[PATCH 1/2] f2fs: ro: compress: fix to avoid caching unaligned extent

[PATCH 1/2] f2fs: ro: compress: fix to avoid caching unaligned extent

[Chao Yu]

Mapping info from dump.f2fs:
i_addr[0x2d] cluster flag    		[0xfffffffe : 4294967294]
i_addr[0x2e]                 		[0x   10428 : 66600]
i_addr[0x2f]                 		[0x   10429 : 66601]
i_addr[0x30]                 		[0x   1042a : 66602]

f2fs_io fiemap 37 1 /mnt/f2fs/disk-58390c8c.raw

Previsouly, it missed to align fofs and ofs_in_node to cluster_size,
result in adding incorrect read extent cache, fix it.

Before:
f2fs_update_read_extent_tree_range: dev = (253,48), ino = 5, pgofs = 37, len = 4, blkaddr = 66600, c_len = 3

After:
f2fs_update_read_extent_tree_range: dev = (253,48), ino = 5, pgofs = 36, len = 4, blkaddr = 66600, c_len = 3

Fixes: 94afd6d6e525 ("f2fs: extent cache: support unaligned extent")
Signed-off-by: Chao Yu <chao@kernel.org>
---
 fs/f2fs/compress.c | 10 ++++++----
 fs/f2fs/f2fs.h     |  6 ++++--
 fs/f2fs/node.c     | 20 ++++++++++++++------
 3 files changed, 24 insertions(+), 12 deletions(-)

diff --git a/fs/f2fs/compress.c b/fs/f2fs/compress.c
index f821681886b8..21f03d119d4d 100644
--- a/fs/f2fs/compress.c
+++ b/fs/f2fs/compress.c
@@ -1841,16 +1841,18 @@ void f2fs_put_page_dic(struct page *page, bool in_task)
  * check whether cluster blocks are contiguous, and add extent cache entry
  * only if cluster blocks are logically and physically contiguous.
  */
-unsigned int f2fs_cluster_blocks_are_contiguous(struct dnode_of_data *dn)
+unsigned int f2fs_cluster_blocks_are_contiguous(struct dnode_of_data *dn,
+						unsigned int ofs_in_node)
 {
-	bool compressed = f2fs_data_blkaddr(dn) == COMPRESS_ADDR;
+	bool compressed = data_blkaddr(dn->inode, dn->node_page,
+					ofs_in_node) == COMPRESS_ADDR;
 	int i = compressed ? 1 : 0;
 	block_t first_blkaddr = data_blkaddr(dn->inode, dn->node_page,
-						dn->ofs_in_node + i);
+							ofs_in_node + i);
 
 	for (i += 1; i < F2FS_I(dn->inode)->i_cluster_size; i++) {
 		block_t blkaddr = data_blkaddr(dn->inode, dn->node_page,
-						dn->ofs_in_node + i);
+							ofs_in_node + i);
 
 		if (!__is_valid_data_blkaddr(blkaddr))
 			break;
diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
index 51701fc66200..33fd02716cf3 100644
--- a/fs/f2fs/f2fs.h
+++ b/fs/f2fs/f2fs.h
@@ -4307,7 +4307,8 @@ struct decompress_io_ctx *f2fs_alloc_dic(struct compress_ctx *cc);
 void f2fs_decompress_end_io(struct decompress_io_ctx *dic, bool failed,
 				bool in_task);
 void f2fs_put_page_dic(struct page *page, bool in_task);
-unsigned int f2fs_cluster_blocks_are_contiguous(struct dnode_of_data *dn);
+unsigned int f2fs_cluster_blocks_are_contiguous(struct dnode_of_data *dn,
+						unsigned int ofs_in_node);
 int f2fs_init_compress_ctx(struct compress_ctx *cc);
 void f2fs_destroy_compress_ctx(struct compress_ctx *cc, bool reuse);
 void f2fs_init_compress_info(struct f2fs_sb_info *sbi);
@@ -4364,7 +4365,8 @@ static inline void f2fs_put_page_dic(struct page *page, bool in_task)
 {
 	WARN_ON_ONCE(1);
 }
-static inline unsigned int f2fs_cluster_blocks_are_contiguous(struct dnode_of_data *dn) { return 0; }
+static inline unsigned int f2fs_cluster_blocks_are_contiguous(
+			struct dnode_of_data *dn, unsigned int ofs_in_node) { return 0; }
 static inline bool f2fs_sanity_check_cluster(struct dnode_of_data *dn) { return false; }
 static inline int f2fs_init_compress_inode(struct f2fs_sb_info *sbi) { return 0; }
 static inline void f2fs_destroy_compress_inode(struct f2fs_sb_info *sbi) { }
diff --git a/fs/f2fs/node.c b/fs/f2fs/node.c
index 51241996b9ec..b3de6d6cdb02 100644
--- a/fs/f2fs/node.c
+++ b/fs/f2fs/node.c
@@ -852,21 +852,29 @@ int f2fs_get_dnode_of_data(struct dnode_of_data *dn, pgoff_t index, int mode)
 
 	if (is_inode_flag_set(dn->inode, FI_COMPRESSED_FILE) &&
 					f2fs_sb_has_readonly(sbi)) {
-		unsigned int c_len = f2fs_cluster_blocks_are_contiguous(dn);
+		unsigned int cluster_size = F2FS_I(dn->inode)->i_cluster_size;
+		unsigned int ofs_in_node = dn->ofs_in_node;
+		pgoff_t fofs = index;
+		unsigned int c_len;
 		block_t blkaddr;
 
+		/* should align fofs and ofs_in_node to cluster_size */
+		if (fofs % cluster_size) {
+			fofs = round_down(fofs, cluster_size);
+			ofs_in_node = round_down(ofs_in_node, cluster_size);
+		}
+
+		c_len = f2fs_cluster_blocks_are_contiguous(dn, ofs_in_node);
 		if (!c_len)
 			goto out;
 
-		blkaddr = f2fs_data_blkaddr(dn);
+		blkaddr = data_blkaddr(dn->inode, dn->node_page, ofs_in_node);
 		if (blkaddr == COMPRESS_ADDR)
 			blkaddr = data_blkaddr(dn->inode, dn->node_page,
-						dn->ofs_in_node + 1);
+						ofs_in_node + 1);
 
 		f2fs_update_read_extent_tree_range_compressed(dn->inode,
-					index, blkaddr,
-					F2FS_I(dn->inode)->i_cluster_size,
-					c_len);
+					fofs, blkaddr, cluster_size, c_len);
 	}
 out:
 	return 0;
-- 
2.40.1

[PATCH 2/2] f2fs: ro: don't start discard thread for readonly image

[Chao Yu]

[ 9299.893835] F2FS-fs (vdd): Allow to mount readonly mode only
mount: /mnt/f2fs: WARNING: source write-protected, mounted read-only.
root@qemu:/ ps -ef|grep f2fs
root          94       2  0 03:46 ?        00:00:00 [kworker/u17:0-f2fs_post_read_wq]
root        6282       2  0 06:21 ?        00:00:00 [f2fs_discard-253:48]

There will be no deletion in readonly image, let's skip starting
discard thread to save system resources.

Signed-off-by: Chao Yu <chao@kernel.org>
---
 fs/f2fs/segment.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
index b486fe4485f9..cc27c5440188 100644
--- a/fs/f2fs/segment.c
+++ b/fs/f2fs/segment.c
@@ -2253,6 +2253,12 @@ int f2fs_start_discard_thread(struct f2fs_sb_info *sbi)
 	struct discard_cmd_control *dcc = SM_I(sbi)->dcc_info;
 	int err = 0;
 
+	if (f2fs_sb_has_readonly(sbi)) {
+		f2fs_info(sbi,
+			"Skip to start discard thread for readonly image");
+		return 0;
+	}
+
 	if (!f2fs_realtime_discard_enable(sbi))
 		return 0;
 
-- 
2.40.1

Re: [f2fs-dev] [PATCH 1/2] f2fs: ro: compress: fix to avoid caching unaligned extent

[patchwork-bot+f2fs]

Hello:

This series was applied to jaegeuk/f2fs.git (dev)
by Jaegeuk Kim <jaegeuk@kernel.org>:

On Mon, 26 Feb 2024 15:35:38 +0800 you wrote:
> Mapping info from dump.f2fs:
> i_addr[0x2d] cluster flag    		[0xfffffffe : 4294967294]
> i_addr[0x2e]                 		[0x   10428 : 66600]
> i_addr[0x2f]                 		[0x   10429 : 66601]
> i_addr[0x30]                 		[0x   1042a : 66602]
> 
> f2fs_io fiemap 37 1 /mnt/f2fs/disk-58390c8c.raw
> 
> [...]

Here is the summary with links:
  - [f2fs-dev,1/2] f2fs: ro: compress: fix to avoid caching unaligned extent
    https://git.kernel.org/jaegeuk/f2fs/c/4b99ecd30429
  - [f2fs-dev,2/2] f2fs: ro: don't start discard thread for readonly image
    https://git.kernel.org/jaegeuk/f2fs/c/a217f1873ab9

You are awesome, thank you!
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