1 files changed, 51 insertions, 14 deletions

diff --git a/fs/read_write.c b/fs/read_write.c
index 2cefa417be34..122a3846d9e1 100644
--- a/fs/read_write.c
+++ b/fs/read_write.c
@@ -41,8 +41,19 @@ static inline int unsigned_offsets(struct file *file)
         return file->f_mode & FMODE_UNSIGNED_OFFSET;
 }
 
-static loff_t lseek_execute(struct file *file, struct inode *inode,
-                loff_t offset, loff_t maxsize)
+/**
+ * vfs_setpos - update the file offset for lseek
+ * @file:       file structure in question
+ * @offset:     file offset to seek to
+ * @maxsize:    maximum file size
+ *
+ * This is a low-level filesystem helper for updating the file offset to
+ * the value specified by @offset if the given offset is valid and it is
+ * not equal to the current file offset.
+ *
+ * Return the specified offset on success and -EINVAL on invalid offset.
+ */
+loff_t vfs_setpos(struct file *file, loff_t offset, loff_t maxsize)
 {
         if (offset < 0 && !unsigned_offsets(file))
                 return -EINVAL;
@@ -55,6 +66,7 @@ static loff_t lseek_execute(struct file *file, struct inode *inode,
         }
         return offset;
 }
+EXPORT_SYMBOL(vfs_setpos);
 
 /**
  * generic_file_llseek_size - generic llseek implementation for regular files
@@ -76,8 +88,6 @@ loff_t
 generic_file_llseek_size(struct file *file, loff_t offset, int whence,
                 loff_t maxsize, loff_t eof)
 {
-        struct inode *inode = file->f_mapping->host;
-
         switch (whence) {
         case SEEK_END:
                 offset += eof;
@@ -97,8 +107,7 @@ generic_file_llseek_size(struct file *file, loff_t offset, int whence,
                  * like SEEK_SET.
                  */
                 spin_lock(&file->f_lock);
-                offset = lseek_execute(file, inode, file->f_pos + offset,
-                                       maxsize);
+                offset = vfs_setpos(file, file->f_pos + offset, maxsize);
                 spin_unlock(&file->f_lock);
                 return offset;
         case SEEK_DATA:
@@ -120,7 +129,7 @@ generic_file_llseek_size(struct file *file, loff_t offset, int whence,
                 break;
         }
 
-        return lseek_execute(file, inode, offset, maxsize);
+        return vfs_setpos(file, offset, maxsize);
 }
 EXPORT_SYMBOL(generic_file_llseek_size);
 
@@ -145,6 +154,26 @@ loff_t generic_file_llseek(struct file *file, loff_t offset, int whence)
 EXPORT_SYMBOL(generic_file_llseek);
 
 /**
+ * fixed_size_llseek - llseek implementation for fixed-sized devices
+ * @file:       file structure to seek on
+ * @offset:     file offset to seek to
+ * @whence:     type of seek
+ * @size:       size of the file
+ *
+ */
+loff_t fixed_size_llseek(struct file *file, loff_t offset, int whence, loff_t size)
+{
+        switch (whence) {
+        case SEEK_SET: case SEEK_CUR: case SEEK_END:
+                return generic_file_llseek_size(file, offset, whence,
+                                                size, size);
+        default:
+                return -EINVAL;
+        }
+}
+EXPORT_SYMBOL(fixed_size_llseek);
+
+/**
  * noop_llseek - No Operation Performed llseek implementation
  * @file:       file structure to seek on
  * @offset:     file offset to seek to
@@ -296,7 +325,7 @@ out_putf:
  * them to something that fits in "int" so that others
  * won't have to do range checks all the time.
  */
-int rw_verify_area(int read_write, struct file *file, loff_t *ppos, size_t count)
+int rw_verify_area(int read_write, struct file *file, const loff_t *ppos, size_t count)
 {
         struct inode *inode;
         loff_t pos;
@@ -477,7 +506,8 @@ SYSCALL_DEFINE3(read, unsigned int, fd, char __user *, buf, size_t, count)
         if (f.file) {
                 loff_t pos = file_pos_read(f.file);
                 ret = vfs_read(f.file, buf, count, &pos);
-                file_pos_write(f.file, pos);
+                if (ret >= 0)
+                        file_pos_write(f.file, pos);
                 fdput(f);
         }
         return ret;
@@ -492,7 +522,8 @@ SYSCALL_DEFINE3(write, unsigned int, fd, const char __user *, buf,
         if (f.file) {
                 loff_t pos = file_pos_read(f.file);
                 ret = vfs_write(f.file, buf, count, &pos);
-                file_pos_write(f.file, pos);
+                if (ret >= 0)
+                        file_pos_write(f.file, pos);
                 fdput(f);
         }
 
@@ -780,7 +811,8 @@ SYSCALL_DEFINE3(readv, unsigned long, fd, const struct iovec __user *, vec,
         if (f.file) {
                 loff_t pos = file_pos_read(f.file);
                 ret = vfs_readv(f.file, vec, vlen, &pos);
-                file_pos_write(f.file, pos);
+                if (ret >= 0)
+                        file_pos_write(f.file, pos);
                 fdput(f);
         }
 
@@ -799,7 +831,8 @@ SYSCALL_DEFINE3(writev, unsigned long, fd, const struct iovec __user *, vec,
         if (f.file) {
                 loff_t pos = file_pos_read(f.file);
                 ret = vfs_writev(f.file, vec, vlen, &pos);
-                file_pos_write(f.file, pos);
+                if (ret >= 0)
+                        file_pos_write(f.file, pos);
                 fdput(f);
         }
 
@@ -959,7 +992,8 @@ COMPAT_SYSCALL_DEFINE3(readv, unsigned long, fd,
                 return -EBADF;
         pos = f.file->f_pos;
         ret = compat_readv(f.file, vec, vlen, &pos);
-        f.file->f_pos = pos;
+        if (ret >= 0)
+                f.file->f_pos = pos;
         fdput(f);
         return ret;
 }
@@ -1025,7 +1059,8 @@ COMPAT_SYSCALL_DEFINE3(writev, unsigned long, fd,
                 return -EBADF;
         pos = f.file->f_pos;
         ret = compat_writev(f.file, vec, vlen, &pos);
-        f.file->f_pos = pos;
+        if (ret >= 0)
+                f.file->f_pos = pos;
         fdput(f);
         return ret;
 }
@@ -1129,7 +1164,9 @@ static ssize_t do_sendfile(int out_fd, int in_fd, loff_t *ppos,
         if (in.file->f_flags & O_NONBLOCK)
                 fl = SPLICE_F_NONBLOCK;
 #endif
+        file_start_write(out.file);
         retval = do_splice_direct(in.file, &pos, out.file, &out_pos, count, fl);
+        file_end_write(out.file);
 
         if (retval > 0) {
                 add_rchar(current, retval);