5 files changed, 256 insertions, 55 deletions

diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
index c831a580bd76..dee45800dc95 100644
--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h
@@ -138,7 +138,7 @@ typedef struct ext4_io_end {
         struct list_head        list;           /* per-file finished AIO list */
         struct inode            *inode;         /* file being written to */
         unsigned int            flag;           /* unwritten or not */
-        int                     error;          /* I/O error code */
+        struct page             *page;          /* page struct for buffer write */
         loff_t                  offset;         /* offset in the file */
         ssize_t                 size;           /* size of the extent */
         struct work_struct      work;           /* data work queue */
@@ -361,7 +361,7 @@ struct ext4_new_group_data {
                                          EXT4_GET_BLOCKS_CREATE_UNINIT_EXT)
         /* Convert extent to initialized after IO complete */
 #define EXT4_GET_BLOCKS_IO_CONVERT_EXT          (EXT4_GET_BLOCKS_CONVERT|\
-                                         EXT4_GET_BLOCKS_IO_CREATE_EXT)
+                                         EXT4_GET_BLOCKS_CREATE_UNINIT_EXT)
 
 /*
  * Flags used by ext4_free_blocks
@@ -702,6 +702,7 @@ struct ext4_inode_info {
 
         /* completed IOs that might need unwritten extents handling */
         struct list_head i_completed_io_list;
+        spinlock_t i_completed_io_lock;
         /* current io_end structure for async DIO write*/
         ext4_io_end_t *cur_aio_dio;
 
@@ -752,6 +753,7 @@ struct ext4_inode_info {
 #define EXT4_MOUNT_QUOTA                0x80000 /* Some quota option set */
 #define EXT4_MOUNT_USRQUOTA             0x100000 /* "old" user quota */
 #define EXT4_MOUNT_GRPQUOTA             0x200000 /* "old" group quota */
+#define EXT4_MOUNT_DIOREAD_NOLOCK       0x400000 /* Enable support for dio read nolocking */
 #define EXT4_MOUNT_JOURNAL_CHECKSUM     0x800000 /* Journal checksums */
 #define EXT4_MOUNT_JOURNAL_ASYNC_COMMIT 0x1000000 /* Journal Async Commit */
 #define EXT4_MOUNT_I_VERSION            0x2000000 /* i_version support */
@@ -1781,6 +1783,15 @@ extern int ext4_move_extents(struct file *o_filp, struct file *d_filp,
                              __u64 len, __u64 *moved_len);
 
 
+/* BH_Uninit flag: blocks are allocated but uninitialized on disk */
+enum ext4_state_bits {
+        BH_Uninit       /* blocks are allocated but uninitialized on disk */
+          = BH_JBDPrivateStart,
+};
+
+BUFFER_FNS(Uninit, uninit)
+TAS_BUFFER_FNS(Uninit, uninit)
+
 /*
  * Add new method to test wether block and inode bitmaps are properly
  * initialized. With uninit_bg reading the block from disk is not enough
diff --git a/fs/ext4/ext4_jbd2.h b/fs/ext4/ext4_jbd2.h
index 05eca817d704..b79ad5126468 100644
--- a/fs/ext4/ext4_jbd2.h
+++ b/fs/ext4/ext4_jbd2.h
@@ -304,4 +304,28 @@ static inline int ext4_should_writeback_data(struct inode *inode)
         return 0;
 }
 
+/*
+ * This function controls whether or not we should try to go down the
+ * dioread_nolock code paths, which makes it safe to avoid taking
+ * i_mutex for direct I/O reads.  This only works for extent-based
+ * files, and it doesn't work for nobh or if data journaling is
+ * enabled, since the dioread_nolock code uses b_private to pass
+ * information back to the I/O completion handler, and this conflicts
+ * with the jbd's use of b_private.
+ */
+static inline int ext4_should_dioread_nolock(struct inode *inode)
+{
+        if (!test_opt(inode->i_sb, DIOREAD_NOLOCK))
+                return 0;
+        if (test_opt(inode->i_sb, NOBH))
+                return 0;
+        if (!S_ISREG(inode->i_mode))
+                return 0;
+        if (!(EXT4_I(inode)->i_flags & EXT4_EXTENTS_FL))
+                return 0;
+        if (ext4_should_journal_data(inode))
+                return 0;
+        return 1;
+}
+
 #endif  /* _EXT4_JBD2_H */
diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c
index 90ba8d9df697..c7f166ab50eb 100644
--- a/fs/ext4/extents.c
+++ b/fs/ext4/extents.c
@@ -1619,7 +1619,7 @@ int ext4_ext_insert_extent(handle_t *handle, struct inode *inode,
         BUG_ON(path[depth].p_hdr == NULL);
 
         /* try to insert block into found extent and return */
-        if (ex && (flag != EXT4_GET_BLOCKS_PRE_IO)
+        if (ex && !(flag & EXT4_GET_BLOCKS_PRE_IO)
                 && ext4_can_extents_be_merged(inode, ex, newext)) {
                 ext_debug("append [%d]%d block to %d:[%d]%d (from %llu)\n",
                                 ext4_ext_is_uninitialized(newext),
@@ -1740,7 +1740,7 @@ has_space:
 
 merge:
         /* try to merge extents to the right */
-        if (flag != EXT4_GET_BLOCKS_PRE_IO)
+        if (!(flag & EXT4_GET_BLOCKS_PRE_IO))
                 ext4_ext_try_to_merge(inode, path, nearex);
 
         /* try to merge extents to the left */
@@ -3065,7 +3065,7 @@ ext4_ext_handle_uninitialized_extents(handle_t *handle, struct inode *inode,
         ext4_ext_show_leaf(inode, path);
 
         /* get_block() before submit the IO, split the extent */
-        if (flags == EXT4_GET_BLOCKS_PRE_IO) {
+        if ((flags & EXT4_GET_BLOCKS_PRE_IO)) {
                 ret = ext4_split_unwritten_extents(handle,
                                                 inode, path, iblock,
                                                 max_blocks, flags);
@@ -3078,10 +3078,12 @@ ext4_ext_handle_uninitialized_extents(handle_t *handle, struct inode *inode,
                         io->flag = EXT4_IO_UNWRITTEN;
                 else
                         ext4_set_inode_state(inode, EXT4_STATE_DIO_UNWRITTEN);
+                if (ext4_should_dioread_nolock(inode))
+                        set_buffer_uninit(bh_result);
                 goto out;
         }
         /* IO end_io complete, convert the filled extent to written */
-        if (flags == EXT4_GET_BLOCKS_CONVERT) {
+        if ((flags & EXT4_GET_BLOCKS_CONVERT)) {
                 ret = ext4_convert_unwritten_extents_endio(handle, inode,
                                                         path);
                 if (ret >= 0)
@@ -3351,21 +3353,21 @@ int ext4_ext_get_blocks(handle_t *handle, struct inode *inode,
         if (flags & EXT4_GET_BLOCKS_UNINIT_EXT){
                 ext4_ext_mark_uninitialized(&newex);
                 /*
-                 * io_end structure was created for every async
-                 * direct IO write to the middle of the file.
-                 * To avoid unecessary convertion for every aio dio rewrite
-                 * to the mid of file, here we flag the IO that is really
-                 * need the convertion.
+                 * io_end structure was created for every IO write to an
+                 * uninitialized extent. To avoid unecessary conversion,
+                 * here we flag the IO that really needs the conversion.
                  * For non asycn direct IO case, flag the inode state
                  * that we need to perform convertion when IO is done.
                  */
-                if (flags == EXT4_GET_BLOCKS_PRE_IO) {
+                if ((flags & EXT4_GET_BLOCKS_PRE_IO)) {
                         if (io)
                                 io->flag = EXT4_IO_UNWRITTEN;
                         else
                                 ext4_set_inode_state(inode,
                                                      EXT4_STATE_DIO_UNWRITTEN);
                 }
+                if (ext4_should_dioread_nolock(inode))
+                        set_buffer_uninit(bh_result);
         }
 
         if (unlikely(EXT4_I(inode)->i_flags & EXT4_EOFBLOCKS_FL)) {
diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index 28f116bdc405..d291310aef6b 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -38,6 +38,7 @@
 #include <linux/uio.h>
 #include <linux/bio.h>
 #include <linux/workqueue.h>
+#include <linux/kernel.h>
 
 #include "ext4_jbd2.h"
 #include "xattr.h"
@@ -1534,6 +1535,8 @@ static void ext4_truncate_failed_write(struct inode *inode)
         ext4_truncate(inode);
 }
 
+static int ext4_get_block_write(struct inode *inode, sector_t iblock,
+                   struct buffer_head *bh_result, int create);
 static int ext4_write_begin(struct file *file, struct address_space *mapping,
                             loff_t pos, unsigned len, unsigned flags,
                             struct page **pagep, void **fsdata)
@@ -1575,8 +1578,12 @@ retry:
         }
         *pagep = page;
 
-        ret = block_write_begin(file, mapping, pos, len, flags, pagep, fsdata,
-                                ext4_get_block);
+        if (ext4_should_dioread_nolock(inode))
+                ret = block_write_begin(file, mapping, pos, len, flags, pagep,
+                                fsdata, ext4_get_block_write);
+        else
+                ret = block_write_begin(file, mapping, pos, len, flags, pagep,
+                                fsdata, ext4_get_block);
 
         if (!ret && ext4_should_journal_data(inode)) {
                 ret = walk_page_buffers(handle, page_buffers(page),
@@ -2092,6 +2099,8 @@ static void mpage_put_bnr_to_bhs(struct mpage_da_data *mpd, sector_t logical,
                                 } else if (buffer_mapped(bh))
                                         BUG_ON(bh->b_blocknr != pblock);
 
+                                if (buffer_uninit(exbh))
+                                        set_buffer_uninit(bh);
                                 cur_logical++;
                                 pblock++;
                         } while ((bh = bh->b_this_page) != head);
@@ -2221,6 +2230,8 @@ static int mpage_da_map_blocks(struct mpage_da_data *mpd)
          */
         new.b_state = 0;
         get_blocks_flags = EXT4_GET_BLOCKS_CREATE;
+        if (ext4_should_dioread_nolock(mpd->inode))
+                get_blocks_flags |= EXT4_GET_BLOCKS_IO_CREATE_EXT;
         if (mpd->b_state & (1 << BH_Delay))
                 get_blocks_flags |= EXT4_GET_BLOCKS_DELALLOC_RESERVE;
 
@@ -2636,6 +2647,9 @@ out:
         return ret;
 }
 
+static int ext4_set_bh_endio(struct buffer_head *bh, struct inode *inode);
+static void ext4_end_io_buffer_write(struct buffer_head *bh, int uptodate);
+
 /*
  * Note that we don't need to start a transaction unless we're journaling data
  * because we should have holes filled from ext4_page_mkwrite(). We even don't
@@ -2683,7 +2697,7 @@ static int ext4_writepage(struct page *page,
         int ret = 0;
         loff_t size;
         unsigned int len;
-        struct buffer_head *page_bufs;
+        struct buffer_head *page_bufs = NULL;
         struct inode *inode = page->mapping->host;
 
         trace_ext4_writepage(inode, page);
@@ -2759,7 +2773,11 @@ static int ext4_writepage(struct page *page,
 
         if (test_opt(inode->i_sb, NOBH) && ext4_should_writeback_data(inode))
                 ret = nobh_writepage(page, noalloc_get_block_write, wbc);
-        else
+        else if (page_bufs && buffer_uninit(page_bufs)) {
+                ext4_set_bh_endio(page_bufs, inode);
+                ret = block_write_full_page_endio(page, noalloc_get_block_write,
+                                            wbc, ext4_end_io_buffer_write);
+        } else
                 ret = block_write_full_page(page, noalloc_get_block_write,
                                             wbc);
 
@@ -3347,11 +3365,45 @@ ext4_readpages(struct file *file, struct address_space *mapping,
         return mpage_readpages(mapping, pages, nr_pages, ext4_get_block);
 }
 
+static void ext4_free_io_end(ext4_io_end_t *io)
+{
+        BUG_ON(!io);
+        if (io->page)
+                put_page(io->page);
+        iput(io->inode);
+        kfree(io);
+}
+
+static void ext4_invalidatepage_free_endio(struct page *page, unsigned long offset)
+{
+        struct buffer_head *head, *bh;
+        unsigned int curr_off = 0;
+
+        if (!page_has_buffers(page))
+                return;
+        head = bh = page_buffers(page);
+        do {
+                if (offset <= curr_off && test_clear_buffer_uninit(bh)
+                                        && bh->b_private) {
+                        ext4_free_io_end(bh->b_private);
+                        bh->b_private = NULL;
+                        bh->b_end_io = NULL;
+                }
+                curr_off = curr_off + bh->b_size;
+                bh = bh->b_this_page;
+        } while (bh != head);
+}
+
 static void ext4_invalidatepage(struct page *page, unsigned long offset)
 {
         journal_t *journal = EXT4_JOURNAL(page->mapping->host);
 
         /*
+         * free any io_end structure allocated for buffers to be discarded
+         */
+        if (ext4_should_dioread_nolock(page->mapping->host))
+                ext4_invalidatepage_free_endio(page, offset);
+        /*
          * If it's a full truncate we just forget about the pending dirtying
          */
         if (offset == 0)
@@ -3471,10 +3523,11 @@ out:
 static int ext4_get_block_write(struct inode *inode, sector_t iblock,
                    struct buffer_head *bh_result, int create)
 {
-        handle_t *handle = NULL;
+        handle_t *handle = ext4_journal_current_handle();
         int ret = 0;
         unsigned max_blocks = bh_result->b_size >> inode->i_blkbits;
         int dio_credits;
+        int started = 0;
 
         ext4_debug("ext4_get_block_write: inode %lu, create flag %d\n",
                    inode->i_ino, create);
@@ -3485,37 +3538,36 @@ static int ext4_get_block_write(struct inode *inode, sector_t iblock,
          */
         create = EXT4_GET_BLOCKS_IO_CREATE_EXT;
 
-        if (max_blocks > DIO_MAX_BLOCKS)
-                max_blocks = DIO_MAX_BLOCKS;
-        dio_credits = ext4_chunk_trans_blocks(inode, max_blocks);
-        handle = ext4_journal_start(inode, dio_credits);
-        if (IS_ERR(handle)) {
-                ret = PTR_ERR(handle);
-                goto out;
+        if (!handle) {
+                if (max_blocks > DIO_MAX_BLOCKS)
+                        max_blocks = DIO_MAX_BLOCKS;
+                dio_credits = ext4_chunk_trans_blocks(inode, max_blocks);
+                handle = ext4_journal_start(inode, dio_credits);
+                if (IS_ERR(handle)) {
+                        ret = PTR_ERR(handle);
+                        goto out;
+                }
+                started = 1;
         }
+
         ret = ext4_get_blocks(handle, inode, iblock, max_blocks, bh_result,
                               create);
         if (ret > 0) {
                 bh_result->b_size = (ret << inode->i_blkbits);
                 ret = 0;
         }
-        ext4_journal_stop(handle);
+        if (started)
+                ext4_journal_stop(handle);
 out:
         return ret;
 }
 
-static void ext4_free_io_end(ext4_io_end_t *io)
-{
-        BUG_ON(!io);
-        iput(io->inode);
-        kfree(io);
-}
-
 static void dump_completed_IO(struct inode * inode)
 {
 #ifdef  EXT4_DEBUG
         struct list_head *cur, *before, *after;
         ext4_io_end_t *io, *io0, *io1;
+        unsigned long flags;
 
         if (list_empty(&EXT4_I(inode)->i_completed_io_list)){
                 ext4_debug("inode %lu completed_io list is empty\n", inode->i_ino);
@@ -3523,6 +3575,7 @@ static void dump_completed_IO(struct inode * inode)
         }
 
         ext4_debug("Dump inode %lu completed_io list \n", inode->i_ino);
+        spin_lock_irqsave(&EXT4_I(inode)->i_completed_io_lock, flags);
         list_for_each_entry(io, &EXT4_I(inode)->i_completed_io_list, list){
                 cur = &io->list;
                 before = cur->prev;
@@ -3533,6 +3586,7 @@ static void dump_completed_IO(struct inode * inode)
                 ext4_debug("io 0x%p from inode %lu,prev 0x%p,next 0x%p\n",
                             io, inode->i_ino, io0, io1);
         }
+        spin_unlock_irqrestore(&EXT4_I(inode)->i_completed_io_lock, flags);
 #endif
 }
 
@@ -3556,9 +3610,7 @@ static int ext4_end_io_nolock(ext4_io_end_t *io)
         if (io->flag != EXT4_IO_UNWRITTEN)
                 return ret;
 
-        if (offset + size <= i_size_read(inode))
-                ret = ext4_convert_unwritten_extents(inode, offset, size);
-
+        ret = ext4_convert_unwritten_extents(inode, offset, size);
         if (ret < 0) {
                 printk(KERN_EMERG "%s: failed to convert unwritten"
                         "extents to written extents, error is %d"
@@ -3577,18 +3629,25 @@ static int ext4_end_io_nolock(ext4_io_end_t *io)
  */
 static void ext4_end_io_work(struct work_struct *work)
 {
-        ext4_io_end_t *io  = container_of(work, ext4_io_end_t, work);
-        struct inode *inode = io->inode;
-        int ret = 0;
+        ext4_io_end_t           *io = container_of(work, ext4_io_end_t, work);
+        struct inode            *inode = io->inode;
+        struct ext4_inode_info  *ei = EXT4_I(inode);
+        unsigned long           flags;
+        int                     ret;
 
         mutex_lock(&inode->i_mutex);
         ret = ext4_end_io_nolock(io);
-        if (ret >= 0) {
-                if (!list_empty(&io->list))
-                        list_del_init(&io->list);
-                ext4_free_io_end(io);
+        if (ret < 0) {
+                mutex_unlock(&inode->i_mutex);
+                return;
         }
+
+        spin_lock_irqsave(&ei->i_completed_io_lock, flags);
+        if (!list_empty(&io->list))
+                list_del_init(&io->list);
+        spin_unlock_irqrestore(&ei->i_completed_io_lock, flags);
         mutex_unlock(&inode->i_mutex);
+        ext4_free_io_end(io);
 }
 
 /*
@@ -3607,15 +3666,18 @@ static void ext4_end_io_work(struct work_struct *work)
 int flush_completed_IO(struct inode *inode)
 {
         ext4_io_end_t *io;
+        struct ext4_inode_info *ei = EXT4_I(inode);
+        unsigned long flags;
         int ret = 0;
         int ret2 = 0;
 
-        if (list_empty(&EXT4_I(inode)->i_completed_io_list))
+        if (list_empty(&ei->i_completed_io_list))
                 return ret;
 
         dump_completed_IO(inode);
-        while (!list_empty(&EXT4_I(inode)->i_completed_io_list)){
-                io = list_entry(EXT4_I(inode)->i_completed_io_list.next,
+        spin_lock_irqsave(&ei->i_completed_io_lock, flags);
+        while (!list_empty(&ei->i_completed_io_list)){
+                io = list_entry(ei->i_completed_io_list.next,
                                 ext4_io_end_t, list);
                 /*
                  * Calling ext4_end_io_nolock() to convert completed
@@ -3631,20 +3693,23 @@ int flush_completed_IO(struct inode *inode)
                  * avoid double converting from both fsync and background work
                  * queue work.
                  */
+                spin_unlock_irqrestore(&ei->i_completed_io_lock, flags);
                 ret = ext4_end_io_nolock(io);
+                spin_lock_irqsave(&ei->i_completed_io_lock, flags);
                 if (ret < 0)
                         ret2 = ret;
                 else
                         list_del_init(&io->list);
         }
+        spin_unlock_irqrestore(&ei->i_completed_io_lock, flags);
         return (ret2 < 0) ? ret2 : 0;
 }
 
-static ext4_io_end_t *ext4_init_io_end (struct inode *inode)
+static ext4_io_end_t *ext4_init_io_end (struct inode *inode, gfp_t flags)
 {
         ext4_io_end_t *io = NULL;
 
-        io = kmalloc(sizeof(*io), GFP_NOFS);
+        io = kmalloc(sizeof(*io), flags);
 
         if (io) {
                 igrab(inode);
@@ -3652,7 +3717,7 @@ static ext4_io_end_t *ext4_init_io_end (struct inode *inode)
                 io->flag = 0;
                 io->offset = 0;
                 io->size = 0;
-                io->error = 0;
+                io->page = NULL;
                 INIT_WORK(&io->work, ext4_end_io_work);
                 INIT_LIST_HEAD(&io->list);
         }
@@ -3665,6 +3730,8 @@ static void ext4_end_io_dio(struct kiocb *iocb, loff_t offset,
 {
         ext4_io_end_t *io_end = iocb->private;
         struct workqueue_struct *wq;
+        unsigned long flags;
+        struct ext4_inode_info *ei;
 
         /* if not async direct IO or dio with 0 bytes write, just return */
         if (!io_end || !size)
@@ -3684,17 +3751,85 @@ static void ext4_end_io_dio(struct kiocb *iocb, loff_t offset,
 
         io_end->offset = offset;
         io_end->size = size;
+        io_end->flag = EXT4_IO_UNWRITTEN;
         wq = EXT4_SB(io_end->inode->i_sb)->dio_unwritten_wq;
 
         /* queue the work to convert unwritten extents to written */
         queue_work(wq, &io_end->work);
 
         /* Add the io_end to per-inode completed aio dio list*/
-        list_add_tail(&io_end->list,
-                 &EXT4_I(io_end->inode)->i_completed_io_list);
+        ei = EXT4_I(io_end->inode);
+        spin_lock_irqsave(&ei->i_completed_io_lock, flags);
+        list_add_tail(&io_end->list, &ei->i_completed_io_list);
+        spin_unlock_irqrestore(&ei->i_completed_io_lock, flags);
         iocb->private = NULL;
 }
 
+static void ext4_end_io_buffer_write(struct buffer_head *bh, int uptodate)
+{
+        ext4_io_end_t *io_end = bh->b_private;
+        struct workqueue_struct *wq;
+        struct inode *inode;
+        unsigned long flags;
+
+        if (!test_clear_buffer_uninit(bh) || !io_end)
+                goto out;
+
+        if (!(io_end->inode->i_sb->s_flags & MS_ACTIVE)) {
+                printk("sb umounted, discard end_io request for inode %lu\n",
+                        io_end->inode->i_ino);
+                ext4_free_io_end(io_end);
+                goto out;
+        }
+
+        io_end->flag = EXT4_IO_UNWRITTEN;
+        inode = io_end->inode;
+
+        /* Add the io_end to per-inode completed io list*/
+        spin_lock_irqsave(&EXT4_I(inode)->i_completed_io_lock, flags);
+        list_add_tail(&io_end->list, &EXT4_I(inode)->i_completed_io_list);
+        spin_unlock_irqrestore(&EXT4_I(inode)->i_completed_io_lock, flags);
+
+        wq = EXT4_SB(inode->i_sb)->dio_unwritten_wq;
+        /* queue the work to convert unwritten extents to written */
+        queue_work(wq, &io_end->work);
+out:
+        bh->b_private = NULL;
+        bh->b_end_io = NULL;
+        clear_buffer_uninit(bh);
+        end_buffer_async_write(bh, uptodate);
+}
+
+static int ext4_set_bh_endio(struct buffer_head *bh, struct inode *inode)
+{
+        ext4_io_end_t *io_end;
+        struct page *page = bh->b_page;
+        loff_t offset = (sector_t)page->index << PAGE_CACHE_SHIFT;
+        size_t size = bh->b_size;
+
+retry:
+        io_end = ext4_init_io_end(inode, GFP_ATOMIC);
+        if (!io_end) {
+                if (printk_ratelimit())
+                        printk(KERN_WARNING "%s: allocation fail\n", __func__);
+                schedule();
+                goto retry;
+        }
+        io_end->offset = offset;
+        io_end->size = size;
+        /*
+         * We need to hold a reference to the page to make sure it
+         * doesn't get evicted before ext4_end_io_work() has a chance
+         * to convert the extent from written to unwritten.
+         */
+        io_end->page = page;
+        get_page(io_end->page);
+
+        bh->b_private = io_end;
+        bh->b_end_io = ext4_end_io_buffer_write;
+        return 0;
+}
+
 /*
  * For ext4 extent files, ext4 will do direct-io write to holes,
  * preallocated extents, and those write extend the file, no need to
@@ -3748,7 +3883,7 @@ static ssize_t ext4_ext_direct_IO(int rw, struct kiocb *iocb,
                 iocb->private = NULL;
                 EXT4_I(inode)->cur_aio_dio = NULL;
                 if (!is_sync_kiocb(iocb)) {
-                        iocb->private = ext4_init_io_end(inode);
+                        iocb->private = ext4_init_io_end(inode, GFP_NOFS);
                         if (!iocb->private)
                                 return -ENOMEM;
                         /*
diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index dc7a97e79e3b..5e8f9077b0fc 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -709,6 +709,7 @@ static struct inode *ext4_alloc_inode(struct super_block *sb)
         ei->i_reserved_quota = 0;
 #endif
         INIT_LIST_HEAD(&ei->i_completed_io_list);
+        spin_lock_init(&ei->i_completed_io_lock);
         ei->cur_aio_dio = NULL;
         ei->i_sync_tid = 0;
         ei->i_datasync_tid = 0;
@@ -926,6 +927,9 @@ static int ext4_show_options(struct seq_file *seq, struct vfsmount *vfs)
         if (test_opt(sb, NOLOAD))
                 seq_puts(seq, ",norecovery");
 
+        if (test_opt(sb, DIOREAD_NOLOCK))
+                seq_puts(seq, ",dioread_nolock");
+
         ext4_show_quota_options(seq, sb);
 
         return 0;
@@ -1109,6 +1113,7 @@ enum {
         Opt_stripe, Opt_delalloc, Opt_nodelalloc,
         Opt_block_validity, Opt_noblock_validity,
         Opt_inode_readahead_blks, Opt_journal_ioprio,
+        Opt_dioread_nolock, Opt_dioread_lock,
         Opt_discard, Opt_nodiscard,
 };
 
@@ -1176,6 +1181,8 @@ static const match_table_t tokens = {
         {Opt_auto_da_alloc, "auto_da_alloc=%u"},
         {Opt_auto_da_alloc, "auto_da_alloc"},
         {Opt_noauto_da_alloc, "noauto_da_alloc"},
+        {Opt_dioread_nolock, "dioread_nolock"},
+        {Opt_dioread_lock, "dioread_lock"},
         {Opt_discard, "discard"},
         {Opt_nodiscard, "nodiscard"},
         {Opt_err, NULL},
@@ -1640,6 +1647,12 @@ set_qf_format:
                 case Opt_nodiscard:
                         clear_opt(sbi->s_mount_opt, DISCARD);
                         break;
+                case Opt_dioread_nolock:
+                        set_opt(sbi->s_mount_opt, DIOREAD_NOLOCK);
+                        break;
+                case Opt_dioread_lock:
+                        clear_opt(sbi->s_mount_opt, DIOREAD_NOLOCK);
+                        break;
                 default:
                         ext4_msg(sb, KERN_ERR,
                                "Unrecognized mount option \"%s\" "
@@ -2795,7 +2808,7 @@ static int ext4_fill_super(struct super_block *sb, void *data, int silent)
               EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_RECOVER)) {
                 ext4_msg(sb, KERN_ERR, "required journal recovery "
                        "suppressed and not mounted read-only");
-                goto failed_mount4;
+                goto failed_mount_wq;
         } else {
                 clear_opt(sbi->s_mount_opt, DATA_FLAGS);
                 set_opt(sbi->s_mount_opt, WRITEBACK_DATA);
@@ -2808,7 +2821,7 @@ static int ext4_fill_super(struct super_block *sb, void *data, int silent)
             !jbd2_journal_set_features(EXT4_SB(sb)->s_journal, 0, 0,
                                        JBD2_FEATURE_INCOMPAT_64BIT)) {
                 ext4_msg(sb, KERN_ERR, "Failed to set 64-bit journal feature");
-                goto failed_mount4;
+                goto failed_mount_wq;
         }
 
         if (test_opt(sb, JOURNAL_ASYNC_COMMIT)) {
@@ -2847,7 +2860,7 @@ static int ext4_fill_super(struct super_block *sb, void *data, int silent)
                     (sbi->s_journal, 0, 0, JBD2_FEATURE_INCOMPAT_REVOKE)) {
                         ext4_msg(sb, KERN_ERR, "Journal does not support "
                                "requested data journaling mode");
-                        goto failed_mount4;
+                        goto failed_mount_wq;
                 }
         default:
                 break;
@@ -2855,13 +2868,17 @@ static int ext4_fill_super(struct super_block *sb, void *data, int silent)
         set_task_ioprio(sbi->s_journal->j_task, journal_ioprio);
 
 no_journal:
-
         if (test_opt(sb, NOBH)) {
                 if (!(test_opt(sb, DATA_FLAGS) == EXT4_MOUNT_WRITEBACK_DATA)) {
                         ext4_msg(sb, KERN_WARNING, "Ignoring nobh option - "
                                 "its supported only with writeback mode");
                         clear_opt(sbi->s_mount_opt, NOBH);
                 }
+                if (test_opt(sb, DIOREAD_NOLOCK)) {
+                        ext4_msg(sb, KERN_WARNING, "dioread_nolock option is "
+                                "not supported with nobh mode");
+                        goto failed_mount_wq;
+                }
         }
         EXT4_SB(sb)->dio_unwritten_wq = create_workqueue("ext4-dio-unwritten");
         if (!EXT4_SB(sb)->dio_unwritten_wq) {
@@ -2926,6 +2943,18 @@ no_journal:
                          "requested data journaling mode");
                 clear_opt(sbi->s_mount_opt, DELALLOC);
         }
+        if (test_opt(sb, DIOREAD_NOLOCK)) {
+                if (test_opt(sb, DATA_FLAGS) == EXT4_MOUNT_JOURNAL_DATA) {
+                        ext4_msg(sb, KERN_WARNING, "Ignoring dioread_nolock "
+                                "option - requested data journaling mode");
+                        clear_opt(sbi->s_mount_opt, DIOREAD_NOLOCK);
+                }
+                if (sb->s_blocksize < PAGE_SIZE) {
+                        ext4_msg(sb, KERN_WARNING, "Ignoring dioread_nolock "
+                                "option - block size is too small");
+                        clear_opt(sbi->s_mount_opt, DIOREAD_NOLOCK);
+                }
+        }
 
         err = ext4_setup_system_zone(sb);
         if (err) {