From 5ca29607331fe37980dc3b488793ef8b1409b722 Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Tue, 17 Jul 2007 04:04:29 -0700 Subject: [PATCH] knfsd: exportfs: remove iget abuse When the exportfs interface was added the expectation was that filesystems provide an operation to convert from a file handle to an inode/dentry, but it kept a backwards compat option that still calls into iget. Calling into iget from non-filesystem code is very bad, because it gives too little information to filesystem, and simply crashes if the filesystem doesn't implement the ->read_inode routine. Fortunately there are only two filesystems left using this fallback: efs and jfs. This patch moves a copy of export_iget to each of those to implement the get_dentry method. While this is a temporary increase of lines of code in the kernel it allows for a much cleaner interface and important code restructuring in later patches. [akpm@linux-foundation.org: add jfs_get_inode_flags() declaration] Signed-off-by: Dave Kleikamp Signed-off-by: Christoph Hellwig Signed-off-by: Neil Brown Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- fs/efs/namei.c | 32 ++++++++++++++++++++++++ fs/efs/super.c | 1 + fs/exportfs/expfs.c | 56 +++--------------------------------------- fs/jfs/jfs_inode.h | 1 + fs/jfs/namei.c | 32 ++++++++++++++++++++++++ fs/jfs/super.c | 1 + include/linux/efs_fs.h | 1 + 7 files changed, 71 insertions(+), 53 deletions(-) diff --git a/fs/efs/namei.c b/fs/efs/namei.c index ed4a207fe2..5276b19423 100644 --- a/fs/efs/namei.c +++ b/fs/efs/namei.c @@ -75,6 +75,38 @@ struct dentry *efs_lookup(struct inode *dir, struct dentry *dentry, struct namei return NULL; } +struct dentry *efs_get_dentry(struct super_block *sb, void *vobjp) +{ + __u32 *objp = vobjp; + unsigned long ino = objp[0]; + __u32 generation = objp[1]; + struct inode *inode; + struct dentry *result; + + if (ino == 0) + return ERR_PTR(-ESTALE); + inode = iget(sb, ino); + if (inode == NULL) + return ERR_PTR(-ENOMEM); + + if (is_bad_inode(inode) || + (generation && inode->i_generation != generation)) { + result = ERR_PTR(-ESTALE); + goto out_iput; + } + + result = d_alloc_anon(inode); + if (!result) { + result = ERR_PTR(-ENOMEM); + goto out_iput; + } + return result; + + out_iput: + iput(inode); + return result; +} + struct dentry *efs_get_parent(struct dentry *child) { struct dentry *parent; diff --git a/fs/efs/super.c b/fs/efs/super.c index 67338d622f..d360c81f3a 100644 --- a/fs/efs/super.c +++ b/fs/efs/super.c @@ -114,6 +114,7 @@ static const struct super_operations efs_superblock_operations = { }; static struct export_operations efs_export_ops = { + .get_dentry = efs_get_dentry, .get_parent = efs_get_parent, }; diff --git a/fs/exportfs/expfs.c b/fs/exportfs/expfs.c index 16287af348..dd132bb7b8 100644 --- a/fs/exportfs/expfs.c +++ b/fs/exportfs/expfs.c @@ -391,61 +391,11 @@ out: return error; } - -static struct dentry *export_iget(struct super_block *sb, unsigned long ino, __u32 generation) +static struct dentry *get_dentry(struct super_block *sb, void *vobjp) { - - /* iget isn't really right if the inode is currently unallocated!! - * This should really all be done inside each filesystem - * - * ext2fs' read_inode has been strengthed to return a bad_inode if - * the inode had been deleted. - * - * Currently we don't know the generation for parent directory, so - * a generation of 0 means "accept any" - */ - struct inode *inode; - struct dentry *result; - if (ino == 0) - return ERR_PTR(-ESTALE); - inode = iget(sb, ino); - if (inode == NULL) - return ERR_PTR(-ENOMEM); - if (is_bad_inode(inode) - || (generation && inode->i_generation != generation) - ) { - /* we didn't find the right inode.. */ - dprintk("fh_verify: Inode %lu, Bad count: %d %d or version %u %u\n", - inode->i_ino, - inode->i_nlink, atomic_read(&inode->i_count), - inode->i_generation, - generation); - - iput(inode); - return ERR_PTR(-ESTALE); - } - /* now to find a dentry. - * If possible, get a well-connected one - */ - result = d_alloc_anon(inode); - if (!result) { - iput(inode); - return ERR_PTR(-ENOMEM); - } - return result; + return ERR_PTR(-ESTALE); } - -static struct dentry *get_object(struct super_block *sb, void *vobjp) -{ - __u32 *objp = vobjp; - unsigned long ino = objp[0]; - __u32 generation = objp[1]; - - return export_iget(sb, ino, generation); -} - - /** * export_encode_fh - default export_operations->encode_fh function * @dentry: the dentry to encode @@ -524,7 +474,7 @@ struct export_operations export_op_default = { .get_name = get_name, .get_parent = get_parent, - .get_dentry = get_object, + .get_dentry = get_dentry, }; EXPORT_SYMBOL(export_op_default); diff --git a/fs/jfs/jfs_inode.h b/fs/jfs/jfs_inode.h index 2374b595f2..f0ec72b263 100644 --- a/fs/jfs/jfs_inode.h +++ b/fs/jfs/jfs_inode.h @@ -32,6 +32,7 @@ extern void jfs_truncate_nolock(struct inode *, loff_t); extern void jfs_free_zero_link(struct inode *); extern struct dentry *jfs_get_parent(struct dentry *dentry); extern void jfs_get_inode_flags(struct jfs_inode_info *); +extern struct dentry *jfs_get_dentry(struct super_block *sb, void *vobjp); extern void jfs_set_inode_flags(struct inode *); extern int jfs_get_block(struct inode *, sector_t, struct buffer_head *, int); diff --git a/fs/jfs/namei.c b/fs/jfs/namei.c index 25161c4121..932797ba43 100644 --- a/fs/jfs/namei.c +++ b/fs/jfs/namei.c @@ -1477,6 +1477,38 @@ static struct dentry *jfs_lookup(struct inode *dip, struct dentry *dentry, struc return dentry; } +struct dentry *jfs_get_dentry(struct super_block *sb, void *vobjp) +{ + __u32 *objp = vobjp; + unsigned long ino = objp[0]; + __u32 generation = objp[1]; + struct inode *inode; + struct dentry *result; + + if (ino == 0) + return ERR_PTR(-ESTALE); + inode = iget(sb, ino); + if (inode == NULL) + return ERR_PTR(-ENOMEM); + + if (is_bad_inode(inode) || + (generation && inode->i_generation != generation)) { + result = ERR_PTR(-ESTALE); + goto out_iput; + } + + result = d_alloc_anon(inode); + if (!result) { + result = ERR_PTR(-ENOMEM); + goto out_iput; + } + return result; + + out_iput: + iput(inode); + return result; +} + struct dentry *jfs_get_parent(struct dentry *dentry) { struct super_block *sb = dentry->d_inode->i_sb; diff --git a/fs/jfs/super.c b/fs/jfs/super.c index 49b652bd96..929fceca79 100644 --- a/fs/jfs/super.c +++ b/fs/jfs/super.c @@ -738,6 +738,7 @@ static const struct super_operations jfs_super_operations = { }; static struct export_operations jfs_export_operations = { + .get_dentry = jfs_get_dentry, .get_parent = jfs_get_parent, }; diff --git a/include/linux/efs_fs.h b/include/linux/efs_fs.h index dfed8009eb..16cb25cbf7 100644 --- a/include/linux/efs_fs.h +++ b/include/linux/efs_fs.h @@ -45,6 +45,7 @@ extern efs_block_t efs_map_block(struct inode *, efs_block_t); extern int efs_get_block(struct inode *, sector_t, struct buffer_head *, int); extern struct dentry *efs_lookup(struct inode *, struct dentry *, struct nameidata *); +extern struct dentry *efs_get_dentry(struct super_block *sb, void *vobjp); extern struct dentry *efs_get_parent(struct dentry *); extern int efs_bmap(struct inode *, int); -- 2.39.5