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dlmfs: convert dlmfs_file_read() to copy_to_user()

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Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
This commit is contained in:
Al Viro 2020-02-18 23:09:25 -05:00
parent 3d3185ae59
commit 0702e4f390
1 changed files with 14 additions and 19 deletions
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33
fs/ocfs2/dlmfs/dlmfs.c
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@ -227,7 +227,7 @@ static ssize_t dlmfs_file_read(struct file *filp,
loff_t *ppos) loff_t *ppos)
{ {
int bytes_left; int bytes_left;
ssize_t readlen, got; ssize_t got;
char *lvb_buf; char *lvb_buf;
struct inode *inode = file_inode(filp); struct inode *inode = file_inode(filp);
@ -237,36 +237,31 @@ static ssize_t dlmfs_file_read(struct file *filp,
if (*ppos >= i_size_read(inode)) if (*ppos >= i_size_read(inode))
return 0; return 0;
/* don't read past the lvb */
if (count > i_size_read(inode) - *ppos)
count = i_size_read(inode) - *ppos;
if (!count) if (!count)
return 0; return 0;
if (!access_ok(buf, count)) lvb_buf = kmalloc(count, GFP_NOFS);
return -EFAULT;
/* don't read past the lvb */
if ((count + *ppos) > i_size_read(inode))
readlen = i_size_read(inode) - *ppos;
else
readlen = count;
lvb_buf = kmalloc(readlen, GFP_NOFS);
if (!lvb_buf) if (!lvb_buf)
return -ENOMEM; return -ENOMEM;
got = user_dlm_read_lvb(inode, lvb_buf, readlen); got = user_dlm_read_lvb(inode, lvb_buf, count);
if (got) { if (got) {
BUG_ON(got != readlen); BUG_ON(got != count);
bytes_left = __copy_to_user(buf, lvb_buf, readlen); bytes_left = copy_to_user(buf, lvb_buf, count);
readlen -= bytes_left; count -= bytes_left;
} else } else
readlen = 0; count = 0;
kfree(lvb_buf); kfree(lvb_buf);
*ppos = *ppos + readlen; *ppos = *ppos + count;
mlog(0, "read %zd bytes\n", readlen); mlog(0, "read %zu bytes\n", count);
return readlen; return count;
} }
static ssize_t dlmfs_file_write(struct file *filp, static ssize_t dlmfs_file_write(struct file *filp,