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-rw-r--r--fs/zonefs/file.c874
1 files changed, 874 insertions, 0 deletions
diff --git a/fs/zonefs/file.c b/fs/zonefs/file.c
new file mode 100644
index 000000000000..ece0f3959b6d
--- /dev/null
+++ b/fs/zonefs/file.c
@@ -0,0 +1,874 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Simple file system for zoned block devices exposing zones as files.
+ *
+ * Copyright (C) 2022 Western Digital Corporation or its affiliates.
+ */
+#include <linux/module.h>
+#include <linux/pagemap.h>
+#include <linux/iomap.h>
+#include <linux/init.h>
+#include <linux/slab.h>
+#include <linux/blkdev.h>
+#include <linux/statfs.h>
+#include <linux/writeback.h>
+#include <linux/quotaops.h>
+#include <linux/seq_file.h>
+#include <linux/parser.h>
+#include <linux/uio.h>
+#include <linux/mman.h>
+#include <linux/sched/mm.h>
+#include <linux/task_io_accounting_ops.h>
+
+#include "zonefs.h"
+
+#include "trace.h"
+
+static int zonefs_read_iomap_begin(struct inode *inode, loff_t offset,
+ loff_t length, unsigned int flags,
+ struct iomap *iomap, struct iomap *srcmap)
+{
+ struct zonefs_inode_info *zi = ZONEFS_I(inode);
+ struct super_block *sb = inode->i_sb;
+ loff_t isize;
+
+ /*
+ * All blocks are always mapped below EOF. If reading past EOF,
+ * act as if there is a hole up to the file maximum size.
+ */
+ mutex_lock(&zi->i_truncate_mutex);
+ iomap->bdev = inode->i_sb->s_bdev;
+ iomap->offset = ALIGN_DOWN(offset, sb->s_blocksize);
+ isize = i_size_read(inode);
+ if (iomap->offset >= isize) {
+ iomap->type = IOMAP_HOLE;
+ iomap->addr = IOMAP_NULL_ADDR;
+ iomap->length = length;
+ } else {
+ iomap->type = IOMAP_MAPPED;
+ iomap->addr = (zi->i_zsector << SECTOR_SHIFT) + iomap->offset;
+ iomap->length = isize - iomap->offset;
+ }
+ mutex_unlock(&zi->i_truncate_mutex);
+
+ trace_zonefs_iomap_begin(inode, iomap);
+
+ return 0;
+}
+
+static const struct iomap_ops zonefs_read_iomap_ops = {
+ .iomap_begin = zonefs_read_iomap_begin,
+};
+
+static int zonefs_write_iomap_begin(struct inode *inode, loff_t offset,
+ loff_t length, unsigned int flags,
+ struct iomap *iomap, struct iomap *srcmap)
+{
+ struct zonefs_inode_info *zi = ZONEFS_I(inode);
+ struct super_block *sb = inode->i_sb;
+ loff_t isize;
+
+ /* All write I/Os should always be within the file maximum size */
+ if (WARN_ON_ONCE(offset + length > zi->i_max_size))
+ return -EIO;
+
+ /*
+ * Sequential zones can only accept direct writes. This is already
+ * checked when writes are issued, so warn if we see a page writeback
+ * operation.
+ */
+ if (WARN_ON_ONCE(zi->i_ztype == ZONEFS_ZTYPE_SEQ &&
+ !(flags & IOMAP_DIRECT)))
+ return -EIO;
+
+ /*
+ * For conventional zones, all blocks are always mapped. For sequential
+ * zones, all blocks after always mapped below the inode size (zone
+ * write pointer) and unwriten beyond.
+ */
+ mutex_lock(&zi->i_truncate_mutex);
+ iomap->bdev = inode->i_sb->s_bdev;
+ iomap->offset = ALIGN_DOWN(offset, sb->s_blocksize);
+ iomap->addr = (zi->i_zsector << SECTOR_SHIFT) + iomap->offset;
+ isize = i_size_read(inode);
+ if (iomap->offset >= isize) {
+ iomap->type = IOMAP_UNWRITTEN;
+ iomap->length = zi->i_max_size - iomap->offset;
+ } else {
+ iomap->type = IOMAP_MAPPED;
+ iomap->length = isize - iomap->offset;
+ }
+ mutex_unlock(&zi->i_truncate_mutex);
+
+ trace_zonefs_iomap_begin(inode, iomap);
+
+ return 0;
+}
+
+static const struct iomap_ops zonefs_write_iomap_ops = {
+ .iomap_begin = zonefs_write_iomap_begin,
+};
+
+static int zonefs_read_folio(struct file *unused, struct folio *folio)
+{
+ return iomap_read_folio(folio, &zonefs_read_iomap_ops);
+}
+
+static void zonefs_readahead(struct readahead_control *rac)
+{
+ iomap_readahead(rac, &zonefs_read_iomap_ops);
+}
+
+/*
+ * Map blocks for page writeback. This is used only on conventional zone files,
+ * which implies that the page range can only be within the fixed inode size.
+ */
+static int zonefs_write_map_blocks(struct iomap_writepage_ctx *wpc,
+ struct inode *inode, loff_t offset)
+{
+ struct zonefs_inode_info *zi = ZONEFS_I(inode);
+
+ if (WARN_ON_ONCE(zi->i_ztype != ZONEFS_ZTYPE_CNV))
+ return -EIO;
+ if (WARN_ON_ONCE(offset >= i_size_read(inode)))
+ return -EIO;
+
+ /* If the mapping is already OK, nothing needs to be done */
+ if (offset >= wpc->iomap.offset &&
+ offset < wpc->iomap.offset + wpc->iomap.length)
+ return 0;
+
+ return zonefs_write_iomap_begin(inode, offset, zi->i_max_size - offset,
+ IOMAP_WRITE, &wpc->iomap, NULL);
+}
+
+static const struct iomap_writeback_ops zonefs_writeback_ops = {
+ .map_blocks = zonefs_write_map_blocks,
+};
+
+static int zonefs_writepages(struct address_space *mapping,
+ struct writeback_control *wbc)
+{
+ struct iomap_writepage_ctx wpc = { };
+
+ return iomap_writepages(mapping, wbc, &wpc, &zonefs_writeback_ops);
+}
+
+static int zonefs_swap_activate(struct swap_info_struct *sis,
+ struct file *swap_file, sector_t *span)
+{
+ struct inode *inode = file_inode(swap_file);
+ struct zonefs_inode_info *zi = ZONEFS_I(inode);
+
+ if (zi->i_ztype != ZONEFS_ZTYPE_CNV) {
+ zonefs_err(inode->i_sb,
+ "swap file: not a conventional zone file\n");
+ return -EINVAL;
+ }
+
+ return iomap_swapfile_activate(sis, swap_file, span,
+ &zonefs_read_iomap_ops);
+}
+
+const struct address_space_operations zonefs_file_aops = {
+ .read_folio = zonefs_read_folio,
+ .readahead = zonefs_readahead,
+ .writepages = zonefs_writepages,
+ .dirty_folio = filemap_dirty_folio,
+ .release_folio = iomap_release_folio,
+ .invalidate_folio = iomap_invalidate_folio,
+ .migrate_folio = filemap_migrate_folio,
+ .is_partially_uptodate = iomap_is_partially_uptodate,
+ .error_remove_page = generic_error_remove_page,
+ .direct_IO = noop_direct_IO,
+ .swap_activate = zonefs_swap_activate,
+};
+
+int zonefs_file_truncate(struct inode *inode, loff_t isize)
+{
+ struct zonefs_inode_info *zi = ZONEFS_I(inode);
+ loff_t old_isize;
+ enum req_op op;
+ int ret = 0;
+
+ /*
+ * Only sequential zone files can be truncated and truncation is allowed
+ * only down to a 0 size, which is equivalent to a zone reset, and to
+ * the maximum file size, which is equivalent to a zone finish.
+ */
+ if (zi->i_ztype != ZONEFS_ZTYPE_SEQ)
+ return -EPERM;
+
+ if (!isize)
+ op = REQ_OP_ZONE_RESET;
+ else if (isize == zi->i_max_size)
+ op = REQ_OP_ZONE_FINISH;
+ else
+ return -EPERM;
+
+ inode_dio_wait(inode);
+
+ /* Serialize against page faults */
+ filemap_invalidate_lock(inode->i_mapping);
+
+ /* Serialize against zonefs_iomap_begin() */
+ mutex_lock(&zi->i_truncate_mutex);
+
+ old_isize = i_size_read(inode);
+ if (isize == old_isize)
+ goto unlock;
+
+ ret = zonefs_zone_mgmt(inode, op);
+ if (ret)
+ goto unlock;
+
+ /*
+ * If the mount option ZONEFS_MNTOPT_EXPLICIT_OPEN is set,
+ * take care of open zones.
+ */
+ if (zi->i_flags & ZONEFS_ZONE_OPEN) {
+ /*
+ * Truncating a zone to EMPTY or FULL is the equivalent of
+ * closing the zone. For a truncation to 0, we need to
+ * re-open the zone to ensure new writes can be processed.
+ * For a truncation to the maximum file size, the zone is
+ * closed and writes cannot be accepted anymore, so clear
+ * the open flag.
+ */
+ if (!isize)
+ ret = zonefs_zone_mgmt(inode, REQ_OP_ZONE_OPEN);
+ else
+ zi->i_flags &= ~ZONEFS_ZONE_OPEN;
+ }
+
+ zonefs_update_stats(inode, isize);
+ truncate_setsize(inode, isize);
+ zi->i_wpoffset = isize;
+ zonefs_account_active(inode);
+
+unlock:
+ mutex_unlock(&zi->i_truncate_mutex);
+ filemap_invalidate_unlock(inode->i_mapping);
+
+ return ret;
+}
+
+static int zonefs_file_fsync(struct file *file, loff_t start, loff_t end,
+ int datasync)
+{
+ struct inode *inode = file_inode(file);
+ int ret = 0;
+
+ if (unlikely(IS_IMMUTABLE(inode)))
+ return -EPERM;
+
+ /*
+ * Since only direct writes are allowed in sequential files, page cache
+ * flush is needed only for conventional zone files.
+ */
+ if (ZONEFS_I(inode)->i_ztype == ZONEFS_ZTYPE_CNV)
+ ret = file_write_and_wait_range(file, start, end);
+ if (!ret)
+ ret = blkdev_issue_flush(inode->i_sb->s_bdev);
+
+ if (ret)
+ zonefs_io_error(inode, true);
+
+ return ret;
+}
+
+static vm_fault_t zonefs_filemap_page_mkwrite(struct vm_fault *vmf)
+{
+ struct inode *inode = file_inode(vmf->vma->vm_file);
+ struct zonefs_inode_info *zi = ZONEFS_I(inode);
+ vm_fault_t ret;
+
+ if (unlikely(IS_IMMUTABLE(inode)))
+ return VM_FAULT_SIGBUS;
+
+ /*
+ * Sanity check: only conventional zone files can have shared
+ * writeable mappings.
+ */
+ if (WARN_ON_ONCE(zi->i_ztype != ZONEFS_ZTYPE_CNV))
+ return VM_FAULT_NOPAGE;
+
+ sb_start_pagefault(inode->i_sb);
+ file_update_time(vmf->vma->vm_file);
+
+ /* Serialize against truncates */
+ filemap_invalidate_lock_shared(inode->i_mapping);
+ ret = iomap_page_mkwrite(vmf, &zonefs_write_iomap_ops);
+ filemap_invalidate_unlock_shared(inode->i_mapping);
+
+ sb_end_pagefault(inode->i_sb);
+ return ret;
+}
+
+static const struct vm_operations_struct zonefs_file_vm_ops = {
+ .fault = filemap_fault,
+ .map_pages = filemap_map_pages,
+ .page_mkwrite = zonefs_filemap_page_mkwrite,
+};
+
+static int zonefs_file_mmap(struct file *file, struct vm_area_struct *vma)
+{
+ /*
+ * Conventional zones accept random writes, so their files can support
+ * shared writable mappings. For sequential zone files, only read
+ * mappings are possible since there are no guarantees for write
+ * ordering between msync() and page cache writeback.
+ */
+ if (ZONEFS_I(file_inode(file))->i_ztype == ZONEFS_ZTYPE_SEQ &&
+ (vma->vm_flags & VM_SHARED) && (vma->vm_flags & VM_MAYWRITE))
+ return -EINVAL;
+
+ file_accessed(file);
+ vma->vm_ops = &zonefs_file_vm_ops;
+
+ return 0;
+}
+
+static loff_t zonefs_file_llseek(struct file *file, loff_t offset, int whence)
+{
+ loff_t isize = i_size_read(file_inode(file));
+
+ /*
+ * Seeks are limited to below the zone size for conventional zones
+ * and below the zone write pointer for sequential zones. In both
+ * cases, this limit is the inode size.
+ */
+ return generic_file_llseek_size(file, offset, whence, isize, isize);
+}
+
+static int zonefs_file_write_dio_end_io(struct kiocb *iocb, ssize_t size,
+ int error, unsigned int flags)
+{
+ struct inode *inode = file_inode(iocb->ki_filp);
+ struct zonefs_inode_info *zi = ZONEFS_I(inode);
+
+ if (error) {
+ zonefs_io_error(inode, true);
+ return error;
+ }
+
+ if (size && zi->i_ztype != ZONEFS_ZTYPE_CNV) {
+ /*
+ * Note that we may be seeing completions out of order,
+ * but that is not a problem since a write completed
+ * successfully necessarily means that all preceding writes
+ * were also successful. So we can safely increase the inode
+ * size to the write end location.
+ */
+ mutex_lock(&zi->i_truncate_mutex);
+ if (i_size_read(inode) < iocb->ki_pos + size) {
+ zonefs_update_stats(inode, iocb->ki_pos + size);
+ zonefs_i_size_write(inode, iocb->ki_pos + size);
+ }
+ mutex_unlock(&zi->i_truncate_mutex);
+ }
+
+ return 0;
+}
+
+static const struct iomap_dio_ops zonefs_write_dio_ops = {
+ .end_io = zonefs_file_write_dio_end_io,
+};
+
+static ssize_t zonefs_file_dio_append(struct kiocb *iocb, struct iov_iter *from)
+{
+ struct inode *inode = file_inode(iocb->ki_filp);
+ struct zonefs_inode_info *zi = ZONEFS_I(inode);
+ struct block_device *bdev = inode->i_sb->s_bdev;
+ unsigned int max = bdev_max_zone_append_sectors(bdev);
+ struct bio *bio;
+ ssize_t size;
+ int nr_pages;
+ ssize_t ret;
+
+ max = ALIGN_DOWN(max << SECTOR_SHIFT, inode->i_sb->s_blocksize);
+ iov_iter_truncate(from, max);
+
+ nr_pages = iov_iter_npages(from, BIO_MAX_VECS);
+ if (!nr_pages)
+ return 0;
+
+ bio = bio_alloc(bdev, nr_pages,
+ REQ_OP_ZONE_APPEND | REQ_SYNC | REQ_IDLE, GFP_NOFS);
+ bio->bi_iter.bi_sector = zi->i_zsector;
+ bio->bi_ioprio = iocb->ki_ioprio;
+ if (iocb_is_dsync(iocb))
+ bio->bi_opf |= REQ_FUA;
+
+ ret = bio_iov_iter_get_pages(bio, from);
+ if (unlikely(ret))
+ goto out_release;
+
+ size = bio->bi_iter.bi_size;
+ task_io_account_write(size);
+
+ if (iocb->ki_flags & IOCB_HIPRI)
+ bio_set_polled(bio, iocb);
+
+ ret = submit_bio_wait(bio);
+
+ /*
+ * If the file zone was written underneath the file system, the zone
+ * write pointer may not be where we expect it to be, but the zone
+ * append write can still succeed. So check manually that we wrote where
+ * we intended to, that is, at zi->i_wpoffset.
+ */
+ if (!ret) {
+ sector_t wpsector =
+ zi->i_zsector + (zi->i_wpoffset >> SECTOR_SHIFT);
+
+ if (bio->bi_iter.bi_sector != wpsector) {
+ zonefs_warn(inode->i_sb,
+ "Corrupted write pointer %llu for zone at %llu\n",
+ wpsector, zi->i_zsector);
+ ret = -EIO;
+ }
+ }
+
+ zonefs_file_write_dio_end_io(iocb, size, ret, 0);
+ trace_zonefs_file_dio_append(inode, size, ret);
+
+out_release:
+ bio_release_pages(bio, false);
+ bio_put(bio);
+
+ if (ret >= 0) {
+ iocb->ki_pos += size;
+ return size;
+ }
+
+ return ret;
+}
+
+/*
+ * Do not exceed the LFS limits nor the file zone size. If pos is under the
+ * limit it becomes a short access. If it exceeds the limit, return -EFBIG.
+ */
+static loff_t zonefs_write_check_limits(struct file *file, loff_t pos,
+ loff_t count)
+{
+ struct inode *inode = file_inode(file);
+ struct zonefs_inode_info *zi = ZONEFS_I(inode);
+ loff_t limit = rlimit(RLIMIT_FSIZE);
+ loff_t max_size = zi->i_max_size;
+
+ if (limit != RLIM_INFINITY) {
+ if (pos >= limit) {
+ send_sig(SIGXFSZ, current, 0);
+ return -EFBIG;
+ }
+ count = min(count, limit - pos);
+ }
+
+ if (!(file->f_flags & O_LARGEFILE))
+ max_size = min_t(loff_t, MAX_NON_LFS, max_size);
+
+ if (unlikely(pos >= max_size))
+ return -EFBIG;
+
+ return min(count, max_size - pos);
+}
+
+static ssize_t zonefs_write_checks(struct kiocb *iocb, struct iov_iter *from)
+{
+ struct file *file = iocb->ki_filp;
+ struct inode *inode = file_inode(file);
+ struct zonefs_inode_info *zi = ZONEFS_I(inode);
+ loff_t count;
+
+ if (IS_SWAPFILE(inode))
+ return -ETXTBSY;
+
+ if (!iov_iter_count(from))
+ return 0;
+
+ if ((iocb->ki_flags & IOCB_NOWAIT) && !(iocb->ki_flags & IOCB_DIRECT))
+ return -EINVAL;
+
+ if (iocb->ki_flags & IOCB_APPEND) {
+ if (zi->i_ztype != ZONEFS_ZTYPE_SEQ)
+ return -EINVAL;
+ mutex_lock(&zi->i_truncate_mutex);
+ iocb->ki_pos = zi->i_wpoffset;
+ mutex_unlock(&zi->i_truncate_mutex);
+ }
+
+ count = zonefs_write_check_limits(file, iocb->ki_pos,
+ iov_iter_count(from));
+ if (count < 0)
+ return count;
+
+ iov_iter_truncate(from, count);
+ return iov_iter_count(from);
+}
+
+/*
+ * Handle direct writes. For sequential zone files, this is the only possible
+ * write path. For these files, check that the user is issuing writes
+ * sequentially from the end of the file. This code assumes that the block layer
+ * delivers write requests to the device in sequential order. This is always the
+ * case if a block IO scheduler implementing the ELEVATOR_F_ZBD_SEQ_WRITE
+ * elevator feature is being used (e.g. mq-deadline). The block layer always
+ * automatically select such an elevator for zoned block devices during the
+ * device initialization.
+ */
+static ssize_t zonefs_file_dio_write(struct kiocb *iocb, struct iov_iter *from)
+{
+ struct inode *inode = file_inode(iocb->ki_filp);
+ struct zonefs_inode_info *zi = ZONEFS_I(inode);
+ struct super_block *sb = inode->i_sb;
+ bool sync = is_sync_kiocb(iocb);
+ bool append = false;
+ ssize_t ret, count;
+
+ /*
+ * For async direct IOs to sequential zone files, refuse IOCB_NOWAIT
+ * as this can cause write reordering (e.g. the first aio gets EAGAIN
+ * on the inode lock but the second goes through but is now unaligned).
+ */
+ if (zi->i_ztype == ZONEFS_ZTYPE_SEQ && !sync &&
+ (iocb->ki_flags & IOCB_NOWAIT))
+ return -EOPNOTSUPP;
+
+ if (iocb->ki_flags & IOCB_NOWAIT) {
+ if (!inode_trylock(inode))
+ return -EAGAIN;
+ } else {
+ inode_lock(inode);
+ }
+
+ count = zonefs_write_checks(iocb, from);
+ if (count <= 0) {
+ ret = count;
+ goto inode_unlock;
+ }
+
+ if ((iocb->ki_pos | count) & (sb->s_blocksize - 1)) {
+ ret = -EINVAL;
+ goto inode_unlock;
+ }
+
+ /* Enforce sequential writes (append only) in sequential zones */
+ if (zi->i_ztype == ZONEFS_ZTYPE_SEQ) {
+ mutex_lock(&zi->i_truncate_mutex);
+ if (iocb->ki_pos != zi->i_wpoffset) {
+ mutex_unlock(&zi->i_truncate_mutex);
+ ret = -EINVAL;
+ goto inode_unlock;
+ }
+ mutex_unlock(&zi->i_truncate_mutex);
+ append = sync;
+ }
+
+ if (append)
+ ret = zonefs_file_dio_append(iocb, from);
+ else
+ ret = iomap_dio_rw(iocb, from, &zonefs_write_iomap_ops,
+ &zonefs_write_dio_ops, 0, NULL, 0);
+ if (zi->i_ztype == ZONEFS_ZTYPE_SEQ &&
+ (ret > 0 || ret == -EIOCBQUEUED)) {
+ if (ret > 0)
+ count = ret;
+
+ /*
+ * Update the zone write pointer offset assuming the write
+ * operation succeeded. If it did not, the error recovery path
+ * will correct it. Also do active seq file accounting.
+ */
+ mutex_lock(&zi->i_truncate_mutex);
+ zi->i_wpoffset += count;
+ zonefs_account_active(inode);
+ mutex_unlock(&zi->i_truncate_mutex);
+ }
+
+inode_unlock:
+ inode_unlock(inode);
+
+ return ret;
+}
+
+static ssize_t zonefs_file_buffered_write(struct kiocb *iocb,
+ struct iov_iter *from)
+{
+ struct inode *inode = file_inode(iocb->ki_filp);
+ struct zonefs_inode_info *zi = ZONEFS_I(inode);
+ ssize_t ret;
+
+ /*
+ * Direct IO writes are mandatory for sequential zone files so that the
+ * write IO issuing order is preserved.
+ */
+ if (zi->i_ztype != ZONEFS_ZTYPE_CNV)
+ return -EIO;
+
+ if (iocb->ki_flags & IOCB_NOWAIT) {
+ if (!inode_trylock(inode))
+ return -EAGAIN;
+ } else {
+ inode_lock(inode);
+ }
+
+ ret = zonefs_write_checks(iocb, from);
+ if (ret <= 0)
+ goto inode_unlock;
+
+ ret = iomap_file_buffered_write(iocb, from, &zonefs_write_iomap_ops);
+ if (ret > 0)
+ iocb->ki_pos += ret;
+ else if (ret == -EIO)
+ zonefs_io_error(inode, true);
+
+inode_unlock:
+ inode_unlock(inode);
+ if (ret > 0)
+ ret = generic_write_sync(iocb, ret);
+
+ return ret;
+}
+
+static ssize_t zonefs_file_write_iter(struct kiocb *iocb, struct iov_iter *from)
+{
+ struct inode *inode = file_inode(iocb->ki_filp);
+
+ if (unlikely(IS_IMMUTABLE(inode)))
+ return -EPERM;
+
+ if (sb_rdonly(inode->i_sb))
+ return -EROFS;
+
+ /* Write operations beyond the zone size are not allowed */
+ if (iocb->ki_pos >= ZONEFS_I(inode)->i_max_size)
+ return -EFBIG;
+
+ if (iocb->ki_flags & IOCB_DIRECT) {
+ ssize_t ret = zonefs_file_dio_write(iocb, from);
+
+ if (ret != -ENOTBLK)
+ return ret;
+ }
+
+ return zonefs_file_buffered_write(iocb, from);
+}
+
+static int zonefs_file_read_dio_end_io(struct kiocb *iocb, ssize_t size,
+ int error, unsigned int flags)
+{
+ if (error) {
+ zonefs_io_error(file_inode(iocb->ki_filp), false);
+ return error;
+ }
+
+ return 0;
+}
+
+static const struct iomap_dio_ops zonefs_read_dio_ops = {
+ .end_io = zonefs_file_read_dio_end_io,
+};
+
+static ssize_t zonefs_file_read_iter(struct kiocb *iocb, struct iov_iter *to)
+{
+ struct inode *inode = file_inode(iocb->ki_filp);
+ struct zonefs_inode_info *zi = ZONEFS_I(inode);
+ struct super_block *sb = inode->i_sb;
+ loff_t isize;
+ ssize_t ret;
+
+ /* Offline zones cannot be read */
+ if (unlikely(IS_IMMUTABLE(inode) && !(inode->i_mode & 0777)))
+ return -EPERM;
+
+ if (iocb->ki_pos >= zi->i_max_size)
+ return 0;
+
+ if (iocb->ki_flags & IOCB_NOWAIT) {
+ if (!inode_trylock_shared(inode))
+ return -EAGAIN;
+ } else {
+ inode_lock_shared(inode);
+ }
+
+ /* Limit read operations to written data */
+ mutex_lock(&zi->i_truncate_mutex);
+ isize = i_size_read(inode);
+ if (iocb->ki_pos >= isize) {
+ mutex_unlock(&zi->i_truncate_mutex);
+ ret = 0;
+ goto inode_unlock;
+ }
+ iov_iter_truncate(to, isize - iocb->ki_pos);
+ mutex_unlock(&zi->i_truncate_mutex);
+
+ if (iocb->ki_flags & IOCB_DIRECT) {
+ size_t count = iov_iter_count(to);
+
+ if ((iocb->ki_pos | count) & (sb->s_blocksize - 1)) {
+ ret = -EINVAL;
+ goto inode_unlock;
+ }
+ file_accessed(iocb->ki_filp);
+ ret = iomap_dio_rw(iocb, to, &zonefs_read_iomap_ops,
+ &zonefs_read_dio_ops, 0, NULL, 0);
+ } else {
+ ret = generic_file_read_iter(iocb, to);
+ if (ret == -EIO)
+ zonefs_io_error(inode, false);
+ }
+
+inode_unlock:
+ inode_unlock_shared(inode);
+
+ return ret;
+}
+
+/*
+ * Write open accounting is done only for sequential files.
+ */
+static inline bool zonefs_seq_file_need_wro(struct inode *inode,
+ struct file *file)
+{
+ struct zonefs_inode_info *zi = ZONEFS_I(inode);
+
+ if (zi->i_ztype != ZONEFS_ZTYPE_SEQ)
+ return false;
+
+ if (!(file->f_mode & FMODE_WRITE))
+ return false;
+
+ return true;
+}
+
+static int zonefs_seq_file_write_open(struct inode *inode)
+{
+ struct zonefs_inode_info *zi = ZONEFS_I(inode);
+ int ret = 0;
+
+ mutex_lock(&zi->i_truncate_mutex);
+
+ if (!zi->i_wr_refcnt) {
+ struct zonefs_sb_info *sbi = ZONEFS_SB(inode->i_sb);
+ unsigned int wro = atomic_inc_return(&sbi->s_wro_seq_files);
+
+ if (sbi->s_mount_opts & ZONEFS_MNTOPT_EXPLICIT_OPEN) {
+
+ if (sbi->s_max_wro_seq_files
+ && wro > sbi->s_max_wro_seq_files) {
+ atomic_dec(&sbi->s_wro_seq_files);
+ ret = -EBUSY;
+ goto unlock;
+ }
+
+ if (i_size_read(inode) < zi->i_max_size) {
+ ret = zonefs_zone_mgmt(inode, REQ_OP_ZONE_OPEN);
+ if (ret) {
+ atomic_dec(&sbi->s_wro_seq_files);
+ goto unlock;
+ }
+ zi->i_flags |= ZONEFS_ZONE_OPEN;
+ zonefs_account_active(inode);
+ }
+ }
+ }
+
+ zi->i_wr_refcnt++;
+
+unlock:
+ mutex_unlock(&zi->i_truncate_mutex);
+
+ return ret;
+}
+
+static int zonefs_file_open(struct inode *inode, struct file *file)
+{
+ int ret;
+
+ ret = generic_file_open(inode, file);
+ if (ret)
+ return ret;
+
+ if (zonefs_seq_file_need_wro(inode, file))
+ return zonefs_seq_file_write_open(inode);
+
+ return 0;
+}
+
+static void zonefs_seq_file_write_close(struct inode *inode)
+{
+ struct zonefs_inode_info *zi = ZONEFS_I(inode);
+ struct super_block *sb = inode->i_sb;
+ struct zonefs_sb_info *sbi = ZONEFS_SB(sb);
+ int ret = 0;
+
+ mutex_lock(&zi->i_truncate_mutex);
+
+ zi->i_wr_refcnt--;
+ if (zi->i_wr_refcnt)
+ goto unlock;
+
+ /*
+ * The file zone may not be open anymore (e.g. the file was truncated to
+ * its maximum size or it was fully written). For this case, we only
+ * need to decrement the write open count.
+ */
+ if (zi->i_flags & ZONEFS_ZONE_OPEN) {
+ ret = zonefs_zone_mgmt(inode, REQ_OP_ZONE_CLOSE);
+ if (ret) {
+ __zonefs_io_error(inode, false);
+ /*
+ * Leaving zones explicitly open may lead to a state
+ * where most zones cannot be written (zone resources
+ * exhausted). So take preventive action by remounting
+ * read-only.
+ */
+ if (zi->i_flags & ZONEFS_ZONE_OPEN &&
+ !(sb->s_flags & SB_RDONLY)) {
+ zonefs_warn(sb,
+ "closing zone at %llu failed %d\n",
+ zi->i_zsector, ret);
+ zonefs_warn(sb,
+ "remounting filesystem read-only\n");
+ sb->s_flags |= SB_RDONLY;
+ }
+ goto unlock;
+ }
+
+ zi->i_flags &= ~ZONEFS_ZONE_OPEN;
+ zonefs_account_active(inode);
+ }
+
+ atomic_dec(&sbi->s_wro_seq_files);
+
+unlock:
+ mutex_unlock(&zi->i_truncate_mutex);
+}
+
+static int zonefs_file_release(struct inode *inode, struct file *file)
+{
+ /*
+ * If we explicitly open a zone we must close it again as well, but the
+ * zone management operation can fail (either due to an IO error or as
+ * the zone has gone offline or read-only). Make sure we don't fail the
+ * close(2) for user-space.
+ */
+ if (zonefs_seq_file_need_wro(inode, file))
+ zonefs_seq_file_write_close(inode);
+
+ return 0;
+}
+
+const struct file_operations zonefs_file_operations = {
+ .open = zonefs_file_open,
+ .release = zonefs_file_release,
+ .fsync = zonefs_file_fsync,
+ .mmap = zonefs_file_mmap,
+ .llseek = zonefs_file_llseek,
+ .read_iter = zonefs_file_read_iter,
+ .write_iter = zonefs_file_write_iter,
+ .splice_read = generic_file_splice_read,
+ .splice_write = iter_file_splice_write,
+ .iopoll = iocb_bio_iopoll,
+};
generated by cgit v1.2.3 (git 2.25.1) at 2024-06-08 14:16:45 +0000