From 59cda49ecf6c9a32fae4942420701b6e087204f6 Mon Sep 17 00:00:00 2001 From: Amir Goldstein Date: Mon, 22 Mar 2021 19:39:44 +0200 Subject: [PATCH] shmem: allow reporting fanotify events with file handles on tmpfs Since kernel v5.1, fanotify_init(2) supports the flag FAN_REPORT_FID for identifying objects using file handle and fsid in events. fanotify_mark(2) fails with -ENODEV when trying to set a mark on filesystems that report null f_fsid in stasfs(2). Use the digest of uuid as f_fsid for tmpfs to uniquely identify tmpfs objects as best as possible and allow setting an fanotify mark that reports events with file handles on tmpfs. Link: https://lore.kernel.org/r/20210322173944.449469-3-amir73il@gmail.com Acked-by: Hugh Dickins Reviewed-by: Christian Brauner Signed-off-by: Amir Goldstein Signed-off-by: Jan Kara --- mm/shmem.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/mm/shmem.c b/mm/shmem.c index b2db4ed..162d8f8 100644 --- a/mm/shmem.c +++ b/mm/shmem.c @@ -2846,6 +2846,9 @@ static int shmem_statfs(struct dentry *dentry, struct kstatfs *buf) buf->f_ffree = sbinfo->free_inodes; } /* else leave those fields 0 like simple_statfs */ + + buf->f_fsid = uuid_to_fsid(dentry->d_sb->s_uuid.b); + return 0; } -- 2.7.4