The commit is pushed to "branch-rh8-4.18.0-240.1.1.vz8.5.x-ovz" and will appear
at https://src.openvz.org/scm/ovz/vzkernel.git
after rh8-4.18.0-240.1.1.vz8.5.51
------>
commit eb1879e7b90c95cf68af4940e6ff2e7936bfa6ac
Author: Kirill Tkhai <[email protected]>
Date: Fri Jul 2 22:53:04 2021 +0300
ploop: Do not read too many pages
When lower delta is less than top delta,
do not read too many pages.
Signed-off-by: Kirill Tkhai <[email protected]>
---
drivers/md/dm-ploop-bat.c | 48 +++++++++++++++++++++++++++++++++--------------
1 file changed, 34 insertions(+), 14 deletions(-)
diff --git a/drivers/md/dm-ploop-bat.c b/drivers/md/dm-ploop-bat.c
index 35275faee935..e4e10df685a2 100644
--- a/drivers/md/dm-ploop-bat.c
+++ b/drivers/md/dm-ploop-bat.c
@@ -317,8 +317,7 @@ static int ploop_delta_check_header(struct ploop *ploop,
u32 *delta_nr_be_ret)
{
u32 bytes, delta_nr_be, offset_clusters, bat_clusters;
- struct rb_node *node = rb_first(md_root);
- struct md_page *md0 = rb_entry(node, struct md_page, node);
+ struct md_page *md0 = md_first_entry(md_root);
struct ploop_pvd_header *d_hdr;
int ret = -EPROTO;
@@ -346,9 +345,10 @@ static int ploop_delta_check_header(struct ploop *ploop,
return ret;
}
-static int convert_bat_entries(struct ploop *ploop, struct rb_root *md_root,
u32 nr_be)
+static int convert_bat_entries(struct ploop *ploop, struct rb_root *md_root,
+ u32 nr_be, u32 nr_pages)
{
- u32 i, end, bytes, bat_clusters, *bat_entries;
+ u32 i, end, bytes, bat_clusters, page_id, *bat_entries;
struct rb_node *node;
struct md_page *md;
int ret = 0;
@@ -356,9 +356,12 @@ static int convert_bat_entries(struct ploop *ploop, struct
rb_root *md_root, u32
bytes = (PLOOP_MAP_OFFSET + nr_be) * sizeof(map_index_t);
bat_clusters = DIV_ROUND_UP(bytes, CLU_SIZE(ploop));
+ page_id = 0;
rb_root_for_each_md_page(md_root, md, node) {
bat_entries = kmap(md->page);
init_be_iter(nr_be, md->id, &i, &end);
+ WARN_ON_ONCE(page_id != md->id);
+ page_id++;
for (; i <= end; i++) {
if (bat_entries[i] == BAT_ENTRY_NONE)
@@ -370,7 +373,7 @@ static int convert_bat_entries(struct ploop *ploop, struct
rb_root *md_root, u32
}
kunmap(md->page);
- if (ret)
+ if (ret || page_id == nr_pages)
break;
}
@@ -380,8 +383,8 @@ static int convert_bat_entries(struct ploop *ploop, struct
rb_root *md_root, u32
int ploop_read_delta_metadata(struct ploop *ploop, struct file *file,
struct rb_root *md_root, u32 *delta_nr_be_ret)
{
+ struct bio_vec bvec_on_stack, *bvec = &bvec_on_stack;
u32 i, size, delta_nr_be, nr_segs;
- struct bio_vec *bvec = NULL;
struct iov_iter iter;
struct rb_node *node;
struct md_page *md;
@@ -390,13 +393,33 @@ int ploop_read_delta_metadata(struct ploop *ploop, struct
file *file,
int ret;
ret = -ENOMEM;
- if (prealloc_md_pages(md_root, 0, ploop->nr_bat_entries))
+ if (prealloc_md_pages(md_root, 0, 1))
goto out;
+ bvec[0].bv_page = md_first_entry(md_root)->page;
+ bvec[0].bv_len = PAGE_SIZE;
+ bvec[0].bv_offset = 0;
- size = (PLOOP_MAP_OFFSET + ploop->nr_bat_entries) * sizeof(map_index_t);
+ iov_iter_bvec(&iter, READ, bvec, 1, PAGE_SIZE);
+ pos = 0;
+
+ len = vfs_iter_read(file, &iter, &pos, 0);
+ if (len != PAGE_SIZE) {
+ ret = len < 0 ? (int)len : -ENODATA;
+ goto out;
+ }
+
+ ret = ploop_delta_check_header(ploop, md_root, &delta_nr_be);
+ if (ret)
+ goto out;
+
+ size = (PLOOP_MAP_OFFSET + delta_nr_be) * sizeof(map_index_t);
size = ALIGN(size, PAGE_SIZE); /* file may be open as direct */
nr_segs = size / PAGE_SIZE;
+ ret = -ENOMEM;
+ if (prealloc_md_pages(md_root, 1, delta_nr_be))
+ goto out;
+
bvec = kvmalloc(sizeof(*bvec) * nr_segs, GFP_KERNEL);
if (!bvec)
goto out;
@@ -421,17 +444,14 @@ int ploop_read_delta_metadata(struct ploop *ploop, struct
file *file,
goto out;
}
- ret = ploop_delta_check_header(ploop, md_root, &delta_nr_be);
- if (ret)
- goto out;
-
- ret = convert_bat_entries(ploop, md_root, delta_nr_be);
+ ret = convert_bat_entries(ploop, md_root, delta_nr_be, nr_segs);
*delta_nr_be_ret = delta_nr_be;
out:
if (ret)
free_md_pages_tree(md_root);
- kvfree(bvec);
+ if (bvec != &bvec_on_stack)
+ kvfree(bvec);
return ret;
}
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