lift generic_write_checks() into callers of __generic_file_write_iter()

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

5 files changed, 60 insertions, 30 deletions

diff --git a/fs/block_dev.c b/fs/block_dev.c
index 6e3de63c3055..bcd7f97beab9 100644
--- a/fs/block_dev.c
+++ b/fs/block_dev.c
@@ -1597,6 +1597,16 @@ ssize_t blkdev_write_iter(struct kiocb *iocb, struct iov_iter *from)
         struct file *file = iocb->ki_filp;
         struct blk_plug plug;
         ssize_t ret;
+        size_t count = iov_iter_count(from);
+
+        ret = generic_write_checks(file, &iocb->ki_pos, &count, 1);
+        if (ret)
+                return ret;
+
+        if (count == 0)
+                return 0;
+
+        iov_iter_truncate(from, count);
 
         blk_start_plug(&plug);
         ret = __generic_file_write_iter(iocb, from);
diff --git a/fs/cifs/file.c b/fs/cifs/file.c
index 3cb04129ddb1..3c5c9bc5cbaf 100644
--- a/fs/cifs/file.c
+++ b/fs/cifs/file.c
@@ -2673,8 +2673,8 @@ cifs_writev(struct kiocb *iocb, struct iov_iter *from)
         struct inode *inode = file->f_mapping->host;
         struct cifsInodeInfo *cinode = CIFS_I(inode);
         struct TCP_Server_Info *server = tlink_tcon(cfile->tlink)->ses->server;
-        ssize_t rc = -EACCES;
-        loff_t lock_pos = iocb->ki_pos;
+        ssize_t rc;
+        size_t count;
 
         /*
          * We need to hold the sem to be sure nobody modifies lock list
@@ -2682,23 +2682,30 @@ cifs_writev(struct kiocb *iocb, struct iov_iter *from)
          */
         down_read(&cinode->lock_sem);
         mutex_lock(&inode->i_mutex);
-        if (file->f_flags & O_APPEND)
-                lock_pos = i_size_read(inode);
-        if (!cifs_find_lock_conflict(cfile, lock_pos, iov_iter_count(from),
+
+        count = iov_iter_count(from);
+        rc = generic_write_checks(file, &iocb->ki_pos, &count, 0);
+        if (rc)
+                goto out;
+
+        if (count == 0)
+                goto out;
+
+        iov_iter_truncate(from, count);
+
+        if (!cifs_find_lock_conflict(cfile, iocb->ki_pos, iov_iter_count(from),
                                      server->vals->exclusive_lock_type, NULL,
-                                     CIFS_WRITE_OP)) {
+                                     CIFS_WRITE_OP))
                 rc = __generic_file_write_iter(iocb, from);
-                mutex_unlock(&inode->i_mutex);
-
-                if (rc > 0) {
-                        ssize_t err;
+        else
+                rc = -EACCES;
+out:
+        mutex_unlock(&inode->i_mutex);
 
-                        err = generic_write_sync(file, iocb->ki_pos - rc, rc);
-                        if (err < 0)
-                                rc = err;
-                }
-        } else {
-                mutex_unlock(&inode->i_mutex);
+        if (rc > 0) {
+                ssize_t err = generic_write_sync(file, iocb->ki_pos - rc, rc);
+                if (err < 0)
+                        rc = err;
         }
         up_read(&cinode->lock_sem);
         return rc;
diff --git a/fs/ext4/file.c b/fs/ext4/file.c
index 9ad03036d9f5..f7cca423dded 100644
--- a/fs/ext4/file.c
+++ b/fs/ext4/file.c
@@ -132,9 +132,8 @@ ext4_file_write_iter(struct kiocb *iocb, struct iov_iter *from)
                         ret = -EFBIG;
                         goto errout;
                 }
-
-                if (pos + length > sbi->s_bitmap_maxbytes)
-                        iov_iter_truncate(from, sbi->s_bitmap_maxbytes - pos);
+                iov_iter_truncate(from, sbi->s_bitmap_maxbytes - pos);
+                length = iov_iter_count(from);
         }
 
         iocb->private = &overwrite;
@@ -172,7 +171,16 @@ ext4_file_write_iter(struct kiocb *iocb, struct iov_iter *from)
                 }
         }
 
+        ret = generic_write_checks(file, &iocb->ki_pos, &length, 0);
+        if (ret)
+                goto out;
+
+        if (length == 0)
+                goto out;
+
+        iov_iter_truncate(from, length);
         ret = __generic_file_write_iter(iocb, from);
+out:
         mutex_unlock(&inode->i_mutex);
 
         if (ret > 0) {
diff --git a/fs/udf/file.c b/fs/udf/file.c
index 78d42548b260..35e81ed99405 100644
--- a/fs/udf/file.c
+++ b/fs/udf/file.c
@@ -151,7 +151,17 @@ static ssize_t udf_file_write_iter(struct kiocb *iocb, struct iov_iter *from)
         } else
                 up_write(&iinfo->i_data_sem);
 
+        retval = generic_write_checks(file, &iocb->ki_pos, &count, 0);
+        if (retval)
+                goto out;
+
+        if (count == 0)
+                goto out;
+
+        iov_iter_truncate(from, count);
+
         retval = __generic_file_write_iter(iocb, from);
+out:
         mutex_unlock(&inode->i_mutex);
 
         if (retval > 0) {
diff --git a/mm/filemap.c b/mm/filemap.c
index 353f82e09e63..a794a7f98743 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -2560,19 +2560,9 @@ ssize_t __generic_file_write_iter(struct kiocb *iocb, struct iov_iter *from)
         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, &iocb->ki_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;
@@ -2651,9 +2641,14 @@ ssize_t generic_file_write_iter(struct kiocb *iocb, struct iov_iter *from)
         struct file *file = iocb->ki_filp;
         struct inode *inode = file->f_mapping->host;
         ssize_t ret;
+        size_t count = iov_iter_count(from);
 
         mutex_lock(&inode->i_mutex);
-        ret = __generic_file_write_iter(iocb, from);
+        ret = generic_write_checks(file, &iocb->ki_pos, &count, 0);
+        if (!ret && count) {
+                iov_iter_truncate(from, count);
+                ret = __generic_file_write_iter(iocb, from);
+        }
         mutex_unlock(&inode->i_mutex);
 
         if (ret > 0) {