The branch stable/14 has been updated by olce:
URL:
https://cgit.FreeBSD.org/src/commit/?id=5e6079209e9b6db2bd2980e1b97e7cb4cf8b5364
commit 5e6079209e9b6db2bd2980e1b97e7cb4cf8b5364
Author: Olivier Certner <o...@freebsd.org>
AuthorDate: 2024-12-06 20:23:59 +0000
Commit: Olivier Certner <o...@freebsd.org>
CommitDate: 2025-01-16 18:07:02 +0000
tmpfs: Rework file handles
Change 'struct tmpfs_fid_data' to behave consistently with the private
structure other FSes use. In a nutshell, make it a full alias of
'struct fid', instead of just using it to fill 'fid_data'. This implies
adding a length field at start (aliasing 'fid_len' of 'struct fid'), and
filling 'fid_len' with the full size of the aliased structure.
To ensure that the new 'struct tmpfs_fid_data' is smaller than 'struct
fid', which the compile-time assert introduced in commit
91b5592a1e1af974 ("fs: Add static asserts for the size of fid
structures") checks (and thus was not strong enough when added), use
'__packed'.
A consequence of this change is that copying the 'struct tmpfs_fid_data'
into a stack-allocated variable becomes unnecessary, we simply rely on
the compiler emitting the proper code on seeing '__packed' (and on the
start of 'struct tmpfs_fid_data' being naturally aligned, which is
normally guaranteed by kernel's malloc() and/or inclusion in 'struct
fhandle').
Reviewed by: markj
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D47956
(cherry picked from commit 1ccbdf561f417f9fe802131d5b1756ac45fd314d)
---
sys/fs/tmpfs/tmpfs.h | 5 ++---
sys/fs/tmpfs/tmpfs_vfsops.c | 16 ++++++----------
sys/fs/tmpfs/tmpfs_vnops.c | 16 ++++------------
3 files changed, 12 insertions(+), 25 deletions(-)
diff --git a/sys/fs/tmpfs/tmpfs.h b/sys/fs/tmpfs/tmpfs.h
index 7ebdffbec84f..277cb599d78b 100644
--- a/sys/fs/tmpfs/tmpfs.h
+++ b/sys/fs/tmpfs/tmpfs.h
@@ -439,11 +439,10 @@ struct tmpfs_mount {
* NFS code.
*/
struct tmpfs_fid_data {
+ unsigned short tfd_len;
ino_t tfd_id;
unsigned long tfd_gen;
-};
-_Static_assert(sizeof(struct tmpfs_fid_data) <= MAXFIDSZ,
- "(struct tmpfs_fid_data) is larger than (struct fid).fid_data");
+} __packed;
struct tmpfs_dir_cursor {
struct tmpfs_dirent *tdc_current;
diff --git a/sys/fs/tmpfs/tmpfs_vfsops.c b/sys/fs/tmpfs/tmpfs_vfsops.c
index 65d54b446849..c404eb81a8d2 100644
--- a/sys/fs/tmpfs/tmpfs_vfsops.c
+++ b/sys/fs/tmpfs/tmpfs_vfsops.c
@@ -586,29 +586,25 @@ static int
tmpfs_fhtovp(struct mount *mp, struct fid *fhp, int flags,
struct vnode **vpp)
{
- struct tmpfs_fid_data tfd;
+ struct tmpfs_fid_data *tfd;
struct tmpfs_mount *tmp;
struct tmpfs_node *node;
int error;
- if (fhp->fid_len != sizeof(tfd))
+ if (fhp->fid_len != sizeof(*tfd))
return (EINVAL);
- /*
- * Copy from fid_data onto the stack to avoid unaligned pointer use.
- * See the comment in sys/mount.h on struct fid for details.
- */
- memcpy(&tfd, fhp->fid_data, fhp->fid_len);
+ tfd = (struct tmpfs_fid_data *)fhp;
tmp = VFS_TO_TMPFS(mp);
- if (tfd.tfd_id >= tmp->tm_nodes_max)
+ if (tfd->tfd_id >= tmp->tm_nodes_max)
return (EINVAL);
TMPFS_LOCK(tmp);
LIST_FOREACH(node, &tmp->tm_nodes_used, tn_entries) {
- if (node->tn_id == tfd.tfd_id &&
- node->tn_gen == tfd.tfd_gen) {
+ if (node->tn_id == tfd->tfd_id &&
+ node->tn_gen == tfd->tfd_gen) {
tmpfs_ref_node(node);
break;
}
diff --git a/sys/fs/tmpfs/tmpfs_vnops.c b/sys/fs/tmpfs/tmpfs_vnops.c
index 4571a2855be3..729feb0329a4 100644
--- a/sys/fs/tmpfs/tmpfs_vnops.c
+++ b/sys/fs/tmpfs/tmpfs_vnops.c
@@ -1684,23 +1684,15 @@ vop_vptofh {
};
*/
{
- struct tmpfs_fid_data tfd;
+ struct tmpfs_fid_data *const tfd = (struct tmpfs_fid_data *)ap->a_fhp;
struct tmpfs_node *node;
- struct fid *fhp;
_Static_assert(sizeof(struct tmpfs_fid_data) <= sizeof(struct fid),
"struct tmpfs_fid_data cannot be larger than struct fid");
node = VP_TO_TMPFS_NODE(ap->a_vp);
- fhp = ap->a_fhp;
- fhp->fid_len = sizeof(tfd);
-
- /*
- * Copy into fid_data from the stack to avoid unaligned pointer use.
- * See the comment in sys/mount.h on struct fid for details.
- */
- tfd.tfd_id = node->tn_id;
- tfd.tfd_gen = node->tn_gen;
- memcpy(fhp->fid_data, &tfd, fhp->fid_len);
+ tfd->tfd_len = sizeof(*tfd);
+ tfd->tfd_gen = node->tn_gen;
+ tfd->tfd_id = node->tn_id;
return (0);
}
