xfs: fix min bufsize bugs in two places
This fixes a bug in two places that I found by inspection. In
xlog_find_verify_cycle() and xlog_write_log_records(), the code
attempts to allocate a buffer to hold as many blocks as possible.
It gives up if the number of blocks to be allocated gets too small.
Right now it uses log->l_sectbb_log as that lower bound, but I'm
sure it's supposed to be the actual log sector size instead. That
is, the lower bound should be (1 << log->l_sectbb_log).
Also define a simple macro xlog_sectbb(log) to represent the number
of basic blocks in a sector for the given log.
(No change from original submission; I have implemented Christoph's
suggestion about storing l_sectsize rather than l_sectbb_log in
a new, separate patch in this series.)
Signed-off-by: Alex Elder <aelder@sgi.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <dchinner@redhat.com>
diff --git a/fs/xfs/xfs_log_recover.c b/fs/xfs/xfs_log_recover.c
index f21eb8a..0d81a90 100644
--- a/fs/xfs/xfs_log_recover.c
+++ b/fs/xfs/xfs_log_recover.c
@@ -66,6 +66,9 @@
((bbs + (log)->l_sectbb_mask + 1) & ~(log)->l_sectbb_mask) : (bbs) )
#define XLOG_SECTOR_ROUNDDOWN_BLKNO(log, bno) ((bno) & ~(log)->l_sectbb_mask)
+/* Number of basic blocks in a log sector */
+#define xlog_sectbb(log) (1 << (log)->l_sectbb_log)
+
STATIC xfs_buf_t *
xlog_get_bp(
xlog_t *log,
@@ -376,12 +379,16 @@
xfs_caddr_t buf = NULL;
int error = 0;
+ /*
+ * Greedily allocate a buffer big enough to handle the full
+ * range of basic blocks we'll be examining. If that fails,
+ * try a smaller size. We need to be able to read at least
+ * a log sector, or we're out of luck.
+ */
bufblks = 1 << ffs(nbblks);
-
while (!(bp = xlog_get_bp(log, bufblks))) {
- /* can't get enough memory to do everything in one big buffer */
bufblks >>= 1;
- if (bufblks <= log->l_sectbb_log)
+ if (bufblks < xlog_sectbb(log))
return ENOMEM;
}
@@ -1158,10 +1165,16 @@
int error = 0;
int i, j = 0;
+ /*
+ * Greedily allocate a buffer big enough to handle the full
+ * range of basic blocks to be written. If that fails, try
+ * a smaller size. We need to be able to write at least a
+ * log sector, or we're out of luck.
+ */
bufblks = 1 << ffs(blocks);
while (!(bp = xlog_get_bp(log, bufblks))) {
bufblks >>= 1;
- if (bufblks <= log->l_sectbb_log)
+ if (bufblks < xlog_sectbb(log))
return ENOMEM;
}