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| author | Yoshihisa Abe <yoshiabe@cs.cmu.edu> | 2010-10-25 02:03:44 -0400 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2010-10-25 08:02:40 -0700 |
| commit | b5ce1d83a62fc109d8e815b1fc71dcdb0d26bc49 (patch) | |
| tree | ea537c1b6436c36bee3b33d8b4f750124fd7d661 /include/linux | |
| parent | 3a99c6319064af3f2e18eb929f638d555dbf7a62 (diff) | |
| download | blackbird-op-linux-b5ce1d83a62fc109d8e815b1fc71dcdb0d26bc49.tar.gz blackbird-op-linux-b5ce1d83a62fc109d8e815b1fc71dcdb0d26bc49.zip | |
Coda: add spin lock to protect accesses to struct coda_inode_info.
We mostly need it to protect cached user permissions. The c_flags field
is advisory, reading the wrong value is harmless and in the worst case
we hit a slow path where we have to make an extra upcall to the
userspace cache manager when revalidating a dentry or inode.
Signed-off-by: Yoshihisa Abe <yoshiabe@cs.cmu.edu>
Signed-off-by: Jan Harkes <jaharkes@cs.cmu.edu>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'include/linux')
| -rw-r--r-- | include/linux/coda_fs_i.h | 13 | ||||
| -rw-r--r-- | include/linux/coda_linux.h | 6 |
2 files changed, 14 insertions, 5 deletions
diff --git a/include/linux/coda_fs_i.h b/include/linux/coda_fs_i.h index b3ef0c461578..e35071b1de0e 100644 --- a/include/linux/coda_fs_i.h +++ b/include/linux/coda_fs_i.h @@ -10,19 +10,24 @@ #include <linux/types.h> #include <linux/list.h> +#include <linux/spinlock.h> #include <linux/coda.h> /* * coda fs inode data + * c_lock protects accesses to c_flags, c_mapcount, c_cached_epoch, c_uid and + * c_cached_perm. + * vfs_inode is set only when the inode is created and never changes. + * c_fid is set when the inode is created and should be considered immutable. */ struct coda_inode_info { - struct CodaFid c_fid; /* Coda identifier */ - u_short c_flags; /* flags (see below) */ - struct list_head c_cilist; /* list of all coda inodes */ + struct CodaFid c_fid; /* Coda identifier */ + u_short c_flags; /* flags (see below) */ unsigned int c_mapcount; /* nr of times this inode is mapped */ unsigned int c_cached_epoch; /* epoch for cached permissions */ vuid_t c_uid; /* fsuid for cached permissions */ - unsigned int c_cached_perm; /* cached access permissions */ + unsigned int c_cached_perm; /* cached access permissions */ + spinlock_t c_lock; struct inode vfs_inode; }; diff --git a/include/linux/coda_linux.h b/include/linux/coda_linux.h index dcc228aa335a..2e914d0771b9 100644 --- a/include/linux/coda_linux.h +++ b/include/linux/coda_linux.h @@ -89,7 +89,11 @@ static __inline__ char *coda_i2s(struct inode *inode) /* this will not zap the inode away */ static __inline__ void coda_flag_inode(struct inode *inode, int flag) { - ITOC(inode)->c_flags |= flag; + struct coda_inode_info *cii = ITOC(inode); + + spin_lock(&cii->c_lock); + cii->c_flags |= flag; + spin_unlock(&cii->c_lock); } #endif |
