From: Erez Zadok Date: Fri, 23 Mar 2007 17:07:14 +0000 (-0400) Subject: Unionfs: Added several BUG_ONs to assert dentry validity X-Git-Url: https://git.fsl.cs.sunysb.edu/?a=commitdiff_plain;h=813e8a2cc7c736ec725e8b0311447a2998daa502;p=unionfs-3.2.y.git Unionfs: Added several BUG_ONs to assert dentry validity This should help catch races between the VFS and the branch-management code. Signed-off-by: Erez Zadok Signed-off-by: Josef 'Jeff' Sipek --- diff --git a/fs/unionfs/inode.c b/fs/unionfs/inode.c index 5c452b6d87d5..97dad8cccc12 100644 --- a/fs/unionfs/inode.c +++ b/fs/unionfs/inode.c @@ -249,6 +249,9 @@ static int unionfs_link(struct dentry *old_dentry, struct inode *dir, struct dentry *whiteout_dentry; char *name = NULL; + BUG_ON(!is_valid_dentry(new_dentry)); + BUG_ON(!is_valid_dentry(old_dentry)); + double_lock_dentry(new_dentry, old_dentry); hidden_new_dentry = unionfs_lower_dentry(new_dentry); @@ -373,6 +376,8 @@ static int unionfs_symlink(struct inode *dir, struct dentry *dentry, int bindex = 0, bstart; char *name = NULL; + BUG_ON(!is_valid_dentry(dentry)); + unionfs_lock_dentry(dentry); /* We start out in the leftmost branch. */ @@ -495,6 +500,8 @@ static int unionfs_mkdir(struct inode *parent, struct dentry *dentry, int mode) int whiteout_unlinked = 0; struct sioq_args args; + BUG_ON(!is_valid_dentry(dentry)); + unionfs_lock_dentry(dentry); bstart = dbstart(dentry); @@ -622,6 +629,8 @@ static int unionfs_mknod(struct inode *dir, struct dentry *dentry, int mode, char *name = NULL; int whiteout_unlinked = 0; + BUG_ON(!is_valid_dentry(dentry)); + unionfs_lock_dentry(dentry); bstart = dbstart(dentry); @@ -724,6 +733,8 @@ static int unionfs_readlink(struct dentry *dentry, char __user * buf, int err; struct dentry *hidden_dentry; + BUG_ON(!is_valid_dentry(dentry)); + unionfs_lock_dentry(dentry); hidden_dentry = unionfs_lower_dentry(dentry); @@ -749,6 +760,8 @@ static void *unionfs_follow_link(struct dentry *dentry, struct nameidata *nd) int len = PAGE_SIZE, err; mm_segment_t old_fs; + BUG_ON(!is_valid_dentry(dentry)); + /* This is freed by the put_link method assuming a successful call. */ buf = kmalloc(len, GFP_KERNEL); if (!buf) { @@ -908,6 +921,8 @@ static int unionfs_setattr(struct dentry *dentry, struct iattr *ia) int i; int copyup = 0; + BUG_ON(!is_valid_dentry(dentry)); + unionfs_lock_dentry(dentry); bstart = dbstart(dentry); bend = dbend(dentry); diff --git a/fs/unionfs/rename.c b/fs/unionfs/rename.c index c9aa0400a3fc..00444929c708 100644 --- a/fs/unionfs/rename.c +++ b/fs/unionfs/rename.c @@ -379,6 +379,9 @@ int unionfs_rename(struct inode *old_dir, struct dentry *old_dentry, int err = 0; struct dentry *wh_dentry; + BUG_ON(!is_valid_dentry(old_dentry)); + BUG_ON(!is_valid_dentry(new_dentry)); + double_lock_dentry(old_dentry, new_dentry); if (!S_ISDIR(old_dentry->d_inode->i_mode)) diff --git a/fs/unionfs/super.c b/fs/unionfs/super.c index 5d1190887924..ec5706b115f1 100644 --- a/fs/unionfs/super.c +++ b/fs/unionfs/super.c @@ -129,6 +129,8 @@ static int unionfs_statfs(struct dentry *dentry, struct kstatfs *buf) int err = 0; struct super_block *sb, *hidden_sb; + BUG_ON(!is_valid_dentry(dentry)); + sb = dentry->d_sb; unionfs_read_lock(sb); diff --git a/fs/unionfs/union.h b/fs/unionfs/union.h index faaa87e7640b..b6fa0a2d72fe 100644 --- a/fs/unionfs/union.h +++ b/fs/unionfs/union.h @@ -399,6 +399,19 @@ static inline int is_robranch(const struct dentry *dentry) return is_robranch_idx(dentry, index); } +/* + * Check if dentry is valid or not, as per our generation numbers. + * @dentry: dentry to check. + * Returns 1 (valid) or 0 (invalid/stale). + */ +static inline int is_valid_dentry(struct dentry *dentry) +{ + BUG_ON(!UNIONFS_D(dentry)); + BUG_ON(!UNIONFS_SB(dentry->d_sb)); + return (atomic_read(&UNIONFS_D(dentry)->generation) == + atomic_read(&UNIONFS_SB(dentry->d_sb)->generation)); +} + /* What do we use for whiteouts. */ #define UNIONFS_WHPFX ".wh." #define UNIONFS_WHLEN 4 diff --git a/fs/unionfs/unlink.c b/fs/unionfs/unlink.c index f5b250ac0df7..dd1dd9c3b53e 100644 --- a/fs/unionfs/unlink.c +++ b/fs/unionfs/unlink.c @@ -74,6 +74,8 @@ int unionfs_unlink(struct inode *dir, struct dentry *dentry) { int err = 0; + BUG_ON(!is_valid_dentry(dentry)); + unionfs_lock_dentry(dentry); err = unionfs_unlink_whiteout(dir, dentry); @@ -122,6 +124,8 @@ int unionfs_rmdir(struct inode *dir, struct dentry *dentry) int err = 0; struct unionfs_dir_state *namelist = NULL; + BUG_ON(!is_valid_dentry(dentry)); + unionfs_lock_dentry(dentry); /* check if this unionfs directory is empty or not */ diff --git a/fs/unionfs/xattr.c b/fs/unionfs/xattr.c index d57f079457e5..6e1f4bd9877e 100644 --- a/fs/unionfs/xattr.c +++ b/fs/unionfs/xattr.c @@ -56,6 +56,8 @@ ssize_t unionfs_getxattr(struct dentry * dentry, const char *name, void *value, struct dentry *hidden_dentry = NULL; int err = -EOPNOTSUPP; + BUG_ON(!is_valid_dentry(dentry)); + unionfs_lock_dentry(dentry); hidden_dentry = unionfs_lower_dentry(dentry); @@ -75,6 +77,8 @@ int unionfs_setxattr(struct dentry *dentry, const char *name, const void *value, struct dentry *hidden_dentry = NULL; int err = -EOPNOTSUPP; + BUG_ON(!is_valid_dentry(dentry)); + unionfs_lock_dentry(dentry); hidden_dentry = unionfs_lower_dentry(dentry); @@ -92,6 +96,8 @@ int unionfs_removexattr(struct dentry *dentry, const char *name) struct dentry *hidden_dentry = NULL; int err = -EOPNOTSUPP; + BUG_ON(!is_valid_dentry(dentry)); + unionfs_lock_dentry(dentry); hidden_dentry = unionfs_lower_dentry(dentry); @@ -110,6 +116,8 @@ ssize_t unionfs_listxattr(struct dentry * dentry, char *list, size_t size) int err = -EOPNOTSUPP; char *encoded_list = NULL; + BUG_ON(!is_valid_dentry(dentry)); + unionfs_lock_dentry(dentry); hidden_dentry = unionfs_lower_dentry(dentry);