From b2b1ff3da6b27285c725eeb6f4c274da0a8e6a60 Mon Sep 17 00:00:00 2001 From: Trond Myklebust Date: Wed, 27 Jun 2018 16:25:40 -0400 Subject: [PATCH] NFS: Allow optimisation of lseek(fd, SEEK_CUR, 0) on directories There should be no need to grab the inode lock if we're only reading the file offset. Signed-off-by: Trond Myklebust --- fs/nfs/dir.c | 26 ++++++++++++++++---------- 1 file changed, 16 insertions(+), 10 deletions(-) diff --git a/fs/nfs/dir.c b/fs/nfs/dir.c index 7a9c14426855..8f8e9e9f2a79 100644 --- a/fs/nfs/dir.c +++ b/fs/nfs/dir.c @@ -904,23 +904,29 @@ static loff_t nfs_llseek_dir(struct file *filp, loff_t offset, int whence) dfprintk(FILE, "NFS: llseek dir(%pD2, %lld, %d)\n", filp, offset, whence); - inode_lock(inode); switch (whence) { - case 1: - offset += filp->f_pos; - case 0: - if (offset >= 0) - break; - default: - offset = -EINVAL; - goto out; + default: + return -EINVAL; + case SEEK_SET: + if (offset < 0) + return -EINVAL; + inode_lock(inode); + break; + case SEEK_CUR: + if (offset == 0) + return filp->f_pos; + inode_lock(inode); + offset += filp->f_pos; + if (offset < 0) { + inode_unlock(inode); + return -EINVAL; + } } if (offset != filp->f_pos) { filp->f_pos = offset; dir_ctx->dir_cookie = 0; dir_ctx->duped = 0; } -out: inode_unlock(inode); return offset; } -- 2.30.2