From 2d902671ce1cd98cdc88d78c481889a1b2996101 Mon Sep 17 00:00:00 2001 From: Miklos Szeredi Date: Thu, 30 Jun 2016 08:53:27 +0200 Subject: [PATCH] vfs: merge .d_select_inode() into .d_real() The two methods essentially do the same: find the real dentry/inode belonging to an overlay dentry. The difference is in the usage: vfs_open() uses ->d_select_inode() and expects the function to perform copy-up if necessary based on the open flags argument. file_dentry() uses ->d_real() passing in the overlay dentry as well as the underlying inode. vfs_rename() uses ->d_select_inode() but passes zero flags. ->d_real() with a zero inode would have worked just as well here. This patch merges the functionality of ->d_select_inode() into ->d_real() by adding an 'open_flags' argument to the latter. [Al Viro] Make the signature of d_real() match that of ->d_real() again. And constify the inode argument, while we are at it. Signed-off-by: Miklos Szeredi --- fs/dcache.c | 3 --- fs/namei.c | 2 +- fs/open.c | 8 ++++---- fs/overlayfs/inode.c | 31 ++++++++++--------------------- fs/overlayfs/overlayfs.h | 2 +- fs/overlayfs/super.c | 20 ++++++++++++++------ include/linux/dcache.h | 28 ++++++++-------------------- include/linux/fs.h | 7 +------ 8 files changed, 39 insertions(+), 62 deletions(-) diff --git a/fs/dcache.c b/fs/dcache.c index d6847d7b123d..5405b89fe8ec 100644 --- a/fs/dcache.c +++ b/fs/dcache.c @@ -1729,7 +1729,6 @@ void d_set_d_op(struct dentry *dentry, const struct dentry_operations *op) DCACHE_OP_REVALIDATE | DCACHE_OP_WEAK_REVALIDATE | DCACHE_OP_DELETE | - DCACHE_OP_SELECT_INODE | DCACHE_OP_REAL)); dentry->d_op = op; if (!op) @@ -1746,8 +1745,6 @@ void d_set_d_op(struct dentry *dentry, const struct dentry_operations *op) dentry->d_flags |= DCACHE_OP_DELETE; if (op->d_prune) dentry->d_flags |= DCACHE_OP_PRUNE; - if (op->d_select_inode) - dentry->d_flags |= DCACHE_OP_SELECT_INODE; if (op->d_real) dentry->d_flags |= DCACHE_OP_REAL; diff --git a/fs/namei.c b/fs/namei.c index 70580ab1445c..bb7a2e0b959c 100644 --- a/fs/namei.c +++ b/fs/namei.c @@ -4328,7 +4328,7 @@ int vfs_rename(struct inode *old_dir, struct dentry *old_dentry, * Check source == target. * On overlayfs need to look at underlying inodes. */ - if (vfs_select_inode(old_dentry, 0) == vfs_select_inode(new_dentry, 0)) + if (d_real_inode(old_dentry) == d_real_inode(new_dentry)) return 0; error = may_delete(old_dir, old_dentry, is_dir); diff --git a/fs/open.c b/fs/open.c index 93ae3cdee4ab..bf66cf1a9f5c 100644 --- a/fs/open.c +++ b/fs/open.c @@ -840,13 +840,13 @@ EXPORT_SYMBOL(file_path); int vfs_open(const struct path *path, struct file *file, const struct cred *cred) { - struct inode *inode = vfs_select_inode(path->dentry, file->f_flags); + struct dentry *dentry = d_real(path->dentry, NULL, file->f_flags); - if (IS_ERR(inode)) - return PTR_ERR(inode); + if (IS_ERR(dentry)) + return PTR_ERR(dentry); file->f_path = *path; - return do_dentry_open(file, inode, NULL, cred); + return do_dentry_open(file, d_backing_inode(dentry), NULL, cred); } struct file *dentry_open(const struct path *path, int flags, diff --git a/fs/overlayfs/inode.c b/fs/overlayfs/inode.c index 1dbeab6cf96e..e08cd94d7b26 100644 --- a/fs/overlayfs/inode.c +++ b/fs/overlayfs/inode.c @@ -325,36 +325,25 @@ static bool ovl_open_need_copy_up(int flags, enum ovl_path_type type, return true; } -struct inode *ovl_d_select_inode(struct dentry *dentry, unsigned file_flags) +int ovl_open_maybe_copy_up(struct dentry *dentry, unsigned int file_flags) { - int err; + int err = 0; struct path realpath; enum ovl_path_type type; - if (d_is_dir(dentry)) - return d_backing_inode(dentry); - type = ovl_path_real(dentry, &realpath); if (ovl_open_need_copy_up(file_flags, type, realpath.dentry)) { err = ovl_want_write(dentry); - if (err) - return ERR_PTR(err); - - if (file_flags & O_TRUNC) - err = ovl_copy_up_truncate(dentry); - else - err = ovl_copy_up(dentry); - ovl_drop_write(dentry); - if (err) - return ERR_PTR(err); - - ovl_path_upper(dentry, &realpath); + if (!err) { + if (file_flags & O_TRUNC) + err = ovl_copy_up_truncate(dentry); + else + err = ovl_copy_up(dentry); + ovl_drop_write(dentry); + } } - if (realpath.dentry->d_flags & DCACHE_OP_SELECT_INODE) - return realpath.dentry->d_op->d_select_inode(realpath.dentry, file_flags); - - return d_backing_inode(realpath.dentry); + return err; } static const struct inode_operations ovl_file_inode_operations = { diff --git a/fs/overlayfs/overlayfs.h b/fs/overlayfs/overlayfs.h index 4bd9b5ba8f42..6b9fd25c5ad4 100644 --- a/fs/overlayfs/overlayfs.h +++ b/fs/overlayfs/overlayfs.h @@ -179,7 +179,7 @@ ssize_t ovl_getxattr(struct dentry *dentry, struct inode *inode, const char *name, void *value, size_t size); ssize_t ovl_listxattr(struct dentry *dentry, char *list, size_t size); int ovl_removexattr(struct dentry *dentry, const char *name); -struct inode *ovl_d_select_inode(struct dentry *dentry, unsigned file_flags); +int ovl_open_maybe_copy_up(struct dentry *dentry, unsigned int file_flags); struct inode *ovl_new_inode(struct super_block *sb, umode_t mode, struct ovl_entry *oe); diff --git a/fs/overlayfs/super.c b/fs/overlayfs/super.c index ce02f46029da..035c176edf00 100644 --- a/fs/overlayfs/super.c +++ b/fs/overlayfs/super.c @@ -304,7 +304,9 @@ static void ovl_dentry_release(struct dentry *dentry) } } -static struct dentry *ovl_d_real(struct dentry *dentry, struct inode *inode) +static struct dentry *ovl_d_real(struct dentry *dentry, + const struct inode *inode, + unsigned int open_flags) { struct dentry *real; @@ -314,6 +316,16 @@ static struct dentry *ovl_d_real(struct dentry *dentry, struct inode *inode) goto bug; } + if (d_is_negative(dentry)) + return dentry; + + if (open_flags) { + int err = ovl_open_maybe_copy_up(dentry, open_flags); + + if (err) + return ERR_PTR(err); + } + real = ovl_dentry_upper(dentry); if (real && (!inode || inode == d_inode(real))) return real; @@ -326,9 +338,7 @@ static struct dentry *ovl_d_real(struct dentry *dentry, struct inode *inode) return real; /* Handle recursion */ - if (real->d_flags & DCACHE_OP_REAL) - return real->d_op->d_real(real, inode); - + return d_real(real, inode, open_flags); bug: WARN(1, "ovl_d_real(%pd4, %s:%lu\n): real dentry not found\n", dentry, inode ? inode->i_sb->s_id : "NULL", inode ? inode->i_ino : 0); @@ -378,13 +388,11 @@ static int ovl_dentry_weak_revalidate(struct dentry *dentry, unsigned int flags) static const struct dentry_operations ovl_dentry_operations = { .d_release = ovl_dentry_release, - .d_select_inode = ovl_d_select_inode, .d_real = ovl_d_real, }; static const struct dentry_operations ovl_reval_dentry_operations = { .d_release = ovl_dentry_release, - .d_select_inode = ovl_d_select_inode, .d_real = ovl_d_real, .d_revalidate = ovl_dentry_revalidate, .d_weak_revalidate = ovl_dentry_weak_revalidate, diff --git a/include/linux/dcache.h b/include/linux/dcache.h index f53fa055021a..45b22de15ede 100644 --- a/include/linux/dcache.h +++ b/include/linux/dcache.h @@ -139,8 +139,7 @@ struct dentry_operations { char *(*d_dname)(struct dentry *, char *, int); struct vfsmount *(*d_automount)(struct path *); int (*d_manage)(struct dentry *, bool); - struct inode *(*d_select_inode)(struct dentry *, unsigned); - struct dentry *(*d_real)(struct dentry *, struct inode *); + struct dentry *(*d_real)(struct dentry *, const struct inode *, unsigned int); } ____cacheline_aligned; /* @@ -206,10 +205,8 @@ struct dentry_operations { #define DCACHE_MAY_FREE 0x00800000 #define DCACHE_FALLTHRU 0x01000000 /* Fall through to lower layer */ -#define DCACHE_OP_SELECT_INODE 0x02000000 /* Unioned entry: dcache op selects inode */ - -#define DCACHE_ENCRYPTED_WITH_KEY 0x04000000 /* dir is encrypted with a valid key */ -#define DCACHE_OP_REAL 0x08000000 +#define DCACHE_ENCRYPTED_WITH_KEY 0x02000000 /* dir is encrypted with a valid key */ +#define DCACHE_OP_REAL 0x04000000 #define DCACHE_PAR_LOOKUP 0x10000000 /* being looked up (with parent locked shared) */ #define DCACHE_DENTRY_CURSOR 0x20000000 @@ -557,25 +554,16 @@ static inline struct dentry *d_backing_dentry(struct dentry *upper) return upper; } -static inline struct dentry *d_real(struct dentry *dentry) +static inline struct dentry *d_real(struct dentry *dentry, + const struct inode *inode, + unsigned int flags) { if (unlikely(dentry->d_flags & DCACHE_OP_REAL)) - return dentry->d_op->d_real(dentry, NULL); + return dentry->d_op->d_real(dentry, inode, flags); else return dentry; } -static inline struct inode *vfs_select_inode(struct dentry *dentry, - unsigned open_flags) -{ - struct inode *inode = d_inode(dentry); - - if (inode && unlikely(dentry->d_flags & DCACHE_OP_SELECT_INODE)) - inode = dentry->d_op->d_select_inode(dentry, open_flags); - - return inode; -} - /** * d_real_inode - Return the real inode * @dentry: The dentry to query @@ -585,7 +573,7 @@ static inline struct inode *vfs_select_inode(struct dentry *dentry, */ static inline struct inode *d_real_inode(struct dentry *dentry) { - return d_backing_inode(d_real(dentry)); + return d_backing_inode(d_real(dentry, NULL, 0)); } diff --git a/include/linux/fs.h b/include/linux/fs.h index dd288148a6b1..bacc0733663c 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -1272,12 +1272,7 @@ static inline struct inode *file_inode(const struct file *f) static inline struct dentry *file_dentry(const struct file *file) { - struct dentry *dentry = file->f_path.dentry; - - if (unlikely(dentry->d_flags & DCACHE_OP_REAL)) - return dentry->d_op->d_real(dentry, file_inode(file)); - else - return dentry; + return d_real(file->f_path.dentry, file_inode(file), 0); } static inline int locks_lock_file_wait(struct file *filp, struct file_lock *fl) -- 2.20.1