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fuse: implement read/write passthrough

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Use the backing file read/write helpers to implement read/write
passthrough to a backing file.

After read/write, we invalidate a/c/mtime/size attributes.

Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
This commit is contained in:
Amir Goldstein 2023-11-22 18:26:04 +02:00 committed by Miklos Szeredi
parent 4a90451bbc
commit 57e1176e60
3 changed files with 84 additions and 6 deletions
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18
fs/fuse/file.c
View File

@ -1693,10 +1693,13 @@ static ssize_t fuse_file_read_iter(struct kiocb *iocb, struct iov_iter *to)
if (FUSE_IS_DAX(inode))
return fuse_dax_read_iter(iocb, to);
if (!(ff->open_flags & FOPEN_DIRECT_IO))
return fuse_cache_read_iter(iocb, to);
else
/* FOPEN_DIRECT_IO overrides FOPEN_PASSTHROUGH */
if (ff->open_flags & FOPEN_DIRECT_IO)
return fuse_direct_read_iter(iocb, to);
else if (fuse_file_passthrough(ff))
return fuse_passthrough_read_iter(iocb, to);
else
return fuse_cache_read_iter(iocb, to);
}
static ssize_t fuse_file_write_iter(struct kiocb *iocb, struct iov_iter *from)
@ -1711,10 +1714,13 @@ static ssize_t fuse_file_write_iter(struct kiocb *iocb, struct iov_iter *from)
if (FUSE_IS_DAX(inode))
return fuse_dax_write_iter(iocb, from);
if (!(ff->open_flags & FOPEN_DIRECT_IO))
return fuse_cache_write_iter(iocb, from);
else
/* FOPEN_DIRECT_IO overrides FOPEN_PASSTHROUGH */
if (ff->open_flags & FOPEN_DIRECT_IO)
return fuse_direct_write_iter(iocb, from);
else if (fuse_file_passthrough(ff))
return fuse_passthrough_write_iter(iocb, from);
else
return fuse_cache_write_iter(iocb, from);
}
static void fuse_writepage_free(struct fuse_writepage_args *wpa)

3
fs/fuse/fuse_i.h
View File

@ -1466,4 +1466,7 @@ static inline struct file *fuse_file_passthrough(struct fuse_file *ff)
#endif
}
ssize_t fuse_passthrough_read_iter(struct kiocb *iocb, struct iov_iter *iter);
ssize_t fuse_passthrough_write_iter(struct kiocb *iocb, struct iov_iter *iter);
#endif /* _FS_FUSE_I_H */

69
fs/fuse/passthrough.c
View File

@ -10,6 +10,75 @@
#include <linux/file.h>
#include <linux/backing-file.h>
static void fuse_file_accessed(struct file *file)
{
struct inode *inode = file_inode(file);
fuse_invalidate_atime(inode);
}
static void fuse_file_modified(struct file *file)
{
struct inode *inode = file_inode(file);
fuse_invalidate_attr_mask(inode, FUSE_STATX_MODSIZE);
}
ssize_t fuse_passthrough_read_iter(struct kiocb *iocb, struct iov_iter *iter)
{
struct file *file = iocb->ki_filp;
struct fuse_file *ff = file->private_data;
struct file *backing_file = fuse_file_passthrough(ff);
size_t count = iov_iter_count(iter);
ssize_t ret;
struct backing_file_ctx ctx = {
.cred = ff->cred,
.user_file = file,
.accessed = fuse_file_accessed,
};
pr_debug("%s: backing_file=0x%p, pos=%lld, len=%zu\n", __func__,
backing_file, iocb->ki_pos, count);
if (!count)
return 0;
ret = backing_file_read_iter(backing_file, iter, iocb, iocb->ki_flags,
&ctx);
return ret;
}
ssize_t fuse_passthrough_write_iter(struct kiocb *iocb,
struct iov_iter *iter)
{
struct file *file = iocb->ki_filp;
struct inode *inode = file_inode(file);
struct fuse_file *ff = file->private_data;
struct file *backing_file = fuse_file_passthrough(ff);
size_t count = iov_iter_count(iter);
ssize_t ret;
struct backing_file_ctx ctx = {
.cred = ff->cred,
.user_file = file,
.end_write = fuse_file_modified,
};
pr_debug("%s: backing_file=0x%p, pos=%lld, len=%zu\n", __func__,
backing_file, iocb->ki_pos, count);
if (!count)
return 0;
inode_lock(inode);
ret = backing_file_write_iter(backing_file, iter, iocb, iocb->ki_flags,
&ctx);
inode_unlock(inode);
return ret;
}
struct fuse_backing *fuse_backing_get(struct fuse_backing *fb)
{
if (fb && refcount_inc_not_zero(&fb->count))