NFS: Fix /proc/mount for legacy binary interface

[firefly-linux-kernel-4.4.55.git] / fs / direct-io.c

diff --git a/fs/direct-io.c b/fs/direct-io.c
index 5949947b060a839327f9b7ff27a915d30e6e7894..7600aacf531dc8ed16ccfb727878d13834a16503 100644 (file)
--- a/fs/direct-io.c
+++ b/fs/direct-io.c
@@ -632,10 +632,26 @@ static int dio_send_cur_page(struct dio *dio)
        int ret = 0;
 
        if (dio->bio) {
+               loff_t cur_offset = dio->block_in_file << dio->blkbits;
+               loff_t bio_next_offset = dio->logical_offset_in_bio +
+                       dio->bio->bi_size;
+
                /*
-                * See whether this new request is contiguous with the old
+                * See whether this new request is contiguous with the old.
+                *
+                * Btrfs cannot handl having logically non-contiguous requests
+                * submitted.  For exmple if you have
+                *
+                * Logical:  [0-4095][HOLE][8192-12287]
+                * Phyiscal: [0-4095]      [4096-8181]
+                *
+                * We cannot submit those pages together as one BIO.  So if our
+                * current logical offset in the file does not equal what would
+                * be the next logical offset in the bio, submit the bio we
+                * have.
                 */
-               if (dio->final_block_in_bio != dio->cur_page_block)
+               if (dio->final_block_in_bio != dio->cur_page_block ||
+                   cur_offset != bio_next_offset)
                        dio_bio_submit(dio);
                /*
                 * Submit now if the underlying fs is about to perform a
@@ -1118,27 +1134,8 @@ direct_io_worker(int rw, struct kiocb *iocb, struct inode *inode,
        return ret;
 }
 
-/*
- * This is a library function for use by filesystem drivers.
- *
- * The locking rules are governed by the flags parameter:
- *  - if the flags value contains DIO_LOCKING we use a fancy locking
- *    scheme for dumb filesystems.
- *    For writes this function is called under i_mutex and returns with
- *    i_mutex held, for reads, i_mutex is not held on entry, but it is
- *    taken and dropped again before returning.
- *    For reads and writes i_alloc_sem is taken in shared mode and released
- *    on I/O completion (which may happen asynchronously after returning to
- *    the caller).
- *
- *  - if the flags value does NOT contain DIO_LOCKING we don't use any
- *    internal locking but rather rely on the filesystem to synchronize
- *    direct I/O reads/writes versus each other and truncate.
- *    For reads and writes both i_mutex and i_alloc_sem are not held on
- *    entry and are never taken.
- */
 ssize_t
-__blockdev_direct_IO(int rw, struct kiocb *iocb, struct inode *inode,
+__blockdev_direct_IO_newtrunc(int rw, struct kiocb *iocb, struct inode *inode,
        struct block_device *bdev, const struct iovec *iov, loff_t offset, 
        unsigned long nr_segs, get_block_t get_block, dio_iodone_t end_io,
        dio_submit_t submit_io, int flags)
@@ -1231,9 +1228,46 @@ __blockdev_direct_IO(int rw, struct kiocb *iocb, struct inode *inode,
                                nr_segs, blkbits, get_block, end_io,
                                submit_io, dio);
 
+out:
+       return retval;
+}
+EXPORT_SYMBOL(__blockdev_direct_IO_newtrunc);
+
+/*
+ * This is a library function for use by filesystem drivers.
+ *
+ * The locking rules are governed by the flags parameter:
+ *  - if the flags value contains DIO_LOCKING we use a fancy locking
+ *    scheme for dumb filesystems.
+ *    For writes this function is called under i_mutex and returns with
+ *    i_mutex held, for reads, i_mutex is not held on entry, but it is
+ *    taken and dropped again before returning.
+ *    For reads and writes i_alloc_sem is taken in shared mode and released
+ *    on I/O completion (which may happen asynchronously after returning to
+ *    the caller).
+ *
+ *  - if the flags value does NOT contain DIO_LOCKING we don't use any
+ *    internal locking but rather rely on the filesystem to synchronize
+ *    direct I/O reads/writes versus each other and truncate.
+ *    For reads and writes both i_mutex and i_alloc_sem are not held on
+ *    entry and are never taken.
+ */
+ssize_t
+__blockdev_direct_IO(int rw, struct kiocb *iocb, struct inode *inode,
+       struct block_device *bdev, const struct iovec *iov, loff_t offset,
+       unsigned long nr_segs, get_block_t get_block, dio_iodone_t end_io,
+       dio_submit_t submit_io, int flags)
+{
+       ssize_t retval;
+
+       retval = __blockdev_direct_IO_newtrunc(rw, iocb, inode, bdev, iov,
+                       offset, nr_segs, get_block, end_io, submit_io, flags);
        /*
         * In case of error extending write may have instantiated a few
         * blocks outside i_size. Trim these off again for DIO_LOCKING.
+        * NOTE: DIO_NO_LOCK/DIO_OWN_LOCK callers have to handle this in
+        * their own manner. This is a further example of where the old
+        * truncate sequence is inadequate.
         *
         * NOTE: filesystems with their own locking have to handle this
         * on their own.
@@ -1241,12 +1275,13 @@ __blockdev_direct_IO(int rw, struct kiocb *iocb, struct inode *inode,
        if (flags & DIO_LOCKING) {
                if (unlikely((rw & WRITE) && retval < 0)) {
                        loff_t isize = i_size_read(inode);
+                       loff_t end = offset + iov_length(iov, nr_segs);
+
                        if (end > isize)
                                vmtruncate(inode, isize);
                }
        }
 
-out:
        return retval;
 }
 EXPORT_SYMBOL(__blockdev_direct_IO);