linux-kernel - [PATCH v2] f2fs: change the way of handling range.len in F2FS_IOC_SEC_TRIM

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Date:   Mon, 13 Jul 2020 12:12:52 +0900
From:   Daeho Jeong <daeho43@...il.com>
To:     linux-kernel@...r.kernel.org,
        linux-f2fs-devel@...ts.sourceforge.net, kernel-team@...roid.com
Cc:     Daeho Jeong <daehojeong@...gle.com>
Subject: [PATCH v2] f2fs: change the way of handling range.len in F2FS_IOC_SEC_TRIM_FILE

From: Daeho Jeong <daehojeong@...gle.com>

Changed the way of handling range.len of F2FS_IOC_SEC_TRIM_FILE.
 1. Added -1 value support for range.len to secure trim the whole blocks
    starting from range.start regardless of i_size.
 2. If the end of the range passes over the end of file, it means until
    the end of file (i_size).
 3. ignored the case of that range.len is zero to prevent the function
    from making end_addr zero and triggering different behaviour of
    the function.

Signed-off-by: Daeho Jeong <daehojeong@...gle.com>
---
Changes in v2:
 - Changed -1 range.len option to mean the whole blocks starting from
   range.start regardless of i_size
---
 fs/f2fs/file.c | 23 ++++++++++++-----------
 1 file changed, 12 insertions(+), 11 deletions(-)

diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c
index 368c80f8e2a1..2485841e3b2d 100644
--- a/fs/f2fs/file.c
+++ b/fs/f2fs/file.c
@@ -3792,7 +3792,7 @@ static int f2fs_sec_trim_file(struct file *filp, unsigned long arg)
 	pgoff_t index, pg_end;
 	block_t prev_block = 0, len = 0;
 	loff_t end_addr;
-	bool to_end;
+	bool to_end = false;
 	int ret = 0;
 
 	if (!(filp->f_mode & FMODE_WRITE))
@@ -3813,23 +3813,23 @@ static int f2fs_sec_trim_file(struct file *filp, unsigned long arg)
 	file_start_write(filp);
 	inode_lock(inode);
 
-	if (f2fs_is_atomic_file(inode) || f2fs_compressed_file(inode)) {
+	if (f2fs_is_atomic_file(inode) || f2fs_compressed_file(inode) ||
+			range.start >= inode->i_size) {
 		ret = -EINVAL;
 		goto err;
 	}
 
-	if (range.start >= inode->i_size) {
-		ret = -EINVAL;
+	if (range.len == 0)
 		goto err;
-	}
 
-	if (inode->i_size - range.start < range.len) {
-		ret = -E2BIG;
-		goto err;
+	if (inode->i_size - range.start > range.len) {
+		end_addr = range.start + range.len;
+	} else {
+		end_addr = range.len == (u64)-1 ?
+			sbi->sb->s_maxbytes : inode->i_size;
+		to_end = true;
 	}
-	end_addr = range.start + range.len;
 
-	to_end = (end_addr == inode->i_size);
 	if (!IS_ALIGNED(range.start, F2FS_BLKSIZE) ||
 			(!to_end && !IS_ALIGNED(end_addr, F2FS_BLKSIZE))) {
 		ret = -EINVAL;
@@ -3846,7 +3846,8 @@ static int f2fs_sec_trim_file(struct file *filp, unsigned long arg)
 	down_write(&F2FS_I(inode)->i_gc_rwsem[WRITE]);
 	down_write(&F2FS_I(inode)->i_mmap_sem);
 
-	ret = filemap_write_and_wait_range(mapping, range.start, end_addr - 1);
+	ret = filemap_write_and_wait_range(mapping, range.start,
+			to_end ? LLONG_MAX : end_addr - 1);
 	if (ret)
 		goto out;
 
-- 
2.27.0.383.g050319c2ae-goog