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Message-Id: <20190627104836.25446-7-hch@lst.de>
Date: Thu, 27 Jun 2019 12:48:29 +0200
From: Christoph Hellwig <hch@....de>
To: "Darrick J . Wong" <darrick.wong@...cle.com>
Cc: Damien Le Moal <Damien.LeMoal@....com>,
Andreas Gruenbacher <agruenba@...hat.com>,
linux-xfs@...r.kernel.org, linux-fsdevel@...r.kernel.org,
linux-kernel@...r.kernel.org
Subject: [PATCH 06/13] xfs: remove XFS_TRANS_NOFS
Instead of a magic flag for xfs_trans_alloc, just ensure all callers
that can't relclaim through the file system use memalloc_nofs_save to
set the per-task nofs flag.
Signed-off-by: Christoph Hellwig <hch@....de>
---
fs/xfs/libxfs/xfs_shared.h | 1 -
fs/xfs/xfs_aops.c | 35 ++++++++++++++++++++++-------------
fs/xfs/xfs_file.c | 12 +++++++++---
fs/xfs/xfs_iomap.c | 2 +-
fs/xfs/xfs_reflink.c | 4 ++--
fs/xfs/xfs_trans.c | 4 +---
6 files changed, 35 insertions(+), 23 deletions(-)
diff --git a/fs/xfs/libxfs/xfs_shared.h b/fs/xfs/libxfs/xfs_shared.h
index b9094709bc79..c45acbd3add9 100644
--- a/fs/xfs/libxfs/xfs_shared.h
+++ b/fs/xfs/libxfs/xfs_shared.h
@@ -65,7 +65,6 @@ void xfs_log_get_max_trans_res(struct xfs_mount *mp,
#define XFS_TRANS_DQ_DIRTY 0x10 /* at least one dquot in trx dirty */
#define XFS_TRANS_RESERVE 0x20 /* OK to use reserved data blocks */
#define XFS_TRANS_NO_WRITECOUNT 0x40 /* do not elevate SB writecount */
-#define XFS_TRANS_NOFS 0x80 /* pass KM_NOFS to kmem_alloc */
/*
* LOWMODE is used by the allocator to activate the lowspace algorithm - when
* free space is running low the extent allocator may choose to allocate an
diff --git a/fs/xfs/xfs_aops.c b/fs/xfs/xfs_aops.c
index 243548b9d0cc..8b3070a40245 100644
--- a/fs/xfs/xfs_aops.c
+++ b/fs/xfs/xfs_aops.c
@@ -138,8 +138,7 @@ xfs_setfilesize_trans_alloc(
struct xfs_trans *tp;
int error;
- error = xfs_trans_alloc(mp, &M_RES(mp)->tr_fsyncts, 0, 0,
- XFS_TRANS_NOFS, &tp);
+ error = xfs_trans_alloc(mp, &M_RES(mp)->tr_fsyncts, 0, 0, 0, &tp);
if (error)
return error;
@@ -240,8 +239,16 @@ xfs_end_ioend(
struct xfs_inode *ip = XFS_I(ioend->io_inode);
xfs_off_t offset = ioend->io_offset;
size_t size = ioend->io_size;
+ unsigned int nofs_flag;
int error;
+ /*
+ * We can do memory allocation here, but aren't in transactional
+ * context. To avoid memory allocation deadlocks set the task-wide
+ * nofs context for the following operations.
+ */
+ nofs_flag = memalloc_nofs_save();
+
/*
* Just clean up the in-memory strutures if the fs has been shut down.
*/
@@ -282,6 +289,8 @@ xfs_end_ioend(
list_del_init(&ioend->io_list);
xfs_destroy_ioend(ioend, error);
}
+
+ memalloc_nofs_restore(nofs_flag);
}
/*
@@ -641,21 +650,19 @@ xfs_submit_ioend(
struct xfs_ioend *ioend,
int status)
{
+ unsigned int nofs_flag;
+
+ /*
+ * We can do memory allocation here, but aren't in transactional
+ * context. To avoid memory allocation deadlocks set the task-wide
+ * nofs context for the following operations.
+ */
+ nofs_flag = memalloc_nofs_save();
+
/* Convert CoW extents to regular */
if (!status && ioend->io_fork == XFS_COW_FORK) {
- /*
- * Yuk. This can do memory allocation, but is not a
- * transactional operation so everything is done in GFP_KERNEL
- * context. That can deadlock, because we hold pages in
- * writeback state and GFP_KERNEL allocations can block on them.
- * Hence we must operate in nofs conditions here.
- */
- unsigned nofs_flag;
-
- nofs_flag = memalloc_nofs_save();
status = xfs_reflink_convert_cow(XFS_I(ioend->io_inode),
ioend->io_offset, ioend->io_size);
- memalloc_nofs_restore(nofs_flag);
}
/* Reserve log space if we might write beyond the on-disk inode size. */
@@ -666,6 +673,8 @@ xfs_submit_ioend(
!ioend->io_append_trans)
status = xfs_setfilesize_trans_alloc(ioend);
+ memalloc_nofs_restore(nofs_flag);
+
ioend->io_bio->bi_private = ioend;
ioend->io_bio->bi_end_io = xfs_end_bio;
diff --git a/fs/xfs/xfs_file.c b/fs/xfs/xfs_file.c
index 916a35cae5e9..f2d806ef8f06 100644
--- a/fs/xfs/xfs_file.c
+++ b/fs/xfs/xfs_file.c
@@ -379,6 +379,7 @@ xfs_dio_write_end_io(
struct inode *inode = file_inode(iocb->ki_filp);
struct xfs_inode *ip = XFS_I(inode);
loff_t offset = iocb->ki_pos;
+ unsigned int nofs_flag;
int error = 0;
trace_xfs_end_io_direct_write(ip, offset, size);
@@ -395,10 +396,11 @@ xfs_dio_write_end_io(
*/
XFS_STATS_ADD(ip->i_mount, xs_write_bytes, size);
+ nofs_flag = memalloc_nofs_save();
if (flags & IOMAP_DIO_COW) {
error = xfs_reflink_end_cow(ip, offset, size);
if (error)
- return error;
+ goto out;
}
/*
@@ -407,8 +409,10 @@ xfs_dio_write_end_io(
* earlier allows a racing dio read to find unwritten extents before
* they are converted.
*/
- if (flags & IOMAP_DIO_UNWRITTEN)
- return xfs_iomap_write_unwritten(ip, offset, size, true);
+ if (flags & IOMAP_DIO_UNWRITTEN) {
+ error = xfs_iomap_write_unwritten(ip, offset, size, true);
+ goto out;
+ }
/*
* We need to update the in-core inode size here so that we don't end up
@@ -430,6 +434,8 @@ xfs_dio_write_end_io(
spin_unlock(&ip->i_flags_lock);
}
+out:
+ memalloc_nofs_restore(nofs_flag);
return error;
}
diff --git a/fs/xfs/xfs_iomap.c b/fs/xfs/xfs_iomap.c
index 6b29452bfba0..461ea023b910 100644
--- a/fs/xfs/xfs_iomap.c
+++ b/fs/xfs/xfs_iomap.c
@@ -782,7 +782,7 @@ xfs_iomap_write_unwritten(
* complete here and might deadlock on the iolock.
*/
error = xfs_trans_alloc(mp, &M_RES(mp)->tr_write, resblks, 0,
- XFS_TRANS_RESERVE | XFS_TRANS_NOFS, &tp);
+ XFS_TRANS_RESERVE, &tp);
if (error)
return error;
diff --git a/fs/xfs/xfs_reflink.c b/fs/xfs/xfs_reflink.c
index 680ae7662a78..0b23c2b29609 100644
--- a/fs/xfs/xfs_reflink.c
+++ b/fs/xfs/xfs_reflink.c
@@ -572,7 +572,7 @@ xfs_reflink_cancel_cow_range(
/* Start a rolling transaction to remove the mappings */
error = xfs_trans_alloc(ip->i_mount, &M_RES(ip->i_mount)->tr_write,
- 0, 0, XFS_TRANS_NOFS, &tp);
+ 0, 0, 0, &tp);
if (error)
goto out;
@@ -631,7 +631,7 @@ xfs_reflink_end_cow_extent(
resblks = XFS_EXTENTADD_SPACE_RES(mp, XFS_DATA_FORK);
error = xfs_trans_alloc(mp, &M_RES(mp)->tr_write, resblks, 0,
- XFS_TRANS_RESERVE | XFS_TRANS_NOFS, &tp);
+ XFS_TRANS_RESERVE, &tp);
if (error)
return error;
diff --git a/fs/xfs/xfs_trans.c b/fs/xfs/xfs_trans.c
index b026f87608ce..2ad3faa12206 100644
--- a/fs/xfs/xfs_trans.c
+++ b/fs/xfs/xfs_trans.c
@@ -264,9 +264,7 @@ xfs_trans_alloc(
* GFP_NOFS allocation context so that we avoid lockdep false positives
* by doing GFP_KERNEL allocations inside sb_start_intwrite().
*/
- tp = kmem_zone_zalloc(xfs_trans_zone,
- (flags & XFS_TRANS_NOFS) ? KM_NOFS : KM_SLEEP);
-
+ tp = kmem_zone_zalloc(xfs_trans_zone, KM_SLEEP);
if (!(flags & XFS_TRANS_NO_WRITECOUNT))
sb_start_intwrite(mp->m_super);
--
2.20.1
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