On 2018年07月06日 11:47, Darrick J. Wong wrote:
On Fri, Jul 06, 2018 at 11:12:24AM +0800, Shan Hai wrote:
Introduce a function to convert an inode from extents to local
format. The conversion happens at writeback time, this avoids
interfering with the delayed allocation and page cache vs
xfs_buf operations, the will be inlined data is directly got
from the page which was read and modified by the iomap write actor.
Signed-off-by: Shan Hai <shan.hai@xxxxxxxxxx>
---
fs/xfs/xfs_aops.c | 60 +++++++++++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 60 insertions(+)
diff --git a/fs/xfs/xfs_aops.c b/fs/xfs/xfs_aops.c
index 8eb3ba3d4d00..ac5a7695f363 100644
--- a/fs/xfs/xfs_aops.c
+++ b/fs/xfs/xfs_aops.c
@@ -9,6 +9,7 @@
#include "xfs_log_format.h"
#include "xfs_trans_resv.h"
#include "xfs_mount.h"
+#include "xfs_defer.h"
#include "xfs_inode.h"
#include "xfs_trans.h"
#include "xfs_inode_item.h"
@@ -887,6 +888,55 @@ xfs_map_cow(
return 0;
}
+static int
+xfs_inode_extents_to_local(
+ xfs_inode_t *ip,
+ int whichfork,
+ struct page *page)
+{
+ struct xfs_mount *mp = ip->i_mount;
+ struct xfs_trans *tp;
+ struct xfs_defer_ops dfops;
+ xfs_fsblock_t first_block;
+ int logflags;
+ int error = 0;
+
+ if (i_size_read(VFS_I(ip)) > XFS_IFORK_DSIZE(ip))
+ return 0;
If it's too big to fit in local format, then isn't this an error?
No, it's not, because the written data travels to writeback means that
the inode is
still in extents format since the higher level write_iter ends the write
process by
copying the data to the data fork when the inode is in local format, it
never let the
local format inode to go down the writeback path.
The xfs_writepage_map will continue as if nothing happens when
xfs_inode_extents_to_local
returns 0.
Thanks
Shan Hai
--D
+ error = xfs_trans_alloc(mp, &M_RES(mp)->tr_itruncate, 0, 0, 0, &tp);
+ if (error)
+ return error;
+
+ xfs_ilock(ip, XFS_ILOCK_EXCL);
+ xfs_trans_ijoin(tp, ip, 0);
+
+ xfs_defer_init(&dfops, &first_block);
+
+ logflags = 0;
+ error = xfs_bmap_extents_to_local(tp, ip, &dfops, &logflags,
+ XFS_DATA_FORK, page);
+ if (error)
+ goto trans_cancel;
+
+ xfs_trans_log_inode(tp, ip, logflags);
+ error = xfs_defer_finish(&tp, &dfops);
+ if (error)
+ goto trans_cancel;
+ error = xfs_trans_commit(tp);
+ if (error)
+ goto error0;
+ xfs_iunlock(ip, XFS_ILOCK_EXCL);
+
+ return 0;
+
+trans_cancel:
+ xfs_defer_cancel(&dfops);
+ xfs_trans_cancel(tp);
+error0:
+ xfs_iunlock(ip, XFS_ILOCK_EXCL);
+ return error;
+}
/*
* We implement an immediate ioend submission policy here to avoid needing to
* chain multiple ioends and hence nest mempool allocations which can violate
@@ -920,6 +970,8 @@ xfs_writepage_map(
int count = 0;
int uptodate = 1;
unsigned int new_type;
+ xfs_inode_t *ip = XFS_I(inode);
+ struct xfs_mount *mp = ip->i_mount;
bh = head = page_buffers(page);
offset = page_offset(page);
@@ -1044,6 +1096,14 @@ xfs_writepage_map(
end_page_writeback(page);
}
+ if (!error) {
+ if (xfs_sb_version_hasinlinedata(&mp->m_sb) &&
+ i_size_read(inode) <= XFS_IFORK_DSIZE(ip)) {
+ error = xfs_inode_extents_to_local(ip, XFS_DATA_FORK,
+ page);
+ }
+ }
+
mapping_set_error(page->mapping, error);
return error;
}
--
2.11.0
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