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f2fs: avoid fi->i_gc_rwsem[WRITE] lock in f2fs_gc

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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>
This commit is contained in:
Jaegeuk Kim 2018-07-25 12:11:56 +09:00
parent 853137cef4
commit 6f8d445506
6 changed files with 92 additions and 68 deletions
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4
fs/f2fs/data.c
View File

@ -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]);
}
}

1
fs/f2fs/f2fs.h
View File

@ -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;

121
fs/f2fs/file.c
View File

@ -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 @@ roll_back:
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);
/* 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;
return ret;
truncate_pagecache(inode, offset);
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 @@ out:
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 @@ err_out:
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]);
inode_unlock(dst);
}
out:
out_src:
up_write(&F2FS_I(src)->i_gc_rwsem[WRITE]);
out_unlock:
if (src != dst)
inode_unlock(dst);
out:
inode_unlock(src);
return ret;
}

26
fs/f2fs/gc.c
View File

@ -882,6 +882,7 @@ next_step:
if (!down_write_trylock(
&F2FS_I(inode)->i_gc_rwsem[WRITE])) {
iput(inode);
sbi->skipped_gc_rwsem++;
continue;
}
@ -911,6 +912,7 @@ next_step:
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 @@ gc_more:
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 @@ gc_more:
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);
}

6
fs/f2fs/segment.c
View File

@ -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;
}

2
fs/f2fs/segment.h
View File

@ -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;