give readdir(2)/getdents(2)/etc. uniform exclusion with lseek()

same as read() on regular files has, and for the same reason.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

7 files changed, 33 insertions, 27 deletions

diff --git a/arch/alpha/kernel/osf_sys.c b/arch/alpha/kernel/osf_sys.c
index 6cc08166ff00..ffb93f499c83 100644
--- a/arch/alpha/kernel/osf_sys.c
+++ b/arch/alpha/kernel/osf_sys.c
@@ -147,7 +147,7 @@ SYSCALL_DEFINE4(osf_getdirentries, unsigned int, fd,
                 long __user *, basep)
 {
         int error;
-        struct fd arg = fdget(fd);
+        struct fd arg = fdget_pos(fd);
         struct osf_dirent_callback buf = {
                 .ctx.actor = osf_filldir,
                 .dirent = dirent,
@@ -164,7 +164,7 @@ SYSCALL_DEFINE4(osf_getdirentries, unsigned int, fd,
         if (count != buf.count)
                 error = count - buf.count;
 
-        fdput(arg);
+        fdput_pos(arg);
         return error;
 }
 
diff --git a/fs/compat.c b/fs/compat.c
index a71936a3f4cb..8754e9aa14ad 100644
--- a/fs/compat.c
+++ b/fs/compat.c
@@ -884,7 +884,7 @@ COMPAT_SYSCALL_DEFINE3(old_readdir, unsigned int, fd,
                 struct compat_old_linux_dirent __user *, dirent, unsigned int, count)
 {
         int error;
-        struct fd f = fdget(fd);
+        struct fd f = fdget_pos(fd);
         struct compat_readdir_callback buf = {
                 .ctx.actor = compat_fillonedir,
                 .dirent = dirent
@@ -897,7 +897,7 @@ COMPAT_SYSCALL_DEFINE3(old_readdir, unsigned int, fd,
         if (buf.result)
                 error = buf.result;
 
-        fdput(f);
+        fdput_pos(f);
         return error;
 }
 
@@ -975,7 +975,7 @@ COMPAT_SYSCALL_DEFINE3(getdents, unsigned int, fd,
         if (!access_ok(VERIFY_WRITE, dirent, count))
                 return -EFAULT;
 
-        f = fdget(fd);
+        f = fdget_pos(fd);
         if (!f.file)
                 return -EBADF;
 
@@ -989,7 +989,7 @@ COMPAT_SYSCALL_DEFINE3(getdents, unsigned int, fd,
                 else
                         error = count - buf.count;
         }
-        fdput(f);
+        fdput_pos(f);
         return error;
 }
 
@@ -1062,7 +1062,7 @@ COMPAT_SYSCALL_DEFINE3(getdents64, unsigned int, fd,
         if (!access_ok(VERIFY_WRITE, dirent, count))
                 return -EFAULT;
 
-        f = fdget(fd);
+        f = fdget_pos(fd);
         if (!f.file)
                 return -EBADF;
 
@@ -1077,7 +1077,7 @@ COMPAT_SYSCALL_DEFINE3(getdents64, unsigned int, fd,
                 else
                         error = count - buf.count;
         }
-        fdput(f);
+        fdput_pos(f);
         return error;
 }
 #endif /* __ARCH_WANT_COMPAT_SYS_GETDENTS64 */
diff --git a/fs/file.c b/fs/file.c
index 1fbc5c0555a9..6b1acdfe59da 100644
--- a/fs/file.c
+++ b/fs/file.c
@@ -784,6 +784,11 @@ unsigned long __fdget_pos(unsigned int fd)
         return v;
 }
 
+void __f_unlock_pos(struct file *f)
+{
+        mutex_unlock(&f->f_pos_lock);
+}
+
 /*
  * We only lock f_pos if we have threads or if the file might be
  * shared with another process. In both cases we'll have an elevated
diff --git a/fs/open.c b/fs/open.c
index 17cb6b1dab75..938a658a5c6d 100644
--- a/fs/open.c
+++ b/fs/open.c
@@ -713,7 +713,7 @@ static int do_dentry_open(struct file *f,
         }
 
         /* POSIX.1-2008/SUSv4 Section XSI 2.9.7 */
-        if (S_ISREG(inode->i_mode))
+        if (S_ISREG(inode->i_mode) || S_ISDIR(inode->i_mode))
                 f->f_mode |= FMODE_ATOMIC_POS;
 
         f->f_op = fops_get(inode->i_fop);
diff --git a/fs/read_write.c b/fs/read_write.c
index cf377cf9dfe3..69c7c3c2955c 100644
--- a/fs/read_write.c
+++ b/fs/read_write.c
@@ -302,18 +302,6 @@ loff_t vfs_llseek(struct file *file, loff_t offset, int whence)
 }
 EXPORT_SYMBOL(vfs_llseek);
 
-static inline struct fd fdget_pos(int fd)
-{
-        return __to_fd(__fdget_pos(fd));
-}
-
-static inline void fdput_pos(struct fd f)
-{
-        if (f.flags & FDPUT_POS_UNLOCK)
-                mutex_unlock(&f.file->f_pos_lock);
-        fdput(f);
-}
-
 SYSCALL_DEFINE3(lseek, unsigned int, fd, off_t, offset, unsigned int, whence)
 {
         off_t retval;
diff --git a/fs/readdir.c b/fs/readdir.c
index bf583e848a1a..d7308b8f6cf7 100644
--- a/fs/readdir.c
+++ b/fs/readdir.c
@@ -112,7 +112,7 @@ SYSCALL_DEFINE3(old_readdir, unsigned int, fd,
                 struct old_linux_dirent __user *, dirent, unsigned int, count)
 {
         int error;
-        struct fd f = fdget(fd);
+        struct fd f = fdget_pos(fd);
         struct readdir_callback buf = {
                 .ctx.actor = fillonedir,
                 .dirent = dirent
@@ -125,7 +125,7 @@ SYSCALL_DEFINE3(old_readdir, unsigned int, fd,
         if (buf.result)
                 error = buf.result;
 
-        fdput(f);
+        fdput_pos(f);
         return error;
 }
 
@@ -209,7 +209,7 @@ SYSCALL_DEFINE3(getdents, unsigned int, fd,
         if (!access_ok(VERIFY_WRITE, dirent, count))
                 return -EFAULT;
 
-        f = fdget(fd);
+        f = fdget_pos(fd);
         if (!f.file)
                 return -EBADF;
 
@@ -223,7 +223,7 @@ SYSCALL_DEFINE3(getdents, unsigned int, fd,
                 else
                         error = count - buf.count;
         }
-        fdput(f);
+        fdput_pos(f);
         return error;
 }
 
@@ -290,7 +290,7 @@ SYSCALL_DEFINE3(getdents64, unsigned int, fd,
         if (!access_ok(VERIFY_WRITE, dirent, count))
                 return -EFAULT;
 
-        f = fdget(fd);
+        f = fdget_pos(fd);
         if (!f.file)
                 return -EBADF;
 
@@ -305,6 +305,6 @@ SYSCALL_DEFINE3(getdents64, unsigned int, fd,
                 else
                         error = count - buf.count;
         }
-        fdput(f);
+        fdput_pos(f);
         return error;
 }
diff --git a/include/linux/file.h b/include/linux/file.h
index f87d30882a24..7444f5feda12 100644
--- a/include/linux/file.h
+++ b/include/linux/file.h
@@ -44,6 +44,7 @@ extern struct file *fget_raw(unsigned int fd);
 extern unsigned long __fdget(unsigned int fd);
 extern unsigned long __fdget_raw(unsigned int fd);
 extern unsigned long __fdget_pos(unsigned int fd);
+extern void __f_unlock_pos(struct file *);
 
 static inline struct fd __to_fd(unsigned long v)
 {
@@ -60,6 +61,18 @@ static inline struct fd fdget_raw(unsigned int fd)
         return __to_fd(__fdget_raw(fd));
 }
 
+static inline struct fd fdget_pos(int fd)
+{
+        return __to_fd(__fdget_pos(fd));
+}
+
+static inline void fdput_pos(struct fd f)
+{
+        if (f.flags & FDPUT_POS_UNLOCK)
+                __f_unlock_pos(f.file);
+        fdput(f);
+}
+
 extern int f_dupfd(unsigned int from, struct file *file, unsigned flags);
 extern int replace_fd(unsigned fd, struct file *file, unsigned flags);
 extern void set_close_on_exec(unsigned int fd, int flag);