From: Sahitya Tummala <stummala@codeaurora.org>
To: Jaegeuk Kim <jaegeuk@kernel.org>, Chao Yu <yuchao0@huawei.com>,
linux-f2fs-devel@lists.sourceforge.net
Cc: Sahitya Tummala <stummala@codeaurora.org>, linux-kernel@vger.kernel.org
Subject: [PATCH v2] f2fs: Fix indefinite loop in f2fs_gc()
Date: Tue, 6 Aug 2019 16:49:56 +0530 [thread overview]
Message-ID: <1565090396-7263-1-git-send-email-stummala@codeaurora.org> (raw)
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.
Signed-off-by: Sahitya Tummala <stummala@codeaurora.org>
---
v2: fix as per Chao's suggestion to handle this error case
fs/f2fs/gc.c | 15 ++++++++++++++-
fs/f2fs/segment.c | 5 +++++
fs/f2fs/segment.h | 3 +++
3 files changed, 22 insertions(+), 1 deletion(-)
diff --git a/fs/f2fs/gc.c b/fs/f2fs/gc.c
index 8974672..321a78a 100644
--- a/fs/f2fs/gc.c
+++ b/fs/f2fs/gc.c
@@ -382,6 +382,14 @@ static int get_victim_by_default(struct f2fs_sb_info *sbi,
nsearched++;
}
+ /*
+ * skip selecting the invalid segno (that is failed due to block
+ * validity check failed during GC) to avoid endless GC loop in
+ * such cases.
+ */
+ if (test_bit(segno, sm->invalid_segmap))
+ goto next;
+
secno = GET_SEC_FROM_SEG(sbi, segno);
if (sec_usage_check(sbi, secno))
@@ -975,6 +983,7 @@ static int gc_data_segment(struct f2fs_sb_info *sbi, struct f2fs_summary *sum,
int off;
int phase = 0;
int submitted = 0;
+ struct sit_info *sit_i = SIT_I(sbi);
start_addr = START_BLOCK(sbi, segno);
@@ -1008,8 +1017,12 @@ static int gc_data_segment(struct f2fs_sb_info *sbi, struct f2fs_summary *sum,
}
/* Get an inode by ino with checking validity */
- if (!is_alive(sbi, entry, &dni, start_addr + off, &nofs))
+ if (!is_alive(sbi, entry, &dni, start_addr + off, &nofs)) {
+ if (!test_and_set_bit(segno, sit_i->invalid_segmap))
+ f2fs_err(sbi, "invalid blkaddr %u in seg %u is found\n",
+ start_addr + off, segno);
continue;
+ }
if (phase == 2) {
f2fs_ra_node_page(sbi, dni.ino);
diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
index a661ac3..d45a1d3 100644
--- a/fs/f2fs/segment.c
+++ b/fs/f2fs/segment.c
@@ -4017,6 +4017,10 @@ static int build_sit_info(struct f2fs_sb_info *sbi)
return -ENOMEM;
#endif
+ sit_i->invalid_segmap = f2fs_kvzalloc(sbi, bitmap_size, GFP_KERNEL);
+ if (!sit_i->invalid_segmap)
+ return -ENOMEM;
+
/* init SIT information */
sit_i->s_ops = &default_salloc_ops;
@@ -4518,6 +4522,7 @@ static void destroy_sit_info(struct f2fs_sb_info *sbi)
#ifdef CONFIG_F2FS_CHECK_FS
kvfree(sit_i->sit_bitmap_mir);
#endif
+ kvfree(sit_i->invalid_segmap);
kvfree(sit_i);
}
diff --git a/fs/f2fs/segment.h b/fs/f2fs/segment.h
index b746028..bc5dbe8 100644
--- a/fs/f2fs/segment.h
+++ b/fs/f2fs/segment.h
@@ -246,6 +246,9 @@ struct sit_info {
unsigned long long min_mtime; /* min. modification time */
unsigned long long max_mtime; /* max. modification time */
+ /* list of segments to be ignored by GC in case of errors */
+ unsigned long *invalid_segmap;
+
unsigned int last_victim[MAX_GC_POLICY]; /* last victim segment # */
};
--
Qualcomm India Private Limited, on behalf of Qualcomm Innovation Center, Inc.
Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, a Linux Foundation Collaborative Project.
next reply other threads:[~2019-08-06 11:25 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-08-06 11:19 Sahitya Tummala [this message]
2019-08-07 2:04 ` [PATCH v2] f2fs: Fix indefinite loop in f2fs_gc() Chao Yu
2019-08-07 3:24 ` Sahitya Tummala
2019-08-07 3:37 ` Chao Yu
2019-08-07 5:14 ` Sahitya Tummala
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