Thanks for your review. I will send patch v2.
>On 2024/8/13 14:11, Yeongjin Gil wrote:
>> In f2fs_do_write_data_page, when the data block is NULL_ADDR, it skips
>> writepage considering that it has been already truncated.
>> This results in an infinite loop as the PAGECACHE_TAG_TOWRITE tag is
>> not cleared during the writeback process for a compressed file
>> including NULL_ADDR in compress_mode=user.
>>
>> This is the reproduction process:
>>
>> 1. dd if=/dev/zero bs=4096 count=1024 seek=1024 of=testfile 2. f2fs_io
>> compress testfile 3. dd if=/dev/zero bs=4096 count=1 conv=notrunc
>> of=testfile 4. f2fs_io decompress testfile
>
>Good catch!
>
>>
>> To prevent the problem, let's check whether the cluster is fully
>> allocated before redirty its pages.
>>
>> Reviewed-by: Sungjong Seo <sj1557....@samsung.com>
>> Reviewed-by: Sunmin Jeong <s_min.je...@samsung.com>
>> Tested-by: Jaewook Kim <jw5454....@samsung.com>
>> Signed-off-by: Yeongjin Gil <youngjin....@samsung.com>
>
>Need a fixes line?
>
>> ---
>> fs/f2fs/compress.c | 34 ++++++++++++++++++++++++++--------
>> fs/f2fs/f2fs.h | 12 ++++++++++++
>> fs/f2fs/file.c | 39 +++++++++++++++++++++------------------
>> 3 files changed, 59 insertions(+), 26 deletions(-)
>>
>> diff --git a/fs/f2fs/compress.c b/fs/f2fs/compress.c index
>> 990b93689b46..09b91d725807 100644
>> --- a/fs/f2fs/compress.c
>> +++ b/fs/f2fs/compress.c
>> @@ -945,7 +945,7 @@ static int __f2fs_get_cluster_blocks(struct inode
>*inode,
>> unsigned int cluster_size = F2FS_I(inode)->i_cluster_size;
>> int count, i;
>>
>> - for (i = 1, count = 1; i < cluster_size; i++) {
>> + for (i = 0, count = 0; i < cluster_size; i++) {
>> block_t blkaddr = data_blkaddr(dn->inode, dn->node_page,
>> dn->ofs_in_node + i);
>>
>> @@ -956,8 +956,8 @@ static int __f2fs_get_cluster_blocks(struct inode
>*inode,
>> return count;
>> }
>>
>> -static int __f2fs_cluster_blocks(struct inode *inode,
>> - unsigned int cluster_idx, bool compr_blks)
>> +static int __f2fs_cluster_blocks(struct inode *inode, unsigned int
>cluster_idx,
>> + enum cluster_check_type type)
>> {
>> struct dnode_of_data dn;
>> unsigned int start_idx = cluster_idx << @@ -978,10 +978,12 @@
>> static int __f2fs_cluster_blocks(struct inode *inode,
>> }
>>
>> if (dn.data_blkaddr == COMPRESS_ADDR) {
>> - if (compr_blks)
>> - ret = __f2fs_get_cluster_blocks(inode, &dn);
>> - else
>> + if (type == COMPR_BLKS)
>> + ret = 1 + __f2fs_get_cluster_blocks(inode, &dn);
>> + else if (type == COMPR_CLUSTER)
>> ret = 1;
>> + } else if (type == DECOMPR_BLKS) {
>> + ret = __f2fs_get_cluster_blocks(inode, &dn);
>> }
>> fail:
>> f2fs_put_dnode(&dn);
>> @@ -991,7 +993,14 @@ static int __f2fs_cluster_blocks(struct inode *inode,
>> /* return # of compressed blocks in compressed cluster */
>> static int f2fs_compressed_blocks(struct compress_ctx *cc)
>> {
>> - return __f2fs_cluster_blocks(cc->inode, cc->cluster_idx, true);
>> + return __f2fs_cluster_blocks(cc->inode, cc->cluster_idx,
>> +COMPR_BLKS); }
>> +
>> +/* return # of raw blocks in non-compressed cluster */ static int
>> +f2fs_decompressed_blocks(struct inode *inode,
>> + unsigned int cluster_idx)
>> +{
>> + return __f2fs_cluster_blocks(inode, cluster_idx, DECOMPR_BLKS);
>> }
>>
>> /* return whether cluster is compressed one or not */ @@ -999,7
>> +1008,16 @@ int f2fs_is_compressed_cluster(struct inode *inode, pgoff_t
>index)
>> {
>> return __f2fs_cluster_blocks(inode,
>> index >> F2FS_I(inode)->i_log_cluster_size,
>> - false);
>> + COMPR_CLUSTER);
>> +}
>> +
>> +/* return whether the cluster is filled with raw blocks */ bool
>> +f2fs_is_non_sparse_cluster(struct inode *inode, pgoff_t index)
>
>f2fs_is_sparse_cluster()?
>
>> +{
>> + unsigned int cluster_idx = index >>
>> +F2FS_I(inode)->i_log_cluster_size;
>> +
>> + return f2fs_decompressed_blocks(inode, cluster_idx) ==
>> + F2FS_I(inode)->i_cluster_size;
>> }
>>
>> static bool cluster_may_compress(struct compress_ctx *cc) diff --git
>> a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h index 51fd5063a69c..6f26c8cb8857
>> 100644
>> --- a/fs/f2fs/f2fs.h
>> +++ b/fs/f2fs/f2fs.h
>> @@ -4302,6 +4302,11 @@ static inline bool
>f2fs_meta_inode_gc_required(struct inode *inode)
>> * compress.c
>> */
>> #ifdef CONFIG_F2FS_FS_COMPRESSION
>> +enum cluster_check_type {
>> + COMPR_CLUSTER,
>> + COMPR_BLKS,
>> + DECOMPR_BLKS
>
>How about?
>
>CLUSTER_IS_COMPR,
>CLUSTER_COMPR_BLKS,
>CLUSTER_RAW_BLKS
>
>> +};
>
>Can you please add some comments for these enums?
>
>> bool f2fs_is_compressed_page(struct page *page);
>> struct page *f2fs_compress_control_page(struct page *page);
>> int f2fs_prepare_compress_overwrite(struct inode *inode, @@ -4328,6
>> +4333,7 @@ int f2fs_write_multi_pages(struct compress_ctx *cc,
>> struct writeback_control *wbc,
>> enum iostat_type io_type);
>> int f2fs_is_compressed_cluster(struct inode *inode, pgoff_t index);
>> +bool f2fs_is_non_sparse_cluster(struct inode *inode, pgoff_t index);
>> void f2fs_update_read_extent_tree_range_compressed(struct inode *inode,
>> pgoff_t fofs, block_t blkaddr,
>> unsigned int llen, unsigned int c_len); @@ -
>4414,6 +4420,12 @@
>> static inline bool f2fs_load_compressed_page(struct f2fs_sb_info *sbi,
>> static inline void f2fs_invalidate_compress_pages(struct f2fs_sb_info
>*sbi,
>> nid_t ino) { }
>> #define inc_compr_inode_stat(inode) do { } while (0)
>> +static inline int f2fs_is_compressed_cluster(
>> + struct inode *inode,
>> + pgoff_t index) { return 0; }
>> +static inline bool f2fs_is_non_sparse_cluster(
>> + struct inode *inode,
>> + pgoff_t index) { return false; }
>> static inline void f2fs_update_read_extent_tree_range_compressed(
>> struct inode *inode,
>> pgoff_t fofs, block_t blkaddr,
>> diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c index
>> 270c32e3385f..fba8b5f216f9 100644
>> --- a/fs/f2fs/file.c
>> +++ b/fs/f2fs/file.c
>> @@ -4220,9 +4220,8 @@ static int f2fs_ioc_decompress_file(struct file
>*filp)
>> struct inode *inode = file_inode(filp);
>> struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
>> struct f2fs_inode_info *fi = F2FS_I(inode);
>> - pgoff_t page_idx = 0, last_idx;
>> - int cluster_size = fi->i_cluster_size;
>> - int count, ret;
>> + pgoff_t page_idx = 0, last_idx, cluster_idx;
>> + int ret;
>>
>> if (!f2fs_sb_has_compression(sbi) ||
>> F2FS_OPTION(sbi).compress_mode != COMPR_MODE_USER) @@ -
>4257,10
>> +4256,15 @@ static int f2fs_ioc_decompress_file(struct file *filp)
>> goto out;
>>
>> last_idx = DIV_ROUND_UP(i_size_read(inode), PAGE_SIZE);
>> + last_idx >>= fi->i_log_cluster_size;
>> +
>> + for (cluster_idx = 0; cluster_idx < last_idx; cluster_idx++) {
>> + page_idx = cluster_idx << fi->i_log_cluster_size;
>> +
>> + if (!f2fs_is_compressed_cluster(inode, page_idx))
>> + continue;
>>
>> - count = last_idx - page_idx;
>> - while (count && count >= cluster_size) {
>> - ret = redirty_blocks(inode, page_idx, cluster_size);
>> + ret = redirty_blocks(inode, page_idx, fi->i_cluster_size);
>> if (ret < 0)
>> break;
>>
>> @@ -4270,9 +4274,6 @@ static int f2fs_ioc_decompress_file(struct file
>*filp)
>> break;
>> }
>>
>> - count -= cluster_size;
>> - page_idx += cluster_size;
>> -
>> cond_resched();
>> if (fatal_signal_pending(current)) {
>> ret = -EINTR;
>> @@ -4299,9 +4300,9 @@ static int f2fs_ioc_compress_file(struct file *filp)
>> {
>> struct inode *inode = file_inode(filp);
>> struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
>> - pgoff_t page_idx = 0, last_idx;
>> - int cluster_size = F2FS_I(inode)->i_cluster_size;
>> - int count, ret;
>> + struct f2fs_inode_info *fi = F2FS_I(inode);
>> + pgoff_t page_idx = 0, last_idx, cluster_idx;
>> + int ret;
>>
>> if (!f2fs_sb_has_compression(sbi) ||
>> F2FS_OPTION(sbi).compress_mode != COMPR_MODE_USER) @@ -
>4335,10
>> +4336,15 @@ static int f2fs_ioc_compress_file(struct file *filp)
>> set_inode_flag(inode, FI_ENABLE_COMPRESS);
>>
>> last_idx = DIV_ROUND_UP(i_size_read(inode), PAGE_SIZE);
>> + last_idx >>= fi->i_log_cluster_size;
>>
>> - count = last_idx - page_idx;
>> - while (count && count >= cluster_size) {
>> - ret = redirty_blocks(inode, page_idx, cluster_size);
>> + for (cluster_idx = 0; cluster_idx < last_idx; cluster_idx++) {
>> + page_idx = cluster_idx << fi->i_log_cluster_size;
>> +
>> + if (!f2fs_is_non_sparse_cluster(inode, page_idx))
>
>if (f2fs_is_sparse_cluster())
> continue;
>
>Thanks,
>
>> + continue;
>> +
>> + ret = redirty_blocks(inode, page_idx, fi->i_cluster_size);
>> if (ret < 0)
>> break;
>>
>> @@ -4348,9 +4354,6 @@ static int f2fs_ioc_compress_file(struct file *filp)
>> break;
>> }
>>
>> - count -= cluster_size;
>> - page_idx += cluster_size;
>> -
>> cond_resched();
>> if (fatal_signal_pending(current)) {
>> ret = -EINTR;
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