips: cm: reprime error cause mips: loongson64: remove unreachable(), fix loongson_poweroff(). sit: check if IPv6 enabled before calling ip6_err_gen_icmpv6_unreach() geneve: should not call rt6_lookup() when ipv6 was disabled KVM: nVMX: unconditionally cancel preemption timer in free_nested (CVE-2019-7221) KVM: x86: work around leak of uninitialized stack contents (CVE-2019-7222) kvm: fix kvm_ioctl_create_device() reference counting (CVE-2019-6974) signal: Better detection of synchronous signals ...
Diffstat (limited to 'fs/iomap.c')
-rw-r--r--fs/iomap.c37
1 files changed, 30 insertions, 7 deletions
diff --git a/fs/iomap.c b/fs/iomap.c
index 0c350e658b7f..6982d3d2bcc6 100644
--- a/fs/iomap.c
+++ b/fs/iomap.c
@@ -116,6 +116,12 @@ iomap_page_create(struct inode *inode, struct page *page)
atomic_set(&iop->read_count, 0);
atomic_set(&iop->write_count, 0);
bitmap_zero(iop->uptodate, PAGE_SIZE / SECTOR_SIZE);
+
+ /*
+ * migrate_page_move_mapping() assumes that pages with private data have
+ * their count elevated by 1.
+ */
+ get_page(page);
set_page_private(page, (unsigned long)iop);
SetPagePrivate(page);
return iop;
@@ -132,6 +138,7 @@ iomap_page_release(struct page *page)
WARN_ON_ONCE(atomic_read(&iop->write_count));
ClearPagePrivate(page);
set_page_private(page, 0);
+ put_page(page);
kfree(iop);
}
@@ -570,8 +577,10 @@ iomap_migrate_page(struct address_space *mapping, struct page *newpage,
if (page_has_private(page)) {
ClearPagePrivate(page);
+ get_page(newpage);
set_page_private(newpage, page_private(page));
set_page_private(page, 0);
+ put_page(page);
SetPagePrivate(newpage);
}
@@ -1806,6 +1815,7 @@ iomap_dio_rw(struct kiocb *iocb, struct iov_iter *iter,
loff_t pos = iocb->ki_pos, start = pos;
loff_t end = iocb->ki_pos + count - 1, ret = 0;
unsigned int flags = IOMAP_DIRECT;
+ bool wait_for_completion = is_sync_kiocb(iocb);
struct blk_plug plug;
struct iomap_dio *dio;
@@ -1825,7 +1835,6 @@ iomap_dio_rw(struct kiocb *iocb, struct iov_iter *iter,
dio->end_io = end_io;
dio->error = 0;
dio->flags = 0;
- dio->wait_for_completion = is_sync_kiocb(iocb);
dio->submit.iter = iter;
dio->submit.waiter = current;
@@ -1880,7 +1889,7 @@ iomap_dio_rw(struct kiocb *iocb, struct iov_iter *iter,
dio_warn_stale_pagecache(iocb->ki_filp);
ret = 0;
- if (iov_iter_rw(iter) == WRITE && !dio->wait_for_completion &&
+ if (iov_iter_rw(iter) == WRITE && !wait_for_completion &&
!inode->i_sb->s_dio_done_wq) {
ret = sb_init_dio_done_wq(inode->i_sb);
if (ret < 0)
@@ -1896,7 +1905,7 @@ iomap_dio_rw(struct kiocb *iocb, struct iov_iter *iter,
if (ret <= 0) {
/* magic error code to fall back to buffered I/O */
if (ret == -ENOTBLK) {
- dio->wait_for_completion = true;
+ wait_for_completion = true;
ret = 0;
}
break;
@@ -1918,8 +1927,24 @@ iomap_dio_rw(struct kiocb *iocb, struct iov_iter *iter,
if (dio->flags & IOMAP_DIO_WRITE_FUA)
dio->flags &= ~IOMAP_DIO_NEED_SYNC;
+ /*
+ * We are about to drop our additional submission reference, which
+ * might be the last reference to the dio. There are three three
+ * different ways we can progress here:
+ *
+ * (a) If this is the last reference we will always complete and free
+ * the dio ourselves.
+ * (b) If this is not the last reference, and we serve an asynchronous
+ * iocb, we must never touch the dio after the decrement, the
+ * I/O completion handler will complete and free it.
+ * (c) If this is not the last reference, but we serve a synchronous
+ * iocb, the I/O completion handler will wake us up on the drop
+ * of the final reference, and we will complete and free it here
+ * after we got woken by the I/O completion handler.
+ */
+ dio->wait_for_completion = wait_for_completion;
if (!atomic_dec_and_test(&dio->ref)) {
- if (!dio->wait_for_completion)
+ if (!wait_for_completion)
return -EIOCBQUEUED;
for (;;) {
@@ -1936,9 +1961,7 @@ iomap_dio_rw(struct kiocb *iocb, struct iov_iter *iter,
__set_current_state(TASK_RUNNING);
}
- ret = iomap_dio_complete(dio);
-
- return ret;
+ return iomap_dio_complete(dio);
out_free_dio:
kfree(dio);