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authorMatthew Wilcox <willy@infradead.org>2019-03-01 11:12:41 -0800
committerDan Williams <dan.j.williams@intel.com>2019-03-01 17:24:48 -0800
commite4b3448bc346fedf36db64124a664a959995b085 (patch)
treeb87a9328845723417fb3fec53b6403945a6b8009 /fs/dax.c
parent0cefc36b32b3a9ee9da9bd055810bf331e4243dd (diff)
downloadlinux-e4b3448bc346fedf36db64124a664a959995b085.tar.bz2
dax: Flush partial PMDs correctly
The radix tree would rewind the index in an iterator to the lowest index of a multi-slot entry. The XArray iterators instead leave the index unchanged, but I overlooked that when converting DAX from the radix tree to the XArray. Adjust the index that we use for flushing to the start of the PMD range. Fixes: c1901cd33cf4 ("page cache: Convert find_get_entries_tag to XArray") Cc: <stable@vger.kernel.org> Reported-by: Piotr Balcer <piotr.balcer@intel.com> Tested-by: Dan Williams <dan.j.williams@intel.com> Reviewed-by: Jan Kara <jack@suse.cz> Signed-off-by: Matthew Wilcox <willy@infradead.org> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Diffstat (limited to 'fs/dax.c')
-rw-r--r--fs/dax.c19
1 files changed, 9 insertions, 10 deletions
diff --git a/fs/dax.c b/fs/dax.c
index c55afa4261d1..ca0671d55aa6 100644
--- a/fs/dax.c
+++ b/fs/dax.c
@@ -843,9 +843,8 @@ unlock_pte:
static int dax_writeback_one(struct xa_state *xas, struct dax_device *dax_dev,
struct address_space *mapping, void *entry)
{
- unsigned long pfn;
+ unsigned long pfn, index, count;
long ret = 0;
- size_t size;
/*
* A page got tagged dirty in DAX mapping? Something is seriously
@@ -894,17 +893,18 @@ static int dax_writeback_one(struct xa_state *xas, struct dax_device *dax_dev,
xas_unlock_irq(xas);
/*
- * Even if dax_writeback_mapping_range() was given a wbc->range_start
- * in the middle of a PMD, the 'index' we are given will be aligned to
- * the start index of the PMD, as will the pfn we pull from 'entry'.
+ * If dax_writeback_mapping_range() was given a wbc->range_start
+ * in the middle of a PMD, the 'index' we use needs to be
+ * aligned to the start of the PMD.
* This allows us to flush for PMD_SIZE and not have to worry about
* partial PMD writebacks.
*/
pfn = dax_to_pfn(entry);
- size = PAGE_SIZE << dax_entry_order(entry);
+ count = 1UL << dax_entry_order(entry);
+ index = xas->xa_index & ~(count - 1);
- dax_entry_mkclean(mapping, xas->xa_index, pfn);
- dax_flush(dax_dev, page_address(pfn_to_page(pfn)), size);
+ dax_entry_mkclean(mapping, index, pfn);
+ dax_flush(dax_dev, page_address(pfn_to_page(pfn)), count * PAGE_SIZE);
/*
* After we have flushed the cache, we can clear the dirty tag. There
* cannot be new dirty data in the pfn after the flush has completed as
@@ -917,8 +917,7 @@ static int dax_writeback_one(struct xa_state *xas, struct dax_device *dax_dev,
xas_clear_mark(xas, PAGECACHE_TAG_DIRTY);
dax_wake_entry(xas, entry, false);
- trace_dax_writeback_one(mapping->host, xas->xa_index,
- size >> PAGE_SHIFT);
+ trace_dax_writeback_one(mapping->host, index, count);
return ret;
put_unlocked: