3 files changed, 57 insertions, 15 deletions

diff --git a/fs/fat/fat.h b/fs/fat/fat.h
index a1c8c4b44fdb..27ac25725954 100644
--- a/fs/fat/fat.h
+++ b/fs/fat/fat.h
@@ -306,7 +306,8 @@ extern long fat_generic_ioctl(struct file *filp, unsigned int cmd,
 extern const struct file_operations fat_file_operations;
 extern const struct inode_operations fat_file_inode_operations;
 extern int fat_setattr(struct dentry * dentry, struct iattr * attr);
-extern void fat_truncate(struct inode *inode);
+extern int fat_setsize(struct inode *inode, loff_t offset);
+extern void fat_truncate_blocks(struct inode *inode, loff_t offset);
 extern int fat_getattr(struct vfsmount *mnt, struct dentry *dentry,
                        struct kstat *stat);
 extern int fat_file_fsync(struct file *file, int datasync);
diff --git a/fs/fat/file.c b/fs/fat/file.c
index 8c13b8acfd2f..990dfae022e5 100644
--- a/fs/fat/file.c
+++ b/fs/fat/file.c
@@ -283,7 +283,7 @@ static int fat_free(struct inode *inode, int skip)
         return fat_free_clusters(inode, free_start);
 }
 
-void fat_truncate(struct inode *inode)
+void fat_truncate_blocks(struct inode *inode, loff_t offset)
 {
         struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb);
         const unsigned int cluster_size = sbi->cluster_size;
@@ -293,10 +293,10 @@ void fat_truncate(struct inode *inode)
          * This protects against truncating a file bigger than it was then
          * trying to write into the hole.
          */
-        if (MSDOS_I(inode)->mmu_private > inode->i_size)
-                MSDOS_I(inode)->mmu_private = inode->i_size;
+        if (MSDOS_I(inode)->mmu_private > offset)
+                MSDOS_I(inode)->mmu_private = offset;
 
-        nr_clusters = (inode->i_size + (cluster_size - 1)) >> sbi->cluster_bits;
+        nr_clusters = (offset + (cluster_size - 1)) >> sbi->cluster_bits;
 
         fat_free(inode, nr_clusters);
         fat_flush_inodes(inode->i_sb, inode, NULL);
@@ -364,6 +364,18 @@ static int fat_allow_set_time(struct msdos_sb_info *sbi, struct inode *inode)
         return 0;
 }
 
+int fat_setsize(struct inode *inode, loff_t offset)
+{
+        int error;
+
+        error = simple_setsize(inode, offset);
+        if (error)
+                return error;
+        fat_truncate_blocks(inode, offset);
+
+        return error;
+}
+
 #define TIMES_SET_FLAGS (ATTR_MTIME_SET | ATTR_ATIME_SET | ATTR_TIMES_SET)
 /* valid file mode bits */
 #define FAT_VALID_MODE  (S_IFREG | S_IFDIR | S_IRWXUGO)
@@ -378,7 +390,8 @@ int fat_setattr(struct dentry *dentry, struct iattr *attr)
         /*
          * Expand the file. Since inode_setattr() updates ->i_size
          * before calling the ->truncate(), but FAT needs to fill the
-         * hole before it.
+         * hole before it. XXX: this is no longer true with new truncate
+         * sequence.
          */
         if (attr->ia_valid & ATTR_SIZE) {
                 if (attr->ia_size > inode->i_size) {
@@ -427,15 +440,20 @@ int fat_setattr(struct dentry *dentry, struct iattr *attr)
                         attr->ia_valid &= ~ATTR_MODE;
         }
 
-        if (attr->ia_valid)
-                error = inode_setattr(inode, attr);
+        if (attr->ia_valid & ATTR_SIZE) {
+                error = fat_setsize(inode, attr->ia_size);
+                if (error)
+                        goto out;
+        }
+
+        generic_setattr(inode, attr);
+        mark_inode_dirty(inode);
 out:
         return error;
 }
 EXPORT_SYMBOL_GPL(fat_setattr);
 
 const struct inode_operations fat_file_inode_operations = {
-        .truncate       = fat_truncate,
         .setattr        = fat_setattr,
         .getattr        = fat_getattr,
 };
diff --git a/fs/fat/inode.c b/fs/fat/inode.c
index ed33904926ee..7bf45aee56d7 100644
--- a/fs/fat/inode.c
+++ b/fs/fat/inode.c
@@ -142,14 +142,29 @@ static int fat_readpages(struct file *file, struct address_space *mapping,
         return mpage_readpages(mapping, pages, nr_pages, fat_get_block);
 }
 
+static void fat_write_failed(struct address_space *mapping, loff_t to)
+{
+        struct inode *inode = mapping->host;
+
+        if (to > inode->i_size) {
+                truncate_pagecache(inode, to, inode->i_size);
+                fat_truncate_blocks(inode, inode->i_size);
+        }
+}
+
 static int fat_write_begin(struct file *file, struct address_space *mapping,
                         loff_t pos, unsigned len, unsigned flags,
                         struct page **pagep, void **fsdata)
 {
+        int err;
+
         *pagep = NULL;
-        return cont_write_begin(file, mapping, pos, len, flags, pagep, fsdata,
-                                fat_get_block,
+        err = cont_write_begin_newtrunc(file, mapping, pos, len, flags,
+                                pagep, fsdata, fat_get_block,
                                 &MSDOS_I(mapping->host)->mmu_private);
+        if (err < 0)
+                fat_write_failed(mapping, pos + len);
+        return err;
 }
 
 static int fat_write_end(struct file *file, struct address_space *mapping,
@@ -159,6 +174,8 @@ static int fat_write_end(struct file *file, struct address_space *mapping,
         struct inode *inode = mapping->host;
         int err;
         err = generic_write_end(file, mapping, pos, len, copied, pagep, fsdata);
+        if (err < len)
+                fat_write_failed(mapping, pos + len);
         if (!(err < 0) && !(MSDOS_I(inode)->i_attrs & ATTR_ARCH)) {
                 inode->i_mtime = inode->i_ctime = CURRENT_TIME_SEC;
                 MSDOS_I(inode)->i_attrs |= ATTR_ARCH;
@@ -172,7 +189,9 @@ static ssize_t fat_direct_IO(int rw, struct kiocb *iocb,
                              loff_t offset, unsigned long nr_segs)
 {
         struct file *file = iocb->ki_filp;
-        struct inode *inode = file->f_mapping->host;
+        struct address_space *mapping = file->f_mapping;
+        struct inode *inode = mapping->host;
+        ssize_t ret;
 
         if (rw == WRITE) {
                 /*
@@ -193,8 +212,12 @@ static ssize_t fat_direct_IO(int rw, struct kiocb *iocb,
          * FAT need to use the DIO_LOCKING for avoiding the race
          * condition of fat_get_block() and ->truncate().
          */
-        return blockdev_direct_IO(rw, iocb, inode, inode->i_sb->s_bdev, iov,
-                                  offset, nr_segs, fat_get_block, NULL);
+        ret = blockdev_direct_IO_newtrunc(rw, iocb, inode, inode->i_sb->s_bdev,
+                                iov, offset, nr_segs, fat_get_block, NULL);
+        if (ret < 0 && (rw & WRITE))
+                fat_write_failed(mapping, offset + iov_length(iov, nr_segs));
+
+        return ret;
 }
 
 static sector_t _fat_bmap(struct address_space *mapping, sector_t block)
@@ -429,7 +452,7 @@ static void fat_delete_inode(struct inode *inode)
 {
         truncate_inode_pages(&inode->i_data, 0);
         inode->i_size = 0;
-        fat_truncate(inode);
+        fat_truncate_blocks(inode, 0);
         clear_inode(inode);
 }