fallocate should be a file operation
Currently all filesystems except XFS implement fallocate asynchronously,
while XFS forced a commit. Both of these are suboptimal - in case of O_SYNC
I/O we really want our allocation on disk, especially for the !KEEP_SIZE
case where we actually grow the file with user-visible zeroes. On the
other hand always commiting the transaction is a bad idea for fast-path
uses of fallocate like for example in recent Samba versions. Given
that block allocation is a data plane operation anyway change it from
an inode operation to a file operation so that we have the file structure
available that lets us check for O_SYNC.
This also includes moving the code around for a few of the filesystems,
and remove the already unnedded S_ISDIR checks given that we only wire
up fallocate for regular files.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/fs/gfs2/file.c b/fs/gfs2/file.c
index fca6689..7cfdcb9 100644
--- a/fs/gfs2/file.c
+++ b/fs/gfs2/file.c
@@ -19,6 +19,8 @@
#include <linux/fs.h>
#include <linux/gfs2_ondisk.h>
#include <linux/ext2_fs.h>
+#include <linux/falloc.h>
+#include <linux/swap.h>
#include <linux/crc32.h>
#include <linux/writeback.h>
#include <asm/uaccess.h>
@@ -610,6 +612,260 @@
return generic_file_aio_write(iocb, iov, nr_segs, pos);
}
+static void empty_write_end(struct page *page, unsigned from,
+ unsigned to)
+{
+ struct gfs2_inode *ip = GFS2_I(page->mapping->host);
+
+ page_zero_new_buffers(page, from, to);
+ flush_dcache_page(page);
+ mark_page_accessed(page);
+
+ if (!gfs2_is_writeback(ip))
+ gfs2_page_add_databufs(ip, page, from, to);
+
+ block_commit_write(page, from, to);
+}
+
+static int write_empty_blocks(struct page *page, unsigned from, unsigned to)
+{
+ unsigned start, end, next;
+ struct buffer_head *bh, *head;
+ int error;
+
+ if (!page_has_buffers(page)) {
+ error = __block_write_begin(page, from, to - from, gfs2_block_map);
+ if (unlikely(error))
+ return error;
+
+ empty_write_end(page, from, to);
+ return 0;
+ }
+
+ bh = head = page_buffers(page);
+ next = end = 0;
+ while (next < from) {
+ next += bh->b_size;
+ bh = bh->b_this_page;
+ }
+ start = next;
+ do {
+ next += bh->b_size;
+ if (buffer_mapped(bh)) {
+ if (end) {
+ error = __block_write_begin(page, start, end - start,
+ gfs2_block_map);
+ if (unlikely(error))
+ return error;
+ empty_write_end(page, start, end);
+ end = 0;
+ }
+ start = next;
+ }
+ else
+ end = next;
+ bh = bh->b_this_page;
+ } while (next < to);
+
+ if (end) {
+ error = __block_write_begin(page, start, end - start, gfs2_block_map);
+ if (unlikely(error))
+ return error;
+ empty_write_end(page, start, end);
+ }
+
+ return 0;
+}
+
+static int fallocate_chunk(struct inode *inode, loff_t offset, loff_t len,
+ int mode)
+{
+ struct gfs2_inode *ip = GFS2_I(inode);
+ struct buffer_head *dibh;
+ int error;
+ u64 start = offset >> PAGE_CACHE_SHIFT;
+ unsigned int start_offset = offset & ~PAGE_CACHE_MASK;
+ u64 end = (offset + len - 1) >> PAGE_CACHE_SHIFT;
+ pgoff_t curr;
+ struct page *page;
+ unsigned int end_offset = (offset + len) & ~PAGE_CACHE_MASK;
+ unsigned int from, to;
+
+ if (!end_offset)
+ end_offset = PAGE_CACHE_SIZE;
+
+ error = gfs2_meta_inode_buffer(ip, &dibh);
+ if (unlikely(error))
+ goto out;
+
+ gfs2_trans_add_bh(ip->i_gl, dibh, 1);
+
+ if (gfs2_is_stuffed(ip)) {
+ error = gfs2_unstuff_dinode(ip, NULL);
+ if (unlikely(error))
+ goto out;
+ }
+
+ curr = start;
+ offset = start << PAGE_CACHE_SHIFT;
+ from = start_offset;
+ to = PAGE_CACHE_SIZE;
+ while (curr <= end) {
+ page = grab_cache_page_write_begin(inode->i_mapping, curr,
+ AOP_FLAG_NOFS);
+ if (unlikely(!page)) {
+ error = -ENOMEM;
+ goto out;
+ }
+
+ if (curr == end)
+ to = end_offset;
+ error = write_empty_blocks(page, from, to);
+ if (!error && offset + to > inode->i_size &&
+ !(mode & FALLOC_FL_KEEP_SIZE)) {
+ i_size_write(inode, offset + to);
+ }
+ unlock_page(page);
+ page_cache_release(page);
+ if (error)
+ goto out;
+ curr++;
+ offset += PAGE_CACHE_SIZE;
+ from = 0;
+ }
+
+ gfs2_dinode_out(ip, dibh->b_data);
+ mark_inode_dirty(inode);
+
+ brelse(dibh);
+
+out:
+ return error;
+}
+
+static void calc_max_reserv(struct gfs2_inode *ip, loff_t max, loff_t *len,
+ unsigned int *data_blocks, unsigned int *ind_blocks)
+{
+ const struct gfs2_sbd *sdp = GFS2_SB(&ip->i_inode);
+ unsigned int max_blocks = ip->i_alloc->al_rgd->rd_free_clone;
+ unsigned int tmp, max_data = max_blocks - 3 * (sdp->sd_max_height - 1);
+
+ for (tmp = max_data; tmp > sdp->sd_diptrs;) {
+ tmp = DIV_ROUND_UP(tmp, sdp->sd_inptrs);
+ max_data -= tmp;
+ }
+ /* This calculation isn't the exact reverse of gfs2_write_calc_reserve,
+ so it might end up with fewer data blocks */
+ if (max_data <= *data_blocks)
+ return;
+ *data_blocks = max_data;
+ *ind_blocks = max_blocks - max_data;
+ *len = ((loff_t)max_data - 3) << sdp->sd_sb.sb_bsize_shift;
+ if (*len > max) {
+ *len = max;
+ gfs2_write_calc_reserv(ip, max, data_blocks, ind_blocks);
+ }
+}
+
+static long gfs2_fallocate(struct file *file, int mode, loff_t offset,
+ loff_t len)
+{
+ struct inode *inode = file->f_path.dentry->d_inode;
+ struct gfs2_sbd *sdp = GFS2_SB(inode);
+ struct gfs2_inode *ip = GFS2_I(inode);
+ unsigned int data_blocks = 0, ind_blocks = 0, rblocks;
+ loff_t bytes, max_bytes;
+ struct gfs2_alloc *al;
+ int error;
+ loff_t next = (offset + len - 1) >> sdp->sd_sb.sb_bsize_shift;
+ next = (next + 1) << sdp->sd_sb.sb_bsize_shift;
+
+ /* We only support the FALLOC_FL_KEEP_SIZE mode */
+ if (mode & ~FALLOC_FL_KEEP_SIZE)
+ return -EOPNOTSUPP;
+
+ offset = (offset >> sdp->sd_sb.sb_bsize_shift) <<
+ sdp->sd_sb.sb_bsize_shift;
+
+ len = next - offset;
+ bytes = sdp->sd_max_rg_data * sdp->sd_sb.sb_bsize / 2;
+ if (!bytes)
+ bytes = UINT_MAX;
+
+ gfs2_holder_init(ip->i_gl, LM_ST_EXCLUSIVE, 0, &ip->i_gh);
+ error = gfs2_glock_nq(&ip->i_gh);
+ if (unlikely(error))
+ goto out_uninit;
+
+ if (!gfs2_write_alloc_required(ip, offset, len))
+ goto out_unlock;
+
+ while (len > 0) {
+ if (len < bytes)
+ bytes = len;
+ al = gfs2_alloc_get(ip);
+ if (!al) {
+ error = -ENOMEM;
+ goto out_unlock;
+ }
+
+ error = gfs2_quota_lock_check(ip);
+ if (error)
+ goto out_alloc_put;
+
+retry:
+ gfs2_write_calc_reserv(ip, bytes, &data_blocks, &ind_blocks);
+
+ al->al_requested = data_blocks + ind_blocks;
+ error = gfs2_inplace_reserve(ip);
+ if (error) {
+ if (error == -ENOSPC && bytes > sdp->sd_sb.sb_bsize) {
+ bytes >>= 1;
+ goto retry;
+ }
+ goto out_qunlock;
+ }
+ max_bytes = bytes;
+ calc_max_reserv(ip, len, &max_bytes, &data_blocks, &ind_blocks);
+ al->al_requested = data_blocks + ind_blocks;
+
+ rblocks = RES_DINODE + ind_blocks + RES_STATFS + RES_QUOTA +
+ RES_RG_HDR + gfs2_rg_blocks(al);
+ if (gfs2_is_jdata(ip))
+ rblocks += data_blocks ? data_blocks : 1;
+
+ error = gfs2_trans_begin(sdp, rblocks,
+ PAGE_CACHE_SIZE/sdp->sd_sb.sb_bsize);
+ if (error)
+ goto out_trans_fail;
+
+ error = fallocate_chunk(inode, offset, max_bytes, mode);
+ gfs2_trans_end(sdp);
+
+ if (error)
+ goto out_trans_fail;
+
+ len -= max_bytes;
+ offset += max_bytes;
+ gfs2_inplace_release(ip);
+ gfs2_quota_unlock(ip);
+ gfs2_alloc_put(ip);
+ }
+ goto out_unlock;
+
+out_trans_fail:
+ gfs2_inplace_release(ip);
+out_qunlock:
+ gfs2_quota_unlock(ip);
+out_alloc_put:
+ gfs2_alloc_put(ip);
+out_unlock:
+ gfs2_glock_dq(&ip->i_gh);
+out_uninit:
+ gfs2_holder_uninit(&ip->i_gh);
+ return error;
+}
+
#ifdef CONFIG_GFS2_FS_LOCKING_DLM
/**
@@ -765,6 +1021,7 @@
.splice_read = generic_file_splice_read,
.splice_write = generic_file_splice_write,
.setlease = gfs2_setlease,
+ .fallocate = gfs2_fallocate,
};
const struct file_operations gfs2_dir_fops = {
@@ -794,6 +1051,7 @@
.splice_read = generic_file_splice_read,
.splice_write = generic_file_splice_write,
.setlease = generic_setlease,
+ .fallocate = gfs2_fallocate,
};
const struct file_operations gfs2_dir_fops_nolock = {