[PATCH 6/8] xfs: split buffered IO write path from xfs_file_aio_write

Dave Chinner
2011-01-04T04:47:04Z

From: Dave Chinner <dchinner@redhat.com>

Complete the split of the different write IO paths by splitting the
buffered IO write path out of xfs_file_aio_write(). This makes the
different mechanisms of the write patchs easier to follow.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
---
fs/xfs/linux-2.6/xfs_file.c | 146 ++++++++++++++++++++-----------------------
1 files changed, 69 insertions(+), 77 deletions(-)

diff --git a/fs/xfs/linux-2.6/xfs_file.c b/fs/xfs/linux-2.6/xfs_file.c
index d546953..7e7805c 100644
--- a/fs/xfs/linux-2.6/xfs_file.c
+++ b/fs/xfs/linux-2.6/xfs_file.c
@@ -724,56 +724,31 @@ xfs_file_dio_aio_write(
}

STATIC ssize_t
-xfs_file_aio_write(
+xfs_file_buffered_aio_write(
struct kiocb *iocb,
const struct iovec *iovp,
unsigned long nr_segs,
- loff_t pos)
+ loff_t pos,
+ size_t ocount,
+ int *iolock)
{
struct file *file = iocb->ki_filp;
struct address_space *mapping = file->f_mapping;
struct inode *inode = mapping->host;
struct xfs_inode *ip = XFS_I(inode);
- struct xfs_mount *mp = ip->i_mount;
- ssize_t ret = 0;
- int ioflags = 0;
+ ssize_t ret;
+ int enospc = 0;
xfs_fsize_t new_size;
- int iolock;
- size_t ocount = 0, count;
-
- XFS_STATS_INC(xs_write_calls);
-
- BUG_ON(iocb->ki_pos != pos);
-
- if (unlikely(file->f_flags & O_DIRECT))
- ioflags |= IO_ISDIRECT;
- if (file->f_mode & FMODE_NOCMTIME)
- ioflags |= IO_INVIS;
-
- ret = generic_segment_checks(iovp, &nr_segs, &ocount, VERIFY_READ);
- if (ret)
- return ret;
-
- count = ocount;
- if (count == 0)
- return 0;
-
- xfs_wait_for_freeze(mp, SB_FREEZE_WRITE);
-
- if (XFS_FORCED_SHUTDOWN(mp))
- return -EIO;
+ size_t count = ocount;

- if (ioflags & IO_ISDIRECT) {
- ret = xfs_file_dio_aio_write(iocb, iovp, nr_segs, pos,
- ocount, &iolock);
- goto done_io;
- }
+ *iolock = XFS_IOLOCK_EXCL;
+ xfs_rw_ilock(ip, XFS_ILOCK_EXCL|*iolock);

- iolock = XFS_IOLOCK_EXCL;
ret = generic_write_checks(file, &pos, &count,
S_ISBLK(inode->i_mode));
if (ret) {
- xfs_rw_iunlock(ip, XFS_ILOCK_EXCL|iolock);
+ xfs_rw_iunlock(ip, XFS_ILOCK_EXCL|*iolock);
+ *iolock = 0;
return ret;
}

@@ -781,69 +756,86 @@ xfs_file_aio_write(
if (new_size > ip->i_size)
ip->i_new_size = new_size;

- if (likely(!(ioflags & IO_INVIS)))
+ if (likely(!(file->f_mode & FMODE_NOCMTIME)))
file_update_time(file);

- /*
- * If the offset is beyond the size of the file, we have a couple
- * of things to do. First, if there is already space allocated
- * we need to either create holes or zero the disk or ...
- *
- * If there is a page where the previous size lands, we need
- * to zero it out up to the new size.
- */
-
if (pos > ip->i_size) {
ret = -xfs_zero_eof(ip, pos, ip->i_size);
if (ret) {
xfs_rw_iunlock(ip, XFS_ILOCK_EXCL);
- goto out_unlock_internal;
+ return ret;
}
}
xfs_rw_iunlock(ip, XFS_ILOCK_EXCL);

- /*
- * If we're writing the file then make sure to clear the
- * setuid and setgid bits if the process is not being run
- * by root. This keeps people from modifying setuid and
- * setgid binaries.
- */
ret = file_remove_suid(file);
if (unlikely(ret))
- goto out_unlock_internal;
+ return ret;

/* We can write back this queue in page reclaim */
current->backing_dev_info = mapping->backing_dev_info;

- if (!(ioflags & IO_ISDIRECT)) {
- int enospc = 0;
-
write_retry:
- trace_xfs_file_buffered_write(ip, count, iocb->ki_pos, ioflags);
- ret = generic_file_buffered_write(iocb, iovp, nr_segs,
- pos, &iocb->ki_pos, count, ret);
- /*
- * if we just got an ENOSPC, flush the inode now we
- * aren't holding any page locks and retry *once*
- */
- if (ret == -ENOSPC && !enospc) {
- ssize_t ret2 = xfs_flush_pages(ip, 0, -1, 0, FI_NONE);
- if (ret2) {
- ret = ret2;
- goto out_unlock_internal;
- }
- enospc = 1;
- goto write_retry;
- }
+ trace_xfs_file_buffered_write(ip, count, iocb->ki_pos, 0);
+ ret = generic_file_buffered_write(iocb, iovp, nr_segs,
+ pos, &iocb->ki_pos, count, ret);
+ /*
+ * if we just got an ENOSPC, flush the inode now we aren't holding any
+ * page locks and retry *once*
+ */
+ if (ret == -ENOSPC && !enospc) {
+ ret = -xfs_flush_pages(ip, 0, -1, 0, FI_NONE);
+ if (ret)
+ return ret;
+ enospc = 1;
+ goto write_retry;
}
-
current->backing_dev_info = NULL;
+ return ret;
+}
+
+STATIC ssize_t
+xfs_file_aio_write(
+ struct kiocb *iocb,
+ const struct iovec *iovp,
+ unsigned long nr_segs,
+ loff_t pos)
+{
+ struct file *file = iocb->ki_filp;
+ struct address_space *mapping = file->f_mapping;
+ struct inode *inode = mapping->host;
+ struct xfs_inode *ip = XFS_I(inode);
+ ssize_t ret;
+ int iolock;
+ size_t ocount = 0;
+
+ XFS_STATS_INC(xs_write_calls);
+
+ BUG_ON(iocb->ki_pos != pos);
+
+ ret = generic_segment_checks(iovp, &nr_segs, &ocount, VERIFY_READ);
+ if (ret)
+ return ret;
+
+ if (ocount == 0)
+ return 0;
+
+ xfs_wait_for_freeze(ip->i_mount, SB_FREEZE_WRITE);
+
+ if (XFS_FORCED_SHUTDOWN(ip->i_mount))
+ return -EIO;
+
+ if (unlikely(file->f_flags & O_DIRECT))
+ ret = xfs_file_dio_aio_write(iocb, iovp, nr_segs, pos,
+ ocount, &iolock);
+ else
+ ret = xfs_file_buffered_aio_write(iocb, iovp, nr_segs, pos,
+ ocount, &iolock);

-done_io:
xfs_aio_write_isize_update(inode, &iocb->ki_pos, ret);

if (ret <= 0)
- goto out_unlock_internal;
+ goto out_unlock;

XFS_STATS_ADD(xs_write_bytes, ret);

@@ -864,7 +856,7 @@ done_io:
ret = error2;
}

- out_unlock_internal:
+out_unlock:
xfs_aio_write_newsize_update(ip);
xfs_rw_iunlock(ip, iolock);
return ret;
--
1.7.2.3