| Message ID | 20170627214828.1029-5-hch@lst.de (mailing list archive) |
|---|---|
| State | Not Applicable |
| Headers | show |
2017-06-27 23:48 GMT+02:00 Christoph Hellwig <hch@lst.de>: > From: Andreas Gruenbacher <agruenba@redhat.com> > > Filesystems can use this for implementing lseek SEEK_HOLE / SEEK_DATA > support via iomap. > > Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com> > [hch: split functions, coding style cleanups] > Signed-off-by: Christoph Hellwig <hch@lst.de> > --- > fs/iomap.c | 98 +++++++++++++++++++++++++++++++++++++++++++++++++++ > include/linux/iomap.h | 4 +++ > 2 files changed, 102 insertions(+) > > diff --git a/fs/iomap.c b/fs/iomap.c > index 4b10892967a5..c90cda33994b 100644 > --- a/fs/iomap.c > +++ b/fs/iomap.c > @@ -584,6 +584,104 @@ int iomap_fiemap(struct inode *inode, struct fiemap_extent_info *fi, > } > EXPORT_SYMBOL_GPL(iomap_fiemap); > > +static loff_t > +iomap_seek_hole_actor(struct inode *inode, loff_t offset, loff_t length, > + void *data, struct iomap *iomap) > +{ > + switch (iomap->type) { > + case IOMAP_UNWRITTEN: > + offset = page_cache_seek_hole_data(inode, offset, length, > + SEEK_HOLE); > + if (offset < 0) > + return length; > + /* fall through */ > + case IOMAP_HOLE: > + *(loff_t *)data = offset; > + return 0; > + default: > + return length; > + } > +} > + > +loff_t > +iomap_seek_hole(struct inode *inode, loff_t offset, const struct iomap_ops *ops) > +{ > + loff_t size = i_size_read(inode); > + loff_t length = size - offset; > + loff_t ret; > + > + /* Nothing to be found beyond the end of the file. */ > + if (offset >= size) > + return -ENXIO; > + > + while (length > 0) { > + ret = iomap_apply(inode, offset, length, IOMAP_REPORT, ops, > + &offset, iomap_seek_hole_actor); > + if (ret < 0) > + return ret; > + if (ret == 0) > + break; > + > + offset += ret; > + length -= ret; > + } > + > + /* The last segment can extend beyond the end of the file. */ > + if (length <= 0) > + return min(offset, size); This shouldn't be true anymore now that the actors don't recompute the length; the above three lines should be obsolete. > + return offset; > +} > +EXPORT_SYMBOL_GPL(iomap_seek_hole); > + > +static loff_t > +iomap_seek_data_actor(struct inode *inode, loff_t offset, loff_t length, > + void *data, struct iomap *iomap) > +{ > + switch (iomap->type) { > + case IOMAP_HOLE: > + return length; > + case IOMAP_UNWRITTEN: > + offset = page_cache_seek_hole_data(inode, offset, length, > + SEEK_DATA); > + if (offset < 0) > + return length; > + /*FALLTHRU*/ > + default: > + *(loff_t *)data = offset; > + return 0; > + } > +} > + > +loff_t > +iomap_seek_data(struct inode *inode, loff_t offset, const struct iomap_ops *ops) > +{ > + loff_t size = i_size_read(inode); > + loff_t length = size - offset; > + loff_t ret; > + > + /* Nothing to be found beyond the end of the file. */ > + if (offset >= size) > + return -ENXIO; > + > + while (length > 0) { > + ret = iomap_apply(inode, offset, length, IOMAP_REPORT, ops, > + &offset, iomap_seek_data_actor); > + if (ret < 0) > + return ret; > + if (ret == 0) > + break; > + > + offset += ret; > + length -= ret; > + } > + > + /* There is an implicit hole at the end of the file. */ This comment makes more sense in iomap_seek_hole now. > + if (length <= 0) > + return -ENXIO; > + return offset; > +} > +EXPORT_SYMBOL_GPL(iomap_seek_data); > + > /* > * Private flags for iomap_dio, must not overlap with the public ones in > * iomap.h: > diff --git a/include/linux/iomap.h b/include/linux/iomap.h > index f753e788da31..8a03f5dcd89b 100644 > --- a/include/linux/iomap.h > +++ b/include/linux/iomap.h > @@ -83,6 +83,10 @@ int iomap_truncate_page(struct inode *inode, loff_t pos, bool *did_zero, > int iomap_page_mkwrite(struct vm_fault *vmf, const struct iomap_ops *ops); > int iomap_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo, > loff_t start, loff_t len, const struct iomap_ops *ops); > +loff_t iomap_seek_hole(struct inode *inode, loff_t offset, > + const struct iomap_ops *ops); > +loff_t iomap_seek_data(struct inode *inode, loff_t offset, > + const struct iomap_ops *ops); > > /* > * Flags for direct I/O ->end_io: > -- > 2.11.0 Thanks, Andreas -- To unsubscribe from this list: send the line "unsubscribe linux-xfs" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/fs/iomap.c b/fs/iomap.c index 4b10892967a5..c90cda33994b 100644 --- a/fs/iomap.c +++ b/fs/iomap.c @@ -584,6 +584,104 @@ int iomap_fiemap(struct inode *inode, struct fiemap_extent_info *fi, } EXPORT_SYMBOL_GPL(iomap_fiemap); +static loff_t +iomap_seek_hole_actor(struct inode *inode, loff_t offset, loff_t length, + void *data, struct iomap *iomap) +{ + switch (iomap->type) { + case IOMAP_UNWRITTEN: + offset = page_cache_seek_hole_data(inode, offset, length, + SEEK_HOLE); + if (offset < 0) + return length; + /* fall through */ + case IOMAP_HOLE: + *(loff_t *)data = offset; + return 0; + default: + return length; + } +} + +loff_t +iomap_seek_hole(struct inode *inode, loff_t offset, const struct iomap_ops *ops) +{ + loff_t size = i_size_read(inode); + loff_t length = size - offset; + loff_t ret; + + /* Nothing to be found beyond the end of the file. */ + if (offset >= size) + return -ENXIO; + + while (length > 0) { + ret = iomap_apply(inode, offset, length, IOMAP_REPORT, ops, + &offset, iomap_seek_hole_actor); + if (ret < 0) + return ret; + if (ret == 0) + break; + + offset += ret; + length -= ret; + } + + /* The last segment can extend beyond the end of the file. */ + if (length <= 0) + return min(offset, size); + return offset; +} +EXPORT_SYMBOL_GPL(iomap_seek_hole); + +static loff_t +iomap_seek_data_actor(struct inode *inode, loff_t offset, loff_t length, + void *data, struct iomap *iomap) +{ + switch (iomap->type) { + case IOMAP_HOLE: + return length; + case IOMAP_UNWRITTEN: + offset = page_cache_seek_hole_data(inode, offset, length, + SEEK_DATA); + if (offset < 0) + return length; + /*FALLTHRU*/ + default: + *(loff_t *)data = offset; + return 0; + } +} + +loff_t +iomap_seek_data(struct inode *inode, loff_t offset, const struct iomap_ops *ops) +{ + loff_t size = i_size_read(inode); + loff_t length = size - offset; + loff_t ret; + + /* Nothing to be found beyond the end of the file. */ + if (offset >= size) + return -ENXIO; + + while (length > 0) { + ret = iomap_apply(inode, offset, length, IOMAP_REPORT, ops, + &offset, iomap_seek_data_actor); + if (ret < 0) + return ret; + if (ret == 0) + break; + + offset += ret; + length -= ret; + } + + /* There is an implicit hole at the end of the file. */ + if (length <= 0) + return -ENXIO; + return offset; +} +EXPORT_SYMBOL_GPL(iomap_seek_data); + /* * Private flags for iomap_dio, must not overlap with the public ones in * iomap.h: diff --git a/include/linux/iomap.h b/include/linux/iomap.h index f753e788da31..8a03f5dcd89b 100644 --- a/include/linux/iomap.h +++ b/include/linux/iomap.h @@ -83,6 +83,10 @@ int iomap_truncate_page(struct inode *inode, loff_t pos, bool *did_zero, int iomap_page_mkwrite(struct vm_fault *vmf, const struct iomap_ops *ops); int iomap_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo, loff_t start, loff_t len, const struct iomap_ops *ops); +loff_t iomap_seek_hole(struct inode *inode, loff_t offset, + const struct iomap_ops *ops); +loff_t iomap_seek_data(struct inode *inode, loff_t offset, + const struct iomap_ops *ops); /* * Flags for direct I/O ->end_io: