Bluetooth: Add "TIZEN_BT" flag

[platform/kernel/linux-rpi.git] / fs / read_write.c

diff --git a/fs/read_write.c b/fs/read_write.c
index 8a2737f..5fb5ee5 100644 (file)
--- a/fs/read_write.c
+++ b/fs/read_write.c
@@ -560,12 +560,13 @@ ssize_t vfs_write(struct file *file, const char __user *buf, size_t count, loff_
 
 static inline loff_t file_pos_read(struct file *file)
 {
-       return file->f_pos;
+       return file->f_mode & FMODE_STREAM ? 0 : file->f_pos;
 }
 
 static inline void file_pos_write(struct file *file, loff_t pos)
 {
-       file->f_pos = pos;
+       if ((file->f_mode & FMODE_STREAM) == 0)
+               file->f_pos = pos;
 }
 
 ssize_t ksys_read(unsigned int fd, char __user *buf, size_t count)
@@ -1241,6 +1242,9 @@ COMPAT_SYSCALL_DEFINE5(preadv64v2, unsigned long, fd,
                const struct compat_iovec __user *,vec,
                unsigned long, vlen, loff_t, pos, rwf_t, flags)
 {
+       if (pos == -1)
+               return do_compat_readv(fd, vec, vlen, flags);
+
        return do_compat_preadv64(fd, vec, vlen, pos, flags);
 }
 #endif
@@ -1347,6 +1351,9 @@ COMPAT_SYSCALL_DEFINE5(pwritev64v2, unsigned long, fd,
                const struct compat_iovec __user *,vec,
                unsigned long, vlen, loff_t, pos, rwf_t, flags)
 {
+       if (pos == -1)
+               return do_compat_writev(fd, vec, vlen, flags);
+
        return do_compat_pwritev64(fd, vec, vlen, pos, flags);
 }
 #endif
@@ -1881,10 +1888,7 @@ int vfs_clone_file_range(struct file *file_in, loff_t pos_in,
 }
 EXPORT_SYMBOL(vfs_clone_file_range);
 
-/*
- * Read a page's worth of file data into the page cache.  Return the page
- * locked.
- */
+/* Read a page's worth of file data into the page cache. */
 static struct page *vfs_dedupe_get_page(struct inode *inode, loff_t offset)
 {
        struct address_space *mapping;
@@ -1900,11 +1904,33 @@ static struct page *vfs_dedupe_get_page(struct inode *inode, loff_t offset)
                put_page(page);
                return ERR_PTR(-EIO);
        }
-       lock_page(page);
        return page;
 }
 
 /*
+ * Lock two pages, ensuring that we lock in offset order if the pages are from
+ * the same file.
+ */
+static void vfs_lock_two_pages(struct page *page1, struct page *page2)
+{
+       /* Always lock in order of increasing index. */
+       if (page1->index > page2->index)
+               swap(page1, page2);
+
+       lock_page(page1);
+       if (page1 != page2)
+               lock_page(page2);
+}
+
+/* Unlock two pages, being careful not to unlock the same page twice. */
+static void vfs_unlock_two_pages(struct page *page1, struct page *page2)
+{
+       unlock_page(page1);
+       if (page1 != page2)
+               unlock_page(page2);
+}
+
+/*
  * Compare extents of two files to see if they are the same.
  * Caller must have locked both inodes to prevent write races.
  */
@@ -1941,10 +1967,24 @@ int vfs_dedupe_file_range_compare(struct inode *src, loff_t srcoff,
                dest_page = vfs_dedupe_get_page(dest, destoff);
                if (IS_ERR(dest_page)) {
                        error = PTR_ERR(dest_page);
-                       unlock_page(src_page);
                        put_page(src_page);
                        goto out_error;
                }
+
+               vfs_lock_two_pages(src_page, dest_page);
+
+               /*
+                * Now that we've locked both pages, make sure they're still
+                * mapped to the file data we're interested in.  If not,
+                * someone is invalidating pages on us and we lose.
+                */
+               if (!PageUptodate(src_page) || !PageUptodate(dest_page) ||
+                   src_page->mapping != src->i_mapping ||
+                   dest_page->mapping != dest->i_mapping) {
+                       same = false;
+                       goto unlock;
+               }
+
                src_addr = kmap_atomic(src_page);
                dest_addr = kmap_atomic(dest_page);
 
@@ -1956,8 +1996,8 @@ int vfs_dedupe_file_range_compare(struct inode *src, loff_t srcoff,
 
                kunmap_atomic(dest_addr);
                kunmap_atomic(src_addr);
-               unlock_page(dest_page);
-               unlock_page(src_page);
+unlock:
+               vfs_unlock_two_pages(src_page, dest_page);
                put_page(dest_page);
                put_page(src_page);