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authorGreg Kroah-Hartman <gregkh@linuxfoundation.org>2018-10-14 09:34:31 +0300
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2018-10-14 09:34:31 +0300
commit3a27203102ebfa67bd0bced05b1def499bb59db2 (patch)
tree1dbcb719202b0fe22c143e913f281f49a1b37c3d /fs
parenta24a0eb9c8972803a8707041fc9ed9080cdaf1b9 (diff)
parent4628a64591e6cee181237060961e98c615c33966 (diff)
downloadlinux-3a27203102ebfa67bd0bced05b1def499bb59db2.tar.xz
Merge tag 'libnvdimm-fixes-4.19-rc8' of git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm
Dan writes: "libnvdimm/dax 4.19-rc8 * Fix a livelock in dax_layout_busy_page() present since v4.18. The lockup triggers when truncating an actively mapped huge page out of a mapping pinned for direct-I/O. * Fix mprotect() clobbers of _PAGE_DEVMAP. Broken since v4.5 mprotect() clears this flag that is needed to communicate the liveness of device pages to the get_user_pages() path." * tag 'libnvdimm-fixes-4.19-rc8' of git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm: mm: Preserve _PAGE_DEVMAP across mprotect() calls filesystem-dax: Fix dax_layout_busy_page() livelock
Diffstat (limited to 'fs')
-rw-r--r--fs/dax.c13
1 files changed, 11 insertions, 2 deletions
diff --git a/fs/dax.c b/fs/dax.c
index 4becbf168b7f..0fb270f0a0ef 100644
--- a/fs/dax.c
+++ b/fs/dax.c
@@ -666,6 +666,8 @@ struct page *dax_layout_busy_page(struct address_space *mapping)
while (index < end && pagevec_lookup_entries(&pvec, mapping, index,
min(end - index, (pgoff_t)PAGEVEC_SIZE),
indices)) {
+ pgoff_t nr_pages = 1;
+
for (i = 0; i < pagevec_count(&pvec); i++) {
struct page *pvec_ent = pvec.pages[i];
void *entry;
@@ -680,8 +682,15 @@ struct page *dax_layout_busy_page(struct address_space *mapping)
xa_lock_irq(&mapping->i_pages);
entry = get_unlocked_mapping_entry(mapping, index, NULL);
- if (entry)
+ if (entry) {
page = dax_busy_page(entry);
+ /*
+ * Account for multi-order entries at
+ * the end of the pagevec.
+ */
+ if (i + 1 >= pagevec_count(&pvec))
+ nr_pages = 1UL << dax_radix_order(entry);
+ }
put_unlocked_mapping_entry(mapping, index, entry);
xa_unlock_irq(&mapping->i_pages);
if (page)
@@ -696,7 +705,7 @@ struct page *dax_layout_busy_page(struct address_space *mapping)
*/
pagevec_remove_exceptionals(&pvec);
pagevec_release(&pvec);
- index++;
+ index += nr_pages;
if (page)
break;