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"
16 #include "afs/sysincludes.h" /* Standard vendor system headers */
17 #include "afsincludes.h" /* Afs-based standard headers */
18 #include "afs/afs_stats.h" /* statistics */
20 /* Linux VM operations
22 * The general model for Linux is to treat vm as a cache that's:
23 * 1) explicitly updated by AFS when AFS writes the data to the cache file.
24 * 2) reads go through the cache. A cache miss is satisfied by the filesystem.
26 * This means flushing VM is not required on this OS.
29 /* Try to discard pages, in order to recycle a vcache entry.
31 * We also make some sanity checks: ref count, open count, held locks.
33 * We also do some non-VM-related chores, such as releasing the cred pointer
34 * (for AIX and Solaris) and releasing the gnode (for AIX).
36 * Locking: afs_xvcache lock is held. If it is dropped and re-acquired,
37 * *slept should be set to warn the caller.
39 * Formerly, afs_xvcache was dropped and re-acquired for Solaris, but now it
40 * is not dropped and re-acquired for any platform. It may be that *slept is
41 * therefore obsolescent.
44 osi_VM_FlushVCache(struct vcache *avc, int *slept)
46 struct inode *ip = AFSTOV(avc);
48 if (VREFCOUNT(avc) > 1)
54 #if LINUX_VERSION_CODE >= KERNEL_VERSION(2,4,0)
55 truncate_inode_pages(&ip->i_data, 0);
56 #elif LINUX_VERSION_CODE >= KERNEL_VERSION(2,2,15)
57 truncate_inode_pages(ip, 0);
59 invalidate_inode_pages(ip);
64 /* Try to invalidate pages, for "fs flush" or "fs flushv"; or
65 * try to free pages, when deleting a file.
67 * Locking: the vcache entry's lock is held. It may be dropped and
70 * Since we drop and re-obtain the lock, we can't guarantee that there won't
71 * be some pages around when we return, newly created by concurrent activity.
74 osi_VM_TryToSmush(struct vcache *avc, struct AFS_UCRED *acred, int sync)
76 struct inode *ip = AFSTOV(avc);
78 #if defined(AFS_LINUX26_ENV)
79 invalidate_inode_pages(ip->i_mapping);
81 invalidate_inode_pages(ip);
85 /* Flush and invalidate pages, for fsync() with INVAL flag
87 * Locking: only the global lock is held.
90 osi_VM_FSyncInval(struct vcache *avc)
95 /* Try to store pages to cache, in order to store a file back to the server.
97 * Locking: the vcache entry's lock is held. It will usually be dropped and
101 osi_VM_StoreAllSegments(struct vcache *avc)
103 struct inode *ip = AFSTOV(avc);
105 if (!avc->f.states & CPageWrite)
106 avc->f.states |= CPageWrite;
108 return; /* someone already writing */
110 #if LINUX_VERSION_CODE >= KERNEL_VERSION(2,4,5)
111 /* filemap_fdatasync() only exported in 2.4.5 and above */
112 ReleaseWriteLock(&avc->lock);
114 #if defined(AFS_LINUX26_ENV)
115 filemap_fdatawrite(ip->i_mapping);
117 filemap_fdatasync(ip->i_mapping);
119 filemap_fdatawait(ip->i_mapping);
121 ObtainWriteLock(&avc->lock, 121);
123 avc->f.states &= ~CPageWrite;
126 /* Purge VM for a file when its callback is revoked.
128 * Locking: No lock is held, not even the global lock.
131 osi_VM_FlushPages(struct vcache *avc, struct AFS_UCRED *credp)
133 #if LINUX_VERSION_CODE >= KERNEL_VERSION(2,4,0)
134 struct inode *ip = AFSTOV(avc);
136 truncate_inode_pages(&ip->i_data, 0);
137 #elif LINUX_VERSION_CODE >= KERNEL_VERSION(2,2,15)
138 struct inode *ip = AFSTOV(avc);
140 truncate_inode_pages(ip, 0);
142 invalidate_inode_pages(AFSTOV(avc));
146 /* Purge pages beyond end-of-file, when truncating a file.
148 * Locking: no lock is held, not even the global lock.
149 * activeV is raised. This is supposed to block pageins, but at present
150 * it only works on Solaris.
153 osi_VM_Truncate(struct vcache *avc, int alen, struct AFS_UCRED *acred)
155 #if LINUX_VERSION_CODE >= KERNEL_VERSION(2,4,0)
156 struct inode *ip = AFSTOV(avc);
158 truncate_inode_pages(&ip->i_data, alen);
159 #elif LINUX_VERSION_CODE >= KERNEL_VERSION(2,2,15)
160 struct inode *ip = AFSTOV(avc);
162 truncate_inode_pages(ip, alen);
164 invalidate_inode_pages(AFSTOV(avc));