| Message ID | 1442003423-6884-9-git-send-email-Anna.Schumaker@Netapp.com (mailing list archive) |
|---|---|
| State | Not Applicable |
| Headers | show |
On Fri, Sep 11, 2015 at 04:30:21PM -0400, Anna Schumaker wrote: > The NFS server will need some kind offallback for filesystems that don't > have any kind of copy acceleration, and it should be generally useful to > have an in-kernel copy to avoid lots of switches between kernel and user > space. > > I make this configurable by adding two new flags. Users who only want a > reflink can pass COPY_FR_REFLINK, and users who want a full data copy can > pass COPY_FR_COPY. The default (flags=0) means to first attempt a > reflink, but use the pagecache if that fails. > > I moved the rw_verify_area() calls into the fallback code since some > filesystems can handle reflinking a large range. > > Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com> > --- > v2: > - Rename COPY_REFLINK -> COPY_FR_REFLINK > - Introduce COPY_FR_COPY flag > - Flags == 0 is really COPY_FR_COPY|COPY_FR_REFLINK > - Drop check for invalid flags > - Move call to do_splice_direct() into a new function > - Move rw_verify_area() checks into the new fallback function > --- > fs/read_write.c | 56 ++++++++++++++++++++++++++++------------------- > include/linux/copy.h | 6 +++++ > include/uapi/linux/Kbuild | 1 + > include/uapi/linux/copy.h | 7 ++++++ > 4 files changed, 48 insertions(+), 22 deletions(-) > create mode 100644 include/linux/copy.h > create mode 100644 include/uapi/linux/copy.h > > diff --git a/fs/read_write.c b/fs/read_write.c > index 363bd3e..ba24884 100644 > --- a/fs/read_write.c > +++ b/fs/read_write.c > @@ -7,6 +7,7 @@ > #include <linux/slab.h> > #include <linux/stat.h> > #include <linux/fcntl.h> > +#include <linux/copy.h> > #include <linux/file.h> > #include <linux/uio.h> > #include <linux/fsnotify.h> > @@ -1329,6 +1330,29 @@ COMPAT_SYSCALL_DEFINE4(sendfile64, int, out_fd, int, in_fd, > } > #endif > > +static ssize_t vfs_copy_file_pagecache(struct file *file_in, loff_t pos_in, > + struct file *file_out, loff_t pos_out, > + size_t len) > +{ > + ssize_t ret; > + > + ret = rw_verify_area(READ, file_in, &pos_in, len); > + if (ret >= 0) { > + len = ret; > + ret = rw_verify_area(WRITE, file_out, &pos_out, len); > + if (ret >= 0) > + len = ret; > + } > + if (ret < 0) > + return ret; > + > + file_start_write(file_out); > + ret = do_splice_direct(file_in, &pos_in, file_out, &pos_out, len, 0); > + file_end_write(file_out); > + > + return ret; > +} > + > /* > * copy_file_range() differs from regular file read and write in that it > * specifically allows return partial success. When it does so is up to > @@ -1338,34 +1362,17 @@ ssize_t vfs_copy_file_range(struct file *file_in, loff_t pos_in, > struct file *file_out, loff_t pos_out, > size_t len, int flags) > { > - struct inode *inode_in; > - struct inode *inode_out; > ssize_t ret; > > - if (flags) > - return -EINVAL; > - > - /* copy_file_range allows full ssize_t len, ignoring MAX_RW_COUNT */ > - ret = rw_verify_area(READ, file_in, &pos_in, len); > - if (ret >= 0) > - ret = rw_verify_area(WRITE, file_out, &pos_out, len); > - if (ret < 0) > - return ret; > + if (flags == 0) > + flags = COPY_FR_COPY | COPY_FR_REFLINK; This function must return -EINVAL if any of the undefined flags bits are set. > > if (!(file_in->f_mode & FMODE_READ) || > !(file_out->f_mode & FMODE_WRITE) || > (file_out->f_flags & O_APPEND) || > - !file_out->f_op || !file_out->f_op->copy_file_range) > + !file_in->f_op) > return -EBADF; > > - inode_in = file_inode(file_in); > - inode_out = file_inode(file_out); > - > - /* make sure offsets don't wrap and the input is inside i_size */ > - if (pos_in + len < pos_in || pos_out + len < pos_out || > - pos_in + len > i_size_read(inode_in)) > - return -EINVAL; > - > if (len == 0) > return 0; > > @@ -1373,8 +1380,13 @@ ssize_t vfs_copy_file_range(struct file *file_in, loff_t pos_in, > if (ret) > return ret; > > - ret = file_out->f_op->copy_file_range(file_in, pos_in, file_out, pos_out, > - len, flags); > + ret = -EOPNOTSUPP; > + if (file_out->f_op->copy_file_range) > + ret = file_out->f_op->copy_file_range(file_in, pos_in, file_out, > + pos_out, len, flags); > + if ((ret < 0) && (flags & COPY_FR_COPY)) > + ret = vfs_copy_file_pagecache(file_in, pos_in, file_out, > + pos_out, len); > if (ret > 0) { > fsnotify_access(file_in); > add_rchar(current, ret); > diff --git a/include/linux/copy.h b/include/linux/copy.h > new file mode 100644 > index 0000000..fd54543 > --- /dev/null > +++ b/include/linux/copy.h > @@ -0,0 +1,6 @@ > +#ifndef _LINUX_COPY_H > +#define _LINUX_COPY_H > + > +#include <uapi/linux/copy.h> > + > +#endif /* _LINUX_COPY_H */ > diff --git a/include/uapi/linux/Kbuild b/include/uapi/linux/Kbuild > index 70ff1d9..d46830a 100644 > --- a/include/uapi/linux/Kbuild > +++ b/include/uapi/linux/Kbuild > @@ -90,6 +90,7 @@ header-y += coda_psdev.h > header-y += coff.h > header-y += connector.h > header-y += const.h > +header-y += copy.h > header-y += cramfs_fs.h > header-y += cuda.h > header-y += cyclades.h > diff --git a/include/uapi/linux/copy.h b/include/uapi/linux/copy.h > new file mode 100644 > index 0000000..2da59a8 > --- /dev/null > +++ b/include/uapi/linux/copy.h > @@ -0,0 +1,7 @@ > +#ifndef _UAPI_LINUX_COPY_H > +#define _UAPI_LINUX_COPY_H > + > +#define COPY_FR_COPY (1 << 0) /* Only do a pagecache copy. */ > +#define COPY_FR_REFLINK (1 << 1) /* Only make a reflink. */ Could I have a COPY_FR_DEDUPE flag too, please? (I don't mind adding it myself when I get around to hooking up XFS, but I was hoping to get it in during the first round). --D > + > +#endif /* _UAPI_LINUX_COPY_H */ > -- > 2.5.1 > > -- > To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On 09/14/2015 11:32 PM, Darrick J. Wong wrote: > On Fri, Sep 11, 2015 at 04:30:21PM -0400, Anna Schumaker wrote: >> The NFS server will need some kind offallback for filesystems that don't >> have any kind of copy acceleration, and it should be generally useful to >> have an in-kernel copy to avoid lots of switches between kernel and user >> space. >> >> I make this configurable by adding two new flags. Users who only want a >> reflink can pass COPY_FR_REFLINK, and users who want a full data copy can >> pass COPY_FR_COPY. The default (flags=0) means to first attempt a >> reflink, but use the pagecache if that fails. >> >> I moved the rw_verify_area() calls into the fallback code since some >> filesystems can handle reflinking a large range. >> >> Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com> >> --- >> v2: >> - Rename COPY_REFLINK -> COPY_FR_REFLINK >> - Introduce COPY_FR_COPY flag >> - Flags == 0 is really COPY_FR_COPY|COPY_FR_REFLINK >> - Drop check for invalid flags >> - Move call to do_splice_direct() into a new function >> - Move rw_verify_area() checks into the new fallback function >> --- >> fs/read_write.c | 56 ++++++++++++++++++++++++++++------------------- >> include/linux/copy.h | 6 +++++ >> include/uapi/linux/Kbuild | 1 + >> include/uapi/linux/copy.h | 7 ++++++ >> 4 files changed, 48 insertions(+), 22 deletions(-) >> create mode 100644 include/linux/copy.h >> create mode 100644 include/uapi/linux/copy.h >> >> diff --git a/fs/read_write.c b/fs/read_write.c >> index 363bd3e..ba24884 100644 >> --- a/fs/read_write.c >> +++ b/fs/read_write.c >> @@ -7,6 +7,7 @@ >> #include <linux/slab.h> >> #include <linux/stat.h> >> #include <linux/fcntl.h> >> +#include <linux/copy.h> >> #include <linux/file.h> >> #include <linux/uio.h> >> #include <linux/fsnotify.h> >> @@ -1329,6 +1330,29 @@ COMPAT_SYSCALL_DEFINE4(sendfile64, int, out_fd, int, in_fd, >> } >> #endif >> >> +static ssize_t vfs_copy_file_pagecache(struct file *file_in, loff_t pos_in, >> + struct file *file_out, loff_t pos_out, >> + size_t len) >> +{ >> + ssize_t ret; >> + >> + ret = rw_verify_area(READ, file_in, &pos_in, len); >> + if (ret >= 0) { >> + len = ret; >> + ret = rw_verify_area(WRITE, file_out, &pos_out, len); >> + if (ret >= 0) >> + len = ret; >> + } >> + if (ret < 0) >> + return ret; >> + >> + file_start_write(file_out); >> + ret = do_splice_direct(file_in, &pos_in, file_out, &pos_out, len, 0); >> + file_end_write(file_out); >> + >> + return ret; >> +} >> + >> /* >> * copy_file_range() differs from regular file read and write in that it >> * specifically allows return partial success. When it does so is up to >> @@ -1338,34 +1362,17 @@ ssize_t vfs_copy_file_range(struct file *file_in, loff_t pos_in, >> struct file *file_out, loff_t pos_out, >> size_t len, int flags) >> { >> - struct inode *inode_in; >> - struct inode *inode_out; >> ssize_t ret; >> >> - if (flags) >> - return -EINVAL; >> - >> - /* copy_file_range allows full ssize_t len, ignoring MAX_RW_COUNT */ >> - ret = rw_verify_area(READ, file_in, &pos_in, len); >> - if (ret >= 0) >> - ret = rw_verify_area(WRITE, file_out, &pos_out, len); >> - if (ret < 0) >> - return ret; >> + if (flags == 0) >> + flags = COPY_FR_COPY | COPY_FR_REFLINK; > > This function must return -EINVAL if any of the undefined flags bits are > set. Sure, I'll add that. > >> >> if (!(file_in->f_mode & FMODE_READ) || >> !(file_out->f_mode & FMODE_WRITE) || >> (file_out->f_flags & O_APPEND) || >> - !file_out->f_op || !file_out->f_op->copy_file_range) >> + !file_in->f_op) >> return -EBADF; >> >> - inode_in = file_inode(file_in); >> - inode_out = file_inode(file_out); >> - >> - /* make sure offsets don't wrap and the input is inside i_size */ >> - if (pos_in + len < pos_in || pos_out + len < pos_out || >> - pos_in + len > i_size_read(inode_in)) >> - return -EINVAL; >> - >> if (len == 0) >> return 0; >> >> @@ -1373,8 +1380,13 @@ ssize_t vfs_copy_file_range(struct file *file_in, loff_t pos_in, >> if (ret) >> return ret; >> >> - ret = file_out->f_op->copy_file_range(file_in, pos_in, file_out, pos_out, >> - len, flags); >> + ret = -EOPNOTSUPP; >> + if (file_out->f_op->copy_file_range) >> + ret = file_out->f_op->copy_file_range(file_in, pos_in, file_out, >> + pos_out, len, flags); >> + if ((ret < 0) && (flags & COPY_FR_COPY)) >> + ret = vfs_copy_file_pagecache(file_in, pos_in, file_out, >> + pos_out, len); >> if (ret > 0) { >> fsnotify_access(file_in); >> add_rchar(current, ret); >> diff --git a/include/linux/copy.h b/include/linux/copy.h >> new file mode 100644 >> index 0000000..fd54543 >> --- /dev/null >> +++ b/include/linux/copy.h >> @@ -0,0 +1,6 @@ >> +#ifndef _LINUX_COPY_H >> +#define _LINUX_COPY_H >> + >> +#include <uapi/linux/copy.h> >> + >> +#endif /* _LINUX_COPY_H */ >> diff --git a/include/uapi/linux/Kbuild b/include/uapi/linux/Kbuild >> index 70ff1d9..d46830a 100644 >> --- a/include/uapi/linux/Kbuild >> +++ b/include/uapi/linux/Kbuild >> @@ -90,6 +90,7 @@ header-y += coda_psdev.h >> header-y += coff.h >> header-y += connector.h >> header-y += const.h >> +header-y += copy.h >> header-y += cramfs_fs.h >> header-y += cuda.h >> header-y += cyclades.h >> diff --git a/include/uapi/linux/copy.h b/include/uapi/linux/copy.h >> new file mode 100644 >> index 0000000..2da59a8 >> --- /dev/null >> +++ b/include/uapi/linux/copy.h >> @@ -0,0 +1,7 @@ >> +#ifndef _UAPI_LINUX_COPY_H >> +#define _UAPI_LINUX_COPY_H >> + >> +#define COPY_FR_COPY (1 << 0) /* Only do a pagecache copy. */ >> +#define COPY_FR_REFLINK (1 << 1) /* Only make a reflink. */ > > Could I have a COPY_FR_DEDUPE flag too, please? > > (I don't mind adding it myself when I get around to hooking up XFS, but I > was hoping to get it in during the first round). I guess I can, but only iff everybody has agreed on using copy for dedupes instead of somethink like fallocate. Anna > > --D > >> + >> +#endif /* _UAPI_LINUX_COPY_H */ >> -- >> 2.5.1 >> >> -- >> To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in >> the body of a message to majordomo@vger.kernel.org >> More majordomo info at http://vger.kernel.org/majordomo-info.html -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Tue, Sep 15, 2015 at 11:58:04AM -0400, Anna Schumaker wrote: > On 09/14/2015 11:32 PM, Darrick J. Wong wrote: > > On Fri, Sep 11, 2015 at 04:30:21PM -0400, Anna Schumaker wrote: > >> The NFS server will need some kind offallback for filesystems that don't > >> have any kind of copy acceleration, and it should be generally useful to > >> have an in-kernel copy to avoid lots of switches between kernel and user > >> space. > >> > >> I make this configurable by adding two new flags. Users who only want a > >> reflink can pass COPY_FR_REFLINK, and users who want a full data copy can > >> pass COPY_FR_COPY. The default (flags=0) means to first attempt a > >> reflink, but use the pagecache if that fails. > >> > >> I moved the rw_verify_area() calls into the fallback code since some > >> filesystems can handle reflinking a large range. > >> > >> Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com> > >> --- > >> v2: > >> - Rename COPY_REFLINK -> COPY_FR_REFLINK > >> - Introduce COPY_FR_COPY flag > >> - Flags == 0 is really COPY_FR_COPY|COPY_FR_REFLINK > >> - Drop check for invalid flags > >> - Move call to do_splice_direct() into a new function > >> - Move rw_verify_area() checks into the new fallback function > >> --- > >> fs/read_write.c | 56 ++++++++++++++++++++++++++++------------------- > >> include/linux/copy.h | 6 +++++ > >> include/uapi/linux/Kbuild | 1 + > >> include/uapi/linux/copy.h | 7 ++++++ > >> 4 files changed, 48 insertions(+), 22 deletions(-) > >> create mode 100644 include/linux/copy.h > >> create mode 100644 include/uapi/linux/copy.h > >> > >> diff --git a/fs/read_write.c b/fs/read_write.c > >> index 363bd3e..ba24884 100644 > >> --- a/fs/read_write.c > >> +++ b/fs/read_write.c > >> @@ -7,6 +7,7 @@ > >> #include <linux/slab.h> > >> #include <linux/stat.h> > >> #include <linux/fcntl.h> > >> +#include <linux/copy.h> > >> #include <linux/file.h> > >> #include <linux/uio.h> > >> #include <linux/fsnotify.h> > >> @@ -1329,6 +1330,29 @@ COMPAT_SYSCALL_DEFINE4(sendfile64, int, out_fd, int, in_fd, > >> } > >> #endif > >> > >> +static ssize_t vfs_copy_file_pagecache(struct file *file_in, loff_t pos_in, > >> + struct file *file_out, loff_t pos_out, > >> + size_t len) > >> +{ > >> + ssize_t ret; > >> + > >> + ret = rw_verify_area(READ, file_in, &pos_in, len); > >> + if (ret >= 0) { > >> + len = ret; > >> + ret = rw_verify_area(WRITE, file_out, &pos_out, len); > >> + if (ret >= 0) > >> + len = ret; > >> + } > >> + if (ret < 0) > >> + return ret; > >> + > >> + file_start_write(file_out); > >> + ret = do_splice_direct(file_in, &pos_in, file_out, &pos_out, len, 0); > >> + file_end_write(file_out); > >> + > >> + return ret; > >> +} > >> + > >> /* > >> * copy_file_range() differs from regular file read and write in that it > >> * specifically allows return partial success. When it does so is up to > >> @@ -1338,34 +1362,17 @@ ssize_t vfs_copy_file_range(struct file *file_in, loff_t pos_in, > >> struct file *file_out, loff_t pos_out, > >> size_t len, int flags) > >> { > >> - struct inode *inode_in; > >> - struct inode *inode_out; > >> ssize_t ret; > >> > >> - if (flags) > >> - return -EINVAL; > >> - > >> - /* copy_file_range allows full ssize_t len, ignoring MAX_RW_COUNT */ > >> - ret = rw_verify_area(READ, file_in, &pos_in, len); > >> - if (ret >= 0) > >> - ret = rw_verify_area(WRITE, file_out, &pos_out, len); > >> - if (ret < 0) > >> - return ret; > >> + if (flags == 0) > >> + flags = COPY_FR_COPY | COPY_FR_REFLINK; > > > > This function must return -EINVAL if any of the undefined flags bits are > > set. > > Sure, I'll add that. > > > > >> > >> if (!(file_in->f_mode & FMODE_READ) || > >> !(file_out->f_mode & FMODE_WRITE) || > >> (file_out->f_flags & O_APPEND) || > >> - !file_out->f_op || !file_out->f_op->copy_file_range) > >> + !file_in->f_op) > >> return -EBADF; > >> > >> - inode_in = file_inode(file_in); > >> - inode_out = file_inode(file_out); > >> - > >> - /* make sure offsets don't wrap and the input is inside i_size */ > >> - if (pos_in + len < pos_in || pos_out + len < pos_out || > >> - pos_in + len > i_size_read(inode_in)) > >> - return -EINVAL; > >> - > >> if (len == 0) > >> return 0; > >> > >> @@ -1373,8 +1380,13 @@ ssize_t vfs_copy_file_range(struct file *file_in, loff_t pos_in, > >> if (ret) > >> return ret; > >> > >> - ret = file_out->f_op->copy_file_range(file_in, pos_in, file_out, pos_out, > >> - len, flags); > >> + ret = -EOPNOTSUPP; > >> + if (file_out->f_op->copy_file_range) > >> + ret = file_out->f_op->copy_file_range(file_in, pos_in, file_out, > >> + pos_out, len, flags); > >> + if ((ret < 0) && (flags & COPY_FR_COPY)) > >> + ret = vfs_copy_file_pagecache(file_in, pos_in, file_out, > >> + pos_out, len); > >> if (ret > 0) { > >> fsnotify_access(file_in); > >> add_rchar(current, ret); > >> diff --git a/include/linux/copy.h b/include/linux/copy.h > >> new file mode 100644 > >> index 0000000..fd54543 > >> --- /dev/null > >> +++ b/include/linux/copy.h > >> @@ -0,0 +1,6 @@ > >> +#ifndef _LINUX_COPY_H > >> +#define _LINUX_COPY_H > >> + > >> +#include <uapi/linux/copy.h> > >> + > >> +#endif /* _LINUX_COPY_H */ > >> diff --git a/include/uapi/linux/Kbuild b/include/uapi/linux/Kbuild > >> index 70ff1d9..d46830a 100644 > >> --- a/include/uapi/linux/Kbuild > >> +++ b/include/uapi/linux/Kbuild > >> @@ -90,6 +90,7 @@ header-y += coda_psdev.h > >> header-y += coff.h > >> header-y += connector.h > >> header-y += const.h > >> +header-y += copy.h > >> header-y += cramfs_fs.h > >> header-y += cuda.h > >> header-y += cyclades.h > >> diff --git a/include/uapi/linux/copy.h b/include/uapi/linux/copy.h > >> new file mode 100644 > >> index 0000000..2da59a8 > >> --- /dev/null > >> +++ b/include/uapi/linux/copy.h > >> @@ -0,0 +1,7 @@ > >> +#ifndef _UAPI_LINUX_COPY_H > >> +#define _UAPI_LINUX_COPY_H > >> + > >> +#define COPY_FR_COPY (1 << 0) /* Only do a pagecache copy. */ > >> +#define COPY_FR_REFLINK (1 << 1) /* Only make a reflink. */ > > > > Could I have a COPY_FR_DEDUPE flag too, please? > > > > (I don't mind adding it myself when I get around to hooking up XFS, but I > > was hoping to get it in during the first round). > > I guess I can, but only iff everybody has agreed on using copy for dedupes > instead of somethink like fallocate. I don't see how fallocate could even handle userspace-directed deduplication since the dedupe operation compares two file ranges and reflinks them if the contents match whereas fallocate only operates on a single file range. A single file range would work if userspace was telling the kernel to start a lengthy search for all duplicates of a particular file's range, but ... yuck. (Granted, the btrfs extent_same ioctl lets userspace call dedupe on multiple files simultaneously, but that's for another day.) --D > > Anna > > > > > --D > > > >> + > >> +#endif /* _UAPI_LINUX_COPY_H */ > >> -- > >> 2.5.1 > >> > >> -- > >> To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in > >> the body of a message to majordomo@vger.kernel.org > >> More majordomo info at http://vger.kernel.org/majordomo-info.html > -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On 2015-09-15 12:38, Darrick J. Wong wrote: > On Tue, Sep 15, 2015 at 11:58:04AM -0400, Anna Schumaker wrote: >> On 09/14/2015 11:32 PM, Darrick J. Wong wrote: >>> On Fri, Sep 11, 2015 at 04:30:21PM -0400, Anna Schumaker wrote: >>>> The NFS server will need some kind offallback for filesystems that don't >>>> have any kind of copy acceleration, and it should be generally useful to >>>> have an in-kernel copy to avoid lots of switches between kernel and user >>>> space. >>>> >>>> I make this configurable by adding two new flags. Users who only want a >>>> reflink can pass COPY_FR_REFLINK, and users who want a full data copy can >>>> pass COPY_FR_COPY. The default (flags=0) means to first attempt a >>>> reflink, but use the pagecache if that fails. >>>> >>>> I moved the rw_verify_area() calls into the fallback code since some >>>> filesystems can handle reflinking a large range. >>>> >>>> Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com> >>>> --- >>>> v2: >>>> - Rename COPY_REFLINK -> COPY_FR_REFLINK >>>> - Introduce COPY_FR_COPY flag >>>> - Flags == 0 is really COPY_FR_COPY|COPY_FR_REFLINK >>>> - Drop check for invalid flags >>>> - Move call to do_splice_direct() into a new function >>>> - Move rw_verify_area() checks into the new fallback function >>>> --- >>>> fs/read_write.c | 56 ++++++++++++++++++++++++++++------------------- >>>> include/linux/copy.h | 6 +++++ >>>> include/uapi/linux/Kbuild | 1 + >>>> include/uapi/linux/copy.h | 7 ++++++ >>>> 4 files changed, 48 insertions(+), 22 deletions(-) >>>> create mode 100644 include/linux/copy.h >>>> create mode 100644 include/uapi/linux/copy.h >>>> >>>> diff --git a/fs/read_write.c b/fs/read_write.c >>>> index 363bd3e..ba24884 100644 >>>> --- a/fs/read_write.c >>>> +++ b/fs/read_write.c >>>> @@ -7,6 +7,7 @@ >>>> #include <linux/slab.h> >>>> #include <linux/stat.h> >>>> #include <linux/fcntl.h> >>>> +#include <linux/copy.h> >>>> #include <linux/file.h> >>>> #include <linux/uio.h> >>>> #include <linux/fsnotify.h> >>>> @@ -1329,6 +1330,29 @@ COMPAT_SYSCALL_DEFINE4(sendfile64, int, out_fd, int, in_fd, >>>> } >>>> #endif >>>> >>>> +static ssize_t vfs_copy_file_pagecache(struct file *file_in, loff_t pos_in, >>>> + struct file *file_out, loff_t pos_out, >>>> + size_t len) >>>> +{ >>>> + ssize_t ret; >>>> + >>>> + ret = rw_verify_area(READ, file_in, &pos_in, len); >>>> + if (ret >= 0) { >>>> + len = ret; >>>> + ret = rw_verify_area(WRITE, file_out, &pos_out, len); >>>> + if (ret >= 0) >>>> + len = ret; >>>> + } >>>> + if (ret < 0) >>>> + return ret; >>>> + >>>> + file_start_write(file_out); >>>> + ret = do_splice_direct(file_in, &pos_in, file_out, &pos_out, len, 0); >>>> + file_end_write(file_out); >>>> + >>>> + return ret; >>>> +} >>>> + >>>> /* >>>> * copy_file_range() differs from regular file read and write in that it >>>> * specifically allows return partial success. When it does so is up to >>>> @@ -1338,34 +1362,17 @@ ssize_t vfs_copy_file_range(struct file *file_in, loff_t pos_in, >>>> struct file *file_out, loff_t pos_out, >>>> size_t len, int flags) >>>> { >>>> - struct inode *inode_in; >>>> - struct inode *inode_out; >>>> ssize_t ret; >>>> >>>> - if (flags) >>>> - return -EINVAL; >>>> - >>>> - /* copy_file_range allows full ssize_t len, ignoring MAX_RW_COUNT */ >>>> - ret = rw_verify_area(READ, file_in, &pos_in, len); >>>> - if (ret >= 0) >>>> - ret = rw_verify_area(WRITE, file_out, &pos_out, len); >>>> - if (ret < 0) >>>> - return ret; >>>> + if (flags == 0) >>>> + flags = COPY_FR_COPY | COPY_FR_REFLINK; >>> >>> This function must return -EINVAL if any of the undefined flags bits are >>> set. >> >> Sure, I'll add that. >> >>> >>>> >>>> if (!(file_in->f_mode & FMODE_READ) || >>>> !(file_out->f_mode & FMODE_WRITE) || >>>> (file_out->f_flags & O_APPEND) || >>>> - !file_out->f_op || !file_out->f_op->copy_file_range) >>>> + !file_in->f_op) >>>> return -EBADF; >>>> >>>> - inode_in = file_inode(file_in); >>>> - inode_out = file_inode(file_out); >>>> - >>>> - /* make sure offsets don't wrap and the input is inside i_size */ >>>> - if (pos_in + len < pos_in || pos_out + len < pos_out || >>>> - pos_in + len > i_size_read(inode_in)) >>>> - return -EINVAL; >>>> - >>>> if (len == 0) >>>> return 0; >>>> >>>> @@ -1373,8 +1380,13 @@ ssize_t vfs_copy_file_range(struct file *file_in, loff_t pos_in, >>>> if (ret) >>>> return ret; >>>> >>>> - ret = file_out->f_op->copy_file_range(file_in, pos_in, file_out, pos_out, >>>> - len, flags); >>>> + ret = -EOPNOTSUPP; >>>> + if (file_out->f_op->copy_file_range) >>>> + ret = file_out->f_op->copy_file_range(file_in, pos_in, file_out, >>>> + pos_out, len, flags); >>>> + if ((ret < 0) && (flags & COPY_FR_COPY)) >>>> + ret = vfs_copy_file_pagecache(file_in, pos_in, file_out, >>>> + pos_out, len); >>>> if (ret > 0) { >>>> fsnotify_access(file_in); >>>> add_rchar(current, ret); >>>> diff --git a/include/linux/copy.h b/include/linux/copy.h >>>> new file mode 100644 >>>> index 0000000..fd54543 >>>> --- /dev/null >>>> +++ b/include/linux/copy.h >>>> @@ -0,0 +1,6 @@ >>>> +#ifndef _LINUX_COPY_H >>>> +#define _LINUX_COPY_H >>>> + >>>> +#include <uapi/linux/copy.h> >>>> + >>>> +#endif /* _LINUX_COPY_H */ >>>> diff --git a/include/uapi/linux/Kbuild b/include/uapi/linux/Kbuild >>>> index 70ff1d9..d46830a 100644 >>>> --- a/include/uapi/linux/Kbuild >>>> +++ b/include/uapi/linux/Kbuild >>>> @@ -90,6 +90,7 @@ header-y += coda_psdev.h >>>> header-y += coff.h >>>> header-y += connector.h >>>> header-y += const.h >>>> +header-y += copy.h >>>> header-y += cramfs_fs.h >>>> header-y += cuda.h >>>> header-y += cyclades.h >>>> diff --git a/include/uapi/linux/copy.h b/include/uapi/linux/copy.h >>>> new file mode 100644 >>>> index 0000000..2da59a8 >>>> --- /dev/null >>>> +++ b/include/uapi/linux/copy.h >>>> @@ -0,0 +1,7 @@ >>>> +#ifndef _UAPI_LINUX_COPY_H >>>> +#define _UAPI_LINUX_COPY_H >>>> + >>>> +#define COPY_FR_COPY (1 << 0) /* Only do a pagecache copy. */ >>>> +#define COPY_FR_REFLINK (1 << 1) /* Only make a reflink. */ >>> >>> Could I have a COPY_FR_DEDUPE flag too, please? >>> >>> (I don't mind adding it myself when I get around to hooking up XFS, but I >>> was hoping to get it in during the first round). >> >> I guess I can, but only iff everybody has agreed on using copy for dedupes >> instead of somethink like fallocate. > > I don't see how fallocate could even handle userspace-directed deduplication > since the dedupe operation compares two file ranges and reflinks them if the > contents match whereas fallocate only operates on a single file range. > > A single file range would work if userspace was telling the kernel to start a > lengthy search for all duplicates of a particular file's range, but ... > yuck. > > (Granted, the btrfs extent_same ioctl lets userspace call dedupe on multiple > files simultaneously, but that's for another day.) > Agreed, having something equivalent to reflinking would be the most sensible interface for deduplicating two files. I can however see fallocate possibly having some value when in-band deduplication is considered (ie, use fallocate to tell the system to include/exclude certain file ranges from in-band deduplication).
diff --git a/fs/read_write.c b/fs/read_write.c index 363bd3e..ba24884 100644 --- a/fs/read_write.c +++ b/fs/read_write.c @@ -7,6 +7,7 @@ #include <linux/slab.h> #include <linux/stat.h> #include <linux/fcntl.h> +#include <linux/copy.h> #include <linux/file.h> #include <linux/uio.h> #include <linux/fsnotify.h> @@ -1329,6 +1330,29 @@ COMPAT_SYSCALL_DEFINE4(sendfile64, int, out_fd, int, in_fd, } #endif +static ssize_t vfs_copy_file_pagecache(struct file *file_in, loff_t pos_in, + struct file *file_out, loff_t pos_out, + size_t len) +{ + ssize_t ret; + + ret = rw_verify_area(READ, file_in, &pos_in, len); + if (ret >= 0) { + len = ret; + ret = rw_verify_area(WRITE, file_out, &pos_out, len); + if (ret >= 0) + len = ret; + } + if (ret < 0) + return ret; + + file_start_write(file_out); + ret = do_splice_direct(file_in, &pos_in, file_out, &pos_out, len, 0); + file_end_write(file_out); + + return ret; +} + /* * copy_file_range() differs from regular file read and write in that it * specifically allows return partial success. When it does so is up to @@ -1338,34 +1362,17 @@ ssize_t vfs_copy_file_range(struct file *file_in, loff_t pos_in, struct file *file_out, loff_t pos_out, size_t len, int flags) { - struct inode *inode_in; - struct inode *inode_out; ssize_t ret; - if (flags) - return -EINVAL; - - /* copy_file_range allows full ssize_t len, ignoring MAX_RW_COUNT */ - ret = rw_verify_area(READ, file_in, &pos_in, len); - if (ret >= 0) - ret = rw_verify_area(WRITE, file_out, &pos_out, len); - if (ret < 0) - return ret; + if (flags == 0) + flags = COPY_FR_COPY | COPY_FR_REFLINK; if (!(file_in->f_mode & FMODE_READ) || !(file_out->f_mode & FMODE_WRITE) || (file_out->f_flags & O_APPEND) || - !file_out->f_op || !file_out->f_op->copy_file_range) + !file_in->f_op) return -EBADF; - inode_in = file_inode(file_in); - inode_out = file_inode(file_out); - - /* make sure offsets don't wrap and the input is inside i_size */ - if (pos_in + len < pos_in || pos_out + len < pos_out || - pos_in + len > i_size_read(inode_in)) - return -EINVAL; - if (len == 0) return 0; @@ -1373,8 +1380,13 @@ ssize_t vfs_copy_file_range(struct file *file_in, loff_t pos_in, if (ret) return ret; - ret = file_out->f_op->copy_file_range(file_in, pos_in, file_out, pos_out, - len, flags); + ret = -EOPNOTSUPP; + if (file_out->f_op->copy_file_range) + ret = file_out->f_op->copy_file_range(file_in, pos_in, file_out, + pos_out, len, flags); + if ((ret < 0) && (flags & COPY_FR_COPY)) + ret = vfs_copy_file_pagecache(file_in, pos_in, file_out, + pos_out, len); if (ret > 0) { fsnotify_access(file_in); add_rchar(current, ret); diff --git a/include/linux/copy.h b/include/linux/copy.h new file mode 100644 index 0000000..fd54543 --- /dev/null +++ b/include/linux/copy.h @@ -0,0 +1,6 @@ +#ifndef _LINUX_COPY_H +#define _LINUX_COPY_H + +#include <uapi/linux/copy.h> + +#endif /* _LINUX_COPY_H */ diff --git a/include/uapi/linux/Kbuild b/include/uapi/linux/Kbuild index 70ff1d9..d46830a 100644 --- a/include/uapi/linux/Kbuild +++ b/include/uapi/linux/Kbuild @@ -90,6 +90,7 @@ header-y += coda_psdev.h header-y += coff.h header-y += connector.h header-y += const.h +header-y += copy.h header-y += cramfs_fs.h header-y += cuda.h header-y += cyclades.h diff --git a/include/uapi/linux/copy.h b/include/uapi/linux/copy.h new file mode 100644 index 0000000..2da59a8 --- /dev/null +++ b/include/uapi/linux/copy.h @@ -0,0 +1,7 @@ +#ifndef _UAPI_LINUX_COPY_H +#define _UAPI_LINUX_COPY_H + +#define COPY_FR_COPY (1 << 0) /* Only do a pagecache copy. */ +#define COPY_FR_REFLINK (1 << 1) /* Only make a reflink. */ + +#endif /* _UAPI_LINUX_COPY_H */
The NFS server will need some kind offallback for filesystems that don't have any kind of copy acceleration, and it should be generally useful to have an in-kernel copy to avoid lots of switches between kernel and user space. I make this configurable by adding two new flags. Users who only want a reflink can pass COPY_FR_REFLINK, and users who want a full data copy can pass COPY_FR_COPY. The default (flags=0) means to first attempt a reflink, but use the pagecache if that fails. I moved the rw_verify_area() calls into the fallback code since some filesystems can handle reflinking a large range. Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com> --- v2: - Rename COPY_REFLINK -> COPY_FR_REFLINK - Introduce COPY_FR_COPY flag - Flags == 0 is really COPY_FR_COPY|COPY_FR_REFLINK - Drop check for invalid flags - Move call to do_splice_direct() into a new function - Move rw_verify_area() checks into the new fallback function --- fs/read_write.c | 56 ++++++++++++++++++++++++++++------------------- include/linux/copy.h | 6 +++++ include/uapi/linux/Kbuild | 1 + include/uapi/linux/copy.h | 7 ++++++ 4 files changed, 48 insertions(+), 22 deletions(-) create mode 100644 include/linux/copy.h create mode 100644 include/uapi/linux/copy.h