xfs: nothing special about 1-block log sector
There are a number of places where a log sector size of 1 uses
special case code. The round_up() and round_down() macros
produce the correct result even when the log sector size is 1, and
this eliminates the need for treating this as a special case.
Signed-off-by: Alex Elder <aelder@sgi.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
diff --git a/fs/xfs/xfs_log_recover.c b/fs/xfs/xfs_log_recover.c
index b5eab63..629e88b 100644
--- a/fs/xfs/xfs_log_recover.c
+++ b/fs/xfs/xfs_log_recover.c
@@ -77,6 +77,11 @@
return bbcount > 0 && bbcount <= log->l_logBBsize;
}
+/*
+ * Allocate a buffer to hold log data. The buffer needs to be able
+ * to map to a range of nbblks basic blocks at any valid (basic
+ * block) offset within the log.
+ */
STATIC xfs_buf_t *
xlog_get_bp(
xlog_t *log,
@@ -89,11 +94,26 @@
return NULL;
}
- if (log->l_sectbb_log) {
- if (nbblks > 1)
- nbblks += xlog_sectbb(log);
- nbblks = round_up(nbblks, xlog_sectbb(log));
- }
+ /*
+ * We do log I/O in units of log sectors (a power-of-2
+ * multiple of the basic block size), so we round up the
+ * requested size to acommodate the basic blocks required
+ * for complete log sectors.
+ *
+ * In addition, the buffer may be used for a non-sector-
+ * aligned block offset, in which case an I/O of the
+ * requested size could extend beyond the end of the
+ * buffer. If the requested size is only 1 basic block it
+ * will never straddle a sector boundary, so this won't be
+ * an issue. Nor will this be a problem if the log I/O is
+ * done in basic blocks (sector size 1). But otherwise we
+ * extend the buffer by one extra log sector to ensure
+ * there's space to accomodate this possiblility.
+ */
+ if (nbblks > 1 && log->l_sectbb_log)
+ nbblks += xlog_sectbb(log);
+ nbblks = round_up(nbblks, xlog_sectbb(log));
+
return xfs_buf_get_noaddr(BBTOB(nbblks), log->l_mp->m_logdev_targp);
}
@@ -142,10 +162,8 @@
return EFSCORRUPTED;
}
- if (log->l_sectbb_log) {
- blk_no = round_down(blk_no, xlog_sectbb(log));
- nbblks = round_up(nbblks, xlog_sectbb(log));
- }
+ blk_no = round_down(blk_no, xlog_sectbb(log));
+ nbblks = round_up(nbblks, xlog_sectbb(log));
ASSERT(nbblks > 0);
ASSERT(BBTOB(nbblks) <= XFS_BUF_SIZE(bp));
@@ -204,10 +222,8 @@
return EFSCORRUPTED;
}
- if (log->l_sectbb_log) {
- blk_no = round_down(blk_no, xlog_sectbb(log));
- nbblks = round_up(nbblks, xlog_sectbb(log));
- }
+ blk_no = round_down(blk_no, xlog_sectbb(log));
+ nbblks = round_up(nbblks, xlog_sectbb(log));
ASSERT(nbblks > 0);
ASSERT(BBTOB(nbblks) <= XFS_BUF_SIZE(bp));