From 6f8d4455060dfb0e32dfb8e685b97caf4ed1be41 Mon Sep 17 00:00:00 2001
From: Jaegeuk Kim <jaegeuk@kernel.org>
Date: Wed, 25 Jul 2018 12:11:56 +0900
Subject: [PATCH] f2fs: avoid fi->i_gc_rwsem[WRITE] lock in f2fs_gc
The f2fs_gc() called by f2fs_balance_fs() requires to be called outside of
fi->i_gc_rwsem[WRITE], since f2fs_gc() can try to grab it in a loop.
If it hits the miximum retrials in GC, let's give a chance to release
gc_mutex for a short time in order not to go into live lock in the worst
case.
Reviewed-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
---
fs/f2fs/data.c | 4 +-
fs/f2fs/f2fs.h | 1 +
fs/f2fs/file.c | 119 ++++++++++++++++++++++++----------------------
fs/f2fs/gc.c | 26 +++++++---
fs/f2fs/segment.c | 6 ++-
fs/f2fs/segment.h | 2 +-
6 files changed, 91 insertions(+), 67 deletions(-)
diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
index bdcb023506a7a..e73ce11de02d4 100644
--- a/fs/f2fs/data.c
+++ b/fs/f2fs/data.c
@@ -2217,14 +2217,14 @@ static void f2fs_write_failed(struct address_space *mapping, loff_t to)
loff_t i_size = i_size_read(inode);
if (to > i_size) {
- down_write(&F2FS_I(inode)->i_mmap_sem);
down_write(&F2FS_I(inode)->i_gc_rwsem[WRITE]);
+ down_write(&F2FS_I(inode)->i_mmap_sem);
truncate_pagecache(inode, i_size);
f2fs_truncate_blocks(inode, i_size, true);
- up_write(&F2FS_I(inode)->i_gc_rwsem[WRITE]);
up_write(&F2FS_I(inode)->i_mmap_sem);
+ up_write(&F2FS_I(inode)->i_gc_rwsem[WRITE]);
}
}
diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
index 170573f8a04a3..96bde026636ff 100644
--- a/fs/f2fs/f2fs.h
+++ b/fs/f2fs/f2fs.h
@@ -1243,6 +1243,7 @@ struct f2fs_sb_info {
unsigned int gc_mode; /* current GC state */
/* for skip statistic */
unsigned long long skipped_atomic_files[2]; /* FG_GC and BG_GC */
+ unsigned long long skipped_gc_rwsem; /* FG_GC only */
/* threshold for gc trials on pinned files */
u64 gc_pin_file_threshold;
diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c
index 1f76cc3fc46b0..5474aaa274b91 100644
--- a/fs/f2fs/file.c
+++ b/fs/f2fs/file.c
@@ -797,8 +797,8 @@ int f2fs_setattr(struct dentry *dentry, struct iattr *attr)
if (attr->ia_valid & ATTR_SIZE) {
bool to_smaller = (attr->ia_size <= i_size_read(inode));
- down_write(&F2FS_I(inode)->i_mmap_sem);
down_write(&F2FS_I(inode)->i_gc_rwsem[WRITE]);
+ down_write(&F2FS_I(inode)->i_mmap_sem);
truncate_setsize(inode, attr->ia_size);
@@ -808,8 +808,8 @@ int f2fs_setattr(struct dentry *dentry, struct iattr *attr)
* do not trim all blocks after i_size if target size is
* larger than i_size.
*/
- up_write(&F2FS_I(inode)->i_gc_rwsem[WRITE]);
up_write(&F2FS_I(inode)->i_mmap_sem);
+ up_write(&F2FS_I(inode)->i_gc_rwsem[WRITE]);
if (err)
return err;
@@ -962,8 +962,8 @@ static int punch_hole(struct inode *inode, loff_t offset, loff_t len)
blk_start = (loff_t)pg_start << PAGE_SHIFT;
blk_end = (loff_t)pg_end << PAGE_SHIFT;
- down_write(&F2FS_I(inode)->i_mmap_sem);
down_write(&F2FS_I(inode)->i_gc_rwsem[WRITE]);
+ down_write(&F2FS_I(inode)->i_mmap_sem);
truncate_inode_pages_range(mapping, blk_start,
blk_end - 1);
@@ -972,8 +972,8 @@ static int punch_hole(struct inode *inode, loff_t offset, loff_t len)
ret = f2fs_truncate_hole(inode, pg_start, pg_end);
f2fs_unlock_op(sbi);
- up_write(&F2FS_I(inode)->i_gc_rwsem[WRITE]);
up_write(&F2FS_I(inode)->i_mmap_sem);
+ up_write(&F2FS_I(inode)->i_gc_rwsem[WRITE]);
}
}
@@ -1188,25 +1188,33 @@ static int __exchange_data_block(struct inode *src_inode,
return ret;
}
-static int f2fs_do_collapse(struct inode *inode, pgoff_t start, pgoff_t end)
+static int f2fs_do_collapse(struct inode *inode, loff_t offset, loff_t len)
{
struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
pgoff_t nrpages = (i_size_read(inode) + PAGE_SIZE - 1) / PAGE_SIZE;
+ pgoff_t start = offset >> PAGE_SHIFT;
+ pgoff_t end = (offset + len) >> PAGE_SHIFT;
int ret;
f2fs_balance_fs(sbi, true);
- f2fs_lock_op(sbi);
- f2fs_drop_extent_tree(inode);
+ /* avoid gc operation during block exchange */
+ down_write(&F2FS_I(inode)->i_gc_rwsem[WRITE]);
+ down_write(&F2FS_I(inode)->i_mmap_sem);
+ f2fs_lock_op(sbi);
+ f2fs_drop_extent_tree(inode);
+ truncate_pagecache(inode, offset);
ret = __exchange_data_block(inode, inode, end, start, nrpages - end, true);
f2fs_unlock_op(sbi);
+
+ up_write(&F2FS_I(inode)->i_mmap_sem);
+ up_write(&F2FS_I(inode)->i_gc_rwsem[WRITE]);
return ret;
}
static int f2fs_collapse_range(struct inode *inode, loff_t offset, loff_t len)
{
- pgoff_t pg_start, pg_end;
loff_t new_size;
int ret;
@@ -1221,25 +1229,17 @@ static int f2fs_collapse_range(struct inode *inode, loff_t offset, loff_t len)
if (ret)
return ret;
- pg_start = offset >> PAGE_SHIFT;
- pg_end = (offset + len) >> PAGE_SHIFT;
-
- /* avoid gc operation during block exchange */
- down_write(&F2FS_I(inode)->i_gc_rwsem[WRITE]);
-
- down_write(&F2FS_I(inode)->i_mmap_sem);
/* write out all dirty pages from offset */
ret = filemap_write_and_wait_range(inode->i_mapping, offset, LLONG_MAX);
if (ret)
- goto out_unlock;
-
- truncate_pagecache(inode, offset);
+ return ret;
- ret = f2fs_do_collapse(inode, pg_start, pg_end);
+ ret = f2fs_do_collapse(inode, offset, len);
if (ret)
- goto out_unlock;
+ return ret;
/* write out all moved pages, if possible */
+ down_write(&F2FS_I(inode)->i_mmap_sem);
filemap_write_and_wait_range(inode->i_mapping, offset, LLONG_MAX);
truncate_pagecache(inode, offset);
@@ -1247,11 +1247,9 @@ static int f2fs_collapse_range(struct inode *inode, loff_t offset, loff_t len)
truncate_pagecache(inode, new_size);
ret = f2fs_truncate_blocks(inode, new_size, true);
+ up_write(&F2FS_I(inode)->i_mmap_sem);
if (!ret)
f2fs_i_size_write(inode, new_size);
-out_unlock:
- up_write(&F2FS_I(inode)->i_mmap_sem);
- up_write(&F2FS_I(inode)->i_gc_rwsem[WRITE]);
return ret;
}
@@ -1317,10 +1315,9 @@ static int f2fs_zero_range(struct inode *inode, loff_t offset, loff_t len,
if (ret)
return ret;
- down_write(&F2FS_I(inode)->i_mmap_sem);
ret = filemap_write_and_wait_range(mapping, offset, offset + len - 1);
if (ret)
- goto out_sem;
+ return ret;
pg_start = ((unsigned long long) offset) >> PAGE_SHIFT;
pg_end = ((unsigned long long) offset + len) >> PAGE_SHIFT;
@@ -1332,7 +1329,7 @@ static int f2fs_zero_range(struct inode *inode, loff_t offset, loff_t len,
ret = fill_zero(inode, pg_start, off_start,
off_end - off_start);
if (ret)
- goto out_sem;
+ return ret;
new_size = max_t(loff_t, new_size, offset + len);
} else {
@@ -1340,7 +1337,7 @@ static int f2fs_zero_range(struct inode *inode, loff_t offset, loff_t len,
ret = fill_zero(inode, pg_start++, off_start,
PAGE_SIZE - off_start);
if (ret)
- goto out_sem;
+ return ret;
new_size = max_t(loff_t, new_size,
(loff_t)pg_start << PAGE_SHIFT);
@@ -1352,6 +1349,7 @@ static int f2fs_zero_range(struct inode *inode, loff_t offset, loff_t len,
pgoff_t end;
down_write(&F2FS_I(inode)->i_gc_rwsem[WRITE]);
+ down_write(&F2FS_I(inode)->i_mmap_sem);
truncate_pagecache_range(inode,
(loff_t)index << PAGE_SHIFT,
@@ -1363,6 +1361,7 @@ static int f2fs_zero_range(struct inode *inode, loff_t offset, loff_t len,
ret = f2fs_get_dnode_of_data(&dn, index, ALLOC_NODE);
if (ret) {
f2fs_unlock_op(sbi);
+ up_write(&F2FS_I(inode)->i_mmap_sem);
up_write(&F2FS_I(inode)->i_gc_rwsem[WRITE]);
goto out;
}
@@ -1374,6 +1373,7 @@ static int f2fs_zero_range(struct inode *inode, loff_t offset, loff_t len,
f2fs_put_dnode(&dn);
f2fs_unlock_op(sbi);
+ up_write(&F2FS_I(inode)->i_mmap_sem);
up_write(&F2FS_I(inode)->i_gc_rwsem[WRITE]);
f2fs_balance_fs(sbi, dn.node_changed);
@@ -1402,9 +1402,6 @@ static int f2fs_zero_range(struct inode *inode, loff_t offset, loff_t len,
else
f2fs_i_size_write(inode, new_size);
}
-out_sem:
- up_write(&F2FS_I(inode)->i_mmap_sem);
-
return ret;
}
@@ -1433,26 +1430,27 @@ static int f2fs_insert_range(struct inode *inode, loff_t offset, loff_t len)
f2fs_balance_fs(sbi, true);
- /* avoid gc operation during block exchange */
- down_write(&F2FS_I(inode)->i_gc_rwsem[WRITE]);
-
down_write(&F2FS_I(inode)->i_mmap_sem);
ret = f2fs_truncate_blocks(inode, i_size_read(inode), true);
+ up_write(&F2FS_I(inode)->i_mmap_sem);
if (ret)
- goto out;
+ return ret;
/* write out all dirty pages from offset */
ret = filemap_write_and_wait_range(inode->i_mapping, offset, LLONG_MAX);
if (ret)
- goto out;
-
- truncate_pagecache(inode, offset);
+ return ret;
pg_start = offset >> PAGE_SHIFT;
pg_end = (offset + len) >> PAGE_SHIFT;
delta = pg_end - pg_start;
idx = (i_size_read(inode) + PAGE_SIZE - 1) / PAGE_SIZE;
+ /* avoid gc operation during block exchange */
+ down_write(&F2FS_I(inode)->i_gc_rwsem[WRITE]);
+ down_write(&F2FS_I(inode)->i_mmap_sem);
+ truncate_pagecache(inode, offset);
+
while (!ret && idx > pg_start) {
nr = idx - pg_start;
if (nr > delta)
@@ -1466,16 +1464,17 @@ static int f2fs_insert_range(struct inode *inode, loff_t offset, loff_t len)
idx + delta, nr, false);
f2fs_unlock_op(sbi);
}
+ up_write(&F2FS_I(inode)->i_mmap_sem);
+ up_write(&F2FS_I(inode)->i_gc_rwsem[WRITE]);
/* write out all moved pages, if possible */
+ down_write(&F2FS_I(inode)->i_mmap_sem);
filemap_write_and_wait_range(inode->i_mapping, offset, LLONG_MAX);
truncate_pagecache(inode, offset);
+ up_write(&F2FS_I(inode)->i_mmap_sem);
if (!ret)
f2fs_i_size_write(inode, new_size);
-out:
- up_write(&F2FS_I(inode)->i_mmap_sem);
- up_write(&F2FS_I(inode)->i_gc_rwsem[WRITE]);
return ret;
}
@@ -1722,8 +1721,6 @@ static int f2fs_ioc_start_atomic_write(struct file *filp)
inode_lock(inode);
- down_write(&F2FS_I(inode)->i_gc_rwsem[WRITE]);
-
if (f2fs_is_atomic_file(inode)) {
if (is_inode_flag_set(inode, FI_ATOMIC_REVOKE_REQUEST))
ret = -EINVAL;
@@ -1734,6 +1731,8 @@ static int f2fs_ioc_start_atomic_write(struct file *filp)
if (ret)
goto out;
+ down_write(&F2FS_I(inode)->i_gc_rwsem[WRITE]);
+
if (!get_dirty_pages(inode))
goto skip_flush;
@@ -1741,18 +1740,20 @@ static int f2fs_ioc_start_atomic_write(struct file *filp)
"Unexpected flush for atomic writes: ino=%lu, npages=%u",
inode->i_ino, get_dirty_pages(inode));
ret = filemap_write_and_wait_range(inode->i_mapping, 0, LLONG_MAX);
- if (ret)
+ if (ret) {
+ up_write(&F2FS_I(inode)->i_gc_rwsem[WRITE]);
goto out;
+ }
skip_flush:
set_inode_flag(inode, FI_ATOMIC_FILE);
clear_inode_flag(inode, FI_ATOMIC_REVOKE_REQUEST);
- f2fs_update_time(F2FS_I_SB(inode), REQ_TIME);
+ up_write(&F2FS_I(inode)->i_gc_rwsem[WRITE]);
+ f2fs_update_time(F2FS_I_SB(inode), REQ_TIME);
F2FS_I(inode)->inmem_task = current;
stat_inc_atomic_write(inode);
stat_update_max_atomic_write(inode);
out:
- up_write(&F2FS_I(inode)->i_gc_rwsem[WRITE]);
inode_unlock(inode);
mnt_drop_write_file(filp);
return ret;
@@ -1770,9 +1771,9 @@ static int f2fs_ioc_commit_atomic_write(struct file *filp)
if (ret)
return ret;
- inode_lock(inode);
+ f2fs_balance_fs(F2FS_I_SB(inode), true);
- down_write(&F2FS_I(inode)->i_gc_rwsem[WRITE]);
+ inode_lock(inode);
if (f2fs_is_volatile_file(inode)) {
ret = -EINVAL;
@@ -1798,7 +1799,6 @@ static int f2fs_ioc_commit_atomic_write(struct file *filp)
clear_inode_flag(inode, FI_ATOMIC_REVOKE_REQUEST);
ret = -EINVAL;
}
- up_write(&F2FS_I(inode)->i_gc_rwsem[WRITE]);
inode_unlock(inode);
mnt_drop_write_file(filp);
return ret;
@@ -2394,15 +2394,10 @@ static int f2fs_move_file_range(struct file *file_in, loff_t pos_in,
}
inode_lock(src);
- down_write(&F2FS_I(src)->i_gc_rwsem[WRITE]);
if (src != dst) {
ret = -EBUSY;
if (!inode_trylock(dst))
goto out;
- if (!down_write_trylock(&F2FS_I(dst)->i_gc_rwsem[WRITE])) {
- inode_unlock(dst);
- goto out;
- }
}
ret = -EINVAL;
@@ -2447,6 +2442,14 @@ static int f2fs_move_file_range(struct file *file_in, loff_t pos_in,
goto out_unlock;
f2fs_balance_fs(sbi, true);
+
+ down_write(&F2FS_I(src)->i_gc_rwsem[WRITE]);
+ if (src != dst) {
+ ret = -EBUSY;
+ if (!down_write_trylock(&F2FS_I(dst)->i_gc_rwsem[WRITE]))
+ goto out_src;
+ }
+
f2fs_lock_op(sbi);
ret = __exchange_data_block(src, dst, pos_in >> F2FS_BLKSIZE_BITS,
pos_out >> F2FS_BLKSIZE_BITS,
@@ -2459,13 +2462,15 @@ static int f2fs_move_file_range(struct file *file_in, loff_t pos_in,
f2fs_i_size_write(dst, dst_osize);
}
f2fs_unlock_op(sbi);
-out_unlock:
- if (src != dst) {
+
+ if (src != dst)
up_write(&F2FS_I(dst)->i_gc_rwsem[WRITE]);
+out_src:
+ up_write(&F2FS_I(src)->i_gc_rwsem[WRITE]);
+out_unlock:
+ if (src != dst)
inode_unlock(dst);
- }
out:
- up_write(&F2FS_I(src)->i_gc_rwsem[WRITE]);
inode_unlock(src);
return ret;
}
diff --git a/fs/f2fs/gc.c b/fs/f2fs/gc.c
index 76a22b3773bc0..c598ae5ecbfa4 100644
--- a/fs/f2fs/gc.c
+++ b/fs/f2fs/gc.c
@@ -882,6 +882,7 @@ static void gc_data_segment(struct f2fs_sb_info *sbi, struct f2fs_summary *sum,
if (!down_write_trylock(
&F2FS_I(inode)->i_gc_rwsem[WRITE])) {
iput(inode);
+ sbi->skipped_gc_rwsem++;
continue;
}
@@ -911,6 +912,7 @@ static void gc_data_segment(struct f2fs_sb_info *sbi, struct f2fs_summary *sum,
continue;
if (!down_write_trylock(
&fi->i_gc_rwsem[WRITE])) {
+ sbi->skipped_gc_rwsem++;
up_write(&fi->i_gc_rwsem[READ]);
continue;
}
@@ -1048,6 +1050,7 @@ int f2fs_gc(struct f2fs_sb_info *sbi, bool sync,
.iroot = RADIX_TREE_INIT(gc_list.iroot, GFP_NOFS),
};
unsigned long long last_skipped = sbi->skipped_atomic_files[FG_GC];
+ unsigned long long first_skipped;
unsigned int skipped_round = 0, round = 0;
trace_f2fs_gc_begin(sbi->sb, sync, background,
@@ -1060,6 +1063,8 @@ int f2fs_gc(struct f2fs_sb_info *sbi, bool sync,
prefree_segments(sbi));
cpc.reason = __get_cp_reason(sbi);
+ sbi->skipped_gc_rwsem = 0;
+ first_skipped = last_skipped;
gc_more:
if (unlikely(!(sbi->sb->s_flags & SB_ACTIVE))) {
ret = -EINVAL;
@@ -1101,7 +1106,8 @@ int f2fs_gc(struct f2fs_sb_info *sbi, bool sync,
total_freed += seg_freed;
if (gc_type == FG_GC) {
- if (sbi->skipped_atomic_files[FG_GC] > last_skipped)
+ if (sbi->skipped_atomic_files[FG_GC] > last_skipped ||
+ sbi->skipped_gc_rwsem)
skipped_round++;
last_skipped = sbi->skipped_atomic_files[FG_GC];
round++;
@@ -1110,15 +1116,23 @@ int f2fs_gc(struct f2fs_sb_info *sbi, bool sync,
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)
- f2fs_drop_inmem_pages_all(sbi, true);
+ if (sync)
+ goto stop;
+
+ if (has_not_enough_free_secs(sbi, sec_freed, 0)) {
+ if (skipped_round <= MAX_SKIP_GC_COUNT ||
+ skipped_round * 2 < round) {
segno = NULL_SEGNO;
goto gc_more;
}
+ if (first_skipped < last_skipped &&
+ (last_skipped - first_skipped) >
+ sbi->skipped_gc_rwsem) {
+ f2fs_drop_inmem_pages_all(sbi, true);
+ segno = NULL_SEGNO;
+ goto gc_more;
+ }
if (gc_type == FG_GC)
ret = f2fs_write_checkpoint(sbi, &cpc);
}
diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
index 20650e25117b2..7dcfe38e70cc1 100644
--- a/fs/f2fs/segment.c
+++ b/fs/f2fs/segment.c
@@ -445,8 +445,10 @@ int f2fs_commit_inmem_pages(struct inode *inode)
int err;
f2fs_balance_fs(sbi, true);
- f2fs_lock_op(sbi);
+ down_write(&fi->i_gc_rwsem[WRITE]);
+
+ f2fs_lock_op(sbi);
set_inode_flag(inode, FI_ATOMIC_COMMIT);
mutex_lock(&fi->inmem_lock);
@@ -461,6 +463,8 @@ int f2fs_commit_inmem_pages(struct inode *inode)
clear_inode_flag(inode, FI_ATOMIC_COMMIT);
f2fs_unlock_op(sbi);
+ up_write(&fi->i_gc_rwsem[WRITE]);
+
return err;
}
diff --git a/fs/f2fs/segment.h b/fs/f2fs/segment.h
index 50495515f0a0d..b3d9e317ff0c1 100644
--- a/fs/f2fs/segment.h
+++ b/fs/f2fs/segment.h
@@ -215,7 +215,7 @@ struct segment_allocation {
#define IS_DUMMY_WRITTEN_PAGE(page) \
(page_private(page) == (unsigned long)DUMMY_WRITTEN_PAGE)
-#define MAX_SKIP_ATOMIC_COUNT 16
+#define MAX_SKIP_GC_COUNT 16
struct inmem_pages {
struct list_head list;
--
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