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author | Andreas Gruenbacher <agruenba@redhat.com> | 2017-06-29 21:43:21 +0300 |
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committer | Darrick J. Wong <darrick.wong@oracle.com> | 2017-07-03 08:46:13 +0300 |
commit | 0ed3b0d45fd39142e418220f518c8959c1a5f596 (patch) | |
tree | 5c629e3654c2959be05fee0875952b419a5718a9 /fs | |
parent | 334fd34d76f237c0ee58dfc400d2c4e34d660544 (diff) | |
download | linux-0ed3b0d45fd39142e418220f518c8959c1a5f596.tar.xz |
vfs: Add iomap_seek_hole and iomap_seek_data helpers
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>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Diffstat (limited to 'fs')
-rw-r--r-- | fs/iomap.c | 94 |
1 files changed, 94 insertions, 0 deletions
diff --git a/fs/iomap.c b/fs/iomap.c index 4b10892967a5..432eed8f091f 100644 --- a/fs/iomap.c +++ b/fs/iomap.c @@ -584,6 +584,100 @@ 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; + } + + 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; + } + + 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: |