From 326c03555b914ff153ba5b40df87fd6e28e7e367 Mon Sep 17 00:00:00 2001 From: Dave Chinner Date: Fri, 5 Oct 2012 11:06:58 +1000 Subject: 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 Reviewed-by: Mark Tinguely Signed-off-by: Ben Myers --- fs/xfs/xfs_bmap.h | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) (limited to 'fs/xfs/xfs_bmap.h') diff --git a/fs/xfs/xfs_bmap.h b/fs/xfs/xfs_bmap.h index 803b56d7ce16..b68c598034c1 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; /* -- cgit v1.2.1