]> git.ipfire.org Git - thirdparty/kernel/linux.git/blobdiff - fs/overlayfs/file.c
fs: factor out backing_file_mmap() helper
[thirdparty/kernel/linux.git] / fs / overlayfs / file.c
index 131621daeb134ac3f9b78ea592b4639d5f29a3f3..05536964d37fdfae71508d15dbfab9bf2f75f38e 100644 (file)
@@ -9,25 +9,11 @@
 #include <linux/xattr.h>
 #include <linux/uio.h>
 #include <linux/uaccess.h>
-#include <linux/splice.h>
 #include <linux/security.h>
-#include <linux/mm.h>
 #include <linux/fs.h>
+#include <linux/backing-file.h>
 #include "overlayfs.h"
 
-#include "../internal.h"       /* for sb_init_dio_done_wq */
-
-struct ovl_aio_req {
-       struct kiocb iocb;
-       refcount_t ref;
-       struct kiocb *orig_iocb;
-       /* used for aio completion */
-       struct work_struct work;
-       long res;
-};
-
-static struct kmem_cache *ovl_aio_request_cachep;
-
 static char ovl_whatisit(struct inode *inode, struct inode *realinode)
 {
        if (realinode != ovl_inode_upper(inode))
@@ -274,83 +260,16 @@ static void ovl_file_accessed(struct file *file)
        touch_atime(&file->f_path);
 }
 
-#define OVL_IOCB_MASK \
-       (IOCB_NOWAIT | IOCB_HIPRI | IOCB_DSYNC | IOCB_SYNC | IOCB_APPEND)
-
-static rwf_t iocb_to_rw_flags(int flags)
-{
-       return (__force rwf_t)(flags & OVL_IOCB_MASK);
-}
-
-static inline void ovl_aio_put(struct ovl_aio_req *aio_req)
-{
-       if (refcount_dec_and_test(&aio_req->ref)) {
-               fput(aio_req->iocb.ki_filp);
-               kmem_cache_free(ovl_aio_request_cachep, aio_req);
-       }
-}
-
-static void ovl_aio_cleanup_handler(struct ovl_aio_req *aio_req)
-{
-       struct kiocb *iocb = &aio_req->iocb;
-       struct kiocb *orig_iocb = aio_req->orig_iocb;
-
-       if (iocb->ki_flags & IOCB_WRITE) {
-               kiocb_end_write(iocb);
-               ovl_file_modified(orig_iocb->ki_filp);
-       }
-
-       orig_iocb->ki_pos = iocb->ki_pos;
-       ovl_aio_put(aio_req);
-}
-
-static void ovl_aio_rw_complete(struct kiocb *iocb, long res)
-{
-       struct ovl_aio_req *aio_req = container_of(iocb,
-                                                  struct ovl_aio_req, iocb);
-       struct kiocb *orig_iocb = aio_req->orig_iocb;
-
-       ovl_aio_cleanup_handler(aio_req);
-       orig_iocb->ki_complete(orig_iocb, res);
-}
-
-static void ovl_aio_complete_work(struct work_struct *work)
-{
-       struct ovl_aio_req *aio_req = container_of(work,
-                                                  struct ovl_aio_req, work);
-
-       ovl_aio_rw_complete(&aio_req->iocb, aio_req->res);
-}
-
-static void ovl_aio_queue_completion(struct kiocb *iocb, long res)
-{
-       struct ovl_aio_req *aio_req = container_of(iocb,
-                                                  struct ovl_aio_req, iocb);
-       struct kiocb *orig_iocb = aio_req->orig_iocb;
-
-       /*
-        * Punt to a work queue to serialize updates of mtime/size.
-        */
-       aio_req->res = res;
-       INIT_WORK(&aio_req->work, ovl_aio_complete_work);
-       queue_work(file_inode(orig_iocb->ki_filp)->i_sb->s_dio_done_wq,
-                  &aio_req->work);
-}
-
-static int ovl_init_aio_done_wq(struct super_block *sb)
-{
-       if (sb->s_dio_done_wq)
-               return 0;
-
-       return sb_init_dio_done_wq(sb);
-}
-
 static ssize_t ovl_read_iter(struct kiocb *iocb, struct iov_iter *iter)
 {
        struct file *file = iocb->ki_filp;
        struct fd real;
-       const struct cred *old_cred;
        ssize_t ret;
+       struct backing_file_ctx ctx = {
+               .cred = ovl_creds(file_inode(file)->i_sb),
+               .user_file = file,
+               .accessed = ovl_file_accessed,
+       };
 
        if (!iov_iter_count(iter))
                return 0;
@@ -359,37 +278,8 @@ static ssize_t ovl_read_iter(struct kiocb *iocb, struct iov_iter *iter)
        if (ret)
                return ret;
 
-       ret = -EINVAL;
-       if (iocb->ki_flags & IOCB_DIRECT &&
-           !(real.file->f_mode & FMODE_CAN_ODIRECT))
-               goto out_fdput;
-
-       old_cred = ovl_override_creds(file_inode(file)->i_sb);
-       if (is_sync_kiocb(iocb)) {
-               rwf_t rwf = iocb_to_rw_flags(iocb->ki_flags);
-
-               ret = vfs_iter_read(real.file, iter, &iocb->ki_pos, rwf);
-       } else {
-               struct ovl_aio_req *aio_req;
-
-               ret = -ENOMEM;
-               aio_req = kmem_cache_zalloc(ovl_aio_request_cachep, GFP_KERNEL);
-               if (!aio_req)
-                       goto out;
-
-               aio_req->orig_iocb = iocb;
-               kiocb_clone(&aio_req->iocb, iocb, get_file(real.file));
-               aio_req->iocb.ki_complete = ovl_aio_rw_complete;
-               refcount_set(&aio_req->ref, 2);
-               ret = vfs_iocb_iter_read(real.file, &aio_req->iocb, iter);
-               ovl_aio_put(aio_req);
-               if (ret != -EIOCBQUEUED)
-                       ovl_aio_cleanup_handler(aio_req);
-       }
-out:
-       revert_creds(old_cred);
-       ovl_file_accessed(file);
-out_fdput:
+       ret = backing_file_read_iter(real.file, iter, iocb, iocb->ki_flags,
+                                    &ctx);
        fdput(real);
 
        return ret;
@@ -400,9 +290,13 @@ static ssize_t ovl_write_iter(struct kiocb *iocb, struct iov_iter *iter)
        struct file *file = iocb->ki_filp;
        struct inode *inode = file_inode(file);
        struct fd real;
-       const struct cred *old_cred;
        ssize_t ret;
        int ifl = iocb->ki_flags;
+       struct backing_file_ctx ctx = {
+               .cred = ovl_creds(inode->i_sb),
+               .user_file = file,
+               .end_write = ovl_file_modified,
+       };
 
        if (!iov_iter_count(iter))
                return 0;
@@ -410,19 +304,11 @@ static ssize_t ovl_write_iter(struct kiocb *iocb, struct iov_iter *iter)
        inode_lock(inode);
        /* Update mode */
        ovl_copyattr(inode);
-       ret = file_remove_privs(file);
-       if (ret)
-               goto out_unlock;
 
        ret = ovl_real_fdget(file, &real);
        if (ret)
                goto out_unlock;
 
-       ret = -EINVAL;
-       if (iocb->ki_flags & IOCB_DIRECT &&
-           !(real.file->f_mode & FMODE_CAN_ODIRECT))
-               goto out_fdput;
-
        if (!ovl_should_sync(OVL_FS(inode->i_sb)))
                ifl &= ~(IOCB_DSYNC | IOCB_SYNC);
 
@@ -431,42 +317,7 @@ static ssize_t ovl_write_iter(struct kiocb *iocb, struct iov_iter *iter)
         * this property in case it is set by the issuer.
         */
        ifl &= ~IOCB_DIO_CALLER_COMP;
-
-       old_cred = ovl_override_creds(file_inode(file)->i_sb);
-       if (is_sync_kiocb(iocb)) {
-               rwf_t rwf = iocb_to_rw_flags(ifl);
-
-               file_start_write(real.file);
-               ret = vfs_iter_write(real.file, iter, &iocb->ki_pos, rwf);
-               file_end_write(real.file);
-               /* Update size */
-               ovl_file_modified(file);
-       } else {
-               struct ovl_aio_req *aio_req;
-
-               ret = ovl_init_aio_done_wq(inode->i_sb);
-               if (ret)
-                       goto out;
-
-               ret = -ENOMEM;
-               aio_req = kmem_cache_zalloc(ovl_aio_request_cachep, GFP_KERNEL);
-               if (!aio_req)
-                       goto out;
-
-               aio_req->orig_iocb = iocb;
-               kiocb_clone(&aio_req->iocb, iocb, get_file(real.file));
-               aio_req->iocb.ki_flags = ifl;
-               aio_req->iocb.ki_complete = ovl_aio_queue_completion;
-               refcount_set(&aio_req->ref, 2);
-               kiocb_start_write(&aio_req->iocb);
-               ret = vfs_iocb_iter_write(real.file, &aio_req->iocb, iter);
-               ovl_aio_put(aio_req);
-               if (ret != -EIOCBQUEUED)
-                       ovl_aio_cleanup_handler(aio_req);
-       }
-out:
-       revert_creds(old_cred);
-out_fdput:
+       ret = backing_file_write_iter(real.file, iter, iocb, ifl, &ctx);
        fdput(real);
 
 out_unlock:
@@ -479,20 +330,21 @@ static ssize_t ovl_splice_read(struct file *in, loff_t *ppos,
                               struct pipe_inode_info *pipe, size_t len,
                               unsigned int flags)
 {
-       const struct cred *old_cred;
        struct fd real;
        ssize_t ret;
+       struct backing_file_ctx ctx = {
+               .cred = ovl_creds(file_inode(in)->i_sb),
+               .user_file = in,
+               .accessed = ovl_file_accessed,
+       };
 
        ret = ovl_real_fdget(in, &real);
        if (ret)
                return ret;
 
-       old_cred = ovl_override_creds(file_inode(in)->i_sb);
-       ret = vfs_splice_read(real.file, ppos, pipe, len, flags);
-       revert_creds(old_cred);
-       ovl_file_accessed(in);
-
+       ret = backing_file_splice_read(real.file, ppos, pipe, len, flags, &ctx);
        fdput(real);
+
        return ret;
 }
 
@@ -508,30 +360,23 @@ static ssize_t ovl_splice_write(struct pipe_inode_info *pipe, struct file *out,
                                loff_t *ppos, size_t len, unsigned int flags)
 {
        struct fd real;
-       const struct cred *old_cred;
        struct inode *inode = file_inode(out);
        ssize_t ret;
+       struct backing_file_ctx ctx = {
+               .cred = ovl_creds(inode->i_sb),
+               .user_file = out,
+               .end_write = ovl_file_modified,
+       };
 
        inode_lock(inode);
        /* Update mode */
        ovl_copyattr(inode);
-       ret = file_remove_privs(out);
-       if (ret)
-               goto out_unlock;
 
        ret = ovl_real_fdget(out, &real);
        if (ret)
                goto out_unlock;
 
-       old_cred = ovl_override_creds(inode->i_sb);
-       file_start_write(real.file);
-
-       ret = iter_file_splice_write(pipe, real.file, ppos, len, flags);
-
-       file_end_write(real.file);
-       /* Update size */
-       ovl_file_modified(out);
-       revert_creds(old_cred);
+       ret = backing_file_splice_write(pipe, real.file, ppos, len, flags, &ctx);
        fdput(real);
 
 out_unlock:
@@ -569,23 +414,13 @@ static int ovl_fsync(struct file *file, loff_t start, loff_t end, int datasync)
 static int ovl_mmap(struct file *file, struct vm_area_struct *vma)
 {
        struct file *realfile = file->private_data;
-       const struct cred *old_cred;
-       int ret;
-
-       if (!realfile->f_op->mmap)
-               return -ENODEV;
+       struct backing_file_ctx ctx = {
+               .cred = ovl_creds(file_inode(file)->i_sb),
+               .user_file = file,
+               .accessed = ovl_file_accessed,
+       };
 
-       if (WARN_ON(file != vma->vm_file))
-               return -EIO;
-
-       vma_set_file(vma, realfile);
-
-       old_cred = ovl_override_creds(file_inode(file)->i_sb);
-       ret = call_mmap(vma->vm_file, vma);
-       revert_creds(old_cred);
-       ovl_file_accessed(file);
-
-       return ret;
+       return backing_file_mmap(realfile, vma, &ctx);
 }
 
 static long ovl_fallocate(struct file *file, int mode, loff_t offset, loff_t len)
@@ -778,19 +613,3 @@ const struct file_operations ovl_file_operations = {
        .copy_file_range        = ovl_copy_file_range,
        .remap_file_range       = ovl_remap_file_range,
 };
-
-int __init ovl_aio_request_cache_init(void)
-{
-       ovl_aio_request_cachep = kmem_cache_create("ovl_aio_req",
-                                                  sizeof(struct ovl_aio_req),
-                                                  0, SLAB_HWCACHE_ALIGN, NULL);
-       if (!ovl_aio_request_cachep)
-               return -ENOMEM;
-
-       return 0;
-}
-
-void ovl_aio_request_cache_destroy(void)
-{
-       kmem_cache_destroy(ovl_aio_request_cachep);
-}