Hi David,
Thanks for cleaning up the patch but tt seems this patch may no longer be needed with the timed wait_on_page patch that Milosz posted. We have been running with Milosz's timeout patch for a few weeks now and have not encountered this deadlock.
Thanks,
Shantanu
On Wednesday, August 6, 2014 7:21 AM, David Howells <dhowells@xxxxxxxxxx> wrote:
>
>
>David Howells <dhowells@xxxxxxxxxx> wrote:
>
>> It seems that your mail client replaced all the tabs in the patch with
>> multiple 0xA0 characters plus a space.
>
>Here's a cleaned up patch that applies.
>
>
>David
>---
>diff --git a/fs/cachefiles/rdwr.c b/fs/cachefiles/rdwr.c
>index 25e745b8eb1b..ebeaaf7ac6f0 100644
>--- a/fs/cachefiles/rdwr.c
>+++ b/fs/cachefiles/rdwr.c
>@@ -916,6 +916,19 @@ int cachefiles_write_page(struct fscache_storage *op, struct page *page)
> } else {
> ret = -EIO;
> if (file->f_op->write) {
>+ struct address_space *mapping = file->f_mapping;
>+ gfp_t gfp_mask = mapping_gfp_mask(mapping);
>+ gfp_t gfp_mask_orig = gfp_mask;
>+
>+ /*
>+ * Clear __GFP_FS to avoid potential deadlock
>+ * during memory reclaim.
>+ */
>+ if (gfp_mask & __GFP_FS) {
>+ gfp_mask &= ~__GFP_FS;
>+ mapping_set_gfp_mask(mapping, gfp_mask);
>+ }
>+
> pos = (loff_t) page->index << PAGE_SHIFT;
>
> /* we mustn't write more data than we have, so we have
>@@ -943,6 +956,9 @@ int cachefiles_write_page(struct fscache_storage *op, struct page *page)
> file_end_write(file);
> if (ret != len)
> ret = -EIO;
>+
>+ if (gfp_mask != gfp_mask_orig)
>+ mapping_set_gfp_mask(gfp_mask_orig);
> }
> fput(file);
>
> }
>
>
--
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