1 files changed, 55 insertions, 28 deletions

diff --git a/fs/buffer.c b/fs/buffer.c
index 5287be18633b..b9bb7ad6897b 100644
--- a/fs/buffer.c
+++ b/fs/buffer.c
@@ -26,6 +26,7 @@
 #include <linux/percpu.h>
 #include <linux/slab.h>
 #include <linux/smp_lock.h>
+#include <linux/capability.h>
 #include <linux/blkdev.h>
 #include <linux/file.h>
 #include <linux/quotaops.h>
@@ -153,14 +154,8 @@ int sync_blockdev(struct block_device *bdev)
 {
         int ret = 0;
 
-        if (bdev) {
-                int err;
-
-                ret = filemap_fdatawrite(bdev->bd_inode->i_mapping);
-                err = filemap_fdatawait(bdev->bd_inode->i_mapping);
-                if (!ret)
-                        ret = err;
-        }
+        if (bdev)
+                ret = filemap_write_and_wait(bdev->bd_inode->i_mapping);
         return ret;
 }
 EXPORT_SYMBOL(sync_blockdev);
@@ -358,11 +353,11 @@ static long do_fsync(unsigned int fd, int datasync)
          * We need to protect against concurrent writers,
          * which could cause livelocks in fsync_buffers_list
          */
-        down(&mapping->host->i_sem);
+        mutex_lock(&mapping->host->i_mutex);
         err = file->f_op->fsync(file, file->f_dentry, datasync);
         if (!ret)
                 ret = err;
-        up(&mapping->host->i_sem);
+        mutex_unlock(&mapping->host->i_mutex);
         err = filemap_fdatawait(mapping);
         if (!ret)
                 ret = err;
@@ -1768,7 +1763,7 @@ static int __block_write_full_page(struct inode *inode, struct page *page,
          * handle that here by just cleaning them.
          */
 
-        block = page->index << (PAGE_CACHE_SHIFT - inode->i_blkbits);
+        block = (sector_t)page->index << (PAGE_CACHE_SHIFT - inode->i_blkbits);
         head = page_buffers(page);
         bh = head;
 
@@ -2160,11 +2155,12 @@ int block_read_full_page(struct page *page, get_block_t *get_block)
  * truncates.  Uses prepare/commit_write to allow the filesystem to
  * deal with the hole.  
  */
-int generic_cont_expand(struct inode *inode, loff_t size)
+static int __generic_cont_expand(struct inode *inode, loff_t size,
+                                 pgoff_t index, unsigned int offset)
 {
         struct address_space *mapping = inode->i_mapping;
         struct page *page;
-        unsigned long index, offset, limit;
+        unsigned long limit;
         int err;
 
         err = -EFBIG;
@@ -2176,24 +2172,24 @@ int generic_cont_expand(struct inode *inode, loff_t size)
         if (size > inode->i_sb->s_maxbytes)
                 goto out;
 
-        offset = (size & (PAGE_CACHE_SIZE-1)); /* Within page */
-
-        /* ugh.  in prepare/commit_write, if from==to==start of block, we 
-        ** skip the prepare.  make sure we never send an offset for the start
-        ** of a block
-        */
-        if ((offset & (inode->i_sb->s_blocksize - 1)) == 0) {
-                offset++;
-        }
-        index = size >> PAGE_CACHE_SHIFT;
         err = -ENOMEM;
         page = grab_cache_page(mapping, index);
         if (!page)
                 goto out;
         err = mapping->a_ops->prepare_write(NULL, page, offset, offset);
-        if (!err) {
-                err = mapping->a_ops->commit_write(NULL, page, offset, offset);
+        if (err) {
+                /*
+                 * ->prepare_write() may have instantiated a few blocks
+                 * outside i_size.  Trim these off again.
+                 */
+                unlock_page(page);
+                page_cache_release(page);
+                vmtruncate(inode, inode->i_size);
+                goto out;
         }
+
+        err = mapping->a_ops->commit_write(NULL, page, offset, offset);
+
         unlock_page(page);
         page_cache_release(page);
         if (err > 0)
@@ -2202,6 +2198,36 @@ out:
         return err;
 }
 
+int generic_cont_expand(struct inode *inode, loff_t size)
+{
+        pgoff_t index;
+        unsigned int offset;
+
+        offset = (size & (PAGE_CACHE_SIZE - 1)); /* Within page */
+
+        /* ugh.  in prepare/commit_write, if from==to==start of block, we
+        ** skip the prepare.  make sure we never send an offset for the start
+        ** of a block
+        */
+        if ((offset & (inode->i_sb->s_blocksize - 1)) == 0) {
+                /* caller must handle this extra byte. */
+                offset++;
+        }
+        index = size >> PAGE_CACHE_SHIFT;
+
+        return __generic_cont_expand(inode, size, index, offset);
+}
+
+int generic_cont_expand_simple(struct inode *inode, loff_t size)
+{
+        loff_t pos = size - 1;
+        pgoff_t index = pos >> PAGE_CACHE_SHIFT;
+        unsigned int offset = (pos & (PAGE_CACHE_SIZE - 1)) + 1;
+
+        /* prepare/commit_write can handle even if from==to==start of block. */
+        return __generic_cont_expand(inode, size, index, offset);
+}
+
 /*
  * For moronic filesystems that do not allow holes in file.
  * We may have to extend the file.
@@ -2313,7 +2339,7 @@ int generic_commit_write(struct file *file, struct page *page,
         __block_commit_write(inode,page,from,to);
         /*
          * No need to use i_size_read() here, the i_size
-         * cannot change under us because we hold i_sem.
+         * cannot change under us because we hold i_mutex.
          */
         if (pos > inode->i_size) {
                 i_size_write(inode, pos);
@@ -2610,7 +2636,7 @@ int block_truncate_page(struct address_space *mapping,
         pgoff_t index = from >> PAGE_CACHE_SHIFT;
         unsigned offset = from & (PAGE_CACHE_SIZE-1);
         unsigned blocksize;
-        pgoff_t iblock;
+        sector_t iblock;
         unsigned length, pos;
         struct inode *inode = mapping->host;
         struct page *page;
@@ -2626,7 +2652,7 @@ int block_truncate_page(struct address_space *mapping,
                 return 0;
 
         length = blocksize - length;
-        iblock = index << (PAGE_CACHE_SHIFT - inode->i_blkbits);
+        iblock = (sector_t)index << (PAGE_CACHE_SHIFT - inode->i_blkbits);
         
         page = grab_cache_page(mapping, index);
         err = -ENOMEM;
@@ -3145,6 +3171,7 @@ EXPORT_SYMBOL(fsync_bdev);
 EXPORT_SYMBOL(generic_block_bmap);
 EXPORT_SYMBOL(generic_commit_write);
 EXPORT_SYMBOL(generic_cont_expand);
+EXPORT_SYMBOL(generic_cont_expand_simple);
 EXPORT_SYMBOL(init_buffer);
 EXPORT_SYMBOL(invalidate_bdev);
 EXPORT_SYMBOL(ll_rw_block);