X-Git-Url: http://git.cascardo.info/?a=blobdiff_plain;f=fs%2Fnamei.c;h=28cb1cd8507c2293864bb2fc67263f9607991d0a;hb=a01e718f7241c53f564402f7acff373eed5bd166;hp=30145f8f21ed5b47e47fba7e29e0434c76e858d0;hpb=ae14dbfaa04180cc07b32ad6c3852d73917878d3;p=cascardo%2Flinux.git diff --git a/fs/namei.c b/fs/namei.c index 30145f8f21ed..28cb1cd8507c 100644 --- a/fs/namei.c +++ b/fs/namei.c @@ -35,6 +35,7 @@ #include #include #include +#include #include #include "internal.h" @@ -265,7 +266,7 @@ static int check_acl(struct inode *inode, int mask) if (!acl) return -EAGAIN; /* no ->get_acl() calls in RCU mode... */ - if (acl == ACL_NOT_CACHED) + if (is_uncached_acl(acl)) return -ECHILD; return posix_acl_permission(inode, acl, mask & ~MAY_NOT_BLOCK); } @@ -1603,32 +1604,42 @@ static struct dentry *lookup_slow(const struct qstr *name, struct dentry *dir, unsigned int flags) { - struct dentry *dentry; - inode_lock(dir->d_inode); - dentry = d_lookup(dir, name); - if (unlikely(dentry)) { + struct dentry *dentry = ERR_PTR(-ENOENT), *old; + struct inode *inode = dir->d_inode; + DECLARE_WAIT_QUEUE_HEAD_ONSTACK(wq); + + inode_lock_shared(inode); + /* Don't go there if it's already dead */ + if (unlikely(IS_DEADDIR(inode))) + goto out; +again: + dentry = d_alloc_parallel(dir, name, &wq); + if (IS_ERR(dentry)) + goto out; + if (unlikely(!d_in_lookup(dentry))) { if ((dentry->d_flags & DCACHE_OP_REVALIDATE) && !(flags & LOOKUP_NO_REVAL)) { int error = d_revalidate(dentry, flags); if (unlikely(error <= 0)) { - if (!error) + if (!error) { d_invalidate(dentry); + dput(dentry); + goto again; + } dput(dentry); dentry = ERR_PTR(error); } } - if (dentry) { - inode_unlock(dir->d_inode); - return dentry; + } else { + old = inode->i_op->lookup(inode, dentry, flags); + d_lookup_done(dentry); + if (unlikely(old)) { + dput(dentry); + dentry = old; } } - dentry = d_alloc(dir, name); - if (unlikely(!dentry)) { - inode_unlock(dir->d_inode); - return ERR_PTR(-ENOMEM); - } - dentry = lookup_real(dir->d_inode, dentry, flags); - inode_unlock(dir->d_inode); +out: + inode_unlock_shared(inode); return dentry; } @@ -1787,55 +1798,144 @@ static int walk_component(struct nameidata *nd, int flags) #include -#ifdef CONFIG_64BIT +#ifdef HASH_MIX + +/* Architecture provides HASH_MIX and fold_hash() in */ -static inline unsigned int fold_hash(unsigned long hash) +#elif defined(CONFIG_64BIT) +/* + * Register pressure in the mixing function is an issue, particularly + * on 32-bit x86, but almost any function requires one state value and + * one temporary. Instead, use a function designed for two state values + * and no temporaries. + * + * This function cannot create a collision in only two iterations, so + * we have two iterations to achieve avalanche. In those two iterations, + * we have six layers of mixing, which is enough to spread one bit's + * influence out to 2^6 = 64 state bits. + * + * Rotate constants are scored by considering either 64 one-bit input + * deltas or 64*63/2 = 2016 two-bit input deltas, and finding the + * probability of that delta causing a change to each of the 128 output + * bits, using a sample of random initial states. + * + * The Shannon entropy of the computed probabilities is then summed + * to produce a score. Ideally, any input change has a 50% chance of + * toggling any given output bit. + * + * Mixing scores (in bits) for (12,45): + * Input delta: 1-bit 2-bit + * 1 round: 713.3 42542.6 + * 2 rounds: 2753.7 140389.8 + * 3 rounds: 5954.1 233458.2 + * 4 rounds: 7862.6 256672.2 + * Perfect: 8192 258048 + * (64*128) (64*63/2 * 128) + */ +#define HASH_MIX(x, y, a) \ + ( x ^= (a), \ + y ^= x, x = rol64(x,12),\ + x += y, y = rol64(y,45),\ + y *= 9 ) + +/* + * Fold two longs into one 32-bit hash value. This must be fast, but + * latency isn't quite as critical, as there is a fair bit of additional + * work done before the hash value is used. + */ +static inline unsigned int fold_hash(unsigned long x, unsigned long y) { - return hash_64(hash, 32); + y ^= x * GOLDEN_RATIO_64; + y *= GOLDEN_RATIO_64; + return y >> 32; } #else /* 32-bit case */ -#define fold_hash(x) (x) +/* + * Mixing scores (in bits) for (7,20): + * Input delta: 1-bit 2-bit + * 1 round: 330.3 9201.6 + * 2 rounds: 1246.4 25475.4 + * 3 rounds: 1907.1 31295.1 + * 4 rounds: 2042.3 31718.6 + * Perfect: 2048 31744 + * (32*64) (32*31/2 * 64) + */ +#define HASH_MIX(x, y, a) \ + ( x ^= (a), \ + y ^= x, x = rol32(x, 7),\ + x += y, y = rol32(y,20),\ + y *= 9 ) + +static inline unsigned int fold_hash(unsigned long x, unsigned long y) +{ + /* Use arch-optimized multiply if one exists */ + return __hash_32(y ^ __hash_32(x)); +} #endif -unsigned int full_name_hash(const unsigned char *name, unsigned int len) +/* + * Return the hash of a string of known length. This is carfully + * designed to match hash_name(), which is the more critical function. + * In particular, we must end by hashing a final word containing 0..7 + * payload bytes, to match the way that hash_name() iterates until it + * finds the delimiter after the name. + */ +unsigned int full_name_hash(const char *name, unsigned int len) { - unsigned long a, mask; - unsigned long hash = 0; + unsigned long a, x = 0, y = 0; for (;;) { + if (!len) + goto done; a = load_unaligned_zeropad(name); if (len < sizeof(unsigned long)) break; - hash += a; - hash *= 9; + HASH_MIX(x, y, a); name += sizeof(unsigned long); len -= sizeof(unsigned long); - if (!len) - goto done; } - mask = bytemask_from_count(len); - hash += mask & a; + x ^= a & bytemask_from_count(len); done: - return fold_hash(hash); + return fold_hash(x, y); } EXPORT_SYMBOL(full_name_hash); +/* Return the "hash_len" (hash and length) of a null-terminated string */ +u64 hashlen_string(const char *name) +{ + unsigned long a = 0, x = 0, y = 0, adata, mask, len; + const struct word_at_a_time constants = WORD_AT_A_TIME_CONSTANTS; + + len = -sizeof(unsigned long); + do { + HASH_MIX(x, y, a); + len += sizeof(unsigned long); + a = load_unaligned_zeropad(name+len); + } while (!has_zero(a, &adata, &constants)); + + adata = prep_zero_mask(a, adata, &constants); + mask = create_zero_mask(adata); + x ^= a & zero_bytemask(mask); + + return hashlen_create(fold_hash(x, y), len + find_zero(mask)); +} +EXPORT_SYMBOL(hashlen_string); + /* * Calculate the length and hash of the path component, and * return the "hash_len" as the result. */ static inline u64 hash_name(const char *name) { - unsigned long a, b, adata, bdata, mask, hash, len; + unsigned long a = 0, b, x = 0, y = 0, adata, bdata, mask, len; const struct word_at_a_time constants = WORD_AT_A_TIME_CONSTANTS; - hash = a = 0; len = -sizeof(unsigned long); do { - hash = (hash + a) * 9; + HASH_MIX(x, y, a); len += sizeof(unsigned long); a = load_unaligned_zeropad(name+len); b = a ^ REPEAT_BYTE('/'); @@ -1843,25 +1943,40 @@ static inline u64 hash_name(const char *name) adata = prep_zero_mask(a, adata, &constants); bdata = prep_zero_mask(b, bdata, &constants); - mask = create_zero_mask(adata | bdata); + x ^= a & zero_bytemask(mask); - hash += a & zero_bytemask(mask); - len += find_zero(mask); - return hashlen_create(fold_hash(hash), len); + return hashlen_create(fold_hash(x, y), len + find_zero(mask)); } -#else +#else /* !CONFIG_DCACHE_WORD_ACCESS: Slow, byte-at-a-time version */ -unsigned int full_name_hash(const unsigned char *name, unsigned int len) +/* Return the hash of a string of known length */ +unsigned int full_name_hash(const char *name, unsigned int len) { unsigned long hash = init_name_hash(); while (len--) - hash = partial_name_hash(*name++, hash); + hash = partial_name_hash((unsigned char)*name++, hash); return end_name_hash(hash); } EXPORT_SYMBOL(full_name_hash); +/* Return the "hash_len" (hash and length) of a null-terminated string */ +u64 hashlen_string(const char *name) +{ + unsigned long hash = init_name_hash(); + unsigned long len = 0, c; + + c = (unsigned char)*name; + while (c) { + len++; + hash = partial_name_hash(c, hash); + c = (unsigned char)name[len]; + } + return hashlen_create(end_name_hash(hash), len); +} +EXPORT_SYMBOL(hashlen_string); + /* * We know there's a real path component here of at least * one character. @@ -1905,7 +2020,7 @@ static int link_path_walk(const char *name, struct nameidata *nd) int type; err = may_lookup(nd); - if (err) + if (err) return err; hash_len = hash_name(name); @@ -2678,7 +2793,7 @@ struct dentry *lock_rename(struct dentry *p1, struct dentry *p2) return NULL; } - mutex_lock(&p1->d_inode->i_sb->s_vfs_rename_mutex); + mutex_lock(&p1->d_sb->s_vfs_rename_mutex); p = d_ancestor(p2, p1); if (p) { @@ -2705,7 +2820,7 @@ void unlock_rename(struct dentry *p1, struct dentry *p2) inode_unlock(p1->d_inode); if (p1 != p2) { inode_unlock(p2->d_inode); - mutex_unlock(&p1->d_inode->i_sb->s_vfs_rename_mutex); + mutex_unlock(&p1->d_sb->s_vfs_rename_mutex); } } EXPORT_SYMBOL(unlock_rename); @@ -2808,7 +2923,7 @@ static inline int open_to_namei_flags(int flag) return flag; } -static int may_o_create(struct path *dir, struct dentry *dentry, umode_t mode) +static int may_o_create(const struct path *dir, struct dentry *dentry, umode_t mode) { int error = security_path_mknod(dir, dentry, mode, 0); if (error) @@ -2837,143 +2952,60 @@ static int may_o_create(struct path *dir, struct dentry *dentry, umode_t mode) static int atomic_open(struct nameidata *nd, struct dentry *dentry, struct path *path, struct file *file, const struct open_flags *op, - bool got_write, bool need_lookup, + int open_flag, umode_t mode, int *opened) { + struct dentry *const DENTRY_NOT_SET = (void *) -1UL; struct inode *dir = nd->path.dentry->d_inode; - unsigned open_flag = open_to_namei_flags(op->open_flag); - umode_t mode; int error; - int acc_mode; - int create_error = 0; - struct dentry *const DENTRY_NOT_SET = (void *) -1UL; - bool excl; - - BUG_ON(dentry->d_inode); - - /* Don't create child dentry for a dead directory. */ - if (unlikely(IS_DEADDIR(dir))) { - error = -ENOENT; - goto out; - } - mode = op->mode; - if ((open_flag & O_CREAT) && !IS_POSIXACL(dir)) - mode &= ~current_umask(); - - excl = (open_flag & (O_EXCL | O_CREAT)) == (O_EXCL | O_CREAT); - if (excl) + if (!(~open_flag & (O_EXCL | O_CREAT))) /* both O_EXCL and O_CREAT */ open_flag &= ~O_TRUNC; - /* - * Checking write permission is tricky, bacuse we don't know if we are - * going to actually need it: O_CREAT opens should work as long as the - * file exists. But checking existence breaks atomicity. The trick is - * to check access and if not granted clear O_CREAT from the flags. - * - * Another problem is returing the "right" error value (e.g. for an - * O_EXCL open we want to return EEXIST not EROFS). - */ - if (((open_flag & (O_CREAT | O_TRUNC)) || - (open_flag & O_ACCMODE) != O_RDONLY) && unlikely(!got_write)) { - if (!(open_flag & O_CREAT)) { - /* - * No O_CREATE -> atomicity not a requirement -> fall - * back to lookup + open - */ - goto no_open; - } else if (open_flag & (O_EXCL | O_TRUNC)) { - /* Fall back and fail with the right error */ - create_error = -EROFS; - goto no_open; - } else { - /* No side effects, safe to clear O_CREAT */ - create_error = -EROFS; - open_flag &= ~O_CREAT; - } - } - - if (open_flag & O_CREAT) { - error = may_o_create(&nd->path, dentry, mode); - if (error) { - create_error = error; - if (open_flag & O_EXCL) - goto no_open; - open_flag &= ~O_CREAT; - } - } - if (nd->flags & LOOKUP_DIRECTORY) open_flag |= O_DIRECTORY; file->f_path.dentry = DENTRY_NOT_SET; file->f_path.mnt = nd->path.mnt; - error = dir->i_op->atomic_open(dir, dentry, file, open_flag, mode, - opened); - if (error < 0) { - if (create_error && error == -ENOENT) - error = create_error; - goto out; - } - - if (error) { /* returned 1, that is */ + error = dir->i_op->atomic_open(dir, dentry, file, + open_to_namei_flags(open_flag), + mode, opened); + d_lookup_done(dentry); + if (!error) { + /* + * We didn't have the inode before the open, so check open + * permission here. + */ + int acc_mode = op->acc_mode; + if (*opened & FILE_CREATED) { + WARN_ON(!(open_flag & O_CREAT)); + fsnotify_create(dir, dentry); + acc_mode = 0; + } + error = may_open(&file->f_path, acc_mode, open_flag); + if (WARN_ON(error > 0)) + error = -EINVAL; + } else if (error > 0) { if (WARN_ON(file->f_path.dentry == DENTRY_NOT_SET)) { error = -EIO; - goto out; - } - if (file->f_path.dentry) { - dput(dentry); - dentry = file->f_path.dentry; - } - if (*opened & FILE_CREATED) - fsnotify_create(dir, dentry); - if (!dentry->d_inode) { - WARN_ON(*opened & FILE_CREATED); - if (create_error) { - error = create_error; - goto out; - } } else { - if (excl && !(*opened & FILE_CREATED)) { - error = -EEXIST; - goto out; + if (file->f_path.dentry) { + dput(dentry); + dentry = file->f_path.dentry; + } + if (*opened & FILE_CREATED) + fsnotify_create(dir, dentry); + if (unlikely(d_is_negative(dentry))) { + error = -ENOENT; + } else { + path->dentry = dentry; + path->mnt = nd->path.mnt; + return 1; } } - goto looked_up; - } - - /* - * We didn't have the inode before the open, so check open permission - * here. - */ - acc_mode = op->acc_mode; - if (*opened & FILE_CREATED) { - WARN_ON(!(open_flag & O_CREAT)); - fsnotify_create(dir, dentry); - acc_mode = 0; } - error = may_open(&file->f_path, acc_mode, open_flag); - if (error) - fput(file); - -out: dput(dentry); return error; - -no_open: - if (need_lookup) { - dentry = lookup_real(dir, dentry, nd->flags); - if (IS_ERR(dentry)) - return PTR_ERR(dentry); - } - if (create_error && !dentry->d_inode) { - error = create_error; - goto out; - } -looked_up: - path->dentry = dentry; - path->mnt = nd->path.mnt; - return 1; } /* @@ -3001,62 +3033,118 @@ static int lookup_open(struct nameidata *nd, struct path *path, { struct dentry *dir = nd->path.dentry; struct inode *dir_inode = dir->d_inode; + int open_flag = op->open_flag; struct dentry *dentry; - int error; - bool need_lookup = false; + int error, create_error = 0; + umode_t mode = op->mode; + DECLARE_WAIT_QUEUE_HEAD_ONSTACK(wq); + + if (unlikely(IS_DEADDIR(dir_inode))) + return -ENOENT; *opened &= ~FILE_CREATED; - dentry = lookup_dcache(&nd->last, dir, nd->flags); - if (IS_ERR(dentry)) - return PTR_ERR(dentry); + dentry = d_lookup(dir, &nd->last); + for (;;) { + if (!dentry) { + dentry = d_alloc_parallel(dir, &nd->last, &wq); + if (IS_ERR(dentry)) + return PTR_ERR(dentry); + } + if (d_in_lookup(dentry)) + break; - if (!dentry) { - dentry = d_alloc(dir, &nd->last); - if (unlikely(!dentry)) - return -ENOMEM; - need_lookup = true; - } else if (dentry->d_inode) { + if (!(dentry->d_flags & DCACHE_OP_REVALIDATE)) + break; + + error = d_revalidate(dentry, nd->flags); + if (likely(error > 0)) + break; + if (error) + goto out_dput; + d_invalidate(dentry); + dput(dentry); + dentry = NULL; + } + if (dentry->d_inode) { /* Cached positive dentry: will open in f_op->open */ goto out_no_open; } - if ((nd->flags & LOOKUP_OPEN) && dir_inode->i_op->atomic_open) { - return atomic_open(nd, dentry, path, file, op, got_write, - need_lookup, opened); + /* + * Checking write permission is tricky, bacuse we don't know if we are + * going to actually need it: O_CREAT opens should work as long as the + * file exists. But checking existence breaks atomicity. The trick is + * to check access and if not granted clear O_CREAT from the flags. + * + * Another problem is returing the "right" error value (e.g. for an + * O_EXCL open we want to return EEXIST not EROFS). + */ + if (open_flag & O_CREAT) { + if (!IS_POSIXACL(dir->d_inode)) + mode &= ~current_umask(); + if (unlikely(!got_write)) { + create_error = -EROFS; + open_flag &= ~O_CREAT; + if (open_flag & (O_EXCL | O_TRUNC)) + goto no_open; + /* No side effects, safe to clear O_CREAT */ + } else { + create_error = may_o_create(&nd->path, dentry, mode); + if (create_error) { + open_flag &= ~O_CREAT; + if (open_flag & O_EXCL) + goto no_open; + } + } + } else if ((open_flag & (O_TRUNC|O_WRONLY|O_RDWR)) && + unlikely(!got_write)) { + /* + * No O_CREATE -> atomicity not a requirement -> fall + * back to lookup + open + */ + goto no_open; } - if (need_lookup) { - BUG_ON(dentry->d_inode); + if (dir_inode->i_op->atomic_open) { + error = atomic_open(nd, dentry, path, file, op, open_flag, + mode, opened); + if (unlikely(error == -ENOENT) && create_error) + error = create_error; + return error; + } - dentry = lookup_real(dir_inode, dentry, nd->flags); - if (IS_ERR(dentry)) - return PTR_ERR(dentry); +no_open: + if (d_in_lookup(dentry)) { + struct dentry *res = dir_inode->i_op->lookup(dir_inode, dentry, + nd->flags); + d_lookup_done(dentry); + if (unlikely(res)) { + if (IS_ERR(res)) { + error = PTR_ERR(res); + goto out_dput; + } + dput(dentry); + dentry = res; + } } /* Negative dentry, just create the file */ - if (!dentry->d_inode && (op->open_flag & O_CREAT)) { - umode_t mode = op->mode; - if (!IS_POSIXACL(dir->d_inode)) - mode &= ~current_umask(); - /* - * This write is needed to ensure that a - * rw->ro transition does not occur between - * the time when the file is created and when - * a permanent write count is taken through - * the 'struct file' in finish_open(). - */ - if (!got_write) { - error = -EROFS; - goto out_dput; - } + if (!dentry->d_inode && (open_flag & O_CREAT)) { *opened |= FILE_CREATED; - error = security_path_mknod(&nd->path, dentry, mode, 0); - if (error) + audit_inode_child(dir_inode, dentry, AUDIT_TYPE_CHILD_CREATE); + if (!dir_inode->i_op->create) { + error = -EACCES; goto out_dput; - error = vfs_create(dir->d_inode, dentry, mode, - nd->flags & LOOKUP_EXCL); + } + error = dir_inode->i_op->create(dir_inode, dentry, mode, + open_flag & O_EXCL); if (error) goto out_dput; + fsnotify_create(dir_inode, dentry); + } + if (unlikely(create_error) && !dentry->d_inode) { + error = create_error; + goto out_dput; } out_no_open: path->dentry = dentry; @@ -3082,9 +3170,7 @@ static int do_last(struct nameidata *nd, int acc_mode = op->acc_mode; unsigned seq; struct inode *inode; - struct path save_parent = { .dentry = NULL, .mnt = NULL }; struct path path; - bool retried = false; int error; nd->flags &= ~LOOKUP_PARENT; @@ -3127,8 +3213,7 @@ static int do_last(struct nameidata *nd, return -EISDIR; } -retry_lookup: - if (op->open_flag & (O_CREAT | O_TRUNC | O_WRONLY | O_RDWR)) { + if (open_flag & (O_CREAT | O_TRUNC | O_WRONLY | O_RDWR)) { error = mnt_want_write(nd->path.mnt); if (!error) got_write = true; @@ -3138,9 +3223,15 @@ retry_lookup: * dropping this one anyway. */ } - inode_lock(dir->d_inode); + if (open_flag & O_CREAT) + inode_lock(dir->d_inode); + else + inode_lock_shared(dir->d_inode); error = lookup_open(nd, &path, file, op, got_write, opened); - inode_unlock(dir->d_inode); + if (open_flag & O_CREAT) + inode_unlock(dir->d_inode); + else + inode_unlock_shared(dir->d_inode); if (error <= 0) { if (error) @@ -3173,6 +3264,10 @@ retry_lookup: got_write = false; } + error = follow_managed(&path, nd); + if (unlikely(error < 0)) + return error; + if (unlikely(d_is_negative(path.dentry))) { path_to_nameidata(&path, nd); return -ENOENT; @@ -3188,10 +3283,6 @@ retry_lookup: return -EEXIST; } - error = follow_managed(&path, nd); - if (unlikely(error < 0)) - return error; - seq = 0; /* out of RCU mode, so the value doesn't matter */ inode = d_backing_inode(path.dentry); finish_lookup: @@ -3202,28 +3293,15 @@ finish_lookup: if (unlikely(error)) return error; - if ((nd->flags & LOOKUP_RCU) || nd->path.mnt != path.mnt) { - path_to_nameidata(&path, nd); - } else { - save_parent.dentry = nd->path.dentry; - save_parent.mnt = mntget(path.mnt); - nd->path.dentry = path.dentry; - - } + path_to_nameidata(&path, nd); nd->inode = inode; nd->seq = seq; /* Why this, you ask? _Now_ we might have grown LOOKUP_JUMPED... */ finish_open: error = complete_walk(nd); - if (error) { - path_put(&save_parent); + if (error) return error; - } audit_inode(nd->name, nd->path.dentry, 0); - if (unlikely(d_is_symlink(nd->path.dentry)) && !(open_flag & O_PATH)) { - error = -ELOOP; - goto out; - } error = -EISDIR; if ((open_flag & O_CREAT) && d_is_dir(nd->path.dentry)) goto out; @@ -3240,64 +3318,30 @@ finish_open: got_write = true; } finish_open_created: - if (likely(!(open_flag & O_PATH))) { - error = may_open(&nd->path, acc_mode, open_flag); - if (error) - goto out; - } + error = may_open(&nd->path, acc_mode, open_flag); + if (error) + goto out; BUG_ON(*opened & FILE_OPENED); /* once it's opened, it's opened */ error = vfs_open(&nd->path, file, current_cred()); - if (!error) { - *opened |= FILE_OPENED; - } else { - if (error == -EOPENSTALE) - goto stale_open; + if (error) goto out; - } + *opened |= FILE_OPENED; opened: error = open_check_o_direct(file); - if (error) - goto exit_fput; - error = ima_file_check(file, op->acc_mode, *opened); - if (error) - goto exit_fput; - - if (will_truncate) { + if (!error) + error = ima_file_check(file, op->acc_mode, *opened); + if (!error && will_truncate) error = handle_truncate(file); - if (error) - goto exit_fput; - } out: + if (unlikely(error) && (*opened & FILE_OPENED)) + fput(file); if (unlikely(error > 0)) { WARN_ON(1); error = -EINVAL; } if (got_write) mnt_drop_write(nd->path.mnt); - path_put(&save_parent); return error; - -exit_fput: - fput(file); - goto out; - -stale_open: - /* If no saved parent or already retried then can't retry */ - if (!save_parent.dentry || retried) - goto out; - - BUG_ON(save_parent.dentry != dir); - path_put(&nd->path); - nd->path = save_parent; - nd->inode = dir->d_inode; - save_parent.mnt = NULL; - save_parent.dentry = NULL; - if (got_write) { - mnt_drop_write(nd->path.mnt); - got_write = false; - } - retried = true; - goto retry_lookup; } static int do_tmpfile(struct nameidata *nd, unsigned flags, @@ -3358,6 +3402,18 @@ out: return error; } +static int do_o_path(struct nameidata *nd, unsigned flags, struct file *file) +{ + struct path path; + int error = path_lookupat(nd, flags, &path); + if (!error) { + audit_inode(nd->name, path.dentry, 0); + error = vfs_open(&path, file, current_cred()); + path_put(&path); + } + return error; +} + static struct file *path_openat(struct nameidata *nd, const struct open_flags *op, unsigned flags) { @@ -3377,6 +3433,13 @@ static struct file *path_openat(struct nameidata *nd, goto out2; } + if (unlikely(file->f_flags & O_PATH)) { + error = do_o_path(nd, flags, file); + if (!error) + opened |= FILE_OPENED; + goto out2; + } + s = path_init(nd, flags); if (IS_ERR(s)) { put_filp(file); @@ -3619,6 +3682,8 @@ retry: switch (mode & S_IFMT) { case 0: case S_IFREG: error = vfs_create(path.dentry->d_inode,dentry,mode,true); + if (!error) + ima_post_path_mknod(dentry); break; case S_IFCHR: case S_IFBLK: error = vfs_mknod(path.dentry->d_inode,dentry,mode, @@ -4532,7 +4597,6 @@ int readlink_copy(char __user *buffer, int buflen, const char *link) out: return len; } -EXPORT_SYMBOL(readlink_copy); /* * A helper for ->readlink(). This should be used *ONLY* for symlinks that