From 19690ddb65dbfc7be1b411fce12d3332acefbfb5 Mon Sep 17 00:00:00 2001 From: Miklos Szeredi Date: Mon, 21 Mar 2011 13:58:06 +0100 Subject: [PATCH] fuse: make fuse_permission() RCU aware Only bail out of fuse_permission() on IPERM_FLAG_RCU when blocking is actually necessary. CC: Nick Piggin Signed-off-by: Miklos Szeredi --- fs/fuse/dir.c | 30 ++++++++++++++++++++++-------- 1 file 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) return err; } +static int fuse_perm_getattr(struct inode *inode, int flags) +{ + if (flags & IPERM_FLAG_RCU) + return -ECHILD; + + return fuse_do_getattr(inode, NULL, NULL); +} + /* * Check permission. The two basic access models of FUSE are: * @@ -989,9 +997,6 @@ static int fuse_permission(struct inode *inode, int mask, unsigned int flags) bool refreshed = false; int err = 0; - if (flags & IPERM_FLAG_RCU) - return -ECHILD; - if (!fuse_allow_task(fc, current)) return -EACCES; @@ -1000,9 +1005,15 @@ static int fuse_permission(struct inode *inode, int mask, unsigned int flags) */ if ((fc->flags & FUSE_DEFAULT_PERMISSIONS) || ((mask & MAY_EXEC) && S_ISREG(inode->i_mode))) { - err = fuse_update_attributes(inode, NULL, NULL, &refreshed); - if (err) - return err; + struct fuse_inode *fi = get_fuse_inode(inode); + + if (fi->i_time < get_jiffies_64()) { + refreshed = true; + + err = fuse_perm_getattr(inode, flags); + if (err) + return err; + } } if (fc->flags & FUSE_DEFAULT_PERMISSIONS) { @@ -1012,7 +1023,7 @@ static int fuse_permission(struct inode *inode, int mask, unsigned int flags) attributes. This is also needed, because the root node will at first have no permissions */ if (err == -EACCES && !refreshed) { - err = fuse_do_getattr(inode, NULL, NULL); + err = fuse_perm_getattr(inode, flags); if (!err) err = generic_permission(inode, mask, flags, NULL); @@ -1023,13 +1034,16 @@ static int fuse_permission(struct inode *inode, int mask, unsigned int flags) noticed immediately, only after the attribute timeout has expired */ } else if (mask & (MAY_ACCESS | MAY_CHDIR)) { + if (flags & IPERM_FLAG_RCU) + return -ECHILD; + err = fuse_access(inode, mask); } else if ((mask & MAY_EXEC) && S_ISREG(inode->i_mode)) { if (!(inode->i_mode & S_IXUGO)) { if (refreshed) return -EACCES; - err = fuse_do_getattr(inode, NULL, NULL); + err = fuse_perm_getattr(inode, flags); if (!err && !(inode->i_mode & S_IXUGO)) return -EACCES; } -- 2.30.2