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authorMiklos Szeredi <mszeredi@suse.cz>2011-03-21 08:58:06 -0400
committerMiklos Szeredi <mszeredi@suse.cz>2011-03-21 08:58:06 -0400
commit19690ddb65dbfc7be1b411fce12d3332acefbfb5 (patch)
treea906399000efeb5221e9a496fc85668243238d49 /fs/fuse/dir.c
parent357ccf2b69bcefa650a54db83702381d1c9d6959 (diff)
fuse: make fuse_permission() RCU aware
Only bail out of fuse_permission() on IPERM_FLAG_RCU when blocking is actually necessary. CC: Nick Piggin <npiggin@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Diffstat (limited to 'fs/fuse/dir.c')
-rw-r--r--fs/fuse/dir.c30
1 files changed, 22 insertions, 8 deletions
diff --git a/fs/fuse/dir.c b/fs/fuse/dir.c
index 8bd0ef9286c3..3b84b913b16e 100644
--- a/fs/fuse/dir.c
+++ b/fs/fuse/dir.c
@@ -970,6 +970,14 @@ static int fuse_access(struct inode *inode, int mask)
970 return err; 970 return err;
971} 971}
972 972
973static int fuse_perm_getattr(struct inode *inode, int flags)
974{
975 if (flags & IPERM_FLAG_RCU)
976 return -ECHILD;
977
978 return fuse_do_getattr(inode, NULL, NULL);
979}
980
973/* 981/*
974 * Check permission. The two basic access models of FUSE are: 982 * Check permission. The two basic access models of FUSE are:
975 * 983 *
@@ -989,9 +997,6 @@ static int fuse_permission(struct inode *inode, int mask, unsigned int flags)
989 bool refreshed = false; 997 bool refreshed = false;
990 int err = 0; 998 int err = 0;
991 999
992 if (flags & IPERM_FLAG_RCU)
993 return -ECHILD;
994
995 if (!fuse_allow_task(fc, current)) 1000 if (!fuse_allow_task(fc, current))
996 return -EACCES; 1001 return -EACCES;
997 1002
@@ -1000,9 +1005,15 @@ static int fuse_permission(struct inode *inode, int mask, unsigned int flags)
1000 */ 1005 */
1001 if ((fc->flags & FUSE_DEFAULT_PERMISSIONS) || 1006 if ((fc->flags & FUSE_DEFAULT_PERMISSIONS) ||
1002 ((mask & MAY_EXEC) && S_ISREG(inode->i_mode))) { 1007 ((mask & MAY_EXEC) && S_ISREG(inode->i_mode))) {
1003 err = fuse_update_attributes(inode, NULL, NULL, &refreshed); 1008 struct fuse_inode *fi = get_fuse_inode(inode);
1004 if (err) 1009
1005 return err; 1010 if (fi->i_time < get_jiffies_64()) {
1011 refreshed = true;
1012
1013 err = fuse_perm_getattr(inode, flags);
1014 if (err)
1015 return err;
1016 }
1006 } 1017 }
1007 1018
1008 if (fc->flags & FUSE_DEFAULT_PERMISSIONS) { 1019 if (fc->flags & FUSE_DEFAULT_PERMISSIONS) {
@@ -1012,7 +1023,7 @@ static int fuse_permission(struct inode *inode, int mask, unsigned int flags)
1012 attributes. This is also needed, because the root 1023 attributes. This is also needed, because the root
1013 node will at first have no permissions */ 1024 node will at first have no permissions */
1014 if (err == -EACCES && !refreshed) { 1025 if (err == -EACCES && !refreshed) {
1015 err = fuse_do_getattr(inode, NULL, NULL); 1026 err = fuse_perm_getattr(inode, flags);
1016 if (!err) 1027 if (!err)
1017 err = generic_permission(inode, mask, 1028 err = generic_permission(inode, mask,
1018 flags, NULL); 1029 flags, NULL);
@@ -1023,13 +1034,16 @@ static int fuse_permission(struct inode *inode, int mask, unsigned int flags)
1023 noticed immediately, only after the attribute 1034 noticed immediately, only after the attribute
1024 timeout has expired */ 1035 timeout has expired */
1025 } else if (mask & (MAY_ACCESS | MAY_CHDIR)) { 1036 } else if (mask & (MAY_ACCESS | MAY_CHDIR)) {
1037 if (flags & IPERM_FLAG_RCU)
1038 return -ECHILD;
1039
1026 err = fuse_access(inode, mask); 1040 err = fuse_access(inode, mask);
1027 } else if ((mask & MAY_EXEC) && S_ISREG(inode->i_mode)) { 1041 } else if ((mask & MAY_EXEC) && S_ISREG(inode->i_mode)) {
1028 if (!(inode->i_mode & S_IXUGO)) { 1042 if (!(inode->i_mode & S_IXUGO)) {
1029 if (refreshed) 1043 if (refreshed)
1030 return -EACCES; 1044 return -EACCES;
1031 1045
1032 err = fuse_do_getattr(inode, NULL, NULL); 1046 err = fuse_perm_getattr(inode, flags);
1033 if (!err && !(inode->i_mode & S_IXUGO)) 1047 if (!err && !(inode->i_mode & S_IXUGO))
1034 return -EACCES; 1048 return -EACCES;
1035 } 1049 }