/* flags used only internally */
_XBF_PAGE_CACHE = (1 << 17),/* backed by pagecache */
- _XBF_KMEM_ALLOC = (1 << 18),/* backed by kmem_alloc() */
+ _XBF_PAGES = (1 << 18), /* backed by refcounted pages */
_XBF_RUN_QUEUES = (1 << 19),/* run block device task queue */
_XBF_DELWRI_Q = (1 << 21), /* buffer on delwri queue */
+
+ /*
+ * Special flag for supporting metadata blocks smaller than a FSB.
+ *
+ * In this case we can have multiple xfs_buf_t on a single page and
+ * need to lock out concurrent xfs_buf_t readers as they only
+ * serialise access to the buffer.
+ *
+ * If the FSB size >= PAGE_CACHE_SIZE case, we have no serialisation
+ * between reads of the page. Hence we can have one thread read the
+ * page and modify it, but then race with another thread that thinks
+ * the page is not up-to-date and hence reads it again.
+ *
+ * The result is that the first modifcation to the page is lost.
+ * This sort of AGF/AGI reading race can happen when unlinking inodes
+ * that require truncation and results in the AGI unlinked list
+ * modifications being lost.
+ */
+ _XBF_PAGE_LOCKED = (1 << 22),
} xfs_buf_flags_t;
typedef enum {
- XBT_FORCE_SLEEP = (0 << 1),
- XBT_FORCE_FLUSH = (1 << 1),
+ XBT_FORCE_SLEEP = 0,
+ XBT_FORCE_FLUSH = 1,
} xfs_buftarg_flags_t;
typedef struct xfs_bufhash {
void *b_fspriv2;
void *b_fspriv3;
unsigned short b_error; /* error code on I/O */
- unsigned short b_locked; /* page array is locked */
unsigned int b_page_count; /* size of page array */
unsigned int b_offset; /* page offset in first page */
struct page **b_pages; /* array of page pointers */
return error;
}
-static inline int xfs_bdwrite(void *mp, xfs_buf_t *bp)
+/*
+ * No error can be returned from xfs_buf_iostart for delwri
+ * buffers as they are queued and no I/O is issued.
+ */
+static inline void xfs_bdwrite(void *mp, xfs_buf_t *bp)
{
bp->b_strat = xfs_bdstrat_cb;
bp->b_fspriv3 = mp;
- return xfs_buf_iostart(bp, XBF_DELWRI | XBF_ASYNC);
+ (void)xfs_buf_iostart(bp, XBF_DELWRI | XBF_ASYNC);
}
#define XFS_bdstrat(bp) xfs_buf_iorequest(bp)
extern void xfs_wait_buftarg(xfs_buftarg_t *);
extern int xfs_setsize_buftarg(xfs_buftarg_t *, unsigned int, unsigned int);
extern int xfs_flush_buftarg(xfs_buftarg_t *, int);
+#ifdef CONFIG_KDB_MODULES
+extern struct list_head *xfs_get_buftarg_list(void);
+#endif
#define xfs_getsize_buftarg(buftarg) block_size((buftarg)->bt_bdev)
#define xfs_readonly_buftarg(buftarg) bdev_read_only((buftarg)->bt_bdev)