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authorLinus Torvalds <torvalds@linux-foundation.org>2018-08-21 18:19:09 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2018-08-21 18:19:09 -0700
commitd9a185f8b49678775ef56ecbdbc7b76970302897 (patch)
tree7ace1b26133e5d796af09e5d71d6531bcb69865c /fs/namespace.c
parentc22fc16d172fba4d19ffd8f2aa8fe67edba63895 (diff)
parent989974c804574d250ac92d44e220081959ac8ac1 (diff)
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Merge tag 'ovl-update-4.19' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/vfs
Pull overlayfs updates from Miklos Szeredi: "This contains two new features: - Stack file operations: this allows removal of several hacks from the VFS, proper interaction of read-only open files with copy-up, possibility to implement fs modifying ioctls properly, and others. - Metadata only copy-up: when file is on lower layer and only metadata is modified (except size) then only copy up the metadata and continue to use the data from the lower file" * tag 'ovl-update-4.19' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/vfs: (66 commits) ovl: Enable metadata only feature ovl: Do not do metacopy only for ioctl modifying file attr ovl: Do not do metadata only copy-up for truncate operation ovl: add helper to force data copy-up ovl: Check redirect on index as well ovl: Set redirect on upper inode when it is linked ovl: Set redirect on metacopy files upon rename ovl: Do not set dentry type ORIGIN for broken hardlinks ovl: Add an inode flag OVL_CONST_INO ovl: Treat metacopy dentries as type OVL_PATH_MERGE ovl: Check redirects for metacopy files ovl: Move some dir related ovl_lookup_single() code in else block ovl: Do not expose metacopy only dentry from d_real() ovl: Open file with data except for the case of fsync ovl: Add helper ovl_inode_realdata() ovl: Store lower data inode in ovl_inode ovl: Fix ovl_getattr() to get number of blocks from lower ovl: Add helper ovl_dentry_lowerdata() to get lower data dentry ovl: Copy up meta inode data from lowest data inode ovl: Modify ovl_lookup() and friends to lookup metacopy dentry ...
Diffstat (limited to 'fs/namespace.c')
-rw-r--r--fs/namespace.c69
1 files changed, 5 insertions, 64 deletions
diff --git a/fs/namespace.c b/fs/namespace.c
index bd2f4c68506a..725d6935fab9 100644
--- a/fs/namespace.c
+++ b/fs/namespace.c
@@ -431,74 +431,20 @@ int __mnt_want_write_file(struct file *file)
}
/**
- * mnt_want_write_file_path - get write access to a file's mount
- * @file: the file who's mount on which to take a write
- *
- * This is like mnt_want_write, but it takes a file and can
- * do some optimisations if the file is open for write already
- *
- * Called by the vfs for cases when we have an open file at hand, but will do an
- * inode operation on it (important distinction for files opened on overlayfs,
- * since the file operations will come from the real underlying file, while
- * inode operations come from the overlay).
- */
-int mnt_want_write_file_path(struct file *file)
-{
- int ret;
-
- sb_start_write(file->f_path.mnt->mnt_sb);
- ret = __mnt_want_write_file(file);
- if (ret)
- sb_end_write(file->f_path.mnt->mnt_sb);
- return ret;
-}
-
-static inline int may_write_real(struct file *file)
-{
- struct dentry *dentry = file->f_path.dentry;
- struct dentry *upperdentry;
-
- /* Writable file? */
- if (file->f_mode & FMODE_WRITER)
- return 0;
-
- /* Not overlayfs? */
- if (likely(!(dentry->d_flags & DCACHE_OP_REAL)))
- return 0;
-
- /* File refers to upper, writable layer? */
- upperdentry = d_real(dentry, NULL, 0, D_REAL_UPPER);
- if (upperdentry &&
- (file_inode(file) == d_inode(upperdentry) ||
- file_inode(file) == d_inode(dentry)))
- return 0;
-
- /* Lower layer: can't write to real file, sorry... */
- return -EPERM;
-}
-
-/**
* mnt_want_write_file - get write access to a file's mount
* @file: the file who's mount on which to take a write
*
* This is like mnt_want_write, but it takes a file and can
* do some optimisations if the file is open for write already
- *
- * Mostly called by filesystems from their ioctl operation before performing
- * modification. On overlayfs this needs to check if the file is on a read-only
- * lower layer and deny access in that case.
*/
int mnt_want_write_file(struct file *file)
{
int ret;
- ret = may_write_real(file);
- if (!ret) {
- sb_start_write(file_inode(file)->i_sb);
- ret = __mnt_want_write_file(file);
- if (ret)
- sb_end_write(file_inode(file)->i_sb);
- }
+ sb_start_write(file_inode(file)->i_sb);
+ ret = __mnt_want_write_file(file);
+ if (ret)
+ sb_end_write(file_inode(file)->i_sb);
return ret;
}
EXPORT_SYMBOL_GPL(mnt_want_write_file);
@@ -538,14 +484,9 @@ void __mnt_drop_write_file(struct file *file)
__mnt_drop_write(file->f_path.mnt);
}
-void mnt_drop_write_file_path(struct file *file)
-{
- mnt_drop_write(file->f_path.mnt);
-}
-
void mnt_drop_write_file(struct file *file)
{
- __mnt_drop_write(file->f_path.mnt);
+ __mnt_drop_write_file(file);
sb_end_write(file_inode(file)->i_sb);
}
EXPORT_SYMBOL(mnt_drop_write_file);