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authorBrian Foster <bfoster@redhat.com>2019-02-06 09:25:29 -0800
committerDarrick J. Wong <darrick.wong@oracle.com>2019-02-11 16:07:01 -0800
commit75d0230314997b18946c96dc3d93c8d61cfdb9a5 (patch)
treed6d27b89f73b07ef1275738d7cba094e653df785 /fs/xfs/xfs_buf.c
parent9b2471797942a5947664818cfe2c6de93b43f37a (diff)
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xfs: clarify documentation for the function to reverify buffers
Improve the documentation around xfs_buf_ensure_ops, which is the function that is responsible for cleaning up the b_ops state of buffers that go through xrep_findroot_block but don't match anything. Rename the function to xfs_buf_reverify. [darrick: this started off as bfoster mods of a previous patch of mine, but the renaming part is now this separate patch.] Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com> Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com> Signed-off-by: Brian Foster <bfoster@redhat.com>
Diffstat (limited to 'fs/xfs/xfs_buf.c')
-rw-r--r--fs/xfs/xfs_buf.c35
1 files changed, 15 insertions, 20 deletions
diff --git a/fs/xfs/xfs_buf.c b/fs/xfs/xfs_buf.c
index 4f5f2ff3f70f..d29246ac3721 100644
--- a/fs/xfs/xfs_buf.c
+++ b/fs/xfs/xfs_buf.c
@@ -776,29 +776,24 @@ _xfs_buf_read(
}
/*
- * Set buffer ops on an unchecked buffer and validate it, if possible.
+ * Reverify a buffer found in cache without an attached ->b_ops.
*
- * If the caller passed in an ops structure and the buffer doesn't have ops
- * assigned, set the ops and use them to verify the contents. If the contents
- * cannot be verified, we'll clear XBF_DONE. We assume the buffer has no
- * recorded errors and is already in XBF_DONE state.
+ * If the caller passed an ops structure and the buffer doesn't have ops
+ * assigned, set the ops and use it to verify the contents. If verification
+ * fails, clear XBF_DONE. We assume the buffer has no recorded errors and is
+ * already in XBF_DONE state on entry.
*
- * Under normal operations, every in-core buffer must have buffer ops assigned
- * to them when the buffer is read in from disk so that we can validate the
- * metadata.
- *
- * However, there are two scenarios where one can encounter in-core buffers
- * that don't have buffer ops. The first is during log recovery of buffers on
- * a V4 filesystem, though these buffers are purged at the end of recovery.
- *
- * The other is online repair, which tries to match arbitrary metadata blocks
- * with btree types in order to find the root. If online repair doesn't match
- * the buffer with /any/ btree type, the buffer remains in memory in DONE state
- * with no ops, and a subsequent read_buf call from elsewhere will not set the
- * ops. This function helps us fix this situation.
+ * Under normal operations, every in-core buffer is verified on read I/O
+ * completion. There are two scenarios that can lead to in-core buffers without
+ * an assigned ->b_ops. The first is during log recovery of buffers on a V4
+ * filesystem, though these buffers are purged at the end of recovery. The
+ * other is online repair, which intentionally reads with a NULL buffer ops to
+ * run several verifiers across an in-core buffer in order to establish buffer
+ * type. If repair can't establish that, the buffer will be left in memory
+ * with NULL buffer ops.
*/
int
-xfs_buf_ensure_ops(
+xfs_buf_reverify(
struct xfs_buf *bp,
const struct xfs_buf_ops *ops)
{
@@ -840,7 +835,7 @@ xfs_buf_read_map(
return bp;
}
- xfs_buf_ensure_ops(bp, ops);
+ xfs_buf_reverify(bp, ops);
if (flags & XBF_ASYNC) {
/*