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f2fs: fix concurrent problem for updating free bitmap 

alloc_nid_failed and scan_nat_page can be called at the same time,
and we haven't protected add_free_nid and update_free_nid_bitmap
with the same nid_list_lock. That could lead to

Thread A				Thread B
- __build_free_nids
 - scan_nat_page
  - add_free_nid
					- alloc_nid_failed
					 - update_free_nid_bitmap
  - update_free_nid_bitmap

scan_nat_page will clear the free bitmap since the nid is PREALLOC_NID,
but alloc_nid_failed needs to set the free bitmap. This results in
free nid with free bitmap cleared.
This patch update the bitmap under the same nid_list_lock in add_free_nid.
And use __GFP_NOFAIL to make sure to update status of free nid correctly.

Signed-off-by: Fan li <fanofcode.li@samsung.com>
Reviewed-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
This commit is contained in:
LiFan 2017-11-22 16:07:23 +08:00 committed by Jaegeuk Kim
parent 2ab56a59ca
commit 5921aaa185
1 changed files with 43 additions and 42 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

85
fs/f2fs/node.c
View File

@ -1812,8 +1812,33 @@ static void __move_free_nid(struct f2fs_sb_info *sbi, struct free_nid *i,
}
}
static void update_free_nid_bitmap(struct f2fs_sb_info *sbi, nid_t nid,
bool set, bool build)
{
struct f2fs_nm_info *nm_i = NM_I(sbi);
unsigned int nat_ofs = NAT_BLOCK_OFFSET(nid);
unsigned int nid_ofs = nid - START_NID(nid);
if (!test_bit_le(nat_ofs, nm_i->nat_block_bitmap))
return;
if (set) {
if (test_bit_le(nid_ofs, nm_i->free_nid_bitmap[nat_ofs]))
return;
__set_bit_le(nid_ofs, nm_i->free_nid_bitmap[nat_ofs]);
nm_i->free_nid_count[nat_ofs]++;
} else {
if (!test_bit_le(nid_ofs, nm_i->free_nid_bitmap[nat_ofs]))
return;
__clear_bit_le(nid_ofs, nm_i->free_nid_bitmap[nat_ofs]);
if (!build)
nm_i->free_nid_count[nat_ofs]--;
}
}
/* return if the nid is recognized as free */
static bool add_free_nid(struct f2fs_sb_info *sbi, nid_t nid, bool build)
static bool add_free_nid(struct f2fs_sb_info *sbi,
nid_t nid, bool build, bool update)
{
struct f2fs_nm_info *nm_i = NM_I(sbi);
struct free_nid *i, *e;
@ -1829,8 +1854,7 @@ static bool add_free_nid(struct f2fs_sb_info *sbi, nid_t nid, bool build)
i->nid = nid;
i->state = FREE_NID;
if (radix_tree_preload(GFP_NOFS))
goto err;
radix_tree_preload(GFP_NOFS | __GFP_NOFAIL);
spin_lock(&nm_i->nid_list_lock);
@ -1871,9 +1895,14 @@ static bool add_free_nid(struct f2fs_sb_info *sbi, nid_t nid, bool build)
ret = true;
err = __insert_free_nid(sbi, i, FREE_NID);
err_out:
if (update) {
update_free_nid_bitmap(sbi, nid, ret, build);
if (!build)
nm_i->available_nids++;
}
spin_unlock(&nm_i->nid_list_lock);
radix_tree_preload_end();
err:
if (err)
kmem_cache_free(free_nid_slab, i);
return ret;
@ -1897,30 +1926,6 @@ static void remove_free_nid(struct f2fs_sb_info *sbi, nid_t nid)
kmem_cache_free(free_nid_slab, i);
}
static void update_free_nid_bitmap(struct f2fs_sb_info *sbi, nid_t nid,
bool set, bool build)
{
struct f2fs_nm_info *nm_i = NM_I(sbi);
unsigned int nat_ofs = NAT_BLOCK_OFFSET(nid);
unsigned int nid_ofs = nid - START_NID(nid);
if (!test_bit_le(nat_ofs, nm_i->nat_block_bitmap))
return;
if (set) {
if (test_bit_le(nid_ofs, nm_i->free_nid_bitmap[nat_ofs]))
return;
__set_bit_le(nid_ofs, nm_i->free_nid_bitmap[nat_ofs]);
nm_i->free_nid_count[nat_ofs]++;
} else {
if (!test_bit_le(nid_ofs, nm_i->free_nid_bitmap[nat_ofs]))
return;
__clear_bit_le(nid_ofs, nm_i->free_nid_bitmap[nat_ofs]);
if (!build)
nm_i->free_nid_count[nat_ofs]--;
}
}
static void scan_nat_page(struct f2fs_sb_info *sbi,
struct page *nat_page, nid_t start_nid)
{
@ -1935,18 +1940,18 @@ static void scan_nat_page(struct f2fs_sb_info *sbi,
i = start_nid % NAT_ENTRY_PER_BLOCK;
for (; i < NAT_ENTRY_PER_BLOCK; i++, start_nid++) {
bool freed = false;
if (unlikely(start_nid >= nm_i->max_nid))
break;
blk_addr = le32_to_cpu(nat_blk->entries[i].block_addr);
f2fs_bug_on(sbi, blk_addr == NEW_ADDR);
if (blk_addr == NULL_ADDR)
freed = add_free_nid(sbi, start_nid, true);
spin_lock(&NM_I(sbi)->nid_list_lock);
update_free_nid_bitmap(sbi, start_nid, freed, true);
spin_unlock(&NM_I(sbi)->nid_list_lock);
if (blk_addr == NULL_ADDR) {
add_free_nid(sbi, start_nid, true, true);
} else {
spin_lock(&NM_I(sbi)->nid_list_lock);
update_free_nid_bitmap(sbi, start_nid, false, true);
spin_unlock(&NM_I(sbi)->nid_list_lock);
}
}
}
@ -1964,7 +1969,7 @@ static void scan_curseg_cache(struct f2fs_sb_info *sbi)
addr = le32_to_cpu(nat_in_journal(journal, i).block_addr);
nid = le32_to_cpu(nid_in_journal(journal, i));
if (addr == NULL_ADDR)
add_free_nid(sbi, nid, true);
add_free_nid(sbi, nid, true, false);
else
remove_free_nid(sbi, nid);
}
@ -1991,7 +1996,7 @@ static void scan_free_nid_bits(struct f2fs_sb_info *sbi)
break;
nid = i * NAT_ENTRY_PER_BLOCK + idx;
add_free_nid(sbi, nid, true);
add_free_nid(sbi, nid, true, false);
if (nm_i->nid_cnt[FREE_NID] >= MAX_FREE_NIDS)
goto out;
@ -2497,11 +2502,7 @@ static void __flush_nat_entry_set(struct f2fs_sb_info *sbi,
nat_reset_flag(ne);
__clear_nat_cache_dirty(NM_I(sbi), set, ne);
if (nat_get_blkaddr(ne) == NULL_ADDR) {
add_free_nid(sbi, nid, false);
spin_lock(&NM_I(sbi)->nid_list_lock);
NM_I(sbi)->available_nids++;
update_free_nid_bitmap(sbi, nid, true, false);
spin_unlock(&NM_I(sbi)->nid_list_lock);
add_free_nid(sbi, nid, false, true);
} else {
spin_lock(&NM_I(sbi)->nid_list_lock);
update_free_nid_bitmap(sbi, nid, false, false);