Commit 17bc6c30 authored by Aneesh Kumar K.V's avatar Aneesh Kumar K.V Committed by Theodore Ts'o
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vfs: Add no_nrwrite_index_update writeback control flag



If no_nrwrite_index_update is set we don't update nr_to_write and
address space writeback_index in write_cache_pages.  This change
enables a file system to skip these updates in write_cache_pages and do
them in the writepages() callback.  This patch will be followed by an
ext4 patch that make use of these new flags.
Signed-off-by: default avatarAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: default avatar"Theodore Ts'o" <tytso@mit.edu>
CC: linux-fsdevel@vger.kernel.org
parent 74baaaae
......@@ -63,6 +63,15 @@ struct writeback_control {
unsigned for_writepages:1; /* This is a writepages() call */
unsigned range_cyclic:1; /* range_start is cyclic */
unsigned more_io:1; /* more io to be dispatched */
/*
* write_cache_pages() won't update wbc->nr_to_write and
* mapping->writeback_index if no_nrwrite_index_update
* is set. write_cache_pages() may write more than we
* requested and we want to make sure nr_to_write and
* writeback_index are updated in a consistent manner
* so we use a single control to update them
*/
unsigned no_nrwrite_index_update:1;
};
/*
......
......@@ -876,6 +876,7 @@ int write_cache_pages(struct address_space *mapping,
pgoff_t end; /* Inclusive */
int scanned = 0;
int range_whole = 0;
long nr_to_write = wbc->nr_to_write;
if (wbc->nonblocking && bdi_write_congested(bdi)) {
wbc->encountered_congestion = 1;
......@@ -939,7 +940,7 @@ retry:
unlock_page(page);
ret = 0;
}
if (ret || (--(wbc->nr_to_write) <= 0))
if (ret || (--nr_to_write <= 0))
done = 1;
if (wbc->nonblocking && bdi_write_congested(bdi)) {
wbc->encountered_congestion = 1;
......@@ -958,8 +959,11 @@ retry:
index = 0;
goto retry;
}
if (wbc->range_cyclic || (range_whole && wbc->nr_to_write > 0))
if (!wbc->no_nrwrite_index_update) {
if (wbc->range_cyclic || (range_whole && nr_to_write > 0))
mapping->writeback_index = index;
wbc->nr_to_write = nr_to_write;
}
return ret;
}
......
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