[PATCH v2] xfs: improve handling of prjquot ENOSPC

[Jian Wen <wenjianhn@gmail.com>]

Don't clear space of the whole fs when the project quota limit is
reached, since it affects the writing performance of files of
the directories that are under quota.

Changes since v1:
- use the want_blockgc_free_quota helper that written by Darrick

Signed-off-by: Jian Wen <wenjian1@xiaomi.com>
---
 fs/xfs/xfs_file.c | 19 ++++++++++++++++++-
 1 file changed, 18 insertions(+), 1 deletion(-)

diff --git a/fs/xfs/xfs_file.c b/fs/xfs/xfs_file.c
index e33e5e13b95f..7764697e7822 100644
--- a/fs/xfs/xfs_file.c
+++ b/fs/xfs/xfs_file.c
@@ -24,6 +24,9 @@
 #include "xfs_pnfs.h"
 #include "xfs_iomap.h"
 #include "xfs_reflink.h"
+#include "xfs_quota.h"
+#include "xfs_dquot_item.h"
+#include "xfs_dquot.h"
 
 #include <linux/dax.h>
 #include <linux/falloc.h>
@@ -761,6 +764,20 @@ xfs_file_dax_write(
 	return ret;
 }
 
+static inline bool want_blockgc_free_quota(struct xfs_inode *ip, int ret)
+{
+	if (ret == -EDQUOT)
+		return true;
+	if (ret != -ENOSPC)
+		return false;
+
+	if (XFS_IS_PQUOTA_ENFORCED(ip->i_mount) &&
+	    ip->i_pdquot && xfs_dquot_lowsp(ip->i_pdquot))
+		return true;
+
+	return false;
+}
+
 STATIC ssize_t
 xfs_file_buffered_write(
 	struct kiocb		*iocb,
@@ -796,7 +813,7 @@ xfs_file_buffered_write(
 	 * running at the same time.  Use a synchronous scan to increase the
 	 * effectiveness of the scan.
 	 */
-	if (ret == -EDQUOT && !cleared_space) {
+	if (want_blockgc_free_quota(ip, ret) && !cleared_space) {
 		xfs_iunlock(ip, iolock);
 		xfs_blockgc_free_quota(ip, XFS_ICWALK_FLAG_SYNC);
 		cleared_space = true;
-- 
2.34.1