[PATCH] f2fs: fix to release compress file for F2FS_IOC_RESERVE_COMPRESS_BLOCKS when has no space

[Yangtao Li]

When the released file is reserving and the space is insufficient,
the fsck flag is set incorrectly, and lead to the file cannot be
reserved and released normally.

$ mount -t f2fs -o compress_extension=*,compress_mode=user /mnt/9p/f2fs.img
	/mnt/f2fs/
$ dd if=/dev/zero of=/mnt/f2fs/800M bs=1M count=800
$ dd if=/dev/zero of=/mnt/f2fs/60M bs=1M count=60
$ f2fs_io compress /mnt/f2fs/60M
$ ./mnt/9p/my_f2fs_io release_cblocks /mnt/f2fs/60M
11520
$ dd if=/dev/zero of=/mnt/f2fs/30M bs=1M count=30
$ f2fs_io reserve_cblocks /mnt/f2fs/60M
[   56.399712] F2FS-fs (loop0): f2fs_reserve_compress_blocks: partial blocks
	were released i_ino=cf iblocks=76104, reserved=5220, compr_blocks=5655,
	run fsck to fix.
F2FS_IOC_RESERVE_COMPRESS_BLOCKS failed: No space left on device

$ ./mnt/9p/my_f2fs_io reserve_cblocks /mnt/f2fs/60M
0
$ ./mnt/9p/my_f2fs_io release_cblocks /mnt/f2fs/60M
F2FS_IOC_RELEASE_COMPRESS_BLOCKS failed: Invalid argument

$ rm /mnt/f2fs/30M
$ ./mnt/9p/my_f2fs_io reserve_cblocks /mnt/f2fs/60M
0
$ ./mnt/9p/my_f2fs_io release_cblocks /mnt/f2fs/60M
F2FS_IOC_RELEASE_COMPRESS_BLOCKS failed: Invalid argument

In this case, let's release back the reserved part of the compressed file.

Fixes: c75488fb4d82 ("f2fs: introduce F2FS_IOC_RESERVE_COMPRESS_BLOCKS")
Signed-off-by: Qi Han <hanqi@xxxxxxxx>
Signed-off-by: Yangtao Li <frank.li@xxxxxxxx>
---
 fs/f2fs/file.c | 97 ++++++++++++++++++++++++++++++++------------------
 1 file changed, 63 insertions(+), 34 deletions(-)

diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c
index 300eae8b5415..8f3f55ac153a 100644
--- a/fs/f2fs/file.c
+++ b/fs/f2fs/file.c
@@ -3427,11 +3427,52 @@ static int release_compress_blocks(struct dnode_of_data *dn, pgoff_t count)
 	return released_blocks;
 }
 
+static int f2fs_do_release_compress_blocks(struct inode *inode,
+			pgoff_t page_count, unsigned int *released_blocks)
+{
+	pgoff_t page_idx = 0;
+	int ret;
+
+	while (page_idx < page_count) {
+		struct dnode_of_data dn;
+		pgoff_t end_offset, count;
+
+		set_new_dnode(&dn, inode, NULL, NULL, 0);
+		ret = f2fs_get_dnode_of_data(&dn, page_idx, LOOKUP_NODE);
+		if (ret) {
+			if (ret == -ENOENT) {
+				page_idx = f2fs_get_next_page_offset(&dn,
+								page_idx);
+				ret = 0;
+				continue;
+			}
+			break;
+		}
+
+		end_offset = ADDRS_PER_PAGE(dn.node_page, inode);
+		count = min(end_offset - dn.ofs_in_node, page_count - page_idx);
+		count = round_up(count, F2FS_I(inode)->i_cluster_size);
+
+		ret = release_compress_blocks(&dn, count);
+
+		f2fs_put_dnode(&dn);
+
+		if (ret < 0)
+			break;
+
+		page_idx += count;
+		if (released_blocks)
+			*released_blocks += ret;
+	}
+
+	return ret;
+}
+
 static int f2fs_release_compress_blocks(struct file *filp, unsigned long arg)
 {
 	struct inode *inode = file_inode(filp);
 	struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
-	pgoff_t page_idx = 0, last_idx;
+	pgoff_t last_idx;
 	unsigned int released_blocks = 0;
 	int ret;
 	int writecount;
@@ -3481,36 +3522,7 @@ static int f2fs_release_compress_blocks(struct file *filp, unsigned long arg)
 
 	last_idx = DIV_ROUND_UP(i_size_read(inode), PAGE_SIZE);
 
-	while (page_idx < last_idx) {
-		struct dnode_of_data dn;
-		pgoff_t end_offset, count;
-
-		set_new_dnode(&dn, inode, NULL, NULL, 0);
-		ret = f2fs_get_dnode_of_data(&dn, page_idx, LOOKUP_NODE);
-		if (ret) {
-			if (ret == -ENOENT) {
-				page_idx = f2fs_get_next_page_offset(&dn,
-								page_idx);
-				ret = 0;
-				continue;
-			}
-			break;
-		}
-
-		end_offset = ADDRS_PER_PAGE(dn.node_page, inode);
-		count = min(end_offset - dn.ofs_in_node, last_idx - page_idx);
-		count = round_up(count, F2FS_I(inode)->i_cluster_size);
-
-		ret = release_compress_blocks(&dn, count);
-
-		f2fs_put_dnode(&dn);
-
-		if (ret < 0)
-			break;
-
-		page_idx += count;
-		released_blocks += ret;
-	}
+	ret = f2fs_do_release_compress_blocks(inode, last_idx, &released_blocks);
 
 	filemap_invalidate_unlock(inode->i_mapping);
 	f2fs_up_write(&F2FS_I(inode)->i_gc_rwsem[WRITE]);
@@ -3585,8 +3597,22 @@ static int reserve_compress_blocks(struct dnode_of_data *dn, pgoff_t count)
 		if (ret)
 			return ret;
 
-		if (reserved != cluster_size - compr_blocks)
-			return -ENOSPC;
+		if (reserved != cluster_size - compr_blocks) {
+			dec_valid_block_count(sbi, dn->inode, reserved);
+
+			for (i = cluster_size - 1; i > 0; i--) {
+				dn->ofs_in_node--;
+				blkaddr = f2fs_data_blkaddr(dn);
+
+				if (__is_valid_data_blkaddr(blkaddr)) {
+					dn->ofs_in_node -= i;
+					return -ENOSPC;
+				}
+
+				dn->data_blkaddr = NULL_ADDR;
+				f2fs_set_data_blkaddr(dn);
+			}
+		}
 
 		f2fs_i_compr_blocks_update(dn->inode, compr_blocks, true);
 
@@ -3604,6 +3630,7 @@ static int f2fs_reserve_compress_blocks(struct file *filp, unsigned long arg)
 	struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
 	pgoff_t page_idx = 0, last_idx;
 	unsigned int reserved_blocks = 0;
+	struct dnode_of_data dn;
 	int ret;
 
 	if (!f2fs_sb_has_compression(F2FS_I_SB(inode)))
@@ -3637,7 +3664,6 @@ static int f2fs_reserve_compress_blocks(struct file *filp, unsigned long arg)
 	last_idx = DIV_ROUND_UP(i_size_read(inode), PAGE_SIZE);
 
 	while (page_idx < last_idx) {
-		struct dnode_of_data dn;
 		pgoff_t end_offset, count;
 
 		set_new_dnode(&dn, inode, NULL, NULL, 0);
@@ -3667,6 +3693,9 @@ static int f2fs_reserve_compress_blocks(struct file *filp, unsigned long arg)
 		reserved_blocks += ret;
 	}
 
+	if (ret == -ENOSPC)
+		f2fs_do_release_compress_blocks(inode, page_idx + dn.ofs_in_node, NULL);
+
 	filemap_invalidate_unlock(inode->i_mapping);
 	f2fs_up_write(&F2FS_I(inode)->i_gc_rwsem[WRITE]);
 
-- 
2.25.1