add new system file

hc

2024-02-20 102a0743326a03cd1a1202ceda21e175b7d3575c

 kernel/fs/xfs/xfs_filestream.c
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@@ -5,22 +5,20 @@
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  * All Rights Reserved.
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  */
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 #include "xfs.h"
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+#include "xfs_shared.h"
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 #include "xfs_format.h"
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 #include "xfs_log_format.h"
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 #include "xfs_trans_resv.h"
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 #include "xfs_sb.h"
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 #include "xfs_mount.h"
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-#include "xfs_defer.h"
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 #include "xfs_inode.h"
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 #include "xfs_bmap.h"
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-#include "xfs_bmap_util.h"
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 #include "xfs_alloc.h"
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 #include "xfs_mru_cache.h"
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-#include "xfs_filestream.h"
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 #include "xfs_trace.h"
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 #include "xfs_ag_resv.h"
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 #include "xfs_trans.h"
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-#include "xfs_shared.h"
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+#include "xfs_filestream.h"
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 struct xfs_fstrm_item {
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 	struct xfs_mru_cache_elem	mru;
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@@ -35,39 +33,7 @@
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 /*
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  * Allocation group filestream associations are tracked with per-ag atomic
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  * counters.  These counters allow xfs_filestream_pick_ag() to tell whether a
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- * particular AG already has active filestreams associated with it. The mount
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- * point's m_peraglock is used to protect these counters from per-ag array
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- * re-allocation during a growfs operation.  When xfs_growfs_data_private() is
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- * about to reallocate the array, it calls xfs_filestream_flush() with the
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- * m_peraglock held in write mode.
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- *
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- * Since xfs_mru_cache_flush() guarantees that all the free functions for all
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- * the cache elements have finished executing before it returns, it's safe for
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- * the free functions to use the atomic counters without m_peraglock protection.
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- * This allows the implementation of xfs_fstrm_free_func() to be agnostic about
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- * whether it was called with the m_peraglock held in read mode, write mode or
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- * not held at all.  The race condition this addresses is the following:
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- *
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- *  - The work queue scheduler fires and pulls a filestream directory cache
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- *    element off the LRU end of the cache for deletion, then gets pre-empted.
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- *  - A growfs operation grabs the m_peraglock in write mode, flushes all the
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- *    remaining items from the cache and reallocates the mount point's per-ag
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- *    array, resetting all the counters to zero.
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- *  - The work queue thread resumes and calls the free function for the element
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- *    it started cleaning up earlier.  In the process it decrements the
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- *    filestreams counter for an AG that now has no references.
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- *
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- * With a shrinkfs feature, the above scenario could panic the system.
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- *
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- * All other uses of the following macros should be protected by either the
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- * m_peraglock held in read mode, or the cache's internal locking exposed by the
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- * interval between a call to xfs_mru_cache_lookup() and a call to
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- * xfs_mru_cache_done().  In addition, the m_peraglock must be held in read mode
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- * when new elements are added to the cache.
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- *
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- * Combined, these locking rules ensure that no associations will ever exist in
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- * the cache that reference per-ag array elements that have since been
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- * reallocated.
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+ * particular AG already has active filestreams associated with it.
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  */
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 int
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 xfs_filestream_peek_ag(
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@@ -161,15 +127,15 @@
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 		if (!pag->pagf_init) {
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 			err = xfs_alloc_pagf_init(mp, NULL, ag, trylock);
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-			if (err && !trylock) {
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-				xfs_perag_put(pag);
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-				return err;
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+			if (err) {
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+				if (err != -EAGAIN) {
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+					xfs_perag_put(pag);
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+					return err;
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+				}
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+				/* Couldn't lock the AGF, skip this AG. */
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+				goto next_ag;
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 			}
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 		}
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-
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-		/* Might fail sometimes during the 1st pass with trylock set. */
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-		if (!pag->pagf_init)
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-			goto next_ag;
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 		/* Keep track of the AG with the most free blocks. */
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 		if (pag->pagf_freeblks > maxfree) {
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@@ -377,7 +343,7 @@
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 		startag = (item->ag + 1) % mp->m_sb.sb_agcount;
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 	}
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-	if (xfs_alloc_is_userdata(ap->datatype))
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+	if (ap->datatype & XFS_ALLOC_USERDATA)
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 		flags |= XFS_PICK_USERDATA;
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 	if (ap->tp->t_flags & XFS_TRANS_LOWMODE)
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 		flags |= XFS_PICK_LOWSPACE;