[PATCH AUTOSEL 6.6 07/51] fs/ntfs3: Fix multithreaded stress test

Sasha Levin
2024-02-13T00:21:01Z

From: Konstantin Komarov <almaz.alexandrovich@paragon-software.com>

[ Upstream commit a8b0c9fc3a2dba07f697ef7825e04363ff12f071 ]

Signed-off-by: Konstantin Komarov <almaz.alexandrovich@paragon-software.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
fs/ntfs3/attrib.c | 21 ++++++++++++++-------
1 file changed, 14 insertions(+), 7 deletions(-)

diff --git a/fs/ntfs3/attrib.c b/fs/ntfs3/attrib.c
index 63f70259edc0..4b78b669a3bd 100644
--- a/fs/ntfs3/attrib.c
+++ b/fs/ntfs3/attrib.c
@@ -886,7 +886,7 @@ int attr_data_get_block(struct ntfs_inode *ni, CLST vcn, CLST clen, CLST *lcn,
struct runs_tree *run = &ni->file.run;
struct ntfs_sb_info *sbi;
u8 cluster_bits;
- struct ATTRIB *attr = NULL, *attr_b;
+ struct ATTRIB *attr, *attr_b;
struct ATTR_LIST_ENTRY *le, *le_b;
struct mft_inode *mi, *mi_b;
CLST hint, svcn, to_alloc, evcn1, next_svcn, asize, end, vcn0, alen;
@@ -904,12 +904,8 @@ int attr_data_get_block(struct ntfs_inode *ni, CLST vcn, CLST clen, CLST *lcn,
*len = 0;
up_read(&ni->file.run_lock);

- if (*len) {
- if (*lcn != SPARSE_LCN || !new)
- return 0; /* Fast normal way without allocation. */
- else if (clen > *len)
- clen = *len;
- }
+ if (*len && (*lcn != SPARSE_LCN || !new))
+ return 0; /* Fast normal way without allocation. */

/* No cluster in cache or we need to allocate cluster in hole. */
sbi = ni->mi.sbi;
@@ -918,6 +914,17 @@ int attr_data_get_block(struct ntfs_inode *ni, CLST vcn, CLST clen, CLST *lcn,
ni_lock(ni);
down_write(&ni->file.run_lock);

+ /* Repeat the code above (under write lock). */
+ if (!run_lookup_entry(run, vcn, lcn, len, NULL))
+ *len = 0;
+
+ if (*len) {
+ if (*lcn != SPARSE_LCN || !new)
+ goto out; /* normal way without allocation. */
+ if (clen > *len)
+ clen = *len;
+ }
+
le_b = NULL;
attr_b = ni_find_attr(ni, NULL, &le_b, ATTR_DATA, NULL, 0, NULL, &mi_b);
if (!attr_b) {
--
2.43.0