Re: [RFC PATCH 3/3] fuse: add per-file DAX flag
From: Vivek Goyal <vgoyal@redhat.com>
Date: 2021-07-16 00:51:23
On Fri, Jul 16, 2021 at 08:40:29AM +0800, Liu Bo wrote:
On Thu, Jul 15, 2021 at 05:30:31PM +0800, Jeffle Xu wrote:quoted
Add one flag for fuse_attr.flags indicating if DAX shall be enabled for this file. When the per-file DAX flag changes for an *opened* file, the state of the file won't be updated until this file is closed and reopened later. Currently it is not implemented yet to change per-file DAX flag inside guest kernel, e.g., by chattr(1).Thanks for the patch, it looks good to me. I think it's a good starting point, what I'd like to discuss here is whether we're going to let chattr to toggle the dax flag.
I have the same question. Why not take chattr approach as taken by ext4/xfs as well. Vivek
My usecase is like, on the fuse server side, if a file is marked as DAX, then it won't change any more. So this 'fuse_attr.flags' works for me at least. thanks, liuboquoted
Signed-off-by: Jeffle Xu <jefflexu@linux.alibaba.com> --- fs/fuse/dax.c | 28 ++++++++++++++++++++++++---- fs/fuse/file.c | 4 ++-- fs/fuse/fuse_i.h | 5 +++-- fs/fuse/inode.c | 4 +++- include/uapi/linux/fuse.h | 5 +++++ 5 files changed, 37 insertions(+), 9 deletions(-)diff --git a/fs/fuse/dax.c b/fs/fuse/dax.c index 4873d764cb66..ed5a430364bb 100644 --- a/fs/fuse/dax.c +++ b/fs/fuse/dax.c@@ -1341,7 +1341,7 @@ static const struct address_space_operations fuse_dax_file_aops = { .invalidatepage = noop_invalidatepage, }; -static bool fuse_should_enable_dax(struct inode *inode) +static bool fuse_should_enable_dax(struct inode *inode, unsigned int flags) { struct fuse_conn *fc = get_fuse_conn(inode); unsigned int mode;@@ -1354,18 +1354,38 @@ static bool fuse_should_enable_dax(struct inode *inode) if (mode == FUSE_DAX_MOUNT_NEVER) return false; - return true; + if (mode == FUSE_DAX_MOUNT_ALWAYS) + return true; + + WARN_ON(mode != FUSE_DAX_MOUNT_INODE); + return flags & FUSE_ATTR_DAX; } -void fuse_dax_inode_init(struct inode *inode) +void fuse_dax_inode_init(struct inode *inode, unsigned int flags) { - if (!fuse_should_enable_dax(inode)) + if (!fuse_should_enable_dax(inode, flags)) return; inode->i_flags |= S_DAX; inode->i_data.a_ops = &fuse_dax_file_aops; } +void fuse_update_dax(struct inode *inode, unsigned int flags) +{ + bool oldstate, newstate; + struct fuse_conn *fc = get_fuse_conn(inode); + + if (!IS_ENABLED(CONFIG_FUSE_DAX) || !fc->dax || + fc->dax->mode != FUSE_DAX_MOUNT_INODE) + return; + + oldstate = IS_DAX(inode); + newstate = flags & FUSE_ATTR_DAX; + + if (oldstate != newstate) + d_mark_dontcache(inode); +} + bool fuse_dax_check_alignment(struct fuse_conn *fc, unsigned int map_alignment) { if (fc->dax && (map_alignment > FUSE_DAX_SHIFT)) {diff --git a/fs/fuse/file.c b/fs/fuse/file.c index 97f860cfc195..cf42af492146 100644 --- a/fs/fuse/file.c +++ b/fs/fuse/file.c@@ -3142,7 +3142,7 @@ static const struct address_space_operations fuse_file_aops = { .write_end = fuse_write_end, }; -void fuse_init_file_inode(struct inode *inode) +void fuse_init_file_inode(struct inode *inode, struct fuse_attr *attr) { struct fuse_inode *fi = get_fuse_inode(inode);@@ -3156,5 +3156,5 @@ void fuse_init_file_inode(struct inode *inode) fi->writepages = RB_ROOT; if (IS_ENABLED(CONFIG_FUSE_DAX)) - fuse_dax_inode_init(inode); + fuse_dax_inode_init(inode, attr->flags); }diff --git a/fs/fuse/fuse_i.h b/fs/fuse/fuse_i.h index f29018323845..b0ecfffd0c7d 100644 --- a/fs/fuse/fuse_i.h +++ b/fs/fuse/fuse_i.h@@ -1000,7 +1000,7 @@ int fuse_notify_poll_wakeup(struct fuse_conn *fc, /** * Initialize file operations on a regular file */ -void fuse_init_file_inode(struct inode *inode); +void fuse_init_file_inode(struct inode *inode, struct fuse_attr *attr); /** * Initialize inode operations on regular files and special files@@ -1252,8 +1252,9 @@ int fuse_dax_conn_alloc(struct fuse_conn *fc, unsigned int mode, struct dax_device *dax_dev); void fuse_dax_conn_free(struct fuse_conn *fc); bool fuse_dax_inode_alloc(struct super_block *sb, struct fuse_inode *fi); -void fuse_dax_inode_init(struct inode *inode); +void fuse_dax_inode_init(struct inode *inode, unsigned int flags); void fuse_dax_inode_cleanup(struct inode *inode); +void fuse_update_dax(struct inode *inode, unsigned int flags); bool fuse_dax_check_alignment(struct fuse_conn *fc, unsigned int map_alignment); void fuse_dax_cancel_work(struct fuse_conn *fc);diff --git a/fs/fuse/inode.c b/fs/fuse/inode.c index f6b46395edb2..47ebb1a394d2 100644 --- a/fs/fuse/inode.c +++ b/fs/fuse/inode.c@@ -269,6 +269,8 @@ void fuse_change_attributes(struct inode *inode, struct fuse_attr *attr, if (inval) invalidate_inode_pages2(inode->i_mapping); } + + fuse_update_dax(inode, attr->flags); } static void fuse_init_inode(struct inode *inode, struct fuse_attr *attr)@@ -281,7 +283,7 @@ static void fuse_init_inode(struct inode *inode, struct fuse_attr *attr) inode->i_ctime.tv_nsec = attr->ctimensec; if (S_ISREG(inode->i_mode)) { fuse_init_common(inode); - fuse_init_file_inode(inode); + fuse_init_file_inode(inode, attr); } else if (S_ISDIR(inode->i_mode)) fuse_init_dir(inode); else if (S_ISLNK(inode->i_mode))diff --git a/include/uapi/linux/fuse.h b/include/uapi/linux/fuse.h index 36ed092227fa..9ee088ddbe2a 100644 --- a/include/uapi/linux/fuse.h +++ b/include/uapi/linux/fuse.h@@ -184,6 +184,9 @@ * * 7.34 * - add FUSE_SYNCFS + * + * 7.35 + * - add FUSE_ATTR_DAX */ #ifndef _LINUX_FUSE_H@@ -449,8 +452,10 @@ struct fuse_file_lock { * fuse_attr flags * * FUSE_ATTR_SUBMOUNT: Object is a submount root + * FUSE_ATTR_DAX: Enable DAX for this file in per-file DAX mode */ #define FUSE_ATTR_SUBMOUNT (1 << 0) +#define FUSE_ATTR_DAX (1 << 1) /** * Open flags-- 2.27.0
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