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 #if LINUX_VERSION_CODE >= KERNEL_VERSION(2,4,0)
53 return vmtruncate(ip, 0);
54 #elif LINUX_VERSION_CODE >= KERNEL_VERSION(2,2,15)
55 truncate_inode_pages(ip, 0);
57 invalidate_inode_pages(ip);
62 /* Try to invalidate pages, for "fs flush" or "fs flushv"; or
63 * try to free pages, when deleting a file.
65 * Locking: the vcache entry's lock is held. It may be dropped and
68 * Since we drop and re-obtain the lock, we can't guarantee that there won't
69 * be some pages around when we return, newly created by concurrent activity.
72 osi_VM_TryToSmush(struct vcache *avc, AFS_UCRED *acred, int sync)
74 struct inode *ip = AFSTOV(avc);
76 invalidate_inode_pages(ip);
79 /* Flush and invalidate pages, for fsync() with INVAL flag
81 * Locking: only the global lock is held.
84 osi_VM_FSyncInval(struct vcache *avc)
89 /* Try to store pages to cache, in order to store a file back to the server.
91 * Locking: the vcache entry's lock is held. It will usually be dropped and
95 osi_VM_StoreAllSegments(struct vcache *avc)
97 struct inode *ip = AFSTOV(avc);
99 if (avc->f.states & CPageWrite)
100 return; /* someone already writing */
102 #if LINUX_VERSION_CODE >= KERNEL_VERSION(2,4,5)
103 /* filemap_fdatasync() only exported in 2.4.5 and above */
104 ReleaseWriteLock(&avc->lock);
106 filemap_fdatasync(ip->i_mapping);
107 filemap_fdatawait(ip->i_mapping);
109 ObtainWriteLock(&avc->lock, 121);
113 /* Purge VM for a file when its callback is revoked.
115 * Locking: No lock is held, not even the global lock.
118 /* Note that for speed some of our Linux vnodeops do not initialise credp
119 * before calling osi_FlushPages(). If credp is ever required on Linux,
120 * then these callers should be updated.
123 osi_VM_FlushPages(struct vcache *avc, AFS_UCRED *credp)
125 #if LINUX_VERSION_CODE >= KERNEL_VERSION(2,4,0)
126 struct inode *ip = AFSTOV(avc);
128 truncate_inode_pages(&ip->i_data, 0);
129 #elif LINUX_VERSION_CODE >= KERNEL_VERSION(2,2,15)
130 struct inode *ip = AFSTOV(avc);
132 truncate_inode_pages(ip, 0);
134 invalidate_inode_pages(AFSTOV(avc));
138 /* Purge pages beyond end-of-file, when truncating a file.
140 * Locking: no lock is held, not even the global lock.
141 * activeV is raised. This is supposed to block pageins, but at present
142 * it only works on Solaris.
145 osi_VM_Truncate(struct vcache *avc, int alen, AFS_UCRED *acred)
147 #if LINUX_VERSION_CODE >= KERNEL_VERSION(2,4,0)
148 vmtruncate(AFSTOV(avc), alen);
149 #elif LINUX_VERSION_CODE >= KERNEL_VERSION(2,2,15)
150 struct inode *ip = AFSTOV(avc);
152 truncate_inode_pages(ip, alen);
154 invalidate_inode_pages(AFSTOV(avc));