fix ufs write vs readpage race when writing into a hole

Followup to the 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>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Al Viro 2015-09-09 10:16:39 +01:00 committed by Linus Torvalds
parent daf0e1ed57
commit bd2843fe1f

View File

@ -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);