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 #include "osi_compat.h"
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. It must not be dropped.
39 osi_VM_FlushVCache(struct vcache
*avc
)
41 struct inode
*ip
= AFSTOV(avc
);
43 if (VREFCOUNT(avc
) > 1)
49 return afs_truncate(ip
, 0);
52 /* Try to invalidate pages, for "fs flush" or "fs flushv"; or
53 * try to free pages, when deleting a file.
55 * Locking: the vcache entry's lock is held. It may be dropped and
58 * Since we drop and re-obtain the lock, we can't guarantee that there won't
59 * be some pages around when we return, newly created by concurrent activity.
62 osi_VM_TryToSmush(struct vcache
*avc
, afs_ucred_t
*acred
, int sync
)
64 struct inode
*ip
= AFSTOV(avc
);
66 invalidate_remote_inode(ip
);
69 /* Flush and invalidate pages, for fsync() with INVAL flag
71 * Locking: only the global lock is held.
74 osi_VM_FSyncInval(struct vcache
*avc
)
79 /* Try to store pages to cache, in order to store a file back to the server.
81 * Locking: the vcache entry's lock is held. It will usually be dropped and
85 osi_VM_StoreAllSegments(struct vcache
*avc
)
87 struct inode
*ip
= AFSTOV(avc
);
89 if (!list_empty(&avc
->pagewriters
))
90 return; /* someone already writing */
92 /* filemap_fdatasync() only exported in 2.4.5 and above */
93 ReleaseWriteLock(&avc
->lock
);
95 filemap_fdatawrite(ip
->i_mapping
);
96 filemap_fdatawait(ip
->i_mapping
);
98 ObtainWriteLock(&avc
->lock
, 121);
101 /* Purge VM for a file when its callback is revoked.
103 * Locking: No lock is held, not even the global lock.
106 /* Note that for speed some of our Linux vnodeops do not initialise credp
107 * before calling osi_FlushPages(). If credp is ever required on Linux,
108 * then these callers should be updated.
111 osi_VM_FlushPages(struct vcache
*avc
, afs_ucred_t
*credp
)
113 struct inode
*ip
= AFSTOV(avc
);
115 afs_linux_lock_inode(ip
);
116 truncate_inode_pages(&ip
->i_data
, 0);
117 afs_linux_unlock_inode(ip
);
120 /* Purge pages beyond end-of-file, when truncating a file.
122 * Locking: no lock is held, not even the global lock.
123 * activeV is raised. This is supposed to block pageins, but at present
124 * it only works on Solaris.
127 osi_VM_Truncate(struct vcache
*avc
, int alen
, afs_ucred_t
*acred
)
129 afs_truncate(AFSTOV(avc
), alen
);