From ddb95d45fbdda8d80f4883eb627f78cf471cce01 Mon Sep 17 00:00:00 2001 From: Mark Johnston Date: Thu, 7 Nov 2024 18:23:32 +0000 Subject: [PATCH] p9fs: Use UNLINKAT instead of REMOVE to implement removals REMOVE doesn't work properly in the face of hard links. Use UNLINKAT instead, which is implemented by qemu and bhyve and lets the client specify the name being removed. PR: 282432 Reviewed by: dfr Differential Revision: https://reviews.freebsd.org/D47438 --- sys/fs/p9fs/p9_client.c | 21 +++++++++++++++++++++ sys/fs/p9fs/p9_client.h | 1 + sys/fs/p9fs/p9_protocol.h | 2 ++ sys/fs/p9fs/p9fs_vnops.c | 21 ++++++++++++++------- 4 files changed, 38 insertions(+), 7 deletions(-) diff --git a/sys/fs/p9fs/p9_client.c b/sys/fs/p9fs/p9_client.c index 45d24870306..547de98c4c0 100644 --- a/sys/fs/p9fs/p9_client.c +++ b/sys/fs/p9fs/p9_client.c @@ -669,6 +669,27 @@ p9_client_remove(struct p9_fid *fid) return (error); } +int +p9_client_unlink(struct p9_fid *dfid, const char *name, int32_t flags) +{ + int error; + struct p9_client *clnt; + struct p9_req_t *req; + + error = 0; + clnt = dfid->clnt; + + req = p9_client_request(clnt, P9PROTO_TUNLINKAT, &error, "dsd", + dfid->fid, name, flags); + if (error != 0) { + P9_DEBUG(PROTO, "RUNLINKAT fid %d\n", dfid->fid); + return (error); + } + + p9_free_req(clnt, req); + return (error); +} + /* Inform the file server that the current file represented by fid is no longer * needed by the client. Any allocated fid on the server needs a clunk to be * destroyed. diff --git a/sys/fs/p9fs/p9_client.h b/sys/fs/p9fs/p9_client.h index 8597c0732ba..79d402c174e 100644 --- a/sys/fs/p9fs/p9_client.h +++ b/sys/fs/p9fs/p9_client.h @@ -140,6 +140,7 @@ int p9_client_write(struct p9_fid *fid, uint64_t offset, uint32_t count, char *d int p9_client_file_create(struct p9_fid *fid, char *name, uint32_t perm, int mode, char *extension); int p9_client_remove(struct p9_fid *fid); +int p9_client_unlink(struct p9_fid *dfid, const char *name, int32_t flags); int p9_dirent_read(struct p9_client *clnt, char *buf, int start, int len, struct p9_dirent *dirent); int p9_client_statfs(struct p9_fid *fid, struct p9_statfs *stat); diff --git a/sys/fs/p9fs/p9_protocol.h b/sys/fs/p9fs/p9_protocol.h index ddd8571adc8..7ffd7dd67bc 100644 --- a/sys/fs/p9fs/p9_protocol.h +++ b/sys/fs/p9fs/p9_protocol.h @@ -267,6 +267,8 @@ struct p9_iattr_dotl { #define P9PROTO_TGETATTR_BLK 512 +#define P9PROTO_UNLINKAT_REMOVEDIR 0x200 + /* PDU buffer used for SG lists. */ struct p9_buffer { uint32_t size; diff --git a/sys/fs/p9fs/p9fs_vnops.c b/sys/fs/p9fs/p9fs_vnops.c index 14951e96b59..cfb50c70401 100644 --- a/sys/fs/p9fs/p9fs_vnops.c +++ b/sys/fs/p9fs/p9fs_vnops.c @@ -1497,7 +1497,8 @@ out: * After that, does a node metadata cleanup on client side. */ static int -remove_common(struct p9fs_node *np, struct ucred *cred) +remove_common(struct p9fs_node *dnp, struct p9fs_node *np, const char *name, + struct ucred *cred) { int error; struct p9fs_session *vses; @@ -1508,21 +1509,23 @@ remove_common(struct p9fs_node *np, struct ucred *cred) vses = np->p9fs_ses; vp = P9FS_NTOV(np); - vfid = p9fs_get_fid(vses->clnt, np, cred, VFID, -1, &error); + vfid = p9fs_get_fid(vses->clnt, dnp, cred, VFID, -1, &error); if (error != 0) return (error); - error = p9_client_remove(vfid); + error = p9_client_unlink(vfid, name, + np->v_node->v_type == VDIR ? P9PROTO_UNLINKAT_REMOVEDIR : 0); if (error != 0) return (error); /* Remove all non-open fids associated with the vp */ - p9fs_fid_remove_all(np, TRUE); + if (np->inode.i_links_count == 1) + p9fs_fid_remove_all(np, TRUE); /* Invalidate all entries of vnode from name cache and hash list. */ cache_purge(vp); - vfs_hash_remove(vp); + np->flags |= P9FS_NODE_DELETED; return (error); @@ -1537,8 +1540,10 @@ p9fs_remove(struct vop_remove_args *ap) struct vnode *dvp; struct p9fs_node *dnp; struct p9fs_inode *dinode; + struct componentname *cnp; int error; + cnp = ap->a_cnp; vp = ap->a_vp; np = P9FS_VTON(vp); dvp = ap->a_dvp; @@ -1550,7 +1555,7 @@ p9fs_remove(struct vop_remove_args *ap) if (vp->v_type == VDIR) return (EISDIR); - error = remove_common(np, ap->a_cnp->cn_cred); + error = remove_common(dnp, np, cnp->cn_nameptr, cnp->cn_cred); if (error == 0) P9FS_DECR_LINKS(dinode); @@ -1566,8 +1571,10 @@ p9fs_rmdir(struct vop_rmdir_args *ap) struct vnode *dvp; struct p9fs_node *dnp; struct p9fs_inode *dinode; + struct componentname *cnp; int error; + cnp = ap->a_cnp; vp = ap->a_vp; np = P9FS_VTON(vp); dvp = ap->a_dvp; @@ -1576,7 +1583,7 @@ p9fs_rmdir(struct vop_rmdir_args *ap) P9_DEBUG(VOPS, "%s: vp %p node %p \n", __func__, vp, np); - error = remove_common(np, ap->a_cnp->cn_cred); + error = remove_common(dnp, np, cnp->cn_nameptr, cnp->cn_cred); if (error == 0) P9FS_DECR_LINKS(dinode);