X-Git-Url: https://git.proxmox.com/?a=blobdiff_plain;f=fs%2Fexportfs%2Fexpfs.c;h=cc91227d3bb88dcdce06b83806baf6dd7f912225;hb=e5093ff05d36c64e8f36a9ddb26358256dc133ea;hp=8adb32a9387a3e6cb76ba0cf80b9873d51dad3bd;hpb=b4b613fd83853f8c688b3de20ab1a42331257975;p=mirror_ubuntu-artful-kernel.git diff --git a/fs/exportfs/expfs.c b/fs/exportfs/expfs.c index 8adb32a9387a..cc91227d3bb8 100644 --- a/fs/exportfs/expfs.c +++ b/fs/exportfs/expfs.c @@ -1,4 +1,13 @@ - +/* + * Copyright (C) Neil Brown 2002 + * Copyright (C) Christoph Hellwig 2007 + * + * This file contains the code mapping from inodes to NFS file handles, + * and for mapping back from file handles to dentries. + * + * For details on why we do all the strange and hairy things in here + * take a look at Documentation/filesystems/Exporting. + */ #include #include #include @@ -9,32 +18,19 @@ #define dprintk(fmt, args...) do{}while(0) -static int get_name(struct dentry *dentry, char *name, +static int get_name(struct vfsmount *mnt, struct dentry *dentry, char *name, struct dentry *child); -static struct dentry *exportfs_get_dentry(struct super_block *sb, void *obj) +static int exportfs_get_name(struct vfsmount *mnt, struct dentry *dir, + char *name, struct dentry *child) { - struct dentry *result = ERR_PTR(-ESTALE); - - if (sb->s_export_op->get_dentry) { - result = sb->s_export_op->get_dentry(sb, obj); - if (!result) - result = ERR_PTR(-ESTALE); - } - - return result; -} - -static int exportfs_get_name(struct dentry *dir, char *name, - struct dentry *child) -{ - struct export_operations *nop = dir->d_sb->s_export_op; + const struct export_operations *nop = dir->d_sb->s_export_op; if (nop->get_name) return nop->get_name(dir, name, child); else - return get_name(dir, name, child); + return get_name(mnt, dir, name, child); } /* @@ -98,7 +94,7 @@ find_disconnected_root(struct dentry *dentry) * It may already be, as the flag isn't always updated when connection happens. */ static int -reconnect_path(struct super_block *sb, struct dentry *target_dir) +reconnect_path(struct vfsmount *mnt, struct dentry *target_dir) { char nbuf[NAME_MAX+1]; int noprogress = 0; @@ -121,7 +117,7 @@ reconnect_path(struct super_block *sb, struct dentry *target_dir) pd->d_flags &= ~DCACHE_DISCONNECTED; spin_unlock(&pd->d_lock); noprogress = 0; - } else if (pd == sb->s_root) { + } else if (pd == mnt->mnt_sb->s_root) { printk(KERN_ERR "export: Eeek filesystem root is not connected, impossible\n"); spin_lock(&pd->d_lock); pd->d_flags &= ~DCACHE_DISCONNECTED; @@ -147,21 +143,21 @@ reconnect_path(struct super_block *sb, struct dentry *target_dir) struct dentry *npd; mutex_lock(&pd->d_inode->i_mutex); - if (sb->s_export_op->get_parent) - ppd = sb->s_export_op->get_parent(pd); + if (mnt->mnt_sb->s_export_op->get_parent) + ppd = mnt->mnt_sb->s_export_op->get_parent(pd); mutex_unlock(&pd->d_inode->i_mutex); if (IS_ERR(ppd)) { err = PTR_ERR(ppd); dprintk("%s: get_parent of %ld failed, err %d\n", - __FUNCTION__, pd->d_inode->i_ino, err); + __func__, pd->d_inode->i_ino, err); dput(pd); break; } - dprintk("%s: find name of %lu in %lu\n", __FUNCTION__, + dprintk("%s: find name of %lu in %lu\n", __func__, pd->d_inode->i_ino, ppd->d_inode->i_ino); - err = exportfs_get_name(ppd, nbuf, pd); + err = exportfs_get_name(mnt, ppd, nbuf, pd); if (err) { dput(ppd); dput(pd); @@ -172,14 +168,14 @@ reconnect_path(struct super_block *sb, struct dentry *target_dir) continue; break; } - dprintk("%s: found name: %s\n", __FUNCTION__, nbuf); + dprintk("%s: found name: %s\n", __func__, nbuf); mutex_lock(&ppd->d_inode->i_mutex); npd = lookup_one_len(nbuf, ppd, strlen(nbuf)); mutex_unlock(&ppd->d_inode->i_mutex); if (IS_ERR(npd)) { err = PTR_ERR(npd); dprintk("%s: lookup failed: %d\n", - __FUNCTION__, err); + __func__, err); dput(ppd); dput(pd); break; @@ -192,7 +188,7 @@ reconnect_path(struct super_block *sb, struct dentry *target_dir) if (npd == pd) noprogress = 0; else - printk("%s: npd != pd\n", __FUNCTION__); + printk("%s: npd != pd\n", __func__); dput(npd); dput(ppd); if (IS_ROOT(pd)) { @@ -214,125 +210,6 @@ reconnect_path(struct super_block *sb, struct dentry *target_dir) return 0; } -/** - * find_exported_dentry - helper routine to implement export_operations->decode_fh - * @sb: The &super_block identifying the filesystem - * @obj: An opaque identifier of the object to be found - passed to - * get_inode - * @parent: An optional opqaue identifier of the parent of the object. - * @acceptable: A function used to test possible &dentries to see if they are - * acceptable - * @context: A parameter to @acceptable so that it knows on what basis to - * judge. - * - * find_exported_dentry is the central helper routine to enable file systems - * to provide the decode_fh() export_operation. It's main task is to take - * an &inode, find or create an appropriate &dentry structure, and possibly - * splice this into the dcache in the correct place. - * - * The decode_fh() operation provided by the filesystem should call - * find_exported_dentry() with the same parameters that it received except - * that instead of the file handle fragment, pointers to opaque identifiers - * for the object and optionally its parent are passed. The default decode_fh - * routine passes one pointer to the start of the filehandle fragment, and - * one 8 bytes into the fragment. It is expected that most filesystems will - * take this approach, though the offset to the parent identifier may well be - * different. - * - * find_exported_dentry() will call get_dentry to get an dentry pointer from - * the file system. If any &dentry in the d_alias list is acceptable, it will - * be returned. Otherwise find_exported_dentry() will attempt to splice a new - * &dentry into the dcache using get_name() and get_parent() to find the - * appropriate place. - */ - -struct dentry * -find_exported_dentry(struct super_block *sb, void *obj, void *parent, - int (*acceptable)(void *context, struct dentry *de), - void *context) -{ - struct dentry *result, *alias; - int err = -ESTALE; - - /* - * Attempt to find the inode. - */ - result = exportfs_get_dentry(sb, obj); - if (IS_ERR(result)) - return result; - - if (S_ISDIR(result->d_inode->i_mode)) { - if (!(result->d_flags & DCACHE_DISCONNECTED)) { - if (acceptable(context, result)) - return result; - err = -EACCES; - goto err_result; - } - - err = reconnect_path(sb, result); - if (err) - goto err_result; - } else { - struct dentry *target_dir, *nresult; - char nbuf[NAME_MAX+1]; - - alias = find_acceptable_alias(result, acceptable, context); - if (alias) - return alias; - - if (parent == NULL) - goto err_result; - - target_dir = exportfs_get_dentry(sb,parent); - if (IS_ERR(target_dir)) { - err = PTR_ERR(target_dir); - goto err_result; - } - - err = reconnect_path(sb, target_dir); - if (err) { - dput(target_dir); - goto err_result; - } - - /* - * As we weren't after a directory, have one more step to go. - */ - err = exportfs_get_name(target_dir, nbuf, result); - if (!err) { - mutex_lock(&target_dir->d_inode->i_mutex); - nresult = lookup_one_len(nbuf, target_dir, - strlen(nbuf)); - mutex_unlock(&target_dir->d_inode->i_mutex); - if (!IS_ERR(nresult)) { - if (nresult->d_inode) { - dput(result); - result = nresult; - } else - dput(nresult); - } - } - dput(target_dir); - } - - alias = find_acceptable_alias(result, acceptable, context); - if (alias) - return alias; - - /* drat - I just cannot find anything acceptable */ - dput(result); - /* It might be justifiable to return ESTALE here, - * but the filehandle at-least looks reasonable good - * and it may just be a permission problem, so returning - * -EACCESS is safer - */ - return ERR_PTR(-EACCES); - - err_result: - dput(result); - return ERR_PTR(err); -} - struct getdents_callback { char *name; /* name that was found. It already points to a buffer NAME_MAX+1 is size */ @@ -370,8 +247,8 @@ static int filldir_one(void * __buf, const char * name, int len, * calls readdir on the parent until it finds an entry with * the same inode number as the child, and returns that. */ -static int get_name(struct dentry *dentry, char *name, - struct dentry *child) +static int get_name(struct vfsmount *mnt, struct dentry *dentry, + char *name, struct dentry *child) { struct inode *dir = dentry->d_inode; int error; @@ -387,7 +264,7 @@ static int get_name(struct dentry *dentry, char *name, /* * Open the directory ... */ - file = dentry_open(dget(dentry), NULL, O_RDONLY); + file = dentry_open(dget(dentry), mntget(mnt), O_RDONLY); error = PTR_ERR(file); if (IS_ERR(file)) goto out; @@ -434,100 +311,177 @@ out: * can be used to check that it is still valid. It places them in the * filehandle fragment where export_decode_fh expects to find them. */ -static int export_encode_fh(struct dentry *dentry, __u32 *fh, int *max_len, - int connectable) +static int export_encode_fh(struct dentry *dentry, struct fid *fid, + int *max_len, int connectable) { struct inode * inode = dentry->d_inode; int len = *max_len; - int type = 1; + int type = FILEID_INO32_GEN; if (len < 2 || (connectable && len < 4)) return 255; len = 2; - fh[0] = inode->i_ino; - fh[1] = inode->i_generation; + fid->i32.ino = inode->i_ino; + fid->i32.gen = inode->i_generation; if (connectable && !S_ISDIR(inode->i_mode)) { struct inode *parent; spin_lock(&dentry->d_lock); parent = dentry->d_parent->d_inode; - fh[2] = parent->i_ino; - fh[3] = parent->i_generation; + fid->i32.parent_ino = parent->i_ino; + fid->i32.parent_gen = parent->i_generation; spin_unlock(&dentry->d_lock); len = 4; - type = 2; + type = FILEID_INO32_GEN_PARENT; } *max_len = len; return type; } - -/** - * export_decode_fh - default export_operations->decode_fh function - * @sb: The superblock - * @fh: pointer to the file handle fragment - * @fh_len: length of file handle fragment - * @acceptable: function for testing acceptability of dentrys - * @context: context for @acceptable - * - * This is the default decode_fh() function. - * a fileid_type of 1 indicates that the filehandlefragment - * just contains an object identifier understood by get_dentry. - * a fileid_type of 2 says that there is also a directory - * identifier 8 bytes in to the filehandlefragement. - */ -static struct dentry *export_decode_fh(struct super_block *sb, __u32 *fh, int fh_len, - int fileid_type, - int (*acceptable)(void *context, struct dentry *de), - void *context) -{ - __u32 parent[2]; - parent[0] = parent[1] = 0; - if (fh_len < 2 || fileid_type > 2) - return NULL; - if (fileid_type == 2) { - if (fh_len > 2) parent[0] = fh[2]; - if (fh_len > 3) parent[1] = fh[3]; - } - return find_exported_dentry(sb, fh, parent, - acceptable, context); -} - -int exportfs_encode_fh(struct dentry *dentry, __u32 *fh, int *max_len, +int exportfs_encode_fh(struct dentry *dentry, struct fid *fid, int *max_len, int connectable) { - struct export_operations *nop = dentry->d_sb->s_export_op; + const struct export_operations *nop = dentry->d_sb->s_export_op; int error; if (nop->encode_fh) - error = nop->encode_fh(dentry, fh, max_len, connectable); + error = nop->encode_fh(dentry, fid->raw, max_len, connectable); else - error = export_encode_fh(dentry, fh, max_len, connectable); + error = export_encode_fh(dentry, fid, max_len, connectable); return error; } EXPORT_SYMBOL_GPL(exportfs_encode_fh); -struct dentry *exportfs_decode_fh(struct vfsmount *mnt, __u32 *fh, int fh_len, - int fileid_type, int (*acceptable)(void *, struct dentry *), - void *context) +struct dentry *exportfs_decode_fh(struct vfsmount *mnt, struct fid *fid, + int fh_len, int fileid_type, + int (*acceptable)(void *, struct dentry *), void *context) { - struct export_operations *nop = mnt->mnt_sb->s_export_op; - struct dentry *result; + const struct export_operations *nop = mnt->mnt_sb->s_export_op; + struct dentry *result, *alias; + int err; - if (nop->decode_fh) { - result = nop->decode_fh(mnt->mnt_sb, fh, fh_len, fileid_type, - acceptable, context); + /* + * Try to get any dentry for the given file handle from the filesystem. + */ + result = nop->fh_to_dentry(mnt->mnt_sb, fid, fh_len, fileid_type); + if (!result) + result = ERR_PTR(-ESTALE); + if (IS_ERR(result)) + return result; + + if (S_ISDIR(result->d_inode->i_mode)) { + /* + * This request is for a directory. + * + * On the positive side there is only one dentry for each + * directory inode. On the negative side this implies that we + * to ensure our dentry is connected all the way up to the + * filesystem root. + */ + if (result->d_flags & DCACHE_DISCONNECTED) { + err = reconnect_path(mnt, result); + if (err) + goto err_result; + } + + if (!acceptable(context, result)) { + err = -EACCES; + goto err_result; + } + + return result; } else { - result = export_decode_fh(mnt->mnt_sb, fh, fh_len, fileid_type, - acceptable, context); + /* + * It's not a directory. Life is a little more complicated. + */ + struct dentry *target_dir, *nresult; + char nbuf[NAME_MAX+1]; + + /* + * See if either the dentry we just got from the filesystem + * or any alias for it is acceptable. This is always true + * if this filesystem is exported without the subtreecheck + * option. If the filesystem is exported with the subtree + * check option there's a fair chance we need to look at + * the parent directory in the file handle and make sure + * it's connected to the filesystem root. + */ + alias = find_acceptable_alias(result, acceptable, context); + if (alias) + return alias; + + /* + * Try to extract a dentry for the parent directory from the + * file handle. If this fails we'll have to give up. + */ + err = -ESTALE; + if (!nop->fh_to_parent) + goto err_result; + + target_dir = nop->fh_to_parent(mnt->mnt_sb, fid, + fh_len, fileid_type); + if (!target_dir) + goto err_result; + err = PTR_ERR(target_dir); + if (IS_ERR(target_dir)) + goto err_result; + + /* + * And as usual we need to make sure the parent directory is + * connected to the filesystem root. The VFS really doesn't + * like disconnected directories.. + */ + err = reconnect_path(mnt, target_dir); + if (err) { + dput(target_dir); + goto err_result; + } + + /* + * Now that we've got both a well-connected parent and a + * dentry for the inode we're after, make sure that our + * inode is actually connected to the parent. + */ + err = exportfs_get_name(mnt, target_dir, nbuf, result); + if (!err) { + mutex_lock(&target_dir->d_inode->i_mutex); + nresult = lookup_one_len(nbuf, target_dir, + strlen(nbuf)); + mutex_unlock(&target_dir->d_inode->i_mutex); + if (!IS_ERR(nresult)) { + if (nresult->d_inode) { + dput(result); + result = nresult; + } else + dput(nresult); + } + } + + /* + * At this point we are done with the parent, but it's pinned + * by the child dentry anyway. + */ + dput(target_dir); + + /* + * And finally make sure the dentry is actually acceptable + * to NFSD. + */ + alias = find_acceptable_alias(result, acceptable, context); + if (!alias) { + err = -EACCES; + goto err_result; + } + + return alias; } - return result; + err_result: + dput(result); + return ERR_PTR(err); } EXPORT_SYMBOL_GPL(exportfs_decode_fh); -EXPORT_SYMBOL(find_exported_dentry); - MODULE_LICENSE("GPL");