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-rw-r--r--fs/fat/dir.c13
-rw-r--r--fs/fat/fatent.c3
2 files changed, 14 insertions, 2 deletions
diff --git a/fs/fat/dir.c b/fs/fat/dir.c
index 1bda2ab6745b..814ad2c2ba80 100644
--- a/fs/fat/dir.c
+++ b/fs/fat/dir.c
@@ -1100,8 +1100,11 @@ static int fat_zeroed_cluster(struct inode *dir, sector_t blknr, int nr_used,
err = -ENOMEM;
goto error;
}
+ /* Avoid race with userspace read via bdev */
+ lock_buffer(bhs[n]);
memset(bhs[n]->b_data, 0, sb->s_blocksize);
set_buffer_uptodate(bhs[n]);
+ unlock_buffer(bhs[n]);
mark_buffer_dirty_inode(bhs[n], dir);
n++;
@@ -1158,6 +1161,8 @@ int fat_alloc_new_dir(struct inode *dir, struct timespec64 *ts)
fat_time_unix2fat(sbi, ts, &time, &date, &time_cs);
de = (struct msdos_dir_entry *)bhs[0]->b_data;
+ /* Avoid race with userspace read via bdev */
+ lock_buffer(bhs[0]);
/* filling the new directory slots ("." and ".." entries) */
memcpy(de[0].name, MSDOS_DOT, MSDOS_NAME);
memcpy(de[1].name, MSDOS_DOTDOT, MSDOS_NAME);
@@ -1180,6 +1185,7 @@ int fat_alloc_new_dir(struct inode *dir, struct timespec64 *ts)
de[0].size = de[1].size = 0;
memset(de + 2, 0, sb->s_blocksize - 2 * sizeof(*de));
set_buffer_uptodate(bhs[0]);
+ unlock_buffer(bhs[0]);
mark_buffer_dirty_inode(bhs[0], dir);
err = fat_zeroed_cluster(dir, blknr, 1, bhs, MAX_BUF_PER_PAGE);
@@ -1237,11 +1243,14 @@ static int fat_add_new_entries(struct inode *dir, void *slots, int nr_slots,
/* fill the directory entry */
copy = min(size, sb->s_blocksize);
+ /* Avoid race with userspace read via bdev */
+ lock_buffer(bhs[n]);
memcpy(bhs[n]->b_data, slots, copy);
- slots += copy;
- size -= copy;
set_buffer_uptodate(bhs[n]);
+ unlock_buffer(bhs[n]);
mark_buffer_dirty_inode(bhs[n], dir);
+ slots += copy;
+ size -= copy;
if (!size)
break;
n++;
diff --git a/fs/fat/fatent.c b/fs/fat/fatent.c
index 265983635f2b..3647c65a0f48 100644
--- a/fs/fat/fatent.c
+++ b/fs/fat/fatent.c
@@ -388,8 +388,11 @@ static int fat_mirror_bhs(struct super_block *sb, struct buffer_head **bhs,
err = -ENOMEM;
goto error;
}
+ /* Avoid race with userspace read via bdev */
+ lock_buffer(c_bh);
memcpy(c_bh->b_data, bhs[n]->b_data, sb->s_blocksize);
set_buffer_uptodate(c_bh);
+ unlock_buffer(c_bh);
mark_buffer_dirty_inode(c_bh, sbi->fat_inode);
if (sb->s_flags & SB_SYNCHRONOUS)
err = sync_dirty_buffer(c_bh);