From fa0a21269f807bb2e95b8b642c4a739714780172 Mon Sep 17 00:00:00 2001 From: "J. Bruce Fields" Date: Tue, 27 Jul 2010 16:48:54 -0400 Subject: [PATCH] nfsd: bypass readahead cache when have struct file The readahead cache compensates for the fact that the NFS server currently does an open and close on every IO operation in the NFSv2 and NFSv3 case. In the NFSv4 case we have long-lived struct files associated with client opens, so there's no need for this. In fact, concurrent IO's using trying to modify the same file->f_ra may cause problems. So, don't bother with the readahead cache in that case. Note eventually we'll likely do this in the v2/v3 case as well by keeping a cache of struct files instead of struct file_ra_state's. Signed-off-by: J. Bruce Fields --- fs/nfsd/vfs.c | 62 +++++++++++++++++++++++++++++++-------------------- 1 file changed, 38 insertions(+), 24 deletions(-) diff --git a/fs/nfsd/vfs.c b/fs/nfsd/vfs.c index 5ca984bbd7d3..31d32aeda2c2 100644 --- a/fs/nfsd/vfs.c +++ b/fs/nfsd/vfs.c @@ -904,7 +904,6 @@ nfsd_vfs_read(struct svc_rqst *rqstp, struct svc_fh *fhp, struct file *file, loff_t offset, struct kvec *vec, int vlen, unsigned long *count) { struct inode *inode; - struct raparms *ra; mm_segment_t oldfs; __be32 err; int host_err; @@ -915,12 +914,6 @@ nfsd_vfs_read(struct svc_rqst *rqstp, struct svc_fh *fhp, struct file *file, if (svc_msnfs(fhp) && !lock_may_read(inode, offset, *count)) goto out; - /* Get readahead parameters */ - ra = nfsd_get_raparms(inode->i_sb->s_dev, inode->i_ino); - - if (ra && ra->p_set) - file->f_ra = ra->p_ra; - if (file->f_op->splice_read && rqstp->rq_splice_ok) { struct splice_desc sd = { .len = 0, @@ -938,16 +931,6 @@ nfsd_vfs_read(struct svc_rqst *rqstp, struct svc_fh *fhp, struct file *file, set_fs(oldfs); } - /* Write back readahead params */ - if (ra) { - struct raparm_hbucket *rab = &raparm_hash[ra->p_hindex]; - spin_lock(&rab->pb_lock); - ra->p_ra = file->f_ra; - ra->p_set = 1; - ra->p_count--; - spin_unlock(&rab->pb_lock); - } - if (host_err >= 0) { nfsdstats.io_read += host_err; *count = host_err; @@ -1082,6 +1065,42 @@ out: return err; } +static __be32 nfsd_open_read(struct svc_rqst *rqstp, struct svc_fh *fhp, + loff_t offset, struct kvec *vec, int vlen, unsigned long *count) +{ + struct file *file; + struct inode *inode; + struct raparms *ra; + __be32 err; + + err = nfsd_open(rqstp, fhp, S_IFREG, NFSD_MAY_READ, &file); + if (err) + return err; + + inode = file->f_path.dentry->d_inode; + + /* Get readahead parameters */ + ra = nfsd_get_raparms(inode->i_sb->s_dev, inode->i_ino); + + if (ra && ra->p_set) + file->f_ra = ra->p_ra; + + err = nfsd_vfs_read(rqstp, fhp, file, offset, vec, vlen, count); + + /* Write back readahead params */ + if (ra) { + struct raparm_hbucket *rab = &raparm_hash[ra->p_hindex]; + spin_lock(&rab->pb_lock); + ra->p_ra = file->f_ra; + ra->p_set = 1; + ra->p_count--; + spin_unlock(&rab->pb_lock); + } + + nfsd_close(file); + return err; +} + /* * Read data from a file. count must contain the requested read count * on entry. On return, *count contains the number of bytes actually read. @@ -1100,13 +1119,8 @@ nfsd_read(struct svc_rqst *rqstp, struct svc_fh *fhp, struct file *file, if (err) goto out; err = nfsd_vfs_read(rqstp, fhp, file, offset, vec, vlen, count); - } else { - err = nfsd_open(rqstp, fhp, S_IFREG, NFSD_MAY_READ, &file); - if (err) - goto out; - err = nfsd_vfs_read(rqstp, fhp, file, offset, vec, vlen, count); - nfsd_close(file); - } + } else + err = nfsd_open_read(rqstp, fhp, offset, vec, vlen, count); out: return err; } -- 2.39.2