*/
const char *yaffs_fs_c_version =
- "$Id: yaffs_fs.c,v 1.87 2009-11-11 02:11:13 charles Exp $";
+ "$Id: yaffs_fs.c,v 1.89 2009-11-29 21:50:10 charles Exp $";
extern const char *yaffs_guts_c_version;
#include <linux/version.h>
.write_super = yaffs_write_super,
};
-/* YAFFS uses two locks per yaffs_Device.
- * dirLock: r/w lock Must be held when accessing directory structure.
- * grossLock: Lock when accessing yaffs internals.
- *
- * Locking rules:
- * If you're going to take dirLock then you must take if before
- * taking grossLock.
- * ie. Don't call yaffs_DirLockxxx() while holding grossLock.
- *
- * Todo:
- * Investigate changing to mutexes etc and improve debugging.
- */
-static void yaffs_DirLockInitialise(yaffs_Device *dev)
+static void yaffs_GrossLock(yaffs_Device *dev)
{
- init_rwsem(&dev->dirLock);
+ T(YAFFS_TRACE_OS, ("yaffs locking %p\n", current));
+ down(&dev->grossLock);
+ T(YAFFS_TRACE_OS, ("yaffs locked %p\n", current));
}
-static void yaffs_DirLockRead(yaffs_Device *dev)
+static void yaffs_GrossUnlock(yaffs_Device *dev)
{
- T(YAFFS_TRACE_OS, ("yaffs locking dir read %p\n", current));
- down_read(&dev->dirLock);
- T(YAFFS_TRACE_OS, ("yaffs locked dir read %p\n", current));
+ T(YAFFS_TRACE_OS, ("yaffs unlocking %p\n", current));
+ up(&dev->grossLock);
}
-static void yaffs_DirUnlockRead(yaffs_Device *dev)
-{
- T(YAFFS_TRACE_OS, ("yaffs unlocking dir read %p\n", current));
- up_read(&dev->dirLock);
-}
-static void yaffs_DirLockWrite(yaffs_Device *dev)
-{
- T(YAFFS_TRACE_OS, ("yaffs locking dir write %p\n", current));
- down_write(&dev->dirLock);
- T(YAFFS_TRACE_OS, ("yaffs locked dir write %p\n", current));
-}
+/*-----------------------------------------------------------------*/
+/* Directory search context allows us to unlock access to yaffs during
+ * filldir without causing problems with the directory being modified.
+ * This is similar to the tried and tested mechanism used in yaffs direct.
+ *
+ * A search context iterates along a doubly linked list of siblings in the
+ * directory. If the iterating object is deleted then this would corrupt
+ * the list iteration, likely causing a crash. The search context avoids
+ * this by using the removeObjectCallback to move the search context to the
+ * next object before the object is deleted.
+ *
+ * Many readdirs (and thus seach conexts) may be alive simulateously so
+ * each yaffs_Device has a list of these.
+ *
+ * A seach context lives for the duration of a readdir.
+ *
+ * All these functions must be called while yaffs is locked.
+ */
-static void yaffs_DirUnlockWrite(yaffs_Device *dev)
-{
- T(YAFFS_TRACE_OS, ("yaffs unlocking dir write %p\n", current));
- up_write(&dev->dirLock);
+struct yaffs_SearchContext {
+ yaffs_Device *dev;
+ yaffs_Object *dirObj;
+ yaffs_Object *nextReturn;
+ struct ylist_head others;
+};
+
+/*
+ * yaffs_NewSearch() creates a new search context, initialises it and
+ * adds it to the device's search context list.
+ *
+ * Called at start of readdir.
+ */
+static struct yaffs_SearchContext * yaffs_NewSearch(yaffs_Object *dir)
+{
+ yaffs_Device *dev = dir->myDev;
+ struct yaffs_SearchContext *sc = YMALLOC(sizeof(struct yaffs_SearchContext));
+ if(sc){
+ sc->dirObj = dir;
+ sc->dev = dev;
+ if( ylist_empty(&sc->dirObj->variant.directoryVariant.children))
+ sc->nextReturn = NULL;
+ else
+ sc->nextReturn = ylist_entry(
+ dir->variant.directoryVariant.children.next,
+ yaffs_Object,siblings);
+ YINIT_LIST_HEAD(&sc->others);
+ ylist_add(&sc->others,&dev->searchContexts);
+ }
+ return sc;
}
-static void yaffs_GrossLockInitialise(yaffs_Device *dev)
+/*
+ * yaffs_EndSearch() disposes of a search context and cleans up.
+ */
+static void yaffs_EndSearch(struct yaffs_SearchContext * sc)
{
- init_MUTEX(&dev->grossLock);
+ if(sc){
+ ylist_del(&sc->others);
+ YFREE(sc);
+ }
}
-static void yaffs_GrossLock(yaffs_Device *dev)
+/*
+ * yaffs_SearchAdvance() moves a search context to the next object.
+ * Called when the search iterates or when an object removal causes
+ * the search context to be moved to the next object.
+ */
+static void yaffs_SearchAdvance(struct yaffs_SearchContext *sc)
{
- T(YAFFS_TRACE_OS, ("yaffs locking %p\n", current));
- down(&dev->grossLock);
- T(YAFFS_TRACE_OS, ("yaffs locked %p\n", current));
+ if(!sc)
+ return;
+
+ if( sc->nextReturn == NULL ||
+ ylist_empty(&sc->dirObj->variant.directoryVariant.children))
+ sc->nextReturn = NULL;
+ else {
+ struct ylist_head *next = sc->nextReturn->siblings.next;
+
+ if( next == &sc->dirObj->variant.directoryVariant.children)
+ sc->nextReturn = NULL; /* end of list */
+ else
+ sc->nextReturn = ylist_entry(next,yaffs_Object,siblings);
+ }
}
-static void yaffs_GrossUnlock(yaffs_Device *dev)
+/*
+ * yaffs_RemoveObjectCallback() is called when an object is unlinked.
+ * We check open search contexts and advance any which are currently
+ * on the object being iterated.
+ */
+static void yaffs_RemoveObjectCallback(yaffs_Object *obj)
{
- T(YAFFS_TRACE_OS, ("yaffs unlocking %p\n", current));
- up(&dev->grossLock);
+
+ struct ylist_head *i;
+ struct yaffs_SearchContext *sc;
+ struct ylist_head *search_contexts = &obj->myDev->searchContexts;
+
+
+ /* Iterate through the directory search contexts.
+ * If any are currently on the object being removed, then advance
+ * the search context to the next object to prevent a hanging pointer.
+ */
+ ylist_for_each(i, search_contexts) {
+ if (i) {
+ sc = ylist_entry(i, struct yaffs_SearchContext,others);
+ if(sc->nextReturn == obj)
+ yaffs_SearchAdvance(sc);
+ }
+ }
+
}
+/*-----------------------------------------------------------------*/
+
static int yaffs_readlink(struct dentry *dentry, char __user *buffer,
int buflen)
{
int ret;
yaffs_Device *dev = yaffs_DentryToObject(dentry)->myDev;
-
- yaffs_DirLockRead(dev);
+
yaffs_GrossLock(dev);
alias = yaffs_GetSymlinkAlias(yaffs_DentryToObject(dentry));
yaffs_GrossUnlock(dev);
- yaffs_DirUnlockRead(dev);
if (!alias)
return -ENOMEM;
int ret;
yaffs_Device *dev = yaffs_DentryToObject(dentry)->myDev;
- yaffs_DirLockRead(dev);
yaffs_GrossLock(dev);
alias = yaffs_GetSymlinkAlias(yaffs_DentryToObject(dentry));
yaffs_GrossUnlock(dev);
- yaffs_DirUnlockRead(dev);
if (!alias) {
ret = -ENOMEM;
yaffs_Device *dev = yaffs_InodeToObject(dir)->myDev;
- yaffs_DirLockRead(dev);
yaffs_GrossLock(dev);
T(YAFFS_TRACE_OS,
/* Can't hold gross lock when calling yaffs_get_inode() */
yaffs_GrossUnlock(dev);
- yaffs_DirUnlockRead(dev);
if (obj) {
T(YAFFS_TRACE_OS,
if (obj) {
dev = obj->myDev;
- yaffs_DirLockRead(dev);
yaffs_GrossLock(dev);
/* Clear the association between the inode and
yaffs_HandleDeferedFree(obj);
yaffs_GrossUnlock(dev);
- yaffs_DirUnlockRead(dev);
}
}
if (obj) {
dev = obj->myDev;
- yaffs_DirLockWrite(dev);
yaffs_GrossLock(dev);
yaffs_DeleteObject(obj);
yaffs_GrossUnlock(dev);
- yaffs_DirUnlockWrite(dev);
}
#if (LINUX_VERSION_CODE > KERNEL_VERSION(2, 6, 13))
truncate_inode_pages(&inode->i_data, 0);
("yaffs_file_flush object %d (%s)\n", obj->objectId,
obj->dirty ? "dirty" : "clean"));
- yaffs_DirLockRead(dev);
yaffs_GrossLock(dev);
yaffs_FlushFile(obj, 1,0);
yaffs_GrossUnlock(dev);
- yaffs_DirUnlockRead(dev);
return 0;
}
pg_buf = kmap(pg);
/* FIXME: Can kmap fail? */
- yaffs_DirLockRead(dev);
yaffs_GrossLock(dev);
ret = yaffs_ReadDataFromFile(obj, pg_buf,
PAGE_CACHE_SIZE);
yaffs_GrossUnlock(dev);
- yaffs_DirUnlockRead(dev);
if (ret >= 0)
ret = 0;
buffer = kmap(page);
obj = yaffs_InodeToObject(inode);
- yaffs_DirLockRead(obj->myDev);
yaffs_GrossLock(obj->myDev);
T(YAFFS_TRACE_OS,
(int)obj->variant.fileVariant.fileSize, (int)inode->i_size));
yaffs_GrossUnlock(obj->myDev);
- yaffs_DirUnlockRead(obj->myDev);
kunmap(page);
SetPageUptodate(page);
dev = obj->myDev;
- yaffs_DirLockRead(dev);
yaffs_GrossLock(dev);
inode = f->f_dentry->d_inode;
}
yaffs_GrossUnlock(dev);
- yaffs_DirUnlockRead(dev);
-
return (nWritten == 0) && (n > 0) ? -ENOSPC : nWritten;
}
dev = obj->myDev;
- yaffs_DirLockRead(dev);
yaffs_GrossLock(dev);
nFreeChunks = yaffs_GetNumberOfFreeChunks(dev);
yaffs_GrossUnlock(dev);
- yaffs_DirUnlockRead(dev);
return (nFreeChunks > 20) ? 1 : 0;
}
static void yaffs_release_space(struct file *f)
{
+ yaffs_Object *obj;
+ yaffs_Device *dev;
+
+
+ obj = yaffs_DentryToObject(f->f_dentry);
+
+ dev = obj->myDev;
+
+ yaffs_GrossLock(dev);
+
+
+ yaffs_GrossUnlock(dev);
}
static int yaffs_readdir(struct file *f, void *dirent, filldir_t filldir)
{
yaffs_Object *obj;
yaffs_Device *dev;
+ struct yaffs_SearchContext *sc;
struct inode *inode = f->f_dentry->d_inode;
unsigned long offset, curoffs;
- struct ylist_head *i;
yaffs_Object *l;
+ int retVal = 0;
char name[YAFFS_MAX_NAME_LENGTH + 1];
obj = yaffs_DentryToObject(f->f_dentry);
dev = obj->myDev;
- yaffs_DirLockRead(dev);
yaffs_GrossLock(dev);
offset = f->f_pos;
+ sc = yaffs_NewSearch(obj);
+ if(!sc){
+ retVal = -ENOMEM;
+ goto unlock_out;
+ }
+
T(YAFFS_TRACE_OS, ("yaffs_readdir: starting at %d\n", (int)offset));
if (offset == 0) {
T(YAFFS_TRACE_OS,
("yaffs_readdir: entry . ino %d \n",
(int)inode->i_ino));
-
yaffs_GrossUnlock(dev);
-
if (filldir(dirent, ".", 1, offset, inode->i_ino, DT_DIR) < 0)
goto out;
-
yaffs_GrossLock(dev);
-
offset++;
f->f_pos++;
}
T(YAFFS_TRACE_OS,
("yaffs_readdir: entry .. ino %d \n",
(int)f->f_dentry->d_parent->d_inode->i_ino));
-
yaffs_GrossUnlock(dev);
-
if (filldir(dirent, "..", 2, offset,
f->f_dentry->d_parent->d_inode->i_ino, DT_DIR) < 0)
goto out;
-
yaffs_GrossLock(dev);
-
offset++;
f->f_pos++;
}
f->f_version = inode->i_version;
}
- ylist_for_each(i, &obj->variant.directoryVariant.children) {
+ while(sc->nextReturn){
curoffs++;
+ l = sc->nextReturn;
if (curoffs >= offset) {
- l = ylist_entry(i, yaffs_Object, siblings);
+ int this_inode = yaffs_GetObjectInode(l);
+ int this_type = yaffs_GetObjectType(l);
yaffs_GetObjectName(l, name,
YAFFS_MAX_NAME_LENGTH + 1);
("yaffs_readdir: %s inode %d\n", name,
yaffs_GetObjectInode(l)));
- yaffs_GrossUnlock(dev);
+ yaffs_GrossUnlock(dev);
if (filldir(dirent,
name,
strlen(name),
offset,
- yaffs_GetObjectInode(l),
- yaffs_GetObjectType(l)) < 0)
+ this_inode,
+ this_type) < 0)
goto out;
- yaffs_GrossLock(dev);
+ yaffs_GrossLock(dev);
offset++;
f->f_pos++;
}
+ yaffs_SearchAdvance(sc);
}
+unlock_out:
yaffs_GrossUnlock(dev);
out:
- yaffs_DirUnlockRead(dev);
+ yaffs_EndSearch(sc);
- return 0;
+ return retVal;
}
/*
dev = parent->myDev;
- yaffs_DirLockWrite(dev);
yaffs_GrossLock(dev);
switch (mode & S_IFMT) {
/* Can not call yaffs_get_inode() with gross lock held */
yaffs_GrossUnlock(dev);
- yaffs_DirUnlockWrite(dev);
if (obj) {
inode = yaffs_get_inode(dir->i_sb, mode, rdev, obj);
dev = yaffs_InodeToObject(dir)->myDev;
- yaffs_DirLockWrite(dev);
yaffs_GrossLock(dev);
retVal = yaffs_Unlink(yaffs_InodeToObject(dir), dentry->d_name.name);
if (retVal == YAFFS_OK) {
dentry->d_inode->i_nlink--;
dir->i_version++;
- }
-
- yaffs_GrossUnlock(dev);
- yaffs_DirUnlockWrite(dev);
-
- if( retVal == YAFFS_OK){
+ yaffs_GrossUnlock(dev);
mark_inode_dirty(dentry->d_inode);
update_dir_time(dir);
return 0;
}
-
+ yaffs_GrossUnlock(dev);
return -ENOTEMPTY;
}
obj = yaffs_InodeToObject(inode);
dev = obj->myDev;
- yaffs_DirLockWrite(dev);
yaffs_GrossLock(dev);
if (!S_ISDIR(inode->i_mode)) /* Don't link directories */
}
yaffs_GrossUnlock(dev);
- yaffs_DirUnlockWrite(dev);
if (link){
update_dir_time(dir);
T(YAFFS_TRACE_OS, ("yaffs_symlink\n"));
dev = yaffs_InodeToObject(dir)->myDev;
- yaffs_DirLockWrite(dev);
yaffs_GrossLock(dev);
obj = yaffs_MknodSymLink(yaffs_InodeToObject(dir), dentry->d_name.name,
S_IFLNK | S_IRWXUGO, uid, gid, symname);
yaffs_GrossUnlock(dev);
- yaffs_DirUnlockWrite(dev);
if (obj) {
struct inode *inode;
dev = obj->myDev;
T(YAFFS_TRACE_OS, ("yaffs_sync_object\n"));
- yaffs_DirLockRead(dev);
yaffs_GrossLock(dev);
yaffs_FlushFile(obj, 1, datasync);
yaffs_GrossUnlock(dev);
- yaffs_DirUnlockRead(dev);
return 0;
}
T(YAFFS_TRACE_OS, ("yaffs_rename\n"));
dev = yaffs_InodeToObject(old_dir)->myDev;
- yaffs_DirLockWrite(dev);
yaffs_GrossLock(dev);
/* Check if the target is an existing directory that is not empty. */
new_dentry->d_name.name);
}
yaffs_GrossUnlock(dev);
- yaffs_DirUnlockWrite(dev);
if (retVal == YAFFS_OK) {
if (target) {
error = inode_change_ok(inode, attr);
if (error == 0) {
dev = yaffs_InodeToObject(inode)->myDev;
- yaffs_DirLockRead(dev);
yaffs_GrossLock(dev);
if (yaffs_SetAttributes(yaffs_InodeToObject(inode), attr) ==
YAFFS_OK) {
error = -EPERM;
}
yaffs_GrossUnlock(dev);
- yaffs_DirUnlockRead(dev);
if (!error)
error = inode_setattr(inode, attr);
}
T(YAFFS_TRACE_OS, ("yaffs_statfs\n"));
- yaffs_DirLockRead(dev);
yaffs_GrossLock(dev);
buf->f_type = YAFFS_MAGIC;
buf->f_bavail = buf->f_bfree;
yaffs_GrossUnlock(dev);
- yaffs_DirUnlockRead(dev);
return 0;
}
T(YAFFS_TRACE_OS, ("yaffs_do_sync_fs\n"));
if (sb->s_dirt) {
- yaffs_DirLockRead(dev);
yaffs_GrossLock(dev);
if (dev) {
}
yaffs_GrossUnlock(dev);
- yaffs_DirUnlockRead(dev);
sb->s_dirt = 0;
}
* need to lock again.
*/
- yaffs_DirLockRead(dev);
yaffs_GrossLock(dev);
obj = yaffs_FindObjectByNumber(dev, inode->i_ino);
yaffs_FillInodeFromObject(inode, obj);
yaffs_GrossUnlock(dev);
- yaffs_DirUnlockRead(dev);
unlock_new_inode(inode);
return inode;
T(YAFFS_TRACE_OS,
("yaffs_read_inode for %d\n", (int)inode->i_ino));
- yaffs_DirLockRead(dev);
yaffs_GrossLock(dev);
obj = yaffs_FindObjectByNumber(dev, inode->i_ino);
yaffs_FillInodeFromObject(inode, obj);
yaffs_GrossUnlock(dev);
- yaffs_DirUnlockRead(dev);
}
#endif
T(YAFFS_TRACE_OS,
("yaffs_remount_fs: %s: RO\n", dev->name));
- yaffs_DirLockWrite(dev);
+
yaffs_GrossLock(dev);
yaffs_FlushEntireDeviceCache(dev);
mtd->sync(mtd);
yaffs_GrossUnlock(dev);
- yaffs_DirUnlockWrite(dev);
} else {
T(YAFFS_TRACE_OS,
("yaffs_remount_fs: %s: RW\n", dev->name));
T(YAFFS_TRACE_OS, ("yaffs_put_super\n"));
- yaffs_DirLockWrite(dev);
yaffs_GrossLock(dev);
yaffs_FlushEntireDeviceCache(dev);
yaffs_Deinitialise(dev);
yaffs_GrossUnlock(dev);
- yaffs_DirUnlockWrite(dev);
/* we assume this is protected by lock_kernel() in mount/umount */
ylist_del(&dev->devList);
/* we assume this is protected by lock_kernel() in mount/umount */
ylist_add_tail(&dev->devList, &yaffs_dev_list);
-
- yaffs_DirLockInitialise(dev);
- yaffs_GrossLockInitialise(dev);
- yaffs_DirLockWrite(dev);
+ /* Directory search handling...*/
+ YINIT_LIST_HEAD(&dev->searchContexts);
+ dev->removeObjectCallback = yaffs_RemoveObjectCallback;
+
+ init_MUTEX(&dev->grossLock);
+
yaffs_GrossLock(dev);
err = yaffs_GutsInitialise(dev);
/* Release lock before yaffs_get_inode() */
yaffs_GrossUnlock(dev);
- yaffs_DirUnlockWrite(dev);
/* Create root inode */
if (err == YAFFS_OK)
projects / yaffs2.git / blobdiff