UDF: Add support for O_DIRECT

Add support for the O_DIRECT flag.  There are two cases to deal with:

1. Small files stored in the ICB (inode control block?): just return 0
from the new udf_adinicb_direct_IO() handler to fall back to buffered
I/O.

2. Larger files, not stored in the ICB: nothing special here.  Just call
blockdev_direct_IO() from our new udf_direct_IO() handler and tidy up
any blocks instantiated outside i_size on error.  This is pretty
standard.  Factor error handling code out of udf_write_begin() into new
function udf_write_failed() so it can also be called by udf_direct_IO().

Also change the whitespace in udf_aops to make it a bit neater.

Signed-off-by: Ian Abbott <abbotti@mev.co.uk>
Signed-off-by: Jan Kara <jack@suse.cz>

diff --git a/arch/um/os-Linux/time.c b/arch/um/os-Linux/time.c
index f60238559af309e00b031eedb17ad02ec77516d8..0748fe0c8a73dfa07aad69af8db1e4dcf5194550 100644 (file)
--- a/arch/um/os-Linux/time.c
+++ b/arch/um/os-Linux/time.c
@@ -114,7 +114,7 @@ static void deliver_alarm(void)
        skew += this_tick - last_tick;
 
        while (skew >= one_tick) {
-               alarm_handler(SIGVTALRM, NULL);
+               alarm_handler(SIGVTALRM, NULL, NULL);
                skew -= one_tick;
        }
 

diff --git a/fs/udf/file.c b/fs/udf/file.c
index d1c6093fd3d3c8a204b6cca9dfc8ced300da075f..77b5953eaac87f708ed0ff6889eff5775dd3b465 100644 (file)
--- a/fs/udf/file.c
+++ b/fs/udf/file.c
@@ -118,11 +118,20 @@ static int udf_adinicb_write_end(struct file *file,
        return simple_write_end(file, mapping, pos, len, copied, page, fsdata);
 }
 
+static ssize_t udf_adinicb_direct_IO(int rw, struct kiocb *iocb,
+                                    const struct iovec *iov,
+                                    loff_t offset, unsigned long nr_segs)
+{
+       /* Fallback to buffered I/O. */
+       return 0;
+}
+
 const struct address_space_operations udf_adinicb_aops = {
        .readpage       = udf_adinicb_readpage,
        .writepage      = udf_adinicb_writepage,
        .write_begin    = udf_adinicb_write_begin,
        .write_end      = udf_adinicb_write_end,
+       .direct_IO      = udf_adinicb_direct_IO,
 };
 
 static ssize_t udf_file_aio_write(struct kiocb *iocb, const struct iovec *iov,

diff --git a/fs/udf/inode.c b/fs/udf/inode.c
index 1a0588e77a2f77054a1dba91574f92a5286442bf..41d58309d6a853be17aa3710ea8f0cb8371f0604 100644 (file)
--- a/fs/udf/inode.c
+++ b/fs/udf/inode.c
@@ -95,6 +95,22 @@ void udf_evict_inode(struct inode *inode)
        }
 }
 
+static void udf_write_failed(struct address_space *mapping, loff_t to)
+{
+       struct inode *inode = mapping->host;
+       struct udf_inode_info *iinfo = UDF_I(inode);
+       loff_t isize = inode->i_size;
+
+       if (to > isize) {
+               truncate_pagecache(inode, to, isize);
+               if (iinfo->i_alloc_type != ICBTAG_FLAG_AD_IN_ICB) {
+                       down_write(&iinfo->i_data_sem);
+                       udf_truncate_extents(inode);
+                       up_write(&iinfo->i_data_sem);
+               }
+       }
+}
+
 static int udf_writepage(struct page *page, struct writeback_control *wbc)
 {
        return block_write_full_page(page, udf_get_block, wbc);
@@ -124,21 +140,24 @@ static int udf_write_begin(struct file *file, struct address_space *mapping,
        int ret;
 
        ret = block_write_begin(mapping, pos, len, flags, pagep, udf_get_block);
-       if (unlikely(ret)) {
-               struct inode *inode = mapping->host;
-               struct udf_inode_info *iinfo = UDF_I(inode);
-               loff_t isize = inode->i_size;
-
-               if (pos + len > isize) {
-                       truncate_pagecache(inode, pos + len, isize);
-                       if (iinfo->i_alloc_type != ICBTAG_FLAG_AD_IN_ICB) {
-                               down_write(&iinfo->i_data_sem);
-                               udf_truncate_extents(inode);
-                               up_write(&iinfo->i_data_sem);
-                       }
-               }
-       }
+       if (unlikely(ret))
+               udf_write_failed(mapping, pos + len);
+       return ret;
+}
 
+static ssize_t udf_direct_IO(int rw, struct kiocb *iocb,
+                            const struct iovec *iov,
+                            loff_t offset, unsigned long nr_segs)
+{
+       struct file *file = iocb->ki_filp;
+       struct address_space *mapping = file->f_mapping;
+       struct inode *inode = mapping->host;
+       ssize_t ret;
+
+       ret = blockdev_direct_IO(rw, iocb, inode, iov, offset, nr_segs,
+                                 udf_get_block);
+       if (unlikely(ret < 0 && (rw & WRITE)))
+               udf_write_failed(mapping, offset + iov_length(iov, nr_segs));
        return ret;
 }
 
@@ -152,8 +171,9 @@ const struct address_space_operations udf_aops = {
        .readpages      = udf_readpages,
        .writepage      = udf_writepage,
        .writepages     = udf_writepages,
-       .write_begin            = udf_write_begin,
-       .write_end              = generic_write_end,
+       .write_begin    = udf_write_begin,
+       .write_end      = generic_write_end,
+       .direct_IO      = udf_direct_IO,
        .bmap           = udf_bmap,
 };