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[104.196.36.241]) by smtp.googlemail.com with ESMTPSA id s11sm616323vsl.8.2021.08.20.12.59.37 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 20 Aug 2021 12:59:38 -0700 (PDT) From: Leah Rumancik To: stable@vger.kernel.org Cc: miklos@szeredi.hu, Murphy Zhou , Miklos Szeredi Subject: [PATCH] ovl: add splice file read write helper Date: Fri, 20 Aug 2021 19:59:29 +0000 Message-Id: <20210820195929.1926705-1-leah.rumancik@gmail.com> X-Mailer: git-send-email 2.33.0.rc2.250.ged5fa647cd-goog MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Murphy Zhou Now overlayfs falls back to use default file splice read and write, which is not compatiple with overlayfs, returning EFAULT. xfstests generic/591 can reproduce part of this. Tested this patch with xfstests auto group tests. [ Needed in 5.4 to fix a deadlock triggered via xfstests overlay/019 -- Leah Rumancik ] Signed-off-by: Murphy Zhou Signed-off-by: Miklos Szeredi --- fs/overlayfs/file.c | 47 +++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 47 insertions(+) diff --git a/fs/overlayfs/file.c b/fs/overlayfs/file.c index 7a08a576f7b2..ab5e92897270 100644 --- a/fs/overlayfs/file.c +++ b/fs/overlayfs/file.c @@ -9,6 +9,9 @@ #include #include #include +#include +#include +#include #include "overlayfs.h" static char ovl_whatisit(struct inode *inode, struct inode *realinode) @@ -293,6 +296,48 @@ static ssize_t ovl_write_iter(struct kiocb *iocb, struct iov_iter *iter) return ret; } +static ssize_t ovl_splice_read(struct file *in, loff_t *ppos, + struct pipe_inode_info *pipe, size_t len, + unsigned int flags) +{ + ssize_t ret; + struct fd real; + const struct cred *old_cred; + + ret = ovl_real_fdget(in, &real); + if (ret) + return ret; + + old_cred = ovl_override_creds(file_inode(in)->i_sb); + ret = generic_file_splice_read(real.file, ppos, pipe, len, flags); + revert_creds(old_cred); + + ovl_file_accessed(in); + fdput(real); + return ret; +} + +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; + ssize_t ret; + + ret = ovl_real_fdget(out, &real); + if (ret) + return ret; + + old_cred = ovl_override_creds(file_inode(out)->i_sb); + ret = iter_file_splice_write(pipe, real.file, ppos, len, flags); + revert_creds(old_cred); + + ovl_file_accessed(out); + fdput(real); + return ret; +} + static int ovl_fsync(struct file *file, loff_t start, loff_t end, int datasync) { struct fd real; @@ -649,6 +694,8 @@ const struct file_operations ovl_file_operations = { .fadvise = ovl_fadvise, .unlocked_ioctl = ovl_ioctl, .compat_ioctl = ovl_compat_ioctl, + .splice_read = ovl_splice_read, + .splice_write = ovl_splice_write, .copy_file_range = ovl_copy_file_range, .remap_file_range = ovl_remap_file_range,