From d1665e414297c3a46fd80cb8242ad0c8e82acae7 Mon Sep 17 00:00:00 2001 From: Steven Whitehouse Date: Tue, 14 Feb 2006 11:54:42 +0000 Subject: [GFS2] Put back O_DIRECT support This patch adds back O_DIRECT support with various caveats attached: 1. Journaled data can be read via O_DIRECT since its now the same on disk format as normal data files. 2. Journaled data writes with O_DIRECT will be failed sliently back to normal writes (should we really do this I wonder or should we return an error instead?) 3. Stuffed files will be failed back to normal buffered I/O 4. All the usual corner cases (write beyond current end of file, write to an unallocated block) will also revert to normal buffered I/O. The I/O path is slightly odd as reads arrive at the page cache layer with the lock for the file already held, but writes arrive unlocked. Signed-off-by: Steven Whitehouse --- fs/gfs2/ops_address.c | 72 +++++++++++++++++++++++++++++++++++++++++---------- fs/gfs2/ops_file.c | 29 ++++++++++++--------- 2 files changed, 75 insertions(+), 26 deletions(-) diff --git a/fs/gfs2/ops_address.c b/fs/gfs2/ops_address.c index b14357e89421..74706f352780 100644 --- a/fs/gfs2/ops_address.c +++ b/fs/gfs2/ops_address.c @@ -14,6 +14,7 @@ #include #include #include +#include #include #include "gfs2.h" @@ -555,30 +556,73 @@ static int gfs2_invalidatepage(struct page *page, unsigned long offset) return ret; } -static ssize_t gfs2_direct_IO(int rw, struct kiocb *iocb, const struct iovec *iov, - loff_t offset, unsigned long nr_segs) +static ssize_t gfs2_direct_IO_write(struct kiocb *iocb, const struct iovec *iov, + loff_t offset, unsigned long nr_segs) +{ + struct file *file = iocb->ki_filp; + struct inode *inode = file->f_mapping->host; + struct gfs2_inode *ip = get_v2ip(inode); + struct gfs2_holder gh; + int rv; + + /* + * Shared lock, even though its write, since we do no allocation + * on this path. All we need change is atime. + */ + gfs2_holder_init(ip->i_gl, LM_ST_SHARED, GL_ATIME, &gh); + rv = gfs2_glock_nq_m_atime(1, &gh); + if (rv) + goto out; + + /* + * Should we return an error here? I can't see that O_DIRECT for + * a journaled file makes any sense. For now we'll silently fall + * back to buffered I/O, likewise we do the same for stuffed + * files since they are (a) small and (b) unaligned. + */ + if (gfs2_is_jdata(ip)) + goto out; + + if (gfs2_is_stuffed(ip)) + goto out; + + rv = __blockdev_direct_IO(WRITE, iocb, inode, inode->i_sb->s_bdev, + iov, offset, nr_segs, get_blocks_noalloc, + NULL, DIO_OWN_LOCKING); +out: + gfs2_glock_dq_m(1, &gh); + gfs2_holder_uninit(&gh); + + return rv; +} + +/** + * gfs2_direct_IO + * + * This is called with a shared lock already held for the read path. + * Currently, no locks are held when the write path is called. + */ +static ssize_t gfs2_direct_IO(int rw, struct kiocb *iocb, + const struct iovec *iov, loff_t offset, + unsigned long nr_segs) { struct file *file = iocb->ki_filp; struct inode *inode = file->f_mapping->host; struct gfs2_inode *ip = get_v2ip(inode); struct gfs2_sbd *sdp = ip->i_sbd; - get_blocks_t *gb = get_blocks; atomic_inc(&sdp->sd_ops_address); - if (gfs2_is_jdata(ip)) - return -EINVAL; + if (rw == WRITE) + return gfs2_direct_IO_write(iocb, iov, offset, nr_segs); - if (rw == WRITE) { - return -EOPNOTSUPP; /* for now */ - } else { - if (gfs2_assert_warn(sdp, gfs2_glock_is_locked_by_me(ip->i_gl)) || - gfs2_assert_warn(sdp, !gfs2_is_stuffed(ip))) - return -EINVAL; - } + if (gfs2_assert_warn(sdp, gfs2_glock_is_locked_by_me(ip->i_gl)) || + gfs2_assert_warn(sdp, !gfs2_is_stuffed(ip))) + return -EINVAL; - return blockdev_direct_IO(rw, iocb, inode, inode->i_sb->s_bdev, iov, - offset, nr_segs, gb, NULL); + return __blockdev_direct_IO(READ, iocb, inode, inode->i_sb->s_bdev, iov, + offset, nr_segs, get_blocks, NULL, + DIO_OWN_LOCKING); } struct address_space_operations gfs2_file_aops = { diff --git a/fs/gfs2/ops_file.c b/fs/gfs2/ops_file.c index 56820b39a993..bcde7a0b76f1 100644 --- a/fs/gfs2/ops_file.c +++ b/fs/gfs2/ops_file.c @@ -176,16 +176,16 @@ static ssize_t __gfs2_file_aio_read(struct kiocb *iocb, * If any segment has a negative length, or the cumulative * length ever wraps negative then return -EINVAL. */ - count += iv->iov_len; - if (unlikely((ssize_t)(count|iv->iov_len) < 0)) - return -EINVAL; - if (access_ok(VERIFY_WRITE, iv->iov_base, iv->iov_len)) - continue; - if (seg == 0) - return -EFAULT; - nr_segs = seg; - count -= iv->iov_len; /* This segment is no good */ - break; + count += iv->iov_len; + if (unlikely((ssize_t)(count|iv->iov_len) < 0)) + return -EINVAL; + if (access_ok(VERIFY_WRITE, iv->iov_base, iv->iov_len)) + continue; + if (seg == 0) + return -EFAULT; + nr_segs = seg; + count -= iv->iov_len; /* This segment is no good */ + break; } /* coalesce the iovecs and go direct-to-BIO for O_DIRECT */ @@ -204,10 +204,14 @@ static ssize_t __gfs2_file_aio_read(struct kiocb *iocb, retval = gfs2_glock_nq_m_atime(1, &gh); if (retval) goto out; - + if (gfs2_is_stuffed(ip)) { + gfs2_glock_dq_m(1, &gh); + gfs2_holder_uninit(&gh); + goto fallback_to_normal; + } size = i_size_read(inode); if (pos < size) { - retval = gfs2_direct_IO_read(iocb, iov, pos, nr_segs); + retval = gfs2_direct_IO_read(iocb, iov, pos, nr_segs); if (retval > 0 && !is_sync_kiocb(iocb)) retval = -EIOCBQUEUED; if (retval > 0) @@ -219,6 +223,7 @@ static ssize_t __gfs2_file_aio_read(struct kiocb *iocb, goto out; } +fallback_to_normal: retval = 0; if (count) { for (seg = 0; seg < nr_segs; seg++) { -- cgit v1.2.2