| Message ID | 20240103084126.513354-5-hch@lst.de (mailing list archive) |
|---|---|
| State | Superseded |
| Headers | show |
| Series | [01/15] shmem: move the shmem_mapping assert into shmem_get_folio_gfp | expand |
On Wed, Jan 03, 2024 at 08:41:15AM +0000, Christoph Hellwig wrote: > vfs_getattr is needed to query inode attributes for unknown underlying > file systems. But shmemfs is well known for users of shmem_file_setup > and shmem_read_mapping_page_gfp that rely on it not needing specific > inode revalidation and having a normal mapping. Remove the detour > through the getattr method and an extra wrapper, and just read the > inode size and i_bytes directly in the scrub tracing code. > > Signed-off-by: Christoph Hellwig <hch@lst.de> > --- > fs/xfs/scrub/trace.h | 34 ++++++++++------------------------ > fs/xfs/scrub/xfile.c | 19 ------------------- > fs/xfs/scrub/xfile.h | 7 ------- > 3 files changed, 10 insertions(+), 50 deletions(-) > > diff --git a/fs/xfs/scrub/trace.h b/fs/xfs/scrub/trace.h > index 6bbb4e8639dca6..ed9e044f6d603c 100644 > --- a/fs/xfs/scrub/trace.h > +++ b/fs/xfs/scrub/trace.h > @@ -861,18 +861,11 @@ TRACE_EVENT(xfile_destroy, > __field(loff_t, size) > ), > TP_fast_assign( > - struct xfile_stat statbuf; > - int ret; > - > - ret = xfile_stat(xf, &statbuf); > - if (!ret) { > - __entry->bytes = statbuf.bytes; > - __entry->size = statbuf.size; > - } else { > - __entry->bytes = -1; > - __entry->size = -1; > - } > - __entry->ino = file_inode(xf->file)->i_ino; > + struct inode *inode = file_inode(xf->file); > + > + __entry->ino = inode->i_ino; > + __entry->bytes = inode->i_bytes; Shouldn't this be (i_blocks << 9) + i_bytes? > + __entry->size = i_size_read(inode); > ), > TP_printk("xfino 0x%lx mem_bytes 0x%llx isize 0x%llx", > __entry->ino, > @@ -891,19 +884,12 @@ DECLARE_EVENT_CLASS(xfile_class, > __field(unsigned long long, bytecount) > ), > TP_fast_assign( > - struct xfile_stat statbuf; > - int ret; > - > - ret = xfile_stat(xf, &statbuf); > - if (!ret) { > - __entry->bytes_used = statbuf.bytes; > - __entry->size = statbuf.size; > - } else { > - __entry->bytes_used = -1; > - __entry->size = -1; > - } > - __entry->ino = file_inode(xf->file)->i_ino; > + struct inode *inode = file_inode(xf->file); > + > + __entry->ino = inode->i_ino; > + __entry->bytes_used = inode->i_bytes; Here too. > __entry->pos = pos; > + __entry->size = i_size_read(inode); > __entry->bytecount = bytecount; > ), > TP_printk("xfino 0x%lx mem_bytes 0x%llx pos 0x%llx bytecount 0x%llx isize 0x%llx", > diff --git a/fs/xfs/scrub/xfile.c b/fs/xfs/scrub/xfile.c > index 090c3ead43fdf1..87654cdd5ac6f9 100644 > --- a/fs/xfs/scrub/xfile.c > +++ b/fs/xfs/scrub/xfile.c > @@ -291,25 +291,6 @@ xfile_seek_data( > return ret; > } > > -/* Query stat information for an xfile. */ > -int > -xfile_stat( > - struct xfile *xf, > - struct xfile_stat *statbuf) > -{ > - struct kstat ks; > - int error; > - > - error = vfs_getattr_nosec(&xf->file->f_path, &ks, > - STATX_SIZE | STATX_BLOCKS, AT_STATX_DONT_SYNC); > - if (error) > - return error; > - > - statbuf->size = ks.size; > - statbuf->bytes = ks.blocks << SECTOR_SHIFT; > - return 0; > -} > - > /* > * Grab the (locked) page for a memory object. The object cannot span a page > * boundary. Returns 0 (and a locked page) if successful, -ENOTBLK if we > diff --git a/fs/xfs/scrub/xfile.h b/fs/xfs/scrub/xfile.h > index d56643b0f429e1..c602d11560d8ee 100644 > --- a/fs/xfs/scrub/xfile.h > +++ b/fs/xfs/scrub/xfile.h > @@ -63,13 +63,6 @@ xfile_obj_store(struct xfile *xf, const void *buf, size_t count, loff_t pos) > > loff_t xfile_seek_data(struct xfile *xf, loff_t pos); > > -struct xfile_stat { > - loff_t size; > - unsigned long long bytes; > -}; > - > -int xfile_stat(struct xfile *xf, struct xfile_stat *statbuf); Removing this function will put some distance between the kernel and xfsprogs xfile implementations, since userspace can't do failure-free fstat. OTOH I guess if xfile_stat fails in userspace, our xfile is screwed and we probably have to abort the whole program anyway. For the kernel I like getting rid of this clutter, modulo the question above. --D > - > int xfile_get_page(struct xfile *xf, loff_t offset, unsigned int len, > struct xfile_page *xbuf); > int xfile_put_page(struct xfile *xf, struct xfile_page *xbuf); > -- > 2.39.2 > >
On Wed, Jan 03, 2024 at 03:45:33PM -0800, Darrick J. Wong wrote: > > + __entry->bytes = inode->i_bytes; > > Shouldn't this be (i_blocks << 9) + i_bytes? Actually this should just be doing: __entry->bytes = inode->i_blocks << SECTOR_SHIFT; The bytes name here really confused me. Or we could change the trace point to just report i_block directly and not rename it to bytes and change the unit?
On Thu, Jan 04, 2024 at 07:14:15AM +0100, Christoph Hellwig wrote: > On Wed, Jan 03, 2024 at 03:45:33PM -0800, Darrick J. Wong wrote: > > > + __entry->bytes = inode->i_bytes; > > > > Shouldn't this be (i_blocks << 9) + i_bytes? > > Actually this should just be doing: > > __entry->bytes = inode->i_blocks << SECTOR_SHIFT; > > The bytes name here really confused me. Me too. It looks like some weird way to encode the bytes used by the file using a u64 sector count and a u16 byte count for ... some reason? XFS (and thankfully tmpfs) seem to ignore all that entirely. > Or we could change the trace > point to just report i_block directly and not rename it to bytes and > change the unit? I prefer to keep the tracepoint in bytes because that's a little easier than rshifting by 9 in my head. --D
diff --git a/fs/xfs/scrub/trace.h b/fs/xfs/scrub/trace.h index 6bbb4e8639dca6..ed9e044f6d603c 100644 --- a/fs/xfs/scrub/trace.h +++ b/fs/xfs/scrub/trace.h @@ -861,18 +861,11 @@ TRACE_EVENT(xfile_destroy, __field(loff_t, size) ), TP_fast_assign( - struct xfile_stat statbuf; - int ret; - - ret = xfile_stat(xf, &statbuf); - if (!ret) { - __entry->bytes = statbuf.bytes; - __entry->size = statbuf.size; - } else { - __entry->bytes = -1; - __entry->size = -1; - } - __entry->ino = file_inode(xf->file)->i_ino; + struct inode *inode = file_inode(xf->file); + + __entry->ino = inode->i_ino; + __entry->bytes = inode->i_bytes; + __entry->size = i_size_read(inode); ), TP_printk("xfino 0x%lx mem_bytes 0x%llx isize 0x%llx", __entry->ino, @@ -891,19 +884,12 @@ DECLARE_EVENT_CLASS(xfile_class, __field(unsigned long long, bytecount) ), TP_fast_assign( - struct xfile_stat statbuf; - int ret; - - ret = xfile_stat(xf, &statbuf); - if (!ret) { - __entry->bytes_used = statbuf.bytes; - __entry->size = statbuf.size; - } else { - __entry->bytes_used = -1; - __entry->size = -1; - } - __entry->ino = file_inode(xf->file)->i_ino; + struct inode *inode = file_inode(xf->file); + + __entry->ino = inode->i_ino; + __entry->bytes_used = inode->i_bytes; __entry->pos = pos; + __entry->size = i_size_read(inode); __entry->bytecount = bytecount; ), TP_printk("xfino 0x%lx mem_bytes 0x%llx pos 0x%llx bytecount 0x%llx isize 0x%llx", diff --git a/fs/xfs/scrub/xfile.c b/fs/xfs/scrub/xfile.c index 090c3ead43fdf1..87654cdd5ac6f9 100644 --- a/fs/xfs/scrub/xfile.c +++ b/fs/xfs/scrub/xfile.c @@ -291,25 +291,6 @@ xfile_seek_data( return ret; } -/* Query stat information for an xfile. */ -int -xfile_stat( - struct xfile *xf, - struct xfile_stat *statbuf) -{ - struct kstat ks; - int error; - - error = vfs_getattr_nosec(&xf->file->f_path, &ks, - STATX_SIZE | STATX_BLOCKS, AT_STATX_DONT_SYNC); - if (error) - return error; - - statbuf->size = ks.size; - statbuf->bytes = ks.blocks << SECTOR_SHIFT; - return 0; -} - /* * Grab the (locked) page for a memory object. The object cannot span a page * boundary. Returns 0 (and a locked page) if successful, -ENOTBLK if we diff --git a/fs/xfs/scrub/xfile.h b/fs/xfs/scrub/xfile.h index d56643b0f429e1..c602d11560d8ee 100644 --- a/fs/xfs/scrub/xfile.h +++ b/fs/xfs/scrub/xfile.h @@ -63,13 +63,6 @@ xfile_obj_store(struct xfile *xf, const void *buf, size_t count, loff_t pos) loff_t xfile_seek_data(struct xfile *xf, loff_t pos); -struct xfile_stat { - loff_t size; - unsigned long long bytes; -}; - -int xfile_stat(struct xfile *xf, struct xfile_stat *statbuf); - int xfile_get_page(struct xfile *xf, loff_t offset, unsigned int len, struct xfile_page *xbuf); int xfile_put_page(struct xfile *xf, struct xfile_page *xbuf);
vfs_getattr is needed to query inode attributes for unknown underlying file systems. But shmemfs is well known for users of shmem_file_setup and shmem_read_mapping_page_gfp that rely on it not needing specific inode revalidation and having a normal mapping. Remove the detour through the getattr method and an extra wrapper, and just read the inode size and i_bytes directly in the scrub tracing code. Signed-off-by: Christoph Hellwig <hch@lst.de> --- fs/xfs/scrub/trace.h | 34 ++++++++++------------------------ fs/xfs/scrub/xfile.c | 19 ------------------- fs/xfs/scrub/xfile.h | 7 ------- 3 files changed, 10 insertions(+), 50 deletions(-)