diff options
Diffstat (limited to 'fs/xfs/xfs_filestream.h')
| -rw-r--r-- | fs/xfs/xfs_filestream.h | 62 |
1 files changed, 0 insertions, 62 deletions
diff --git a/fs/xfs/xfs_filestream.h b/fs/xfs/xfs_filestream.h index 4aba67c5f64..09dd9af4543 100644 --- a/fs/xfs/xfs_filestream.h +++ b/fs/xfs/xfs_filestream.h @@ -42,67 +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. - */ -static inline int -xfs_filestream_peek_ag( - xfs_mount_t *mp, - xfs_agnumber_t agno) -{ - return atomic_read(&mp->m_perag[agno].pagf_fstrms); -} - -static inline int -xfs_filestream_get_ag( - xfs_mount_t *mp, - xfs_agnumber_t agno) -{ - return atomic_inc_return(&mp->m_perag[agno].pagf_fstrms); -} - -static inline int -xfs_filestream_put_ag( - xfs_mount_t *mp, - xfs_agnumber_t agno) -{ - return atomic_dec_return(&mp->m_perag[agno].pagf_fstrms); -} - /* allocation selection flags */ typedef enum xfs_fstrm_alloc { XFS_PICK_USERDATA = 1, @@ -114,7 +53,6 @@ int xfs_filestream_init(void); void xfs_filestream_uninit(void); int xfs_filestream_mount(struct xfs_mount *mp); void xfs_filestream_unmount(struct xfs_mount *mp); -void xfs_filestream_flush(struct xfs_mount *mp); xfs_agnumber_t xfs_filestream_lookup_ag(struct xfs_inode *ip); int xfs_filestream_associate(struct xfs_inode *dip, struct xfs_inode *ip); void xfs_filestream_deassociate(struct xfs_inode *ip); |