Commit aa5c158e authored by Dave Chinner's avatar Dave Chinner Committed by Ben Myers
Browse files

xfs: kill XBF_DONTBLOCK 



Just about all callers of xfs_buf_read() and xfs_buf_get() use XBF_DONTBLOCK.
This is used to make memory allocation use GFP_NOFS rather than GFP_KERNEL to
avoid recursion through memory reclaim back into the filesystem.

All the blocking get calls in growfs occur inside a transaction, even though
they are no part of the transaction, so all allocation will be GFP_NOFS due to
the task flag PF_TRANS being set. The blocking read calls occur during log
recovery, so they will probably be unaffected by converting to GFP_NOFS
allocations.

Hence make XBF_DONTBLOCK behaviour always occur for buffers and kill the flag.

Signed-off-by: default avatarDave Chinner <dchinner@redhat.com>
Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
Reviewed-by: default avatarMark Tinguely <tinguely@sgi.com>
Signed-off-by: default avatarBen Myers <bpm@sgi.com>
parent 7ca790a5

fs/xfs/xfs_attr.c

+1 −2
Original line number Diff line number Diff line
@@ -2114,8 +2114,7 @@ xfs_attr_rmtval_set(xfs_da_args_t *args) 
		dblkno = XFS_FSB_TO_DADDR(mp, map.br_startblock),

		blkcnt = XFS_FSB_TO_BB(mp, map.br_blockcount);



		bp = xfs_buf_get(mp->m_ddev_targp, dblkno, blkcnt,

				 XBF_DONT_BLOCK);

		bp = xfs_buf_get(mp->m_ddev_targp, dblkno, blkcnt, 0);

		if (!bp)

			return ENOMEM;

fs/xfs/xfs_buf.c

+7 −11
Original line number Diff line number Diff line
@@ -56,11 +56,7 @@ static struct workqueue_struct *xfslogd_workqueue; 
#endif



#define xb_to_gfp(flags) \

	((((flags) & XBF_READ_AHEAD) ? __GFP_NORETRY : \

	  ((flags) & XBF_DONT_BLOCK) ? GFP_NOFS : GFP_KERNEL) | __GFP_NOWARN)



#define xb_to_km(flags) \

	 (((flags) & XBF_DONT_BLOCK) ? KM_NOFS : KM_SLEEP)

	((((flags) & XBF_READ_AHEAD) ? __GFP_NORETRY : GFP_NOFS) | __GFP_NOWARN)





static inline int
@@ -178,14 +174,14 @@ xfs_buf_alloc( 
{

	struct xfs_buf		*bp;



	bp = kmem_zone_zalloc(xfs_buf_zone, xb_to_km(flags));

	bp = kmem_zone_zalloc(xfs_buf_zone, KM_NOFS);

	if (unlikely(!bp))

		return NULL;



	/*

	 * We don't want certain flags to appear in b_flags.

	 */

	flags &= ~(XBF_MAPPED|XBF_DONT_BLOCK|XBF_READ_AHEAD);

	flags &= ~(XBF_MAPPED|XBF_READ_AHEAD);



	atomic_set(&bp->b_hold, 1);

	atomic_set(&bp->b_lru_ref, 1);
@@ -239,7 +235,7 @@ _xfs_buf_get_pages( 
			bp->b_pages = bp->b_page_array;

		} else {

			bp->b_pages = kmem_alloc(sizeof(struct page *) *

					page_count, xb_to_km(flags));

						 page_count, KM_NOFS);

			if (bp->b_pages == NULL)

				return -ENOMEM;

		}
@@ -316,7 +312,7 @@ xfs_buf_allocate_memory( 
	 */

	size = BBTOB(bp->b_length);

	if (size < PAGE_SIZE) {

		bp->b_addr = kmem_alloc(size, xb_to_km(flags));

		bp->b_addr = kmem_alloc(size, KM_NOFS);

		if (!bp->b_addr) {

			/* low memory - use alloc_page loop instead */

			goto use_alloc_page;
@@ -659,7 +655,7 @@ xfs_buf_readahead( 
		return;



	xfs_buf_read(target, blkno, numblks,

		     XBF_TRYLOCK|XBF_ASYNC|XBF_READ_AHEAD|XBF_DONT_BLOCK);

		     XBF_TRYLOCK|XBF_ASYNC|XBF_READ_AHEAD);

}



/*
@@ -750,7 +746,7 @@ xfs_buf_associate_memory( 
	bp->b_pages = NULL;

	bp->b_addr = mem;



	rval = _xfs_buf_get_pages(bp, page_count, XBF_DONT_BLOCK);

	rval = _xfs_buf_get_pages(bp, page_count, 0);

	if (rval)

		return rval;

fs/xfs/xfs_buf.h

+0 −2
Original line number Diff line number Diff line
@@ -53,7 +53,6 @@ typedef enum { 


/* flags used only as arguments to access routines */

#define XBF_TRYLOCK	(1 << 16)/* lock requested, but do not wait */

#define XBF_DONT_BLOCK	(1 << 17)/* do not block in current thread */



/* flags used only internally */

#define _XBF_PAGES	(1 << 20)/* backed by refcounted pages */
@@ -74,7 +73,6 @@ typedef unsigned int xfs_buf_flags_t; 
	{ XBF_FUA,		"FUA" }, \

	{ XBF_FLUSH,		"FLUSH" }, \

	{ XBF_TRYLOCK,		"TRYLOCK" }, 	/* should never be set */\

	{ XBF_DONT_BLOCK,	"DONT_BLOCK" },	/* ditto */\

	{ _XBF_PAGES,		"PAGES" }, \

	{ _XBF_KMEM,		"KMEM" }, \

	{ _XBF_DELWRI_Q,	"DELWRI_Q" }

fs/xfs/xfs_trans_buf.c

+4 −21
Original line number Diff line number Diff line
@@ -148,8 +148,7 @@ xfs_trans_get_buf(xfs_trans_t *tp, 
	 * Default to a normal get_buf() call if the tp is NULL.

	 */

	if (tp == NULL)

		return xfs_buf_get(target_dev, blkno, len,

				   flags | XBF_DONT_BLOCK);

		return xfs_buf_get(target_dev, blkno, len, flags);



	/*

	 * If we find the buffer in the cache with this transaction
@@ -174,15 +173,7 @@ xfs_trans_get_buf(xfs_trans_t *tp, 
		return (bp);

	}



	/*

	 * We always specify the XBF_DONT_BLOCK flag within a transaction

	 * so that get_buf does not try to push out a delayed write buffer

	 * which might cause another transaction to take place (if the

	 * buffer was delayed alloc).  Such recursive transactions can

	 * easily deadlock with our current transaction as well as cause

	 * us to run out of stack space.

	 */

	bp = xfs_buf_get(target_dev, blkno, len, flags | XBF_DONT_BLOCK);

	bp = xfs_buf_get(target_dev, blkno, len, flags);

	if (bp == NULL) {

		return NULL;

	}
@@ -283,7 +274,7 @@ xfs_trans_read_buf( 
	 * Default to a normal get_buf() call if the tp is NULL.

	 */

	if (tp == NULL) {

		bp = xfs_buf_read(target, blkno, len, flags | XBF_DONT_BLOCK);

		bp = xfs_buf_read(target, blkno, len, flags);

		if (!bp)

			return (flags & XBF_TRYLOCK) ?

					EAGAIN : XFS_ERROR(ENOMEM);
@@ -367,15 +358,7 @@ xfs_trans_read_buf( 
		return 0;

	}



	/*

	 * We always specify the XBF_DONT_BLOCK flag within a transaction

	 * so that get_buf does not try to push out a delayed write buffer

	 * which might cause another transaction to take place (if the

	 * buffer was delayed alloc).  Such recursive transactions can

	 * easily deadlock with our current transaction as well as cause

	 * us to run out of stack space.

	 */

	bp = xfs_buf_read(target, blkno, len, flags | XBF_DONT_BLOCK);

	bp = xfs_buf_read(target, blkno, len, flags);

	if (bp == NULL) {

		*bpp = NULL;

		return (flags & XBF_TRYLOCK) ?

fs/xfs/xfs_vnodeops.c

+2 −2
Original line number Diff line number Diff line
@@ -82,7 +82,7 @@ xfs_readlink_bmap( 
		byte_cnt = XFS_FSB_TO_B(mp, mval[n].br_blockcount);



		bp = xfs_buf_read(mp->m_ddev_targp, d, BTOBB(byte_cnt),

				  XBF_MAPPED | XBF_DONT_BLOCK);

				  XBF_MAPPED);

		if (!bp)

			return XFS_ERROR(ENOMEM);

		error = bp->b_error;
@@ -1966,7 +1966,7 @@ xfs_zero_remaining_bytes( 


	bp = xfs_buf_get_uncached(XFS_IS_REALTIME_INODE(ip) ?

					mp->m_rtdev_targp : mp->m_ddev_targp,

				BTOBB(mp->m_sb.sb_blocksize), XBF_DONT_BLOCK);

				  BTOBB(mp->m_sb.sb_blocksize), 0);

	if (!bp)

		return XFS_ERROR(ENOMEM);

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