1 files changed, 38 insertions, 76 deletions

diff --git a/mm/filemap.c b/mm/filemap.c
index 12548d03c11d..6bf5e42d560a 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -1693,7 +1693,7 @@ generic_file_read_iter(struct kiocb *iocb, struct iov_iter *iter)
         loff_t *ppos = &iocb->ki_pos;
         loff_t pos = *ppos;
 
-        if (io_is_direct(file)) {
+        if (iocb->ki_flags & IOCB_DIRECT) {
                 struct address_space *mapping = file->f_mapping;
                 struct inode *inode = mapping->host;
                 size_t count = iov_iter_count(iter);
@@ -1706,7 +1706,7 @@ generic_file_read_iter(struct kiocb *iocb, struct iov_iter *iter)
                                         pos + count - 1);
                 if (!retval) {
                         struct iov_iter data = *iter;
-                        retval = mapping->a_ops->direct_IO(READ, iocb, &data, pos);
+                        retval = mapping->a_ops->direct_IO(iocb, &data, pos);
                 }
 
                 if (retval > 0) {
@@ -2259,41 +2259,38 @@ EXPORT_SYMBOL(read_cache_page_gfp);
  * Returns appropriate error code that caller should return or
  * zero in case that write should be allowed.
  */
-inline int generic_write_checks(struct file *file, loff_t *pos, size_t *count, int isblk)
+inline ssize_t generic_write_checks(struct kiocb *iocb, struct iov_iter *from)
 {
+        struct file *file = iocb->ki_filp;
         struct inode *inode = file->f_mapping->host;
         unsigned long limit = rlimit(RLIMIT_FSIZE);
+        loff_t pos;
 
-        if (unlikely(*pos < 0))
-                return -EINVAL;
+        if (!iov_iter_count(from))
+                return 0;
 
-        if (!isblk) {
-                /* FIXME: this is for backwards compatibility with 2.4 */
-                if (file->f_flags & O_APPEND)
-                        *pos = i_size_read(inode);
+        /* FIXME: this is for backwards compatibility with 2.4 */
+        if (iocb->ki_flags & IOCB_APPEND)
+                iocb->ki_pos = i_size_read(inode);
 
-                if (limit != RLIM_INFINITY) {
-                        if (*pos >= limit) {
-                                send_sig(SIGXFSZ, current, 0);
-                                return -EFBIG;
-                        }
-                        if (*count > limit - (typeof(limit))*pos) {
-                                *count = limit - (typeof(limit))*pos;
-                        }
+        pos = iocb->ki_pos;
+
+        if (limit != RLIM_INFINITY) {
+                if (iocb->ki_pos >= limit) {
+                        send_sig(SIGXFSZ, current, 0);
+                        return -EFBIG;
                 }
+                iov_iter_truncate(from, limit - (unsigned long)pos);
         }
 
         /*
          * LFS rule
          */
-        if (unlikely(*pos + *count > MAX_NON_LFS &&
+        if (unlikely(pos + iov_iter_count(from) > MAX_NON_LFS &&
                                 !(file->f_flags & O_LARGEFILE))) {
-                if (*pos >= MAX_NON_LFS) {
+                if (pos >= MAX_NON_LFS)
                         return -EFBIG;
-                }
-                if (*count > MAX_NON_LFS - (unsigned long)*pos) {
-                        *count = MAX_NON_LFS - (unsigned long)*pos;
-                }
+                iov_iter_truncate(from, MAX_NON_LFS - (unsigned long)pos);
         }
 
         /*
@@ -2303,34 +2300,11 @@ inline int generic_write_checks(struct file *file, loff_t *pos, size_t *count, i
          * exceeded without writing data we send a signal and return EFBIG.
          * Linus frestrict idea will clean these up nicely..
          */
-        if (likely(!isblk)) {
-                if (unlikely(*pos >= inode->i_sb->s_maxbytes)) {
-                        if (*count || *pos > inode->i_sb->s_maxbytes) {
-                                return -EFBIG;
-                        }
-                        /* zero-length writes at ->s_maxbytes are OK */
-                }
+        if (unlikely(pos >= inode->i_sb->s_maxbytes))
+                return -EFBIG;
 
-                if (unlikely(*pos + *count > inode->i_sb->s_maxbytes))
-                        *count = inode->i_sb->s_maxbytes - *pos;
-        } else {
-#ifdef CONFIG_BLOCK
-                loff_t isize;
-                if (bdev_read_only(I_BDEV(inode)))
-                        return -EPERM;
-                isize = i_size_read(inode);
-                if (*pos >= isize) {
-                        if (*count || *pos > isize)
-                                return -ENOSPC;
-                }
-
-                if (*pos + *count > isize)
-                        *count = isize - *pos;
-#else
-                return -EPERM;
-#endif
-        }
-        return 0;
+        iov_iter_truncate(from, inode->i_sb->s_maxbytes - pos);
+        return iov_iter_count(from);
 }
 EXPORT_SYMBOL(generic_write_checks);
 
@@ -2394,7 +2368,7 @@ generic_file_direct_write(struct kiocb *iocb, struct iov_iter *from, loff_t pos)
         }
 
         data = *from;
-        written = mapping->a_ops->direct_IO(WRITE, iocb, &data, pos);
+        written = mapping->a_ops->direct_IO(iocb, &data, pos);
 
         /*
          * Finally, try again to invalidate clean pages which might have been
@@ -2556,23 +2530,12 @@ ssize_t __generic_file_write_iter(struct kiocb *iocb, struct iov_iter *from)
         struct file *file = iocb->ki_filp;
         struct address_space * mapping = file->f_mapping;
         struct inode    *inode = mapping->host;
-        loff_t          pos = iocb->ki_pos;
         ssize_t         written = 0;
         ssize_t         err;
         ssize_t         status;
-        size_t          count = iov_iter_count(from);
 
         /* We can write back this queue in page reclaim */
         current->backing_dev_info = inode_to_bdi(inode);
-        err = generic_write_checks(file, &pos, &count, S_ISBLK(inode->i_mode));
-        if (err)
-                goto out;
-
-        if (count == 0)
-                goto out;
-
-        iov_iter_truncate(from, count);
-
         err = file_remove_suid(file);
         if (err)
                 goto out;
@@ -2581,10 +2544,10 @@ ssize_t __generic_file_write_iter(struct kiocb *iocb, struct iov_iter *from)
         if (err)
                 goto out;
 
-        if (io_is_direct(file)) {
-                loff_t endbyte;
+        if (iocb->ki_flags & IOCB_DIRECT) {
+                loff_t pos, endbyte;
 
-                written = generic_file_direct_write(iocb, from, pos);
+                written = generic_file_direct_write(iocb, from, iocb->ki_pos);
                 /*
                  * If the write stopped short of completing, fall back to
                  * buffered writes.  Some filesystems do this for writes to
@@ -2592,13 +2555,10 @@ ssize_t __generic_file_write_iter(struct kiocb *iocb, struct iov_iter *from)
                  * not succeed (even if it did, DAX does not handle dirty
                  * page-cache pages correctly).
                  */
-                if (written < 0 || written == count || IS_DAX(inode))
+                if (written < 0 || !iov_iter_count(from) || IS_DAX(inode))
                         goto out;
 
-                pos += written;
-                count -= written;
-
-                status = generic_perform_write(file, from, pos);
+                status = generic_perform_write(file, from, pos = iocb->ki_pos);
                 /*
                  * If generic_perform_write() returned a synchronous error
                  * then we want to return the number of bytes which were
@@ -2610,15 +2570,15 @@ ssize_t __generic_file_write_iter(struct kiocb *iocb, struct iov_iter *from)
                         err = status;
                         goto out;
                 }
-                iocb->ki_pos = pos + status;
                 /*
                  * We need to ensure that the page cache pages are written to
                  * disk and invalidated to preserve the expected O_DIRECT
                  * semantics.
                  */
                 endbyte = pos + status - 1;
-                err = filemap_write_and_wait_range(file->f_mapping, pos, endbyte);
+                err = filemap_write_and_wait_range(mapping, pos, endbyte);
                 if (err == 0) {
+                        iocb->ki_pos = endbyte + 1;
                         written += status;
                         invalidate_mapping_pages(mapping,
                                                  pos >> PAGE_CACHE_SHIFT,
@@ -2630,9 +2590,9 @@ ssize_t __generic_file_write_iter(struct kiocb *iocb, struct iov_iter *from)
                          */
                 }
         } else {
-                written = generic_perform_write(file, from, pos);
-                if (likely(written >= 0))
-                        iocb->ki_pos = pos + written;
+                written = generic_perform_write(file, from, iocb->ki_pos);
+                if (likely(written > 0))
+                        iocb->ki_pos += written;
         }
 out:
         current->backing_dev_info = NULL;
@@ -2656,7 +2616,9 @@ ssize_t generic_file_write_iter(struct kiocb *iocb, struct iov_iter *from)
         ssize_t ret;
 
         mutex_lock(&inode->i_mutex);
-        ret = __generic_file_write_iter(iocb, from);
+        ret = generic_write_checks(iocb, from);
+        if (ret > 0)
+                ret = __generic_file_write_iter(iocb, from);
         mutex_unlock(&inode->i_mutex);
 
         if (ret > 0) {