[PATCH] fs/ntfs3: fix mount failure on 64K page-size kernels

[PATCH] fs/ntfs3: fix mount failure on 64K page-size kernels

[Jamie Nguyen]

On 64K page-size kernels, mounting NTFS volumes smaller than ~650 MB
fails with EINVAL. The issue is in log_replay(): the initial log page
size probe uses PAGE_SIZE (65536) instead of DefaultLogPageSize (4096)
when PAGE_SIZE exceeds DefaultLogPageSize * 2.

This makes norm_file_page() require the $LogFile to be at least
50 * 65536 = 3.2 MB, but mkfs.ntfs creates a $LogFile of only ~1.5 MB
for a typical 300 MB volume. norm_file_page() returns 0 and the mount
is rejected with EINVAL.

On 4K kernels the #if guard evaluates to true, so use_default=true is
passed and DefaultLogPageSize (4096) is used, requiring only ~200 KB.
This path works fine.

Fix this by always passing use_default=true, which forces the initial
probe to use DefaultLogPageSize regardless of the kernel's PAGE_SIZE.
This is safe because, after reading the on-disk restart area, log_replay()
already re-adjusts log->page_size to match the volume's actual
sys_page_size.

Also fix read_log_page() to pass log->page_size instead of PAGE_SIZE to
ntfs_fix_post_read(), matching the actual buffer size.

Fixes: b46acd6a6a62 ("fs/ntfs3: Add NTFS journal")
Signed-off-by: Jamie Nguyen <jamien@nvidia.com>
---
 fs/ntfs3/fslog.c | 6 +-----
 1 file changed, 1 insertion(+), 5 deletions(-)

diff --git a/fs/ntfs3/fslog.c b/fs/ntfs3/fslog.c
index 38934e6978ec..4a6cfa3441d9 100644
--- a/fs/ntfs3/fslog.c
+++ b/fs/ntfs3/fslog.c
@@ -1170,7 +1170,7 @@ static int read_log_page(struct ntfs_log *log, u32 vbo,
 		goto out;
 
 	if (page_buf->rhdr.sign != NTFS_FFFF_SIGNATURE)
-		ntfs_fix_post_read(&page_buf->rhdr, PAGE_SIZE, false);
+		ntfs_fix_post_read(&page_buf->rhdr, log->page_size, false);
 
 	if (page_buf != *buffer)
 		memcpy(*buffer, Add2Ptr(page_buf, page_off), bytes);
@@ -3782,11 +3782,7 @@ int log_replay(struct ntfs_inode *ni, bool *initialized)
 	log->l_size = log->orig_file_size = ni->vfs_inode.i_size;
 
 	/* Get the size of page. NOTE: To replay we can use default page. */
-#if PAGE_SIZE >= DefaultLogPageSize && PAGE_SIZE <= DefaultLogPageSize * 2
 	log->page_size = norm_file_page(PAGE_SIZE, &log->l_size, true);
-#else
-	log->page_size = norm_file_page(PAGE_SIZE, &log->l_size, false);
-#endif
 	if (!log->page_size) {
 		err = -EINVAL;
 		goto out;
-- 
2.43.0