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Subject[PATCH] fix ufs write vs. readpage race when writing into a hole
	Followup to UFS series - with the way we clear the new blocks (via
buffer cache, possibly on more than a page worth of file) we really should
not insert a reference to new block into inode block tree until after we'd
cleared it.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
---
diff --git a/fs/ufs/balloc.c b/fs/ufs/balloc.c
index fb8b54e..dc5fae6 100644
--- a/fs/ufs/balloc.c
+++ b/fs/ufs/balloc.c
@@ -417,14 +417,14 @@ u64 ufs_new_fragments(struct inode *inode, void *p, u64 fragment,
if (oldcount == 0) {
result = ufs_alloc_fragments (inode, cgno, goal, count, err);
if (result) {
+ ufs_clear_frags(inode, result + oldcount,
+ newcount - oldcount, locked_page != NULL);
write_seqlock(&UFS_I(inode)->meta_lock);
ufs_cpu_to_data_ptr(sb, p, result);
write_sequnlock(&UFS_I(inode)->meta_lock);
*err = 0;
UFS_I(inode)->i_lastfrag =
max(UFS_I(inode)->i_lastfrag, fragment + count);
- ufs_clear_frags(inode, result + oldcount,
- newcount - oldcount, locked_page != NULL);
}
mutex_unlock(&UFS_SB(sb)->s_lock);
UFSD("EXIT, result %llu\n", (unsigned long long)result);

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