* [PATCHES] namei cleanups @ 2021-06-08 11:38 Al Viro 2021-06-08 11:39 ` [PATCH 1/4] switch file_open_root() to struct path Al Viro 2021-06-08 12:12 ` [PATCHES] namei cleanups Christian Brauner 0 siblings, 2 replies; 6+ messages in thread From: Al Viro @ 2021-06-08 11:38 UTC (permalink / raw) To: linux-fsdevel; +Cc: linux-kernel Small namei.c patch series, mostly to simplify the rules for nameidata state. It's in #work.namei and it's actually from the previous cycle - didn't post it for review in time... Changes visible outside of fs/namei.c: file_open_root() calling conventions change, some freed bits in LOOKUP_... space. ^ permalink raw reply [flat|nested] 6+ messages in thread
* [PATCH 1/4] switch file_open_root() to struct path 2021-06-08 11:38 [PATCHES] namei cleanups Al Viro @ 2021-06-08 11:39 ` Al Viro 2021-06-08 11:39 ` [PATCH 2/4] take LOOKUP_{ROOT,ROOT_GRABBED,JUMPED} out of LOOKUP_... space Al Viro ` (2 more replies) 2021-06-08 12:12 ` [PATCHES] namei cleanups Christian Brauner 1 sibling, 3 replies; 6+ messages in thread From: Al Viro @ 2021-06-08 11:39 UTC (permalink / raw) To: linux-fsdevel; +Cc: linux-kernel ... and provide file_open_root_mnt(), using the root of given mount. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> --- Documentation/filesystems/porting.rst | 9 +++++++++ arch/um/drivers/mconsole_kern.c | 2 +- fs/coredump.c | 4 ++-- fs/fhandle.c | 2 +- fs/internal.h | 2 +- fs/kernel_read_file.c | 2 +- fs/namei.c | 8 +++----- fs/open.c | 4 ++-- fs/proc/proc_sysctl.c | 2 +- include/linux/fs.h | 8 +++++++- kernel/usermode_driver.c | 2 +- 11 files changed, 29 insertions(+), 16 deletions(-) diff --git a/Documentation/filesystems/porting.rst b/Documentation/filesystems/porting.rst index 0302035781be..9bb2b35f90bb 100644 --- a/Documentation/filesystems/porting.rst +++ b/Documentation/filesystems/porting.rst @@ -890,3 +890,12 @@ been called or returned with non -EIOCBQUEUED code. mnt_want_write_file() can now only be paired with mnt_drop_write_file(), whereas previously it could be paired with mnt_drop_write() as well. + +--- + +**mandatory** + +Calling conventions for file_open_root() changed; now it takes struct path * +instead of passing mount and dentry separately. For callers that used to +pass <mnt, mnt->mnt_root> pair (i.e. the root of given mount), a new helper +is provided - file_open_root_mnt(). In-tree users adjusted. diff --git a/arch/um/drivers/mconsole_kern.c b/arch/um/drivers/mconsole_kern.c index 6d00af25ec6b..c42b10024e26 100644 --- a/arch/um/drivers/mconsole_kern.c +++ b/arch/um/drivers/mconsole_kern.c @@ -140,7 +140,7 @@ void mconsole_proc(struct mc_request *req) mconsole_reply(req, "Proc not available", 1, 0); goto out; } - file = file_open_root(mnt->mnt_root, mnt, ptr, O_RDONLY, 0); + file = file_open_root_mnt(mnt, ptr, O_RDONLY, 0); if (IS_ERR(file)) { mconsole_reply(req, "Failed to open file", 1, 0); printk(KERN_ERR "open /proc/%s: %ld\n", ptr, PTR_ERR(file)); diff --git a/fs/coredump.c b/fs/coredump.c index 1c0fdc1aa70b..087db444b06b 100644 --- a/fs/coredump.c +++ b/fs/coredump.c @@ -755,8 +755,8 @@ void do_coredump(const kernel_siginfo_t *siginfo) task_lock(&init_task); get_fs_root(init_task.fs, &root); task_unlock(&init_task); - cprm.file = file_open_root(root.dentry, root.mnt, - cn.corename, open_flags, 0600); + cprm.file = file_open_root(&root, cn.corename, + open_flags, 0600); path_put(&root); } else { cprm.file = filp_open(cn.corename, open_flags, 0600); diff --git a/fs/fhandle.c b/fs/fhandle.c index ec6feeccc276..6630c69c23a2 100644 --- a/fs/fhandle.c +++ b/fs/fhandle.c @@ -229,7 +229,7 @@ static long do_handle_open(int mountdirfd, struct file_handle __user *ufh, path_put(&path); return fd; } - file = file_open_root(path.dentry, path.mnt, "", open_flag, 0); + file = file_open_root(&path, "", open_flag, 0); if (IS_ERR(file)) { put_unused_fd(fd); retval = PTR_ERR(file); diff --git a/fs/internal.h b/fs/internal.h index 6aeae7ef3380..3ce8edbaa3ca 100644 --- a/fs/internal.h +++ b/fs/internal.h @@ -129,7 +129,7 @@ struct open_flags { }; extern struct file *do_filp_open(int dfd, struct filename *pathname, const struct open_flags *op); -extern struct file *do_file_open_root(struct dentry *, struct vfsmount *, +extern struct file *do_file_open_root(const struct path *, const char *, const struct open_flags *); extern struct open_how build_open_how(int flags, umode_t mode); extern int build_open_flags(const struct open_how *how, struct open_flags *op); diff --git a/fs/kernel_read_file.c b/fs/kernel_read_file.c index 90d255fbdd9b..87aac4c72c37 100644 --- a/fs/kernel_read_file.c +++ b/fs/kernel_read_file.c @@ -160,7 +160,7 @@ int kernel_read_file_from_path_initns(const char *path, loff_t offset, get_fs_root(init_task.fs, &root); task_unlock(&init_task); - file = file_open_root(root.dentry, root.mnt, path, O_RDONLY, 0); + file = file_open_root(&root, path, O_RDONLY, 0); path_put(&root); if (IS_ERR(file)) return PTR_ERR(file); diff --git a/fs/namei.c b/fs/namei.c index 48a2f288e802..4b6cf4974dd7 100644 --- a/fs/namei.c +++ b/fs/namei.c @@ -3533,7 +3533,7 @@ struct file *do_filp_open(int dfd, struct filename *pathname, return filp; } -struct file *do_file_open_root(struct dentry *dentry, struct vfsmount *mnt, +struct file *do_file_open_root(const struct path *root, const char *name, const struct open_flags *op) { struct nameidata nd; @@ -3541,16 +3541,14 @@ struct file *do_file_open_root(struct dentry *dentry, struct vfsmount *mnt, struct filename *filename; int flags = op->lookup_flags | LOOKUP_ROOT; - nd.root.mnt = mnt; - nd.root.dentry = dentry; - - if (d_is_symlink(dentry) && op->intent & LOOKUP_OPEN) + if (d_is_symlink(root->dentry) && op->intent & LOOKUP_OPEN) return ERR_PTR(-ELOOP); filename = getname_kernel(name); if (IS_ERR(filename)) return ERR_CAST(filename); + nd.root = *root; set_nameidata(&nd, -1, filename); file = path_openat(&nd, op, flags | LOOKUP_RCU); if (unlikely(file == ERR_PTR(-ECHILD))) diff --git a/fs/open.c b/fs/open.c index e53af13b5835..b3c904e82e2a 100644 --- a/fs/open.c +++ b/fs/open.c @@ -1156,7 +1156,7 @@ struct file *filp_open(const char *filename, int flags, umode_t mode) } EXPORT_SYMBOL(filp_open); -struct file *file_open_root(struct dentry *dentry, struct vfsmount *mnt, +struct file *file_open_root(const struct path *root, const char *filename, int flags, umode_t mode) { struct open_flags op; @@ -1164,7 +1164,7 @@ struct file *file_open_root(struct dentry *dentry, struct vfsmount *mnt, int err = build_open_flags(&how, &op); if (err) return ERR_PTR(err); - return do_file_open_root(dentry, mnt, filename, &op); + return do_file_open_root(root, filename, &op); } EXPORT_SYMBOL(file_open_root); diff --git a/fs/proc/proc_sysctl.c b/fs/proc/proc_sysctl.c index 984e42f8cb11..6606f21fc195 100644 --- a/fs/proc/proc_sysctl.c +++ b/fs/proc/proc_sysctl.c @@ -1806,7 +1806,7 @@ static int process_sysctl_arg(char *param, char *val, panic("%s: Failed to allocate path for %s\n", __func__, param); strreplace(path, '.', '/'); - file = file_open_root((*proc_mnt)->mnt_root, *proc_mnt, path, O_WRONLY, 0); + file = file_open_root_mnt(*proc_mnt, path, O_WRONLY, 0); if (IS_ERR(file)) { err = PTR_ERR(file); if (err == -ENOENT) diff --git a/include/linux/fs.h b/include/linux/fs.h index ec8f3ddf4a6a..1acea2bb9d60 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -2632,8 +2632,14 @@ extern long do_sys_open(int dfd, const char __user *filename, int flags, umode_t mode); extern struct file *file_open_name(struct filename *, int, umode_t); extern struct file *filp_open(const char *, int, umode_t); -extern struct file *file_open_root(struct dentry *, struct vfsmount *, +extern struct file *file_open_root(const struct path *, const char *, int, umode_t); +static inline struct file *file_open_root_mnt(struct vfsmount *mnt, + const char *name, int flags, umode_t mode) +{ + return file_open_root(&(struct path){.mnt = mnt, .dentry = mnt->mnt_root}, + name, flags, mode); +} extern struct file * dentry_open(const struct path *, int, const struct cred *); extern struct file * open_with_fake_path(const struct path *, int, struct inode*, const struct cred *); diff --git a/kernel/usermode_driver.c b/kernel/usermode_driver.c index 0b35212ffc3d..78353cb73836 100644 --- a/kernel/usermode_driver.c +++ b/kernel/usermode_driver.c @@ -26,7 +26,7 @@ static struct vfsmount *blob_to_mnt(const void *data, size_t len, const char *na if (IS_ERR(mnt)) return mnt; - file = file_open_root(mnt->mnt_root, mnt, name, O_CREAT | O_WRONLY, 0700); + file = file_open_root_mnt(mnt, name, O_CREAT | O_WRONLY, 0700); if (IS_ERR(file)) { mntput(mnt); return ERR_CAST(file); -- 2.11.0 ^ permalink raw reply related [flat|nested] 6+ messages in thread
* [PATCH 2/4] take LOOKUP_{ROOT,ROOT_GRABBED,JUMPED} out of LOOKUP_... space 2021-06-08 11:39 ` [PATCH 1/4] switch file_open_root() to struct path Al Viro @ 2021-06-08 11:39 ` Al Viro 2021-06-08 11:39 ` [PATCH 3/4] teach set_nameidata() to handle setting the root as well Al Viro 2021-06-08 11:39 ` [PATCH 4/4] namei: make sure nd->depth is always valid Al Viro 2 siblings, 0 replies; 6+ messages in thread From: Al Viro @ 2021-06-08 11:39 UTC (permalink / raw) To: linux-fsdevel; +Cc: linux-kernel 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> --- 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 4b6cf4974dd7..622b9f15bf1c 100644 --- a/fs/namei.c +++ b/fs/namei.c @@ -554,7 +554,7 @@ 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; @@ -573,6 +573,10 @@ 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; @@ -583,6 +587,7 @@ static void set_nameidata(struct nameidata *p, int dfd, struct filename *name) p->path.dentry = NULL; p->total_link_count = old ? old->total_link_count : 0; p->saved = old; + p->state = 0; current->nameidata = p; } @@ -645,9 +650,9 @@ 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; @@ -710,9 +715,9 @@ 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); } @@ -849,8 +854,9 @@ 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; nd->flags &= ~LOOKUP_CACHED; if (!try_to_unlazy(nd)) return -ECHILD; @@ -877,7 +883,7 @@ 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))) @@ -915,7 +921,7 @@ 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; } @@ -948,7 +954,7 @@ 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; } @@ -976,7 +982,7 @@ 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: @@ -1424,7 +1430,7 @@ 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; /* @@ -1469,7 +1475,7 @@ 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); @@ -2220,7 +2226,7 @@ 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: @@ -2228,7 +2234,7 @@ 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); @@ -2302,14 +2308,15 @@ 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))) @@ -2384,7 +2391,7 @@ 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; @@ -2423,7 +2430,7 @@ 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); @@ -2447,11 +2454,11 @@ 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); @@ -3539,7 +3546,7 @@ 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); @@ -3548,8 +3555,9 @@ 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 b9605b2b46e7..be9a2b349ca7 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. */ -- 2.11.0 ^ permalink raw reply related [flat|nested] 6+ messages in thread
* [PATCH 3/4] teach set_nameidata() to handle setting the root as well 2021-06-08 11:39 ` [PATCH 1/4] switch file_open_root() to struct path Al Viro 2021-06-08 11:39 ` [PATCH 2/4] take LOOKUP_{ROOT,ROOT_GRABBED,JUMPED} out of LOOKUP_... space Al Viro @ 2021-06-08 11:39 ` Al Viro 2021-06-08 11:39 ` [PATCH 4/4] namei: make sure nd->depth is always valid Al Viro 2 siblings, 0 replies; 6+ messages in thread From: Al Viro @ 2021-06-08 11:39 UTC (permalink / raw) To: linux-fsdevel; +Cc: linux-kernel That way we don't need the callers to mess with manually setting any fields of nameidata instances. Old set_nameidata() gets renamed (__set_nameidata()), new becomes an inlined helper that takes a struct path pointer and deals with setting nd->root and putting ND_ROOT_PRESET in nd->state when new argument is non-NULL. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> --- fs/namei.c | 28 ++++++++++++++++------------ 1 file changed, 16 insertions(+), 12 deletions(-) diff --git a/fs/namei.c b/fs/namei.c index 622b9f15bf1c..40ffb249aa7f 100644 --- a/fs/namei.c +++ b/fs/namei.c @@ -577,7 +577,7 @@ struct nameidata { #define ND_ROOT_GRABBED 2 #define ND_JUMPED 4 -static void set_nameidata(struct nameidata *p, int dfd, struct filename *name) +static void __set_nameidata(struct nameidata *p, int dfd, struct filename *name) { struct nameidata *old = current->nameidata; p->stack = p->internal; @@ -587,10 +587,20 @@ static void set_nameidata(struct nameidata *p, int dfd, struct filename *name) p->path.dentry = NULL; p->total_link_count = old ? old->total_link_count : 0; p->saved = old; - p->state = 0; current->nameidata = p; } +static inline void set_nameidata(struct nameidata *p, int dfd, struct filename *name, + const struct path *root) +{ + __set_nameidata(p, dfd, name); + p->state = 0; + if (unlikely(root)) { + p->state = ND_ROOT_PRESET; + p->root = *root; + } +} + static void restore_nameidata(void) { struct nameidata *now = current->nameidata, *old = now->saved; @@ -2454,11 +2464,7 @@ 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; - nd.state = ND_ROOT_PRESET; - } + set_nameidata(&nd, dfd, name, root); retval = path_lookupat(&nd, flags | LOOKUP_RCU, path); if (unlikely(retval == -ECHILD)) retval = path_lookupat(&nd, flags, path); @@ -2499,7 +2505,7 @@ static struct filename *filename_parentat(int dfd, struct filename *name, if (IS_ERR(name)) return name; - set_nameidata(&nd, dfd, name); + set_nameidata(&nd, dfd, name, NULL); retval = path_parentat(&nd, flags | LOOKUP_RCU, parent); if (unlikely(retval == -ECHILD)) retval = path_parentat(&nd, flags, parent); @@ -3530,7 +3536,7 @@ struct file *do_filp_open(int dfd, struct filename *pathname, int flags = op->lookup_flags; struct file *filp; - set_nameidata(&nd, dfd, pathname); + set_nameidata(&nd, dfd, pathname, NULL); filp = path_openat(&nd, op, flags | LOOKUP_RCU); if (unlikely(filp == ERR_PTR(-ECHILD))) filp = path_openat(&nd, op, flags); @@ -3555,9 +3561,7 @@ struct file *do_file_open_root(const struct path *root, if (IS_ERR(filename)) return ERR_CAST(filename); - set_nameidata(&nd, -1, filename); - nd.root = *root; - nd.state = ND_ROOT_PRESET; + set_nameidata(&nd, -1, filename, root); file = path_openat(&nd, op, flags | LOOKUP_RCU); if (unlikely(file == ERR_PTR(-ECHILD))) file = path_openat(&nd, op, flags); -- 2.11.0 ^ permalink raw reply related [flat|nested] 6+ messages in thread
* [PATCH 4/4] namei: make sure nd->depth is always valid 2021-06-08 11:39 ` [PATCH 1/4] switch file_open_root() to struct path Al Viro 2021-06-08 11:39 ` [PATCH 2/4] take LOOKUP_{ROOT,ROOT_GRABBED,JUMPED} out of LOOKUP_... space Al Viro 2021-06-08 11:39 ` [PATCH 3/4] teach set_nameidata() to handle setting the root as well Al Viro @ 2021-06-08 11:39 ` Al Viro 2 siblings, 0 replies; 6+ messages in thread From: Al Viro @ 2021-06-08 11:39 UTC (permalink / raw) To: linux-fsdevel; +Cc: linux-kernel Zero it in set_nameidata() rather than in path_init(). That way it always matches the number of valid nd->stack[] entries. Since terminate_walk() does zero it (after having emptied the stack), we don't need to reinitialize it in subsequent path_init(). Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> --- fs/namei.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/fs/namei.c b/fs/namei.c index 40ffb249aa7f..d38b17ad604c 100644 --- a/fs/namei.c +++ b/fs/namei.c @@ -581,6 +581,7 @@ static void __set_nameidata(struct nameidata *p, int dfd, struct filename *name) { struct nameidata *old = current->nameidata; p->stack = p->internal; + p->depth = 0; p->dfd = dfd; p->name = name; p->path.mnt = NULL; @@ -2320,7 +2321,6 @@ static const char *path_init(struct nameidata *nd, unsigned flags) 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); -- 2.11.0 ^ permalink raw reply related [flat|nested] 6+ messages in thread
* Re: [PATCHES] namei cleanups 2021-06-08 11:38 [PATCHES] namei cleanups Al Viro 2021-06-08 11:39 ` [PATCH 1/4] switch file_open_root() to struct path Al Viro @ 2021-06-08 12:12 ` Christian Brauner 1 sibling, 0 replies; 6+ messages in thread From: Christian Brauner @ 2021-06-08 12:12 UTC (permalink / raw) To: Al Viro; +Cc: linux-fsdevel, linux-kernel On Tue, Jun 08, 2021 at 11:38:40AM +0000, Al Viro wrote: > Small namei.c patch series, mostly to simplify the rules > for nameidata state. It's in #work.namei and it's actually from > the previous cycle - didn't post it for review in time... > > Changes visible outside of fs/namei.c: file_open_root() > calling conventions change, some freed bits in LOOKUP_... space. Ah that's the follow-up to the io_uring fix from last cycle. Nice cleanup. Acked-by: Christian Brauner <christian.brauner@ubuntu.com> ^ permalink raw reply [flat|nested] 6+ messages in thread
end of thread, other threads:[~2021-06-08 12:12 UTC | newest]
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2021-06-08 11:38 [PATCHES] namei cleanups Al Viro
2021-06-08 11:39 ` [PATCH 1/4] switch file_open_root() to struct path Al Viro
2021-06-08 11:39 ` [PATCH 2/4] take LOOKUP_{ROOT,ROOT_GRABBED,JUMPED} out of LOOKUP_... space Al Viro
2021-06-08 11:39 ` [PATCH 3/4] teach set_nameidata() to handle setting the root as well Al Viro
2021-06-08 11:39 ` [PATCH 4/4] namei: make sure nd->depth is always valid Al Viro
2021-06-08 12:12 ` [PATCHES] namei cleanups Christian Brauner
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