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: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Mark Tinguely <tinguely@sgi.com>
Signed-off-by: Ben Myers <bpm@sgi.com>

1 files changed, 0 insertions, 2 deletions

diff --git a/fs/xfs/xfs_buf.h b/fs/xfs/xfs_buf.h
index 512d9a6776a5..846dee3d8dac 100644
--- a/fs/xfs/xfs_buf.h
+++ b/fs/xfs/xfs_buf.h
@@ -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" }