[PATCH v6 7/7] fs/xfs: Add dax dedupe support
From: Shiyang Ruan <hidden>
Date: 2021-05-19 06:01:58
Also in:
linux-fsdevel, lkml
Subsystem:
filesystems (vfs and infrastructure), the rest, xfs filesystem · Maintainers:
Alexander Viro, Christian Brauner, Linus Torvalds, Carlos Maiolino
Introduce xfs_mmaplock_two_inodes_and_break_dax_layout() for dax files who are going to be deduped. After that, call compare range function only when files are both DAX or not. Signed-off-by: Shiyang Ruan <redacted> --- fs/xfs/xfs_file.c | 2 +- fs/xfs/xfs_inode.c | 57 ++++++++++++++++++++++++++++++++++++++++++++ fs/xfs/xfs_inode.h | 1 + fs/xfs/xfs_reflink.c | 4 ++-- 4 files changed, 61 insertions(+), 3 deletions(-)
diff --git a/fs/xfs/xfs_file.c b/fs/xfs/xfs_file.c
index 38d8eca05aee..bd5002d38df4 100644
--- a/fs/xfs/xfs_file.c
+++ b/fs/xfs/xfs_file.c@@ -823,7 +823,7 @@ xfs_wait_dax_page( xfs_ilock(ip, XFS_MMAPLOCK_EXCL); } -static int +int xfs_break_dax_layouts( struct inode *inode, bool *retry)
diff --git a/fs/xfs/xfs_inode.c b/fs/xfs/xfs_inode.c
index 0369eb22c1bb..d5e2791969ba 100644
--- a/fs/xfs/xfs_inode.c
+++ b/fs/xfs/xfs_inode.c@@ -3711,6 +3711,59 @@ xfs_iolock_two_inodes_and_break_layout( return 0; } +static int +xfs_mmaplock_two_inodes_and_break_dax_layout( + struct xfs_inode *ip1, + struct xfs_inode *ip2) +{ + int error, attempts = 0; + bool retry; + struct page *page; + struct xfs_log_item *lp; + + if (ip1->i_ino > ip2->i_ino) + swap(ip1, ip2); + +again: + retry = false; + /* Lock the first inode */ + xfs_ilock(ip1, XFS_MMAPLOCK_EXCL); + error = xfs_break_dax_layouts(VFS_I(ip1), &retry); + if (error || retry) { + xfs_iunlock(ip1, XFS_MMAPLOCK_EXCL); + goto again; + } + + if (ip1 == ip2) + return 0; + + /* Nested lock the second inode */ + lp = &ip1->i_itemp->ili_item; + if (lp && test_bit(XFS_LI_IN_AIL, &lp->li_flags)) { + if (!xfs_ilock_nowait(ip2, + xfs_lock_inumorder(XFS_MMAPLOCK_EXCL, 1))) { + xfs_iunlock(ip1, XFS_MMAPLOCK_EXCL); + if ((++attempts % 5) == 0) + delay(1); /* Don't just spin the CPU */ + goto again; + } + } else + xfs_ilock(ip2, xfs_lock_inumorder(XFS_MMAPLOCK_EXCL, 1)); + /* + * We cannot use xfs_break_dax_layouts() directly here because it may + * need to unlock & lock the XFS_MMAPLOCK_EXCL which is not suitable + * for this nested lock case. + */ + page = dax_layout_busy_page(VFS_I(ip2)->i_mapping); + if (page && page_ref_count(page) != 1) { + xfs_iunlock(ip2, XFS_MMAPLOCK_EXCL); + xfs_iunlock(ip1, XFS_MMAPLOCK_EXCL); + goto again; + } + + return 0; +} + /* * Lock two inodes so that userspace cannot initiate I/O via file syscalls or * mmap activity.
@@ -3725,6 +3778,10 @@ xfs_ilock2_io_mmap( ret = xfs_iolock_two_inodes_and_break_layout(VFS_I(ip1), VFS_I(ip2)); if (ret) return ret; + + if (IS_DAX(VFS_I(ip1)) && IS_DAX(VFS_I(ip2))) + return xfs_mmaplock_two_inodes_and_break_dax_layout(ip1, ip2); + if (ip1 == ip2) xfs_ilock(ip1, XFS_MMAPLOCK_EXCL); else
diff --git a/fs/xfs/xfs_inode.h b/fs/xfs/xfs_inode.h
index ca826cfba91c..2d0b344fb100 100644
--- a/fs/xfs/xfs_inode.h
+++ b/fs/xfs/xfs_inode.h@@ -457,6 +457,7 @@ enum xfs_prealloc_flags { int xfs_update_prealloc_flags(struct xfs_inode *ip, enum xfs_prealloc_flags flags); +int xfs_break_dax_layouts(struct inode *inode, bool *retry); int xfs_break_layouts(struct inode *inode, uint *iolock, enum layout_break_reason reason);
diff --git a/fs/xfs/xfs_reflink.c b/fs/xfs/xfs_reflink.c
index 9a780948dbd0..ff308304c5cd 100644
--- a/fs/xfs/xfs_reflink.c
+++ b/fs/xfs/xfs_reflink.c@@ -1324,8 +1324,8 @@ xfs_reflink_remap_prep( if (XFS_IS_REALTIME_INODE(src) || XFS_IS_REALTIME_INODE(dest)) goto out_unlock; - /* Don't share DAX file data for now. */ - if (IS_DAX(inode_in) || IS_DAX(inode_out)) + /* Don't share DAX file data with non-DAX file. */ + if (IS_DAX(inode_in) != IS_DAX(inode_out)) goto out_unlock; if (!IS_DAX(inode_in))
--
2.31.1