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-rw-r--r--fs/ext4/file.c263
1 files changed, 14 insertions, 249 deletions
diff --git a/fs/ext4/file.c b/fs/ext4/file.c
index b937078bcff3..ad204d2724ac 100644
--- a/fs/ext4/file.c
+++ b/fs/ext4/file.c
@@ -21,6 +21,7 @@
#include <linux/time.h>
#include <linux/fs.h>
+#include <linux/iomap.h>
#include <linux/mount.h>
#include <linux/path.h>
#include <linux/dax.h>
@@ -424,248 +425,6 @@ static int ext4_file_open(struct inode * inode, struct file * filp)
}
/*
- * Here we use ext4_map_blocks() to get a block mapping for a extent-based
- * file rather than ext4_ext_walk_space() because we can introduce
- * SEEK_DATA/SEEK_HOLE for block-mapped and extent-mapped file at the same
- * function. When extent status tree has been fully implemented, it will
- * track all extent status for a file and we can directly use it to
- * retrieve the offset for SEEK_DATA/SEEK_HOLE.
- */
-
-/*
- * When we retrieve the offset for SEEK_DATA/SEEK_HOLE, we would need to
- * lookup page cache to check whether or not there has some data between
- * [startoff, endoff] because, if this range contains an unwritten extent,
- * we determine this extent as a data or a hole according to whether the
- * page cache has data or not.
- */
-static int ext4_find_unwritten_pgoff(struct inode *inode,
- int whence,
- ext4_lblk_t end_blk,
- loff_t *offset)
-{
- struct pagevec pvec;
- unsigned int blkbits;
- pgoff_t index;
- pgoff_t end;
- loff_t endoff;
- loff_t startoff;
- loff_t lastoff;
- int found = 0;
-
- blkbits = inode->i_sb->s_blocksize_bits;
- startoff = *offset;
- lastoff = startoff;
- endoff = (loff_t)end_blk << blkbits;
-
- index = startoff >> PAGE_SHIFT;
- end = (endoff - 1) >> PAGE_SHIFT;
-
- pagevec_init(&pvec, 0);
- do {
- int i;
- unsigned long nr_pages;
-
- nr_pages = pagevec_lookup_range(&pvec, inode->i_mapping,
- &index, end);
- if (nr_pages == 0)
- break;
-
- for (i = 0; i < nr_pages; i++) {
- struct page *page = pvec.pages[i];
- struct buffer_head *bh, *head;
-
- /*
- * If current offset is smaller than the page offset,
- * there is a hole at this offset.
- */
- if (whence == SEEK_HOLE && lastoff < endoff &&
- lastoff < page_offset(pvec.pages[i])) {
- found = 1;
- *offset = lastoff;
- goto out;
- }
-
- lock_page(page);
-
- if (unlikely(page->mapping != inode->i_mapping)) {
- unlock_page(page);
- continue;
- }
-
- if (!page_has_buffers(page)) {
- unlock_page(page);
- continue;
- }
-
- if (page_has_buffers(page)) {
- lastoff = page_offset(page);
- bh = head = page_buffers(page);
- do {
- if (lastoff + bh->b_size <= startoff)
- goto next;
- if (buffer_uptodate(bh) ||
- buffer_unwritten(bh)) {
- if (whence == SEEK_DATA)
- found = 1;
- } else {
- if (whence == SEEK_HOLE)
- found = 1;
- }
- if (found) {
- *offset = max_t(loff_t,
- startoff, lastoff);
- unlock_page(page);
- goto out;
- }
-next:
- lastoff += bh->b_size;
- bh = bh->b_this_page;
- } while (bh != head);
- }
-
- lastoff = page_offset(page) + PAGE_SIZE;
- unlock_page(page);
- }
-
- pagevec_release(&pvec);
- } while (index <= end);
-
- /* There are no pages upto endoff - that would be a hole in there. */
- if (whence == SEEK_HOLE && lastoff < endoff) {
- found = 1;
- *offset = lastoff;
- }
-out:
- pagevec_release(&pvec);
- return found;
-}
-
-/*
- * ext4_seek_data() retrieves the offset for SEEK_DATA.
- */
-static loff_t ext4_seek_data(struct file *file, loff_t offset, loff_t maxsize)
-{
- struct inode *inode = file->f_mapping->host;
- struct extent_status es;
- ext4_lblk_t start, last, end;
- loff_t dataoff, isize;
- int blkbits;
- int ret;
-
- inode_lock(inode);
-
- isize = i_size_read(inode);
- if (offset < 0 || offset >= isize) {
- inode_unlock(inode);
- return -ENXIO;
- }
-
- blkbits = inode->i_sb->s_blocksize_bits;
- start = offset >> blkbits;
- last = start;
- end = isize >> blkbits;
- dataoff = offset;
-
- do {
- ret = ext4_get_next_extent(inode, last, end - last + 1, &es);
- if (ret <= 0) {
- /* No extent found -> no data */
- if (ret == 0)
- ret = -ENXIO;
- inode_unlock(inode);
- return ret;
- }
-
- last = es.es_lblk;
- if (last != start)
- dataoff = (loff_t)last << blkbits;
- if (!ext4_es_is_unwritten(&es))
- break;
-
- /*
- * If there is a unwritten extent at this offset,
- * it will be as a data or a hole according to page
- * cache that has data or not.
- */
- if (ext4_find_unwritten_pgoff(inode, SEEK_DATA,
- es.es_lblk + es.es_len, &dataoff))
- break;
- last += es.es_len;
- dataoff = (loff_t)last << blkbits;
- cond_resched();
- } while (last <= end);
-
- inode_unlock(inode);
-
- if (dataoff > isize)
- return -ENXIO;
-
- return vfs_setpos(file, dataoff, maxsize);
-}
-
-/*
- * ext4_seek_hole() retrieves the offset for SEEK_HOLE.
- */
-static loff_t ext4_seek_hole(struct file *file, loff_t offset, loff_t maxsize)
-{
- struct inode *inode = file->f_mapping->host;
- struct extent_status es;
- ext4_lblk_t start, last, end;
- loff_t holeoff, isize;
- int blkbits;
- int ret;
-
- inode_lock(inode);
-
- isize = i_size_read(inode);
- if (offset < 0 || offset >= isize) {
- inode_unlock(inode);
- return -ENXIO;
- }
-
- blkbits = inode->i_sb->s_blocksize_bits;
- start = offset >> blkbits;
- last = start;
- end = isize >> blkbits;
- holeoff = offset;
-
- do {
- ret = ext4_get_next_extent(inode, last, end - last + 1, &es);
- if (ret < 0) {
- inode_unlock(inode);
- return ret;
- }
- /* Found a hole? */
- if (ret == 0 || es.es_lblk > last) {
- if (last != start)
- holeoff = (loff_t)last << blkbits;
- break;
- }
- /*
- * If there is a unwritten extent at this offset,
- * it will be as a data or a hole according to page
- * cache that has data or not.
- */
- if (ext4_es_is_unwritten(&es) &&
- ext4_find_unwritten_pgoff(inode, SEEK_HOLE,
- last + es.es_len, &holeoff))
- break;
-
- last += es.es_len;
- holeoff = (loff_t)last << blkbits;
- cond_resched();
- } while (last <= end);
-
- inode_unlock(inode);
-
- if (holeoff > isize)
- holeoff = isize;
-
- return vfs_setpos(file, holeoff, maxsize);
-}
-
-/*
* ext4_llseek() handles both block-mapped and extent-mapped maxbytes values
* by calling generic_file_llseek_size() with the appropriate maxbytes
* value for each.
@@ -681,18 +440,24 @@ loff_t ext4_llseek(struct file *file, loff_t offset, int whence)
maxbytes = inode->i_sb->s_maxbytes;
switch (whence) {
- case SEEK_SET:
- case SEEK_CUR:
- case SEEK_END:
+ default:
return generic_file_llseek_size(file, offset, whence,
maxbytes, i_size_read(inode));
- case SEEK_DATA:
- return ext4_seek_data(file, offset, maxbytes);
case SEEK_HOLE:
- return ext4_seek_hole(file, offset, maxbytes);
+ inode_lock_shared(inode);
+ offset = iomap_seek_hole(inode, offset, &ext4_iomap_ops);
+ inode_unlock_shared(inode);
+ break;
+ case SEEK_DATA:
+ inode_lock_shared(inode);
+ offset = iomap_seek_data(inode, offset, &ext4_iomap_ops);
+ inode_unlock_shared(inode);
+ break;
}
- return -EINVAL;
+ if (offset < 0)
+ return offset;
+ return vfs_setpos(file, offset, maxbytes);
}
const struct file_operations ext4_file_operations = {
generated by cgit v1.2.3-58-ga151 (git 2.39.0) at 2024-12-15 00:29:52 +0000