2 * Copyright 2000, International Business Machines Corporation and others.
5 * This software has been released under the terms of the IBM Public
6 * License. For details, see the LICENSE file in the top-level source
7 * directory or online at http://www.openafs.org/dl/license10.html
10 #include <afsconfig.h>
11 #include "afs/param.h"
14 #include "afs/sysincludes.h" /* Standard vendor system headers */
15 #include "afsincludes.h" /* Afs-based standard headers */
16 #include "afs/afs_stats.h" /* statistics */
18 /* Linux VM operations
20 * The general model for Linux is to treat vm as a cache that's:
21 * 1) explicitly updated by AFS when AFS writes the data to the cache file.
22 * 2) reads go through the cache. A cache miss is satisfied by the filesystem.
24 * This means flushing VM is not required on this OS.
27 /* Try to discard pages, in order to recycle a vcache entry.
29 * We also make some sanity checks: ref count, open count, held locks.
31 * We also do some non-VM-related chores, such as releasing the cred pointer
32 * (for AIX and Solaris) and releasing the gnode (for AIX).
34 * Locking: afs_xvcache lock is held. If it is dropped and re-acquired,
35 * *slept should be set to warn the caller.
37 * Formerly, afs_xvcache was dropped and re-acquired for Solaris, but now it
38 * is not dropped and re-acquired for any platform. It may be that *slept is
39 * therefore obsolescent.
42 osi_VM_FlushVCache(struct vcache *avc, int *slept)
44 struct inode *ip = AFSTOV(avc);
46 if (VREFCOUNT(avc) > 1)
52 return vmtruncate(ip, 0);
56 /* Try to invalidate pages, for "fs flush" or "fs flushv"; or
57 * try to free pages, when deleting a file.
59 * Locking: the vcache entry's lock is held. It may be dropped and
62 * Since we drop and re-obtain the lock, we can't guarantee that there won't
63 * be some pages around when we return, newly created by concurrent activity.
66 osi_VM_TryToSmush(struct vcache *avc, afs_ucred_t *acred, int sync)
68 struct inode *ip = AFSTOV(avc);
70 invalidate_inode_pages(ip->i_mapping);
73 /* Flush and invalidate pages, for fsync() with INVAL flag
75 * Locking: only the global lock is held.
78 osi_VM_FSyncInval(struct vcache *avc)
83 /* Try to store pages to cache, in order to store a file back to the server.
85 * Locking: the vcache entry's lock is held. It will usually be dropped and
89 osi_VM_StoreAllSegments(struct vcache *avc)
91 struct inode *ip = AFSTOV(avc);
93 if (avc->f.states & CPageWrite)
94 return; /* someone already writing */
96 /* filemap_fdatasync() only exported in 2.4.5 and above */
97 ReleaseWriteLock(&avc->lock);
99 filemap_fdatawrite(ip->i_mapping);
100 filemap_fdatawait(ip->i_mapping);
102 ObtainWriteLock(&avc->lock, 121);
105 /* Purge VM for a file when its callback is revoked.
107 * Locking: No lock is held, not even the global lock.
110 /* Note that for speed some of our Linux vnodeops do not initialise credp
111 * before calling osi_FlushPages(). If credp is ever required on Linux,
112 * then these callers should be updated.
115 osi_VM_FlushPages(struct vcache *avc, afs_ucred_t *credp)
117 struct inode *ip = AFSTOV(avc);
119 truncate_inode_pages(&ip->i_data, 0);
122 /* Purge pages beyond end-of-file, when truncating a file.
124 * Locking: no lock is held, not even the global lock.
125 * activeV is raised. This is supposed to block pageins, but at present
126 * it only works on Solaris.
129 osi_VM_Truncate(struct vcache *avc, int alen, afs_ucred_t *acred)
131 vmtruncate(AFSTOV(avc), alen);