diff options
| -rw-r--r-- | fs/autofs4/root.c | 31 |
1 files changed, 17 insertions, 14 deletions
diff --git a/fs/autofs4/root.c b/fs/autofs4/root.c index 2d4c8a3e604..45ff3d63b75 100644 --- a/fs/autofs4/root.c +++ b/fs/autofs4/root.c @@ -587,19 +587,20 @@ static struct dentry *autofs4_lookup(struct inode *dir, struct dentry *dentry, s unhashed = autofs4_lookup_unhashed(sbi, dentry->d_parent, &dentry->d_name); if (!unhashed) { /* - * Mark the dentry incomplete, but add it. This is needed so - * that the VFS layer knows about the dentry, and we can count - * on catching any lookups through the revalidate. - * - * Let all the hard work be done by the revalidate function that - * needs to be able to do this anyway.. - * - * We need to do this before we release the directory semaphore. + * Mark the dentry incomplete but don't hash it. We do this + * to serialize our inode creation operations (symlink and + * mkdir) which prevents deadlock during the callback to + * the daemon. Subsequent user space lookups for the same + * dentry are placed on the wait queue while the daemon + * itself is allowed passage unresticted so the create + * operation itself can then hash the dentry. Finally, + * we check for the hashed dentry and return the newly + * hashed dentry. */ dentry->d_op = &autofs4_root_dentry_operations; dentry->d_fsdata = NULL; - d_add(dentry, NULL); + d_instantiate(dentry, NULL); } else { struct autofs_info *ino = autofs4_dentry_ino(unhashed); DPRINTK("rehash %p with %p", dentry, unhashed); @@ -607,15 +608,17 @@ static struct dentry *autofs4_lookup(struct inode *dir, struct dentry *dentry, s * If we are racing with expire the request might not * be quite complete but the directory has been removed * so it must have been successful, so just wait for it. + * We need to ensure the AUTOFS_INF_EXPIRING flag is clear + * before continuing as revalidate may fail when calling + * try_to_fill_dentry (returning EAGAIN) if we don't. */ - if (ino && (ino->flags & AUTOFS_INF_EXPIRING)) { + while (ino && (ino->flags & AUTOFS_INF_EXPIRING)) { DPRINTK("wait for incomplete expire %p name=%.*s", unhashed, unhashed->d_name.len, unhashed->d_name.name); autofs4_wait(sbi, unhashed, NFY_NONE); DPRINTK("request completed"); } - d_rehash(unhashed); dentry = unhashed; } @@ -658,7 +661,7 @@ static struct dentry *autofs4_lookup(struct inode *dir, struct dentry *dentry, s * for all system calls, but it should be OK for the operations * we permit from an autofs. */ - if (dentry->d_inode && d_unhashed(dentry)) { + if (!oz_mode && d_unhashed(dentry)) { /* * A user space application can (and has done in the past) * remove and re-create this directory during the callback. @@ -716,7 +719,7 @@ static int autofs4_dir_symlink(struct inode *dir, strcpy(cp, symname); inode = autofs4_get_inode(dir->i_sb, ino); - d_instantiate(dentry, inode); + d_add(dentry, inode); if (dir == dir->i_sb->s_root->d_inode) dentry->d_op = &autofs4_root_dentry_operations; @@ -844,7 +847,7 @@ static int autofs4_dir_mkdir(struct inode *dir, struct dentry *dentry, int mode) return -ENOSPC; inode = autofs4_get_inode(dir->i_sb, ino); - d_instantiate(dentry, inode); + d_add(dentry, inode); if (dir == dir->i_sb->s_root->d_inode) dentry->d_op = &autofs4_root_dentry_operations; |