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f2fs: Fix indefinite loop in f2fs_gc()

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Policy - Foreground GC, LFS and greedy GC mode.

Under this policy, f2fs_gc() loops forever to GC as it doesn't have
enough free segements to proceed and thus it keeps calling gc_more
for the same victim segment.  This can happen if the selected victim
segment could not be GC'd due to failed blkaddr validity check i.e.
is_alive() returns false for the blocks set in current validity map.

Fix this by keeping track of such invalid segments and skip those
segments for selection in get_victim_by_default() to avoid endless
GC loop under such error scenarios. Currently, add this logic under
CONFIG_F2FS_CHECK_FS to be able to root cause the issue in debug
version.

Signed-off-by: Sahitya Tummala <stummala@codeaurora.org>
Reviewed-by: Chao Yu <yuchao0@huawei.com>
[Jaegeuk Kim: fix wrong bitmap size]
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
This commit is contained in:
Sahitya Tummala 2019-08-07 19:10:32 +05:30 committed by Jaegeuk Kim
parent 2fde3dd14e
commit bbf9f7d90f
3 changed files with 46 additions and 9 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

25
fs/f2fs/gc.c
View File

@ -382,6 +382,16 @@ static int get_victim_by_default(struct f2fs_sb_info *sbi,
nsearched++;
}
#ifdef CONFIG_F2FS_CHECK_FS
/*
* skip selecting the invalid segno (that is failed due to block
* validity check failure during GC) to avoid endless GC loop in
* such cases.
*/
if (test_bit(segno, sm->invalid_segmap))
goto next;
#endif
secno = GET_SEC_FROM_SEG(sbi, segno);
if (sec_usage_check(sbi, secno))
@ -627,8 +637,21 @@ static bool is_alive(struct f2fs_sb_info *sbi, struct f2fs_summary *sum,
source_blkaddr = datablock_addr(NULL, node_page, ofs_in_node);
f2fs_put_page(node_page, 1);
if (source_blkaddr != blkaddr)
if (source_blkaddr != blkaddr) {
#ifdef CONFIG_F2FS_CHECK_FS
unsigned int segno = GET_SEGNO(sbi, blkaddr);
unsigned long offset = GET_BLKOFF_FROM_SEG0(sbi, blkaddr);
if (unlikely(check_valid_map(sbi, segno, offset))) {
if (!test_and_set_bit(segno, SIT_I(sbi)->invalid_segmap)) {
f2fs_err(sbi, "mismatched blkaddr %u (source_blkaddr %u) in seg %u\n",
blkaddr, source_blkaddr, segno);
f2fs_bug_on(sbi, 1);
}
}
#endif
return false;
}
return true;
}

27
fs/f2fs/segment.c
View File

@ -817,9 +817,13 @@ static void __remove_dirty_segment(struct f2fs_sb_info *sbi, unsigned int segno,
if (test_and_clear_bit(segno, dirty_i->dirty_segmap[t]))
dirty_i->nr_dirty[t]--;
if (get_valid_blocks(sbi, segno, true) == 0)
if (get_valid_blocks(sbi, segno, true) == 0) {
clear_bit(GET_SEC_FROM_SEG(sbi, segno),
dirty_i->victim_secmap);
#ifdef CONFIG_F2FS_CHECK_FS
clear_bit(segno, SIT_I(sbi)->invalid_segmap);
#endif
}
}
}
@ -3946,7 +3950,7 @@ static int build_sit_info(struct f2fs_sb_info *sbi)
struct sit_info *sit_i;
unsigned int sit_segs, start;
char *src_bitmap, *bitmap;
unsigned int bitmap_size;
unsigned int bitmap_size, main_bitmap_size, sit_bitmap_size;
/* allocate memory for SIT information */
sit_i = f2fs_kzalloc(sbi, sizeof(struct sit_info), GFP_KERNEL);
@ -3962,8 +3966,8 @@ static int build_sit_info(struct f2fs_sb_info *sbi)
if (!sit_i->sentries)
return -ENOMEM;
bitmap_size = f2fs_bitmap_size(MAIN_SEGS(sbi));
sit_i->dirty_sentries_bitmap = f2fs_kvzalloc(sbi, bitmap_size,
main_bitmap_size = f2fs_bitmap_size(MAIN_SEGS(sbi));
sit_i->dirty_sentries_bitmap = f2fs_kvzalloc(sbi, main_bitmap_size,
GFP_KERNEL);
if (!sit_i->dirty_sentries_bitmap)
return -ENOMEM;
@ -4012,17 +4016,23 @@ static int build_sit_info(struct f2fs_sb_info *sbi)
sit_segs = le32_to_cpu(raw_super->segment_count_sit) >> 1;
/* setup SIT bitmap from ckeckpoint pack */
bitmap_size = __bitmap_size(sbi, SIT_BITMAP);
sit_bitmap_size = __bitmap_size(sbi, SIT_BITMAP);
src_bitmap = __bitmap_ptr(sbi, SIT_BITMAP);
sit_i->sit_bitmap = kmemdup(src_bitmap, bitmap_size, GFP_KERNEL);
sit_i->sit_bitmap = kmemdup(src_bitmap, sit_bitmap_size, GFP_KERNEL);
if (!sit_i->sit_bitmap)
return -ENOMEM;
#ifdef CONFIG_F2FS_CHECK_FS
sit_i->sit_bitmap_mir = kmemdup(src_bitmap, bitmap_size, GFP_KERNEL);
sit_i->sit_bitmap_mir = kmemdup(src_bitmap,
sit_bitmap_size, GFP_KERNEL);
if (!sit_i->sit_bitmap_mir)
return -ENOMEM;
sit_i->invalid_segmap = f2fs_kvzalloc(sbi,
main_bitmap_size, GFP_KERNEL);
if (!sit_i->invalid_segmap)
return -ENOMEM;
#endif
/* init SIT information */
@ -4031,7 +4041,7 @@ static int build_sit_info(struct f2fs_sb_info *sbi)
sit_i->sit_base_addr = le32_to_cpu(raw_super->sit_blkaddr);
sit_i->sit_blocks = sit_segs << sbi->log_blocks_per_seg;
sit_i->written_valid_blocks = 0;
sit_i->bitmap_size = bitmap_size;
sit_i->bitmap_size = sit_bitmap_size;
sit_i->dirty_sentries = 0;
sit_i->sents_per_block = SIT_ENTRY_PER_BLOCK;
sit_i->elapsed_time = le64_to_cpu(sbi->ckpt->elapsed_time);
@ -4514,6 +4524,7 @@ static void destroy_sit_info(struct f2fs_sb_info *sbi)
kvfree(sit_i->sit_bitmap);
#ifdef CONFIG_F2FS_CHECK_FS
kvfree(sit_i->sit_bitmap_mir);
kvfree(sit_i->invalid_segmap);
#endif
kvfree(sit_i);
}

3
fs/f2fs/segment.h
View File

@ -230,6 +230,9 @@ struct sit_info {
char *sit_bitmap; /* SIT bitmap pointer */
#ifdef CONFIG_F2FS_CHECK_FS
char *sit_bitmap_mir; /* SIT bitmap mirror */
/* bitmap of segments to be ignored by GC in case of errors */
unsigned long *invalid_segmap;
#endif
unsigned int bitmap_size; /* SIT bitmap size */