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authorLinus Torvalds <torvalds@linux-foundation.org>2017-07-03 10:34:51 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2017-07-03 10:34:51 -0700
commitc6b1e36c8fa04a6680c44fe0321d0370400e90b6 (patch)
tree5110f0639bfa803baa8d213cb21efe37beeaf742 /mm/filemap.c
parent81e3e044897b0875a52953b3fb6241a33428e4f9 (diff)
parenta84ebb837b419787c2ece74efa566c998929cead (diff)
Merge branch 'for-4.13/block' of git://git.kernel.dk/linux-block
Pull core block/IO updates from Jens Axboe: "This is the main pull request for the block layer for 4.13. Not a huge round in terms of features, but there's a lot of churn related to some core cleanups. Note this depends on the UUID tree pull request, that Christoph already sent out. This pull request contains: - A series from Christoph, unifying the error/stats codes in the block layer. We now use blk_status_t everywhere, instead of using different schemes for different places. - Also from Christoph, some cleanups around request allocation and IO scheduler interactions in blk-mq. - And yet another series from Christoph, cleaning up how we handle and do bounce buffering in the block layer. - A blk-mq debugfs series from Bart, further improving on the support we have for exporting internal information to aid debugging IO hangs or stalls. - Also from Bart, a series that cleans up the request initialization differences across types of devices. - A series from Goldwyn Rodrigues, allowing the block layer to return failure if we will block and the user asked for non-blocking. - Patch from Hannes for supporting setting loop devices block size to that of the underlying device. - Two series of patches from Javier, fixing various issues with lightnvm, particular around pblk. - A series from me, adding support for write hints. This comes with NVMe support as well, so applications can help guide data placement on flash to improve performance, latencies, and write amplification. - A series from Ming, improving and hardening blk-mq support for stopping/starting and quiescing hardware queues. - Two pull requests for NVMe updates. Nothing major on the feature side, but lots of cleanups and bug fixes. From the usual crew. - A series from Neil Brown, greatly improving the bio rescue set support. Most notably, this kills the bio rescue work queues, if we don't really need them. - Lots of other little bug fixes that are all over the place" * 'for-4.13/block' of git://git.kernel.dk/linux-block: (217 commits) lightnvm: pblk: set line bitmap check under debug lightnvm: pblk: verify that cache read is still valid lightnvm: pblk: add initialization check lightnvm: pblk: remove target using async. I/Os lightnvm: pblk: use vmalloc for GC data buffer lightnvm: pblk: use right metadata buffer for recovery lightnvm: pblk: schedule if data is not ready lightnvm: pblk: remove unused return variable lightnvm: pblk: fix double-free on pblk init lightnvm: pblk: fix bad le64 assignations nvme: Makefile: remove dead build rule blk-mq: map all HWQ also in hyperthreaded system nvmet-rdma: register ib_client to not deadlock in device removal nvme_fc: fix error recovery on link down. nvmet_fc: fix crashes on bad opcodes nvme_fc: Fix crash when nvme controller connection fails. nvme_fc: replace ioabort msleep loop with completion nvme_fc: fix double calls to nvme_cleanup_cmd() nvme-fabrics: verify that a controller returns the correct NQN nvme: simplify nvme_dev_attrs_are_visible ...
Diffstat (limited to 'mm/filemap.c')
-rw-r--r--mm/filemap.c64
1 files changed, 57 insertions, 7 deletions
diff --git a/mm/filemap.c b/mm/filemap.c
index 6f1be573a5e6..742034e56100 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -376,6 +376,38 @@ int filemap_flush(struct address_space *mapping)
}
EXPORT_SYMBOL(filemap_flush);
+/**
+ * filemap_range_has_page - check if a page exists in range.
+ * @mapping: address space within which to check
+ * @start_byte: offset in bytes where the range starts
+ * @end_byte: offset in bytes where the range ends (inclusive)
+ *
+ * Find at least one page in the range supplied, usually used to check if
+ * direct writing in this range will trigger a writeback.
+ */
+bool filemap_range_has_page(struct address_space *mapping,
+ loff_t start_byte, loff_t end_byte)
+{
+ pgoff_t index = start_byte >> PAGE_SHIFT;
+ pgoff_t end = end_byte >> PAGE_SHIFT;
+ struct pagevec pvec;
+ bool ret;
+
+ if (end_byte < start_byte)
+ return false;
+
+ if (mapping->nrpages == 0)
+ return false;
+
+ pagevec_init(&pvec, 0);
+ if (!pagevec_lookup(&pvec, mapping, index, 1))
+ return false;
+ ret = (pvec.pages[0]->index <= end);
+ pagevec_release(&pvec);
+ return ret;
+}
+EXPORT_SYMBOL(filemap_range_has_page);
+
static int __filemap_fdatawait_range(struct address_space *mapping,
loff_t start_byte, loff_t end_byte)
{
@@ -2038,10 +2070,17 @@ generic_file_read_iter(struct kiocb *iocb, struct iov_iter *iter)
loff_t size;
size = i_size_read(inode);
- retval = filemap_write_and_wait_range(mapping, iocb->ki_pos,
- iocb->ki_pos + count - 1);
- if (retval < 0)
- goto out;
+ if (iocb->ki_flags & IOCB_NOWAIT) {
+ if (filemap_range_has_page(mapping, iocb->ki_pos,
+ iocb->ki_pos + count - 1))
+ return -EAGAIN;
+ } else {
+ retval = filemap_write_and_wait_range(mapping,
+ iocb->ki_pos,
+ iocb->ki_pos + count - 1);
+ if (retval < 0)
+ goto out;
+ }
file_accessed(file);
@@ -2642,6 +2681,9 @@ inline ssize_t generic_write_checks(struct kiocb *iocb, struct iov_iter *from)
pos = iocb->ki_pos;
+ if ((iocb->ki_flags & IOCB_NOWAIT) && !(iocb->ki_flags & IOCB_DIRECT))
+ return -EINVAL;
+
if (limit != RLIM_INFINITY) {
if (iocb->ki_pos >= limit) {
send_sig(SIGXFSZ, current, 0);
@@ -2710,9 +2752,17 @@ generic_file_direct_write(struct kiocb *iocb, struct iov_iter *from)
write_len = iov_iter_count(from);
end = (pos + write_len - 1) >> PAGE_SHIFT;
- written = filemap_write_and_wait_range(mapping, pos, pos + write_len - 1);
- if (written)
- goto out;
+ if (iocb->ki_flags & IOCB_NOWAIT) {
+ /* If there are pages to writeback, return */
+ if (filemap_range_has_page(inode->i_mapping, pos,
+ pos + iov_iter_count(from)))
+ return -EAGAIN;
+ } else {
+ written = filemap_write_and_wait_range(mapping, pos,
+ pos + write_len - 1);
+ if (written)
+ goto out;
+ }
/*
* After a write we want buffered reads to be sure to go to disk to get