Btrfs: don't use highmem for free space cache pages
In order to create the free space cache concurrently with FS modifications,
we need to take a few block group locks.
The cache code also does kmap, which would schedule with the locks held.
Instead of going through kmap_atomic, lets just use lowmem for the cache
pages.
Signed-off-by: Chris Mason <clm@fb.com>
diff --git a/fs/btrfs/free-space-cache.c b/fs/btrfs/free-space-cache.c
index 6886ae0..83532a2 100644
--- a/fs/btrfs/free-space-cache.c
+++ b/fs/btrfs/free-space-cache.c
@@ -85,7 +85,8 @@
}
mapping_set_gfp_mask(inode->i_mapping,
- mapping_gfp_mask(inode->i_mapping) & ~__GFP_FS);
+ mapping_gfp_mask(inode->i_mapping) &
+ ~(GFP_NOFS & ~__GFP_HIGHMEM));
return inode;
}
@@ -310,7 +311,6 @@
static void io_ctl_unmap_page(struct btrfs_io_ctl *io_ctl)
{
if (io_ctl->cur) {
- kunmap(io_ctl->page);
io_ctl->cur = NULL;
io_ctl->orig = NULL;
}
@@ -320,7 +320,7 @@
{
ASSERT(io_ctl->index < io_ctl->num_pages);
io_ctl->page = io_ctl->pages[io_ctl->index++];
- io_ctl->cur = kmap(io_ctl->page);
+ io_ctl->cur = page_address(io_ctl->page);
io_ctl->orig = io_ctl->cur;
io_ctl->size = PAGE_CACHE_SIZE;
if (clear)
@@ -446,10 +446,9 @@
PAGE_CACHE_SIZE - offset);
btrfs_csum_final(crc, (char *)&crc);
io_ctl_unmap_page(io_ctl);
- tmp = kmap(io_ctl->pages[0]);
+ tmp = page_address(io_ctl->pages[0]);
tmp += index;
*tmp = crc;
- kunmap(io_ctl->pages[0]);
}
static int io_ctl_check_crc(struct btrfs_io_ctl *io_ctl, int index)
@@ -466,10 +465,9 @@
if (index == 0)
offset = sizeof(u32) * io_ctl->num_pages;
- tmp = kmap(io_ctl->pages[0]);
+ tmp = page_address(io_ctl->pages[0]);
tmp += index;
val = *tmp;
- kunmap(io_ctl->pages[0]);
io_ctl_map_page(io_ctl, 0);
crc = btrfs_csum_data(io_ctl->orig + offset, crc,