From: Al Viro viro@zeniv.linux.org.uk
mainline inclusion from mainline-5.14-rc1 commit bcba1e7d0d520adba895d9e0800a056f734b0a6a category: bugfix bugzilla: 181657 https://gitee.com/openeuler/kernel/issues/I4DDEL Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i...
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Separate field in nameidata (nd->state) holding the flags that should be internal-only - that way we both get some spare bits in LOOKUP_... and get simpler rules for nd->root lifetime rules, since we can set the replacement of LOOKUP_ROOT (ND_ROOT_PRESET) at the same time we set nd->root.
Signed-off-by: Al Viro viro@zeniv.linux.org.uk
Conflicts: fs/namei.c [ Bugfix 7d01ef7585c0("Make sure nd->path.mnt and nd->path.dentry are always valid pointers") is not applid, the problem to be fixed not exists. Feature 6c6ec2b0a3e0("fs: add support for LOOKUP_CACHED") is not applied. ]
Signed-off-by: Zhihao Cheng chengzhihao1@huawei.com Reviewed-by: Zhang Yi yi.zhang@huawei.com
Signed-off-by: Chen Jun chenjun102@huawei.com --- Documentation/filesystems/path-lookup.rst | 6 +-- fs/namei.c | 54 +++++++++++++---------- fs/nfs/nfstrace.h | 4 -- include/linux/namei.h | 3 -- 4 files changed, 34 insertions(+), 33 deletions(-)
diff --git a/Documentation/filesystems/path-lookup.rst b/Documentation/filesystems/path-lookup.rst index c482e1619e77..ede67f705787 100644 --- a/Documentation/filesystems/path-lookup.rst +++ b/Documentation/filesystems/path-lookup.rst @@ -1321,18 +1321,18 @@ to lookup: RCU-walk, REF-walk, and REF-walk with forced revalidation. yet. This is primarily used to tell the audit subsystem the full context of a particular access being audited.
-``LOOKUP_ROOT`` indicates that the ``root`` field in the ``nameidata`` was +``ND_ROOT_PRESET`` indicates that the ``root`` field in the ``nameidata`` was provided by the caller, so it shouldn't be released when it is no longer needed.
-``LOOKUP_JUMPED`` means that the current dentry was chosen not because +``ND_JUMPED`` means that the current dentry was chosen not because it had the right name but for some other reason. This happens when following "``..``", following a symlink to ``/``, crossing a mount point or accessing a "``/proc/$PID/fd/$FD``" symlink (also known as a "magic link"). In this case the filesystem has not been asked to revalidate the name (with ``d_revalidate()``). In such cases the inode may still need to be revalidated, so ``d_op->d_weak_revalidate()`` is called if -``LOOKUP_JUMPED`` is set when the look completes - which may be at the +``ND_JUMPED`` is set when the look completes - which may be at the final component or, when creating, unlinking, or renaming, at the penultimate component.
Resolution-restriction flags diff --git a/fs/namei.c b/fs/namei.c index 130aa5694f48..c94a814e86b2 100644 --- a/fs/namei.c +++ b/fs/namei.c @@ -504,7 +504,7 @@ struct nameidata { struct qstr last; struct path root; struct inode *inode; /* path.dentry.d_inode */ - unsigned int flags; + unsigned int flags, state; unsigned seq, m_seq, r_seq; int last_type; unsigned depth; @@ -523,6 +523,10 @@ struct nameidata { umode_t dir_mode; } __randomize_layout;
+#define ND_ROOT_PRESET 1 +#define ND_ROOT_GRABBED 2 +#define ND_JUMPED 4 + static void set_nameidata(struct nameidata *p, int dfd, struct filename *name) { struct nameidata *old = current->nameidata; @@ -531,6 +535,7 @@ static void set_nameidata(struct nameidata *p, int dfd, struct filename *name) p->name = name; p->total_link_count = old ? old->total_link_count : 0; p->saved = old; + p->state = 0; current->nameidata = p; }
@@ -593,9 +598,9 @@ static void terminate_walk(struct nameidata *nd) path_put(&nd->path); for (i = 0; i < nd->depth; i++) path_put(&nd->stack[i].link); - if (nd->flags & LOOKUP_ROOT_GRABBED) { + if (nd->state & ND_ROOT_GRABBED) { path_put(&nd->root); - nd->flags &= ~LOOKUP_ROOT_GRABBED; + nd->state &= ~ND_ROOT_GRABBED; } } else { nd->flags &= ~LOOKUP_RCU; @@ -651,9 +656,9 @@ static bool legitimize_root(struct nameidata *nd) if (!nd->root.mnt && (nd->flags & LOOKUP_IS_SCOPED)) return false; /* Nothing to do if nd->root is zero or is managed by the VFS user. */ - if (!nd->root.mnt || (nd->flags & LOOKUP_ROOT)) + if (!nd->root.mnt || (nd->state & ND_ROOT_PRESET)) return true; - nd->flags |= LOOKUP_ROOT_GRABBED; + nd->state |= ND_ROOT_GRABBED; return legitimize_path(nd, &nd->root, nd->root_seq); }
@@ -790,8 +795,9 @@ static int complete_walk(struct nameidata *nd) * We don't want to zero nd->root for scoped-lookups or * externally-managed nd->root. */ - if (!(nd->flags & (LOOKUP_ROOT | LOOKUP_IS_SCOPED))) - nd->root.mnt = NULL; + if (!(nd->state & ND_ROOT_PRESET)) + if (!(nd->flags & LOOKUP_IS_SCOPED)) + nd->root.mnt = NULL; if (!try_to_unlazy(nd)) return -ECHILD; } @@ -817,7 +823,7 @@ static int complete_walk(struct nameidata *nd) return -EXDEV; }
- if (likely(!(nd->flags & LOOKUP_JUMPED))) + if (likely(!(nd->state & ND_JUMPED))) return 0;
if (likely(!(dentry->d_flags & DCACHE_OP_WEAK_REVALIDATE))) @@ -855,7 +861,7 @@ static int set_root(struct nameidata *nd) } while (read_seqcount_retry(&fs->seq, seq)); } else { get_fs_root(fs, &nd->root); - nd->flags |= LOOKUP_ROOT_GRABBED; + nd->state |= ND_ROOT_GRABBED; } return 0; } @@ -888,7 +894,7 @@ static int nd_jump_root(struct nameidata *nd) path_get(&nd->path); nd->inode = nd->path.dentry->d_inode; } - nd->flags |= LOOKUP_JUMPED; + nd->state |= ND_JUMPED; return 0; }
@@ -916,7 +922,7 @@ int nd_jump_link(struct path *path) path_put(&nd->path); nd->path = *path; nd->inode = nd->path.dentry->d_inode; - nd->flags |= LOOKUP_JUMPED; + nd->state |= ND_JUMPED; return 0;
err: @@ -1338,7 +1344,7 @@ static bool __follow_mount_rcu(struct nameidata *nd, struct path *path, if (mounted) { path->mnt = &mounted->mnt; dentry = path->dentry = mounted->mnt.mnt_root; - nd->flags |= LOOKUP_JUMPED; + nd->state |= ND_JUMPED; *seqp = read_seqcount_begin(&dentry->d_seq); *inode = dentry->d_inode; /* @@ -1383,7 +1389,7 @@ static inline int handle_mounts(struct nameidata *nd, struct dentry *dentry, if (unlikely(nd->flags & LOOKUP_NO_XDEV)) ret = -EXDEV; else - nd->flags |= LOOKUP_JUMPED; + nd->state |= ND_JUMPED; } if (unlikely(ret)) { dput(path->dentry); @@ -2129,7 +2135,7 @@ static int link_path_walk(const char *name, struct nameidata *nd) case 2: if (name[1] == '.') { type = LAST_DOTDOT; - nd->flags |= LOOKUP_JUMPED; + nd->state |= ND_JUMPED; } break; case 1: @@ -2137,7 +2143,7 @@ static int link_path_walk(const char *name, struct nameidata *nd) } if (likely(type == LAST_NORM)) { struct dentry *parent = nd->path.dentry; - nd->flags &= ~LOOKUP_JUMPED; + nd->state &= ~ND_JUMPED; if (unlikely(parent->d_flags & DCACHE_OP_HASH)) { struct qstr this = { { .hash_len = hash_len }, .name = name }; err = parent->d_op->d_hash(parent, &this); @@ -2207,14 +2213,15 @@ static const char *path_init(struct nameidata *nd, unsigned flags) if (flags & LOOKUP_RCU) rcu_read_lock();
- nd->flags = flags | LOOKUP_JUMPED; + nd->flags = flags; + nd->state |= ND_JUMPED; nd->depth = 0;
nd->m_seq = __read_seqcount_begin(&mount_lock.seqcount); nd->r_seq = __read_seqcount_begin(&rename_lock.seqcount); smp_rmb();
- if (flags & LOOKUP_ROOT) { + if (nd->state & ND_ROOT_PRESET) { struct dentry *root = nd->root.dentry; struct inode *inode = root->d_inode; if (*s && unlikely(!d_can_lookup(root))) @@ -2291,7 +2298,7 @@ static const char *path_init(struct nameidata *nd, unsigned flags) nd->root_seq = nd->seq; } else { path_get(&nd->root); - nd->flags |= LOOKUP_ROOT_GRABBED; + nd->state |= ND_ROOT_GRABBED; } } return s; @@ -2330,7 +2337,7 @@ static int path_lookupat(struct nameidata *nd, unsigned flags, struct path *path ; if (!err && unlikely(nd->flags & LOOKUP_MOUNTPOINT)) { err = handle_lookup_down(nd); - nd->flags &= ~LOOKUP_JUMPED; // no d_weak_revalidate(), please... + nd->state &= ~ND_JUMPED; // no d_weak_revalidate(), please... } if (!err) err = complete_walk(nd); @@ -2354,11 +2361,11 @@ int filename_lookup(int dfd, struct filename *name, unsigned flags, struct nameidata nd; if (IS_ERR(name)) return PTR_ERR(name); + set_nameidata(&nd, dfd, name); if (unlikely(root)) { nd.root = *root; - flags |= LOOKUP_ROOT; + nd.state = ND_ROOT_PRESET; } - set_nameidata(&nd, dfd, name); retval = path_lookupat(&nd, flags | LOOKUP_RCU, path); if (unlikely(retval == -ECHILD)) retval = path_lookupat(&nd, flags, path); @@ -3399,7 +3406,7 @@ struct file *do_file_open_root(const struct path *root, struct nameidata nd; struct file *file; struct filename *filename; - int flags = op->lookup_flags | LOOKUP_ROOT; + int flags = op->lookup_flags;
if (d_is_symlink(root->dentry) && op->intent & LOOKUP_OPEN) return ERR_PTR(-ELOOP); @@ -3408,8 +3415,9 @@ struct file *do_file_open_root(const struct path *root, if (IS_ERR(filename)) return ERR_CAST(filename);
- nd.root = *root; set_nameidata(&nd, -1, filename); + nd.root = *root; + nd.state = ND_ROOT_PRESET; file = path_openat(&nd, op, flags | LOOKUP_RCU); if (unlikely(file == ERR_PTR(-ECHILD))) file = path_openat(&nd, op, flags); diff --git a/fs/nfs/nfstrace.h b/fs/nfs/nfstrace.h index 5a59dcdce0b2..cb7f49723bbf 100644 --- a/fs/nfs/nfstrace.h +++ b/fs/nfs/nfstrace.h @@ -271,8 +271,6 @@ TRACE_DEFINE_ENUM(LOOKUP_OPEN); TRACE_DEFINE_ENUM(LOOKUP_CREATE); TRACE_DEFINE_ENUM(LOOKUP_EXCL); TRACE_DEFINE_ENUM(LOOKUP_RENAME_TARGET); -TRACE_DEFINE_ENUM(LOOKUP_JUMPED); -TRACE_DEFINE_ENUM(LOOKUP_ROOT); TRACE_DEFINE_ENUM(LOOKUP_EMPTY); TRACE_DEFINE_ENUM(LOOKUP_DOWN);
@@ -288,8 +286,6 @@ TRACE_DEFINE_ENUM(LOOKUP_DOWN); { LOOKUP_CREATE, "CREATE" }, \ { LOOKUP_EXCL, "EXCL" }, \ { LOOKUP_RENAME_TARGET, "RENAME_TARGET" }, \ - { LOOKUP_JUMPED, "JUMPED" }, \ - { LOOKUP_ROOT, "ROOT" }, \ { LOOKUP_EMPTY, "EMPTY" }, \ { LOOKUP_DOWN, "DOWN" })
diff --git a/include/linux/namei.h b/include/linux/namei.h index a4bb992623c4..ca94eb5d2b16 100644 --- a/include/linux/namei.h +++ b/include/linux/namei.h @@ -36,9 +36,6 @@ enum {LAST_NORM, LAST_ROOT, LAST_DOT, LAST_DOTDOT};
/* internal use only */ #define LOOKUP_PARENT 0x0010 -#define LOOKUP_JUMPED 0x1000 -#define LOOKUP_ROOT 0x2000 -#define LOOKUP_ROOT_GRABBED 0x0008
/* Scoping flags for lookup. */ #define LOOKUP_NO_SYMLINKS 0x010000 /* No symlink crossing. */