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| author | Chao Yu <yuchao0@huawei.com> | 2018-05-07 15:28:54 +0300 |
|---|---|---|
| committer | Jaegeuk Kim <jaegeuk@kernel.org> | 2018-05-31 21:31:51 +0300 |
| commit | 2ef79ecb5e906d87475d3e0c49b22425499a89f3 (patch) | |
| tree | 266179c3b3bd4d98a621ce4652729bdb716e1d2f /fs/f2fs/gc.c | |
| parent | 5b0e95398e2bcc18e871758221cc712be4a0a39a (diff) | |
| download | linux-2ef79ecb5e906d87475d3e0c49b22425499a89f3.tar.xz | |
f2fs: avoid stucking GC due to atomic write
f2fs doesn't allow abuse on atomic write class interface, so except
limiting in-mem pages' total memory usage capacity, we need to limit
atomic-write usage as well when filesystem is seriously fragmented,
otherwise we may run into infinite loop during foreground GC because
target blocks in victim segment are belong to atomic opened file for
long time.
Now, we will detect failure due to atomic write in foreground GC, if
the count exceeds threshold, we will drop all atomic written data in
cache, by this, I expect it can keep our system running safely to
prevent Dos attack.
In addition, his patch adds to show GC skip information in debugfs,
now it just shows count of skipped caused by atomic write.
Signed-off-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
Diffstat (limited to 'fs/f2fs/gc.c')
| -rw-r--r-- | fs/f2fs/gc.c | 27 |
1 files changed, 23 insertions, 4 deletions
diff --git a/fs/f2fs/gc.c b/fs/f2fs/gc.c index f02a9fee4b4b..50bb8fc25275 100644 --- a/fs/f2fs/gc.c +++ b/fs/f2fs/gc.c @@ -592,7 +592,7 @@ static bool is_alive(struct f2fs_sb_info *sbi, struct f2fs_summary *sum, * This can be used to move blocks, aka LBAs, directly on disk. */ static void move_data_block(struct inode *inode, block_t bidx, - unsigned int segno, int off) + int gc_type, unsigned int segno, int off) { struct f2fs_io_info fio = { .sbi = F2FS_I_SB(inode), @@ -620,8 +620,11 @@ static void move_data_block(struct inode *inode, block_t bidx, if (!check_valid_map(F2FS_I_SB(inode), segno, off)) goto out; - if (f2fs_is_atomic_file(inode)) + if (f2fs_is_atomic_file(inode)) { + F2FS_I(inode)->i_gc_failures[GC_FAILURE_ATOMIC]++; + F2FS_I_SB(inode)->skipped_atomic_files[gc_type]++; goto out; + } if (f2fs_is_pinned_file(inode)) { f2fs_pin_file_control(inode, true); @@ -733,8 +736,11 @@ static void move_data_page(struct inode *inode, block_t bidx, int gc_type, if (!check_valid_map(F2FS_I_SB(inode), segno, off)) goto out; - if (f2fs_is_atomic_file(inode)) + if (f2fs_is_atomic_file(inode)) { + F2FS_I(inode)->i_gc_failures[GC_FAILURE_ATOMIC]++; + F2FS_I_SB(inode)->skipped_atomic_files[gc_type]++; goto out; + } if (f2fs_is_pinned_file(inode)) { if (gc_type == FG_GC) f2fs_pin_file_control(inode, true); @@ -896,7 +902,8 @@ next_step: start_bidx = start_bidx_of_node(nofs, inode) + ofs_in_node; if (f2fs_post_read_required(inode)) - move_data_block(inode, start_bidx, segno, off); + move_data_block(inode, start_bidx, gc_type, + segno, off); else move_data_page(inode, start_bidx, gc_type, segno, off); @@ -1013,6 +1020,8 @@ int f2fs_gc(struct f2fs_sb_info *sbi, bool sync, .ilist = LIST_HEAD_INIT(gc_list.ilist), .iroot = RADIX_TREE_INIT(gc_list.iroot, GFP_NOFS), }; + unsigned long long last_skipped = sbi->skipped_atomic_files[FG_GC]; + unsigned int skipped_round = 0, round = 0; trace_f2fs_gc_begin(sbi->sb, sync, background, get_pages(sbi, F2FS_DIRTY_NODES), @@ -1064,11 +1073,21 @@ gc_more: sec_freed++; total_freed += seg_freed; + if (gc_type == FG_GC) { + if (sbi->skipped_atomic_files[FG_GC] > last_skipped) + skipped_round++; + last_skipped = sbi->skipped_atomic_files[FG_GC]; + round++; + } + if (gc_type == FG_GC) sbi->cur_victim_sec = NULL_SEGNO; if (!sync) { if (has_not_enough_free_secs(sbi, sec_freed, 0)) { + if (skipped_round > MAX_SKIP_ATOMIC_COUNT && + skipped_round * 2 >= round) + drop_inmem_pages_all(sbi, true); segno = NULL_SEGNO; goto gc_more; } |