[PATCH 7/8] xfs: factor common write setup code

Dave Chinner
2011-01-07T11:29:16Z

From: Dave Chinner <dchinner@redhat.com>

The buffered IO and direct IO write paths share a common set of
checks and limiting code prior to issuing the write. Factor that
into a common helper function.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Alex Elder <aelder@sgi.com>
---
fs/xfs/linux-2.6/xfs_file.c | 128 +++++++++++++++++++-----------------------
1 files changed, 58 insertions(+), 70 deletions(-)

diff --git a/fs/xfs/linux-2.6/xfs_file.c b/fs/xfs/linux-2.6/xfs_file.c
index 9ce5e12..d6ff7ff 100644
--- a/fs/xfs/linux-2.6/xfs_file.c
+++ b/fs/xfs/linux-2.6/xfs_file.c
@@ -620,6 +620,60 @@ out_lock:
}

/*
+ * Common pre-write limit and setup checks.
+ *
+ * Returns with iolock held according to @iolock.
+ */
+STATIC ssize_t
+xfs_file_aio_write_checks(
+ struct file *file,
+ loff_t *pos,
+ size_t *count,
+ int *iolock)
+{
+ struct inode *inode = file->f_mapping->host;
+ struct xfs_inode *ip = XFS_I(inode);
+ xfs_fsize_t new_size;
+ int error = 0;
+
+ xfs_rw_ilock(ip, XFS_ILOCK_EXCL|*iolock);
+
+ error = generic_write_checks(file, pos, count, S_ISBLK(inode->i_mode));
+ if (error) {
+ xfs_rw_iunlock(ip, XFS_ILOCK_EXCL|*iolock);
+ *iolock = 0;
+ return error;
+ }
+
+ new_size = *pos + *count;
+ if (new_size > ip->i_size)
+ ip->i_new_size = new_size;
+
+ if (likely(!(file->f_mode & FMODE_NOCMTIME)))
+ file_update_time(file);
+
+ /*
+ * If the offset is beyond the size of the file, we need to zero any
+ * blocks that fall between the existing EOF and the start of this
+ * write.
+ */
+ if (*pos > ip->i_size)
+ error = -xfs_zero_eof(ip, *pos, ip->i_size);
+
+ xfs_rw_iunlock(ip, XFS_ILOCK_EXCL);
+ if (error)
+ return error;
+
+ /*
+ * 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.
+ */
+ return file_remove_suid(file);
+
+}
+
+/*
* xfs_file_dio_aio_write - handle direct IO writes
*
* Lock the inode appropriately to prepare for and issue a direct IO write.
@@ -644,7 +698,6 @@ xfs_file_dio_aio_write(
struct xfs_inode *ip = XFS_I(inode);
struct xfs_mount *mp = ip->i_mount;
ssize_t ret = 0;
- xfs_fsize_t new_size;
size_t count = ocount;
struct xfs_buftarg *target = XFS_IS_REALTIME_INODE(ip) ?
mp->m_rtdev_targp : mp->m_ddev_targp;
@@ -663,47 +716,9 @@ xfs_file_dio_aio_write(
*iolock = XFS_IOLOCK_EXCL;
else
*iolock = XFS_IOLOCK_SHARED;
- xfs_rw_ilock(ip, XFS_ILOCK_EXCL|*iolock);
-
- ret = generic_write_checks(file, &pos, &count,
- S_ISBLK(inode->i_mode));
- if (ret) {
- xfs_rw_iunlock(ip, XFS_ILOCK_EXCL|*iolock);
- *iolock = 0;
- return ret;
- }
-
- new_size = pos + count;
- if (new_size > ip->i_size)
- ip->i_new_size = new_size;
-
- 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);
- 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))
+ ret = xfs_file_aio_write_checks(file, &pos, &count, iolock);
+ if (ret)
return ret;

if (mapping->nrpages) {
@@ -744,38 +759,11 @@ xfs_file_buffered_aio_write(
struct xfs_inode *ip = XFS_I(inode);
ssize_t ret;
int enospc = 0;
- xfs_fsize_t new_size;
size_t count = ocount;

*iolock = XFS_IOLOCK_EXCL;
- xfs_rw_ilock(ip, XFS_ILOCK_EXCL|*iolock);
-
- ret = generic_write_checks(file, &pos, &count,
- S_ISBLK(inode->i_mode));
- if (ret) {
- xfs_rw_iunlock(ip, XFS_ILOCK_EXCL|*iolock);
- *iolock = 0;
- return ret;
- }
-
- new_size = pos + count;
- if (new_size > ip->i_size)
- ip->i_new_size = new_size;
-
- if (likely(!(file->f_mode & FMODE_NOCMTIME)))
- file_update_time(file);
-
- if (pos > ip->i_size) {
- ret = -xfs_zero_eof(ip, pos, ip->i_size);
- if (ret) {
- xfs_rw_iunlock(ip, XFS_ILOCK_EXCL);
- return ret;
- }
- }
- xfs_rw_iunlock(ip, XFS_ILOCK_EXCL);
-
- ret = file_remove_suid(file);
- if (unlikely(ret))
+ ret = xfs_file_aio_write_checks(file, &pos, &count, iolock);
+ if (ret)
return ret;

/* We can write back this queue in page reclaim */
--
1.7.2.3