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| author | Al Viro <viro@zeniv.linux.org.uk> | 2020-04-23 19:45:27 +0200 |
|---|---|---|
| committer | Al Viro <viro@zeniv.linux.org.uk> | 2020-04-23 19:45:27 +0200 |
| commit | 3815f1be546e752327b5868af103ccdddcc4db77 (patch) | |
| tree | 1aa45836cbf25923241e5221d070af52edb36867 | |
| parent | Linux 5.7-rc1 (diff) | |
| download | linux-3815f1be546e752327b5868af103ccdddcc4db77.tar.xz linux-3815f1be546e752327b5868af103ccdddcc4db77.zip | |
dlmfs_file_write(): fix the bogosity in handling non-zero *ppos
'count' is how much you want written, not the final position.
Moreover, it can legitimately be less than the current position...
Cc: stable@vger.kernel.org
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
| -rw-r--r-- | fs/ocfs2/dlmfs/dlmfs.c | 27 |
1 files changed, 12 insertions, 15 deletions
diff --git a/fs/ocfs2/dlmfs/dlmfs.c b/fs/ocfs2/dlmfs/dlmfs.c index 8e4f1ace467c..1de77f1a600b 100644 --- a/fs/ocfs2/dlmfs/dlmfs.c +++ b/fs/ocfs2/dlmfs/dlmfs.c @@ -275,7 +275,6 @@ static ssize_t dlmfs_file_write(struct file *filp, loff_t *ppos) { int bytes_left; - ssize_t writelen; char *lvb_buf; struct inode *inode = file_inode(filp); @@ -285,32 +284,30 @@ static ssize_t dlmfs_file_write(struct file *filp, if (*ppos >= i_size_read(inode)) return -ENOSPC; + /* don't write past the lvb */ + if (count > i_size_read(inode) - *ppos) + count = i_size_read(inode) - *ppos; + if (!count) return 0; if (!access_ok(buf, count)) return -EFAULT; - /* don't write past the lvb */ - if ((count + *ppos) > i_size_read(inode)) - writelen = i_size_read(inode) - *ppos; - else - writelen = count - *ppos; - - lvb_buf = kmalloc(writelen, GFP_NOFS); + lvb_buf = kmalloc(count, GFP_NOFS); if (!lvb_buf) return -ENOMEM; - bytes_left = copy_from_user(lvb_buf, buf, writelen); - writelen -= bytes_left; - if (writelen) - user_dlm_write_lvb(inode, lvb_buf, writelen); + bytes_left = copy_from_user(lvb_buf, buf, count); + count -= bytes_left; + if (count) + user_dlm_write_lvb(inode, lvb_buf, count); kfree(lvb_buf); - *ppos = *ppos + writelen; - mlog(0, "wrote %zd bytes\n", writelen); - return writelen; + *ppos = *ppos + count; + mlog(0, "wrote %zu bytes\n", count); + return count; } static void dlmfs_init_once(void *foo) |