diff options
Diffstat (limited to 'fs/namei.c')
| -rw-r--r-- | fs/namei.c | 55 |
1 files changed, 55 insertions, 0 deletions
diff --git a/fs/namei.c b/fs/namei.c index cd43ff89fbaa..c7c6b255db2c 100644 --- a/fs/namei.c +++ b/fs/namei.c @@ -1827,6 +1827,20 @@ static struct dentry *lookup_slow(const struct qstr *name, return res; } +static struct dentry *lookup_slow_killable(const struct qstr *name, + struct dentry *dir, + unsigned int flags) +{ + struct inode *inode = dir->d_inode; + struct dentry *res; + + if (inode_lock_shared_killable(inode)) + return ERR_PTR(-EINTR); + res = __lookup_slow(name, dir, flags); + inode_unlock_shared(inode); + return res; +} + static inline int may_lookup(struct mnt_idmap *idmap, struct nameidata *restrict nd) { @@ -3011,6 +3025,47 @@ struct dentry *lookup_one_unlocked(struct mnt_idmap *idmap, struct qstr *name, EXPORT_SYMBOL(lookup_one_unlocked); /** + * lookup_one_positive_killable - lookup single pathname component + * @idmap: idmap of the mount the lookup is performed from + * @name: qstr olding pathname component to lookup + * @base: base directory to lookup from + * + * This helper will yield ERR_PTR(-ENOENT) on negatives. The helper returns + * known positive or ERR_PTR(). This is what most of the users want. + * + * Note that pinned negative with unlocked parent _can_ become positive at any + * time, so callers of lookup_one_unlocked() need to be very careful; pinned + * positives have >d_inode stable, so this one avoids such problems. + * + * This can be used for in-kernel filesystem clients such as file servers. + * + * It should be called without the parent i_rwsem held, and will take + * the i_rwsem itself if necessary. If a fatal signal is pending or + * delivered, it will return %-EINTR if the lock is needed. + */ +struct dentry *lookup_one_positive_killable(struct mnt_idmap *idmap, + struct qstr *name, + struct dentry *base) +{ + int err; + struct dentry *ret; + + err = lookup_one_common(idmap, name, base); + if (err) + return ERR_PTR(err); + + ret = lookup_dcache(name, base, 0); + if (!ret) + ret = lookup_slow_killable(name, base, 0); + if (!IS_ERR(ret) && d_flags_negative(smp_load_acquire(&ret->d_flags))) { + dput(ret); + ret = ERR_PTR(-ENOENT); + } + return ret; +} +EXPORT_SYMBOL(lookup_one_positive_killable); + +/** * lookup_one_positive_unlocked - lookup single pathname component * @idmap: idmap of the mount the lookup is performed from * @name: qstr holding pathname component to lookup |