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author | Linus Torvalds <torvalds@linux-foundation.org> | 2021-07-03 11:41:14 -0700 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2021-07-03 11:41:14 -0700 |
commit | 58ec9059b396a570b208239b4edc45eeb68b14c4 (patch) | |
tree | 9f7943ef6bb77535b0e4b3531b6eae4bf51ec5a5 /fs/namei.c | |
parent | d3acb15a3a1b841dc709c3853ec900170b2478e5 (diff) | |
parent | 7962c7d196e36aa597fadb78c1cb4fe7e209f803 (diff) | |
download | linux-58ec9059b396a570b208239b4edc45eeb68b14c4.tar.gz linux-58ec9059b396a570b208239b4edc45eeb68b14c4.tar.bz2 linux-58ec9059b396a570b208239b4edc45eeb68b14c4.zip |
Merge branch 'work.namei' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs
Pull vfs name lookup updates from Al Viro:
"Small namei.c patch series, mostly to simplify the rules for nameidata
state. It's actually from the previous cycle - but I 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"
* 'work.namei' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
namei: make sure nd->depth is always valid
teach set_nameidata() to handle setting the root as well
take LOOKUP_{ROOT,ROOT_GRABBED,JUMPED} out of LOOKUP_... space
switch file_open_root() to struct path
Diffstat (limited to 'fs/namei.c')
-rw-r--r-- | fs/namei.c | 80 |
1 files changed, 45 insertions, 35 deletions
diff --git a/fs/namei.c b/fs/namei.c index 79b0ff9b151e..bf6d8a738c59 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; @@ -573,10 +573,15 @@ struct nameidata { umode_t dir_mode; } __randomize_layout; -static void set_nameidata(struct nameidata *p, int dfd, struct filename *name) +#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; p->stack = p->internal; + p->depth = 0; p->dfd = dfd; p->name = name; p->path.mnt = NULL; @@ -586,6 +591,17 @@ static void set_nameidata(struct nameidata *p, int dfd, struct filename *name) 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; @@ -645,9 +661,9 @@ 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 +726,9 @@ 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 +865,9 @@ 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 +894,7 @@ 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 +932,7 @@ 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 +965,7 @@ 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 +993,7 @@ 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: @@ -1423,7 +1440,7 @@ 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; /* @@ -1468,7 +1485,7 @@ 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); @@ -2219,7 +2236,7 @@ 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: @@ -2227,7 +2244,7 @@ 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); @@ -2301,14 +2318,14 @@ static const char *path_init(struct nameidata *nd, unsigned flags) if (flags & LOOKUP_RCU) rcu_read_lock(); - nd->flags = flags | LOOKUP_JUMPED; - nd->depth = 0; + nd->flags = flags; + nd->state |= ND_JUMPED; 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))) @@ -2383,7 +2400,7 @@ 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; @@ -2422,7 +2439,7 @@ 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); @@ -2446,11 +2463,7 @@ int filename_lookup(int dfd, struct filename *name, unsigned flags, struct nameidata nd; if (IS_ERR(name)) return PTR_ERR(name); - if (unlikely(root)) { - nd.root = *root; - flags |= LOOKUP_ROOT; - } - set_nameidata(&nd, dfd, name); + set_nameidata(&nd, dfd, name, root); retval = path_lookupat(&nd, flags | LOOKUP_RCU, path); if (unlikely(retval == -ECHILD)) retval = path_lookupat(&nd, flags, path); @@ -2491,7 +2504,7 @@ 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); @@ -3517,7 +3530,7 @@ 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); @@ -3527,25 +3540,22 @@ 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; struct file *file; struct filename *filename; - int flags = op->lookup_flags | LOOKUP_ROOT; - - nd.root.mnt = mnt; - nd.root.dentry = dentry; + int flags = op->lookup_flags; - 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); - set_nameidata(&nd, -1, filename); + 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); |