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authorDave Chinner <dchinner@redhat.com>2012-10-05 11:06:58 +1000
committerBen Myers <bpm@sgi.com>2012-10-18 17:41:56 -0500
commit2455881c0b52f87be539c4c7deab1afff4d8a560 (patch)
treeef2ed6c1f0f10727c929838992d89d54bb821993 /fs/xfs
parenta00416844b8f4b0106344bdfd90fe45a854b1d05 (diff)
xfs: introduce XFS_BMAPI_STACK_SWITCH
Certain allocation paths through xfs_bmapi_write() are in situations where we have limited stack available. These are almost always in the buffered IO writeback path when convertion delayed allocation extents to real extents. The current stack switch occurs for userdata allocations, which means we also do stack switches for preallocation, direct IO and unwritten extent conversion, even those these call chains have never been implicated in a stack overrun. Hence, let's target just the single stack overun offended for stack switches. To do that, introduce a XFS_BMAPI_STACK_SWITCH flag that the caller can pass xfs_bmapi_write() to indicate it should switch stacks if it needs to do allocation. Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Mark Tinguely <tinguely@sgi.com> Signed-off-by: Ben Myers <bpm@sgi.com>
Diffstat (limited to 'fs/xfs')
-rw-r--r--fs/xfs/xfs_alloc.c2
-rw-r--r--fs/xfs/xfs_alloc.h1
-rw-r--r--fs/xfs/xfs_bmap.c4
-rw-r--r--fs/xfs/xfs_bmap.h5
-rw-r--r--fs/xfs/xfs_iomap.c4
5 files changed, 13 insertions, 3 deletions
diff --git a/fs/xfs/xfs_alloc.c b/fs/xfs/xfs_alloc.c
index 0287f3b1b50..43f791bcd8b 100644
--- a/fs/xfs/xfs_alloc.c
+++ b/fs/xfs/xfs_alloc.c
@@ -2447,7 +2447,7 @@ xfs_alloc_vextent(
{
DECLARE_COMPLETION_ONSTACK(done);
- if (!args->userdata)
+ if (!args->stack_switch)
return __xfs_alloc_vextent(args);
diff --git a/fs/xfs/xfs_alloc.h b/fs/xfs/xfs_alloc.h
index 93be4a667ca..ef7d4885dc2 100644
--- a/fs/xfs/xfs_alloc.h
+++ b/fs/xfs/xfs_alloc.h
@@ -123,6 +123,7 @@ typedef struct xfs_alloc_arg {
struct completion *done;
struct work_struct work;
int result;
+ char stack_switch;
} xfs_alloc_arg_t;
/*
diff --git a/fs/xfs/xfs_bmap.c b/fs/xfs/xfs_bmap.c
index e1545ec2f7d..91259554df8 100644
--- a/fs/xfs/xfs_bmap.c
+++ b/fs/xfs/xfs_bmap.c
@@ -2441,6 +2441,7 @@ xfs_bmap_btalloc(
args.tp = ap->tp;
args.mp = mp;
args.fsbno = ap->blkno;
+ args.stack_switch = ap->stack_switch;
/* Trim the allocation back to the maximum an AG can fit. */
args.maxlen = MIN(ap->length, XFS_ALLOC_AG_MAX_USABLE(mp));
@@ -4675,6 +4676,9 @@ xfs_bmapi_allocate(
return error;
}
+ if (flags & XFS_BMAPI_STACK_SWITCH)
+ bma->stack_switch = 1;
+
error = xfs_bmap_alloc(bma);
if (error)
return error;
diff --git a/fs/xfs/xfs_bmap.h b/fs/xfs/xfs_bmap.h
index 803b56d7ce1..b68c598034c 100644
--- a/fs/xfs/xfs_bmap.h
+++ b/fs/xfs/xfs_bmap.h
@@ -77,6 +77,7 @@ typedef struct xfs_bmap_free
* from written to unwritten, otherwise convert from unwritten to written.
*/
#define XFS_BMAPI_CONVERT 0x040
+#define XFS_BMAPI_STACK_SWITCH 0x080
#define XFS_BMAPI_FLAGS \
{ XFS_BMAPI_ENTIRE, "ENTIRE" }, \
@@ -85,7 +86,8 @@ typedef struct xfs_bmap_free
{ XFS_BMAPI_PREALLOC, "PREALLOC" }, \
{ XFS_BMAPI_IGSTATE, "IGSTATE" }, \
{ XFS_BMAPI_CONTIG, "CONTIG" }, \
- { XFS_BMAPI_CONVERT, "CONVERT" }
+ { XFS_BMAPI_CONVERT, "CONVERT" }, \
+ { XFS_BMAPI_STACK_SWITCH, "STACK_SWITCH" }
static inline int xfs_bmapi_aflag(int w)
@@ -133,6 +135,7 @@ typedef struct xfs_bmalloca {
char userdata;/* set if is user data */
char aeof; /* allocated space at eof */
char conv; /* overwriting unwritten extents */
+ char stack_switch;
} xfs_bmalloca_t;
/*
diff --git a/fs/xfs/xfs_iomap.c b/fs/xfs/xfs_iomap.c
index f858b903678..a066cf1766a 100644
--- a/fs/xfs/xfs_iomap.c
+++ b/fs/xfs/xfs_iomap.c
@@ -575,7 +575,9 @@ xfs_iomap_write_allocate(
* pointer that the caller gave to us.
*/
error = xfs_bmapi_write(tp, ip, map_start_fsb,
- count_fsb, 0, &first_block, 1,
+ count_fsb,
+ XFS_BMAPI_STACK_SWITCH,
+ &first_block, 1,
imap, &nimaps, &free_list);
if (error)
goto trans_cancel;