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-rw-r--r--Documentation/filesystems/Locking5
-rw-r--r--Documentation/filesystems/vfs.txt40
-rw-r--r--fs/dcache.c3
-rw-r--r--fs/namei.c2
-rw-r--r--fs/open.c8
-rw-r--r--fs/overlayfs/inode.c31
-rw-r--r--fs/overlayfs/overlayfs.h2
-rw-r--r--fs/overlayfs/super.c20
-rw-r--r--include/linux/dcache.h40
-rw-r--r--include/linux/fs.h7
10 files changed, 80 insertions, 78 deletions
diff --git a/Documentation/filesystems/Locking b/Documentation/filesystems/Locking
index 75eea7ce3d7c..d4def7b78a62 100644
--- a/Documentation/filesystems/Locking
+++ b/Documentation/filesystems/Locking
@@ -20,6 +20,8 @@ prototypes:
char *(*d_dname)((struct dentry *dentry, char *buffer, int buflen);
struct vfsmount *(*d_automount)(struct path *path);
int (*d_manage)(struct dentry *, bool);
+ struct dentry *(*d_real)(struct dentry *, const struct inode *,
+ unsigned int);
locking rules:
rename_lock ->d_lock may block rcu-walk
@@ -34,6 +36,7 @@ d_iput: no no yes no
d_dname: no no no no
d_automount: no no yes no
d_manage: no no yes (ref-walk) maybe
+d_real no no yes no
--------------------------- inode_operations ---------------------------
prototypes:
@@ -66,7 +69,6 @@ prototypes:
struct file *, unsigned open_flag,
umode_t create_mode, int *opened);
int (*tmpfile) (struct inode *, struct dentry *, umode_t);
- int (*dentry_open)(struct dentry *, struct file *, const struct cred *);
locking rules:
all may block
@@ -95,7 +97,6 @@ fiemap: no
update_time: no
atomic_open: yes
tmpfile: no
-dentry_open: no
Additionally, ->rmdir(), ->unlink() and ->rename() have ->i_mutex on
victim.
diff --git a/Documentation/filesystems/vfs.txt b/Documentation/filesystems/vfs.txt
index c61a223ef3ff..01c4f1741c20 100644
--- a/Documentation/filesystems/vfs.txt
+++ b/Documentation/filesystems/vfs.txt
@@ -364,7 +364,6 @@ struct inode_operations {
int (*atomic_open)(struct inode *, struct dentry *, struct file *,
unsigned open_flag, umode_t create_mode, int *opened);
int (*tmpfile) (struct inode *, struct dentry *, umode_t);
- int (*dentry_open)(struct dentry *, struct file *, const struct cred *);
};
Again, all methods are called without any locks being held, unless
@@ -696,13 +695,6 @@ struct address_space_operations {
but instead uses bmap to find out where the blocks in the file
are and uses those addresses directly.
- dentry_open: *WARNING: probably going away soon, do not use!* This is an
- alternative to f_op->open(), the difference is that this method may open
- a file not necessarily originating from the same filesystem as the one
- i_op->open() was called on. It may be useful for stacking filesystems
- which want to allow native I/O directly on underlying files.
-
-
invalidatepage: If a page has PagePrivate set, then invalidatepage
will be called when part or all of the page is to be removed
from the address space. This generally corresponds to either a
@@ -938,6 +930,8 @@ struct dentry_operations {
char *(*d_dname)(struct dentry *, char *, int);
struct vfsmount *(*d_automount)(struct path *);
int (*d_manage)(struct dentry *, bool);
+ struct dentry *(*d_real)(struct dentry *, const struct inode *,
+ unsigned int);
};
d_revalidate: called when the VFS needs to revalidate a dentry. This
@@ -1022,6 +1016,14 @@ struct dentry_operations {
at the end of the buffer, and returns a pointer to the first char.
dynamic_dname() helper function is provided to take care of this.
+ Example :
+
+ static char *pipefs_dname(struct dentry *dent, char *buffer, int buflen)
+ {
+ return dynamic_dname(dentry, buffer, buflen, "pipe:[%lu]",
+ dentry->d_inode->i_ino);
+ }
+
d_automount: called when an automount dentry is to be traversed (optional).
This should create a new VFS mount record and return the record to the
caller. The caller is supplied with a path parameter giving the
@@ -1060,13 +1062,23 @@ struct dentry_operations {
This function is only used if DCACHE_MANAGE_TRANSIT is set on the
dentry being transited from.
-Example :
+ d_real: overlay/union type filesystems implement this method to return one of
+ the underlying dentries hidden by the overlay. It is used in three
+ different modes:
-static char *pipefs_dname(struct dentry *dent, char *buffer, int buflen)
-{
- return dynamic_dname(dentry, buffer, buflen, "pipe:[%lu]",
- dentry->d_inode->i_ino);
-}
+ Called from open it may need to copy-up the file depending on the
+ supplied open flags. This mode is selected with a non-zero flags
+ argument. In this mode the d_real method can return an error.
+
+ Called from file_dentry() it returns the real dentry matching the inode
+ argument. The real dentry may be from a lower layer already copied up,
+ but still referenced from the file. This mode is selected with a
+ non-NULL inode argument. This will always succeed.
+
+ With NULL inode and zero flags the topmost real underlying dentry is
+ returned. This will always succeed.
+
+ This method is never called with both non-NULL inode and non-zero flags.
Each dentry has a pointer to its parent dentry, as well as a hash list
of child dentries. Child dentries are basically like files in a
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 d1cdc60dd68f..d554e86abbe3 100644
--- a/fs/overlayfs/inode.c
+++ b/fs/overlayfs/inode.c
@@ -351,36 +351,25 @@ 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 cfbca53590d0..0d3f2ad45708 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 9a7693d5f8ff..5e254b3a8c56 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..14df83609c7f 100644
--- a/include/linux/dcache.h
+++ b/include/linux/dcache.h
@@ -139,8 +139,8 @@ 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 +206,8 @@ 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 +555,27 @@ static inline struct dentry *d_backing_dentry(struct dentry *upper)
return upper;
}
-static inline struct dentry *d_real(struct dentry *dentry)
+/**
+ * d_real - Return the real dentry
+ * @dentry: the dentry to query
+ * @inode: inode to select the dentry from multiple layers (can be NULL)
+ * @flags: open flags to control copy-up behavior
+ *
+ * If dentry is on an union/overlay, then return the underlying, real dentry.
+ * Otherwise return the dentry itself.
+ *
+ * See also: Documentation/filesystems/vfs.txt
+ */
+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 +585,7 @@ 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)
generated by cgit v1.2.3-55-g7522 (git 2.39.0) at 2024-07-20 06:20:49 +0200