From 0664ce8d0fde731d76fa7e86b3afb54f3a6830ff Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Tue, 20 Jul 2010 17:31:01 +1000 Subject: xfs: clean up filestreams helpers Move xfs_filestream_peek_ag, xxfs_filestream_get_ag and xfs_filestream_put_ag from xfs_filestream.h to xfs_filestream.c where it's only callers are, and remove the inline marker while we're at it to let the compiler decide on the inlining. Also don't return a value from xfs_filestream_put_ag because we don't need it. Signed-off-by: Christoph Hellwig Reviewed-by: Dave Chinner Signed-off-by: Dave Chinner --- fs/xfs/xfs_filestream.h | 82 ------------------------------------------------- 1 file changed, 82 deletions(-) (limited to 'fs/xfs/xfs_filestream.h') diff --git a/fs/xfs/xfs_filestream.h b/fs/xfs/xfs_filestream.h index 260f757bbc5d..09dd9af45434 100644 --- a/fs/xfs/xfs_filestream.h +++ b/fs/xfs/xfs_filestream.h @@ -42,88 +42,6 @@ extern ktrace_t *xfs_filestreams_trace_buf; #endif -/* - * Allocation group filestream associations are tracked with per-ag atomic - * counters. These counters allow _xfs_filestream_pick_ag() to tell whether a - * particular AG already has active filestreams associated with it. The mount - * point's m_peraglock is used to protect these counters from per-ag array - * re-allocation during a growfs operation. When xfs_growfs_data_private() is - * about to reallocate the array, it calls xfs_filestream_flush() with the - * m_peraglock held in write mode. - * - * Since xfs_mru_cache_flush() guarantees that all the free functions for all - * the cache elements have finished executing before it returns, it's safe for - * the free functions to use the atomic counters without m_peraglock protection. - * This allows the implementation of xfs_fstrm_free_func() to be agnostic about - * whether it was called with the m_peraglock held in read mode, write mode or - * not held at all. The race condition this addresses is the following: - * - * - The work queue scheduler fires and pulls a filestream directory cache - * element off the LRU end of the cache for deletion, then gets pre-empted. - * - A growfs operation grabs the m_peraglock in write mode, flushes all the - * remaining items from the cache and reallocates the mount point's per-ag - * array, resetting all the counters to zero. - * - The work queue thread resumes and calls the free function for the element - * it started cleaning up earlier. In the process it decrements the - * filestreams counter for an AG that now has no references. - * - * With a shrinkfs feature, the above scenario could panic the system. - * - * All other uses of the following macros should be protected by either the - * m_peraglock held in read mode, or the cache's internal locking exposed by the - * interval between a call to xfs_mru_cache_lookup() and a call to - * xfs_mru_cache_done(). In addition, the m_peraglock must be held in read mode - * when new elements are added to the cache. - * - * Combined, these locking rules ensure that no associations will ever exist in - * the cache that reference per-ag array elements that have since been - * reallocated. - */ -/* - * xfs_filestream_peek_ag is only used in tracing code - */ -static inline int -xfs_filestream_peek_ag( - xfs_mount_t *mp, - xfs_agnumber_t agno) -{ - struct xfs_perag *pag; - int ret; - - pag = xfs_perag_get(mp, agno); - ret = atomic_read(&pag->pagf_fstrms); - xfs_perag_put(pag); - return ret; -} - -static inline int -xfs_filestream_get_ag( - xfs_mount_t *mp, - xfs_agnumber_t agno) -{ - struct xfs_perag *pag; - int ret; - - pag = xfs_perag_get(mp, agno); - ret = atomic_inc_return(&pag->pagf_fstrms); - xfs_perag_put(pag); - return ret; -} - -static inline int -xfs_filestream_put_ag( - xfs_mount_t *mp, - xfs_agnumber_t agno) -{ - struct xfs_perag *pag; - int ret; - - pag = xfs_perag_get(mp, agno); - ret = atomic_dec_return(&pag->pagf_fstrms); - xfs_perag_put(pag); - return ret; -} - /* allocation selection flags */ typedef enum xfs_fstrm_alloc { XFS_PICK_USERDATA = 1, -- cgit v1.2.3