BMC/Intel-BMC/linux.git/fs/kernfs/symlink.c, branch dev

new helper: free_page_put_link()

2015-05-11T12:13:13+00:00

similar to kfree_put_link() Signed-off-by: Al Viro

switch ->put_link() from dentry to inode

2015-05-11T12:13:12+00:00

only one instance looks at that argument at all; that sole exception wants inode rather than dentry. Signed-off-by: Al Viro

don't pass nameidata to ->follow_link()

2015-05-11T02:20:15+00:00

its only use is getting passed to nd_jump_link(), which can obtain it from current->nameidata Signed-off-by: Al Viro

new ->follow_link() and ->put_link() calling conventions

2015-05-11T02:19:45+00:00

a) instead of storing the symlink body (via nd_set_link()) and returning an opaque pointer later passed to ->put_link(), ->follow_link() _stores_ that opaque pointer (into void * passed by address by caller) and returns the symlink body. Returning ERR_PTR() on error, NULL on jump (procfs magic symlinks) and pointer to symlink body for normal symlinks. Stored pointer is ignored in all cases except the last one. Storing NULL for opaque pointer (or not storing it at all) means no call of ->put_link(). b) the body used to be passed to ->put_link() implicitly (via nameidata). Now only the opaque pointer is. In the cases when we used the symlink body to free stuff, ->follow_link() now should store it as opaque pointer in addition to returning it. Signed-off-by: Al Viro

kernfs: remove kernfs_addrm_cxt

2014-02-07T23:42:40+00:00

kernfs_addrm_cxt and the accompanying kernfs_addrm_start/finish() were added because there were operations which should be performed outside kernfs_mutex after adding and removing kernfs_nodes. The necessary operations were recorded in kernfs_addrm_cxt and performed by kernfs_addrm_finish(); however, after the recent changes which relocated deactivation and unmapping so that they're performed directly during removal, the only operation kernfs_addrm_finish() performs is kernfs_put(), which can be moved inside the removal path too. This patch moves the kernfs_put() of the base ref to __kernfs_remove() and remove kernfs_addrm_cxt and kernfs_addrm_start/finish(). * kernfs_add_one() is updated to grab and release kernfs_mutex itself. sysfs_addrm_start/finish() invocations around it are removed from all users. * __kernfs_remove() puts an unlinked node directly instead of chaining it to kernfs_addrm_cxt. Its callers are updated to grab and release kernfs_mutex instead of calling kernfs_addrm_start/finish() around it. v2: Rebased on top of "kernfs: associate a new kernfs_node with its parent on creation" which dropped @parent from kernfs_add_one(). Signed-off-by: Tejun Heo Signed-off-by: Greg Kroah-Hartman

kernfs: associate a new kernfs_node with its parent on creation

2014-01-17T19:50:07+00:00

Once created, a kernfs_node is always destroyed by kernfs_put(). Since ba7443bc656e ("sysfs, kernfs: implement kernfs_create/destroy_root()"), kernfs_put() depends on kernfs_root() to locate the ino_ida. kernfs_root() in turn depends on kernfs_node->parent being set for !dir nodes. This means that kernfs_put() of a !dir node requires its ->parent to be initialized. This leads to oops when a newly created !dir node is destroyed without going through kernfs_add_one() or after failing kernfs_add_one() before ->parent is set. kernfs_root() invoked from kernfs_put() will try to dereference NULL parent. Fix it by moving parent association to kernfs_new_node() from kernfs_add_one(). kernfs_new_node() now takes @parent instead of @root and determines the root from the parent and also sets the new node's parent properly. @parent parameter is removed from kernfs_add_one(). As there's no parent when creating the root node, __kernfs_new_node() which takes @root as before and doesn't set the parent is used in that case. This ensures that a kernfs_node in any stage in its life has its parent associated and thus can be put. Signed-off-by: Tejun Heo Signed-off-by: Greg Kroah-Hartman

Revert "kernfs: remove KERNFS_REMOVED"

2014-01-13T22:36:03+00:00

This reverts commit ae34372eb8408b3d07e870f1939f99007a730d28. Tejun writes: I'm sorry but can you please revert the whole series? get_active() waiting while a node is deactivated has potential to lead to deadlock and that deactivate/reactivate interface is something fundamentally flawed and that cgroup will have to work with the remove_self() like everybody else. IOW, I think the first posting was correct. Cc: Tejun Heo Signed-off-by: Greg Kroah-Hartman

Revert "kernfs: remove kernfs_addrm_cxt"

2014-01-13T22:20:56+00:00

This reverts commit 99177a34110889a8f2c36420c34e3bcc9bfd8a70. Tejun writes: I'm sorry but can you please revert the whole series? get_active() waiting while a node is deactivated has potential to lead to deadlock and that deactivate/reactivate interface is something fundamentally flawed and that cgroup will have to work with the remove_self() like everybody else. IOW, I think the first posting was correct. Cc: Tejun Heo Signed-off-by: Greg Kroah-Hartman

kernfs: remove kernfs_addrm_cxt

2014-01-10T21:48:08+00:00

kernfs_addrm_cxt and the accompanying kernfs_addrm_start/finish() were added because there were operations which should be performed outside kernfs_mutex after adding and removing kernfs_nodes. The necessary operations were recorded in kernfs_addrm_cxt and performed by kernfs_addrm_finish(); however, after the recent changes which relocated deactivation and unmapping so that they're performed directly during removal, the only operation kernfs_addrm_finish() performs is kernfs_put(), which can be moved inside the removal path too. This patch moves the kernfs_put() of the base ref to __kernfs_remove() and remove kernfs_addrm_cxt and kernfs_addrm_start/finish(). * kernfs_add_one() is updated to grab and release the parent's active ref and kernfs_mutex itself. kernfs_get/put_active() and kernfs_addrm_start/finish() invocations around it are removed from all users. * __kernfs_remove() puts an unlinked node directly instead of chaining it to kernfs_addrm_cxt. Its callers are updated to grab and release kernfs_mutex instead of calling kernfs_addrm_start/finish() around it. v2: Updated to fit the v2 restructuring of removal path. Signed-off-by: Tejun Heo Signed-off-by: Greg Kroah-Hartman

kernfs: remove KERNFS_REMOVED

2014-01-10T21:44:25+00:00

KERNFS_REMOVED is used to mark half-initialized and dying nodes so that they don't show up in lookups and deny adding new nodes under or renaming it; however, its role overlaps those of deactivation and removal from rbtree. It's necessary to deny addition of new children while removal is in progress; however, this role considerably intersects with deactivation - KERNFS_REMOVED prevents new children while deactivation prevents new file operations. There's no reason to have them separate making things more complex than necessary. KERNFS_REMOVED is also used to decide whether a node is still visible to vfs layer, which is rather redundant as equivalent determination can be made by testing whether the node is on its parent's children rbtree or not. This patch removes KERNFS_REMOVED. * Instead of KERNFS_REMOVED, each node now starts its life deactivated. This means that we now use both atomic_add() and atomic_sub() on KN_DEACTIVATED_BIAS, which is INT_MIN. The compiler generates an overflow warnings when negating INT_MIN as the negation can't be represented as a positive number. Nothing is actually broken but let's bump BIAS by one to avoid the warnings for archs which negates the subtrahend.. * KERNFS_REMOVED tests in add and rename paths are replaced with kernfs_get/put_active() of the target nodes. Due to the way the add path is structured now, active ref handling is done in the callers of kernfs_add_one(). This will be consolidated up later. * kernfs_remove_one() is updated to deactivate instead of setting KERNFS_REMOVED. This removes deactivation from kernfs_deactivate(), which is now renamed to kernfs_drain(). * kernfs_dop_revalidate() now tests RB_EMPTY_NODE(&kn->rb) instead of KERNFS_REMOVED and KERNFS_REMOVED test in kernfs_dir_pos() is dropped. A node which is removed from the children rbtree is not included in the iteration in the first place. This means that a node may be visible through vfs a bit longer - it's now also visible after deactivation until the actual removal. This slightly enlarged window difference doesn't make any difference to the userland. * Sanity check on KERNFS_REMOVED in kernfs_put() is replaced with checks on the active ref. * Some comment style updates in the affected area. v2: Reordered before removal path restructuring. kernfs_active() dropped and kernfs_get/put_active() used instead. RB_EMPTY_NODE() used in the lookup paths. Signed-off-by: Tejun Heo Signed-off-by: Greg Kroah-Hartman