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fuse: make fuse_permission() RCU aware

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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>
This commit is contained in:
Miklos Szeredi 2011-03-21 13:58:06 +01:00
parent 357ccf2b69
commit 19690ddb65
1 changed files with 22 additions and 8 deletions
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30
fs/fuse/dir.c
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@ -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;
}