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Btrfs: don't use highmem for free space cache pages

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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>
This commit is contained in:
Chris Mason 2015-04-06 07:48:20 -07:00
parent c9dc4c6578
commit 2b10826800
1 changed files with 5 additions and 7 deletions
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12
fs/btrfs/free-space-cache.c
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@ -85,7 +85,8 @@ static struct inode *__lookup_free_space_inode(struct btrfs_root *root,
}
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_free(struct btrfs_io_ctl *io_ctl)
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 @@ static void io_ctl_map_page(struct btrfs_io_ctl *io_ctl, int clear)
{
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 @@ static void io_ctl_set_crc(struct btrfs_io_ctl *io_ctl, int index)
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 @@ static int io_ctl_check_crc(struct btrfs_io_ctl *io_ctl, int index)
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,