git: bb536de6c0d7 - main - ffs_update(): Do not assume that EBUSY can only come LK_NOWAIT trylock

[Konstantin Belousov]

The branch main has been updated by kib:

URL: https://cgit.FreeBSD.org/src/commit/?id=bb536de6c0d73566e610881e12c55489a7c6ec44

commit bb536de6c0d73566e610881e12c55489a7c6ec44
Author:     Konstantin Belousov <kib at FreeBSD.org>
AuthorDate: 2021-08-26 16:17:39 +0000
Commit:     Konstantin Belousov <kib at FreeBSD.org>
CommitDate: 2021-08-31 04:38:35 +0000

    ffs_update(): Do not assume that EBUSY can only come LK_NOWAIT trylock
    
    Instead do protective check for the local flags and do not interpret
    EBUSY specially if we did not request trylock mode for bread().
    
    Reviewed by:    mckusick
    Reported and tested by: pho
    Sponsored by:   The FreeBSD Foundation
    MFC after:      1 week
---
 sys/ufs/ffs/ffs_inode.c | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/sys/ufs/ffs/ffs_inode.c b/sys/ufs/ffs/ffs_inode.c
index 2bc3da7e603f..1159259fb2b6 100644
--- a/sys/ufs/ffs/ffs_inode.c
+++ b/sys/ufs/ffs/ffs_inode.c
@@ -153,9 +153,14 @@ loop:
 	error = ffs_breadz(VFSTOUFS(vp->v_mount), ITODEVVP(ip), bn, bn,
 	     (int) fs->fs_bsize, NULL, NULL, 0, NOCRED, flags, NULL, &bp);
 	if (error != 0) {
-		if (error != EBUSY)
+		/*
+		 * If EBUSY was returned without GB_LOCK_NOWAIT (which
+		 * requests trylock for buffer lock), it is for some
+		 * other reason and we should not handle it specially.
+		 */
+		if (error != EBUSY || (flags & GB_LOCK_NOWAIT) == 0)
 			return (error);
-		KASSERT((IS_SNAPSHOT(ip)), ("EBUSY from non-snapshot"));
+
 		/*
 		 * Wait for our inode block to become available.
 		 *