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yaml
---
r: 231258
b: refs/heads/master
c: f0d26e8
h: refs/heads/master
v: v3
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Dave Chinner authored and Dave Chinner committed Jan 10, 2011
1 parent b756839 commit 855cf6a
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Showing 2 changed files with 117 additions and 64 deletions.
2 changes: 1 addition & 1 deletion [refs]
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Original file line number Diff line number Diff line change
@@ -1,2 +1,2 @@
---
refs/heads/master: 487f84f3f80bc6f00c59725e822653d3ec174b85
refs/heads/master: f0d26e860b6c496464c5c8165d7df08dabde01fa
179 changes: 116 additions & 63 deletions trunk/fs/xfs/linux-2.6/xfs_file.c
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Original file line number Diff line number Diff line change
Expand Up @@ -628,6 +628,116 @@ xfs_zero_eof(
return error;
}

/*
* xfs_file_dio_aio_write - handle direct IO writes
*
* Lock the inode appropriately to prepare for and issue a direct IO write.
* By spearating it from the buffered write path we remove all the tricky to
* follow locking changes and looping.
*
* Returns with locks held indicated by @iolock and errors indicated by
* negative return values.
*/
STATIC ssize_t
xfs_file_dio_aio_write(
struct kiocb *iocb,
const struct iovec *iovp,
unsigned long nr_segs,
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;
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;

*iolock = 0;
if ((pos & target->bt_smask) || (count & target->bt_smask))
return -XFS_ERROR(EINVAL);

/*
* For direct I/O, if there are cached pages or we're extending
* the file, we need IOLOCK_EXCL until we're sure the bytes at
* the new EOF have been zeroed and/or the cached pages are
* flushed out.
*/
if (mapping->nrpages || pos > ip->i_size)
*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))
return ret;

if (mapping->nrpages) {
WARN_ON(*iolock != XFS_IOLOCK_EXCL);
ret = -xfs_flushinval_pages(ip, (pos & PAGE_CACHE_MASK), -1,
FI_REMAPF_LOCKED);
if (ret)
return ret;
}

if (*iolock == XFS_IOLOCK_EXCL) {
/* demote the lock now the cached pages are gone */
xfs_rw_ilock_demote(ip, XFS_IOLOCK_EXCL);
*iolock = XFS_IOLOCK_SHARED;
}

trace_xfs_file_direct_write(ip, count, iocb->ki_pos, 0);
ret = generic_file_direct_write(iocb, iovp,
&nr_segs, pos, &iocb->ki_pos, count, ocount);

/* No fallback to buffered IO on errors for XFS. */
ASSERT(ret < 0 || ret == count);
return ret;
}

STATIC ssize_t
xfs_file_aio_write(
struct kiocb *iocb,
Expand Down Expand Up @@ -670,12 +780,12 @@ xfs_file_aio_write(

relock:
if (ioflags & IO_ISDIRECT) {
iolock = XFS_IOLOCK_SHARED;
} else {
iolock = XFS_IOLOCK_EXCL;
ret = xfs_file_dio_aio_write(iocb, iovp, nr_segs, pos,
ocount, &iolock);
goto done_io;
}
iolock = XFS_IOLOCK_EXCL;

start:
xfs_rw_ilock(ip, XFS_ILOCK_EXCL|iolock);
ret = generic_write_checks(file, &pos, &count,
S_ISBLK(inode->i_mode));
Expand All @@ -684,30 +794,6 @@ xfs_file_aio_write(
return ret;
}

if (ioflags & IO_ISDIRECT) {
xfs_buftarg_t *target =
XFS_IS_REALTIME_INODE(ip) ?
mp->m_rtdev_targp : mp->m_ddev_targp;

if ((pos & target->bt_smask) || (count & target->bt_smask)) {
xfs_rw_iunlock(ip, XFS_ILOCK_EXCL|iolock);
return XFS_ERROR(-EINVAL);
}

/*
* For direct I/O, if there are cached pages or we're extending
* the file, we need IOLOCK_EXCL until we're sure the bytes at
* the new EOF have been zeroed and/or the cached pages are
* flushed out. Upgrade the I/O lock and start again.
*/
if (iolock != XFS_IOLOCK_EXCL &&
(mapping->nrpages || pos > ip->i_size)) {
xfs_rw_iunlock(ip, XFS_ILOCK_EXCL|iolock);
iolock = XFS_IOLOCK_EXCL;
goto start;
}
}

new_size = pos + count;
if (new_size > ip->i_size)
ip->i_new_size = new_size;
Expand Down Expand Up @@ -746,41 +832,7 @@ xfs_file_aio_write(
/* We can write back this queue in page reclaim */
current->backing_dev_info = mapping->backing_dev_info;

if ((ioflags & IO_ISDIRECT)) {
if (mapping->nrpages) {
WARN_ON(iolock != XFS_IOLOCK_EXCL);
ret = -xfs_flushinval_pages(ip,
(pos & PAGE_CACHE_MASK),
-1, FI_REMAPF_LOCKED);
if (ret)
goto out_unlock_internal;
}

if (iolock == XFS_IOLOCK_EXCL) {
/* demote the lock now the cached pages are gone */
xfs_rw_ilock_demote(ip, XFS_IOLOCK_EXCL);
iolock = XFS_IOLOCK_SHARED;
}

trace_xfs_file_direct_write(ip, count, iocb->ki_pos, ioflags);
ret = generic_file_direct_write(iocb, iovp,
&nr_segs, pos, &iocb->ki_pos, count, ocount);

/*
* direct-io write to a hole: fall through to buffered I/O
* for completing the rest of the request.
*/
if (ret >= 0 && ret != count) {
XFS_STATS_ADD(xs_write_bytes, ret);

pos += ret;
count -= ret;

ioflags &= ~IO_ISDIRECT;
xfs_rw_iunlock(ip, iolock);
goto relock;
}
} else {
if (!(ioflags & IO_ISDIRECT)) {
int enospc = 0;

write_retry:
Expand All @@ -802,6 +854,7 @@ xfs_file_aio_write(

current->backing_dev_info = NULL;

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

if (ret <= 0)
Expand Down

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