diff options
| -rw-r--r-- | fs/xfs/Kconfig | 1 | ||||
| -rw-r--r-- | fs/xfs/Makefile | 2 | ||||
| -rw-r--r-- | fs/xfs/scrub/trace.c | 4 | ||||
| -rw-r--r-- | fs/xfs/scrub/trace.h | 121 | ||||
| -rw-r--r-- | fs/xfs/scrub/xfarray.c | 369 | ||||
| -rw-r--r-- | fs/xfs/scrub/xfarray.h | 57 | ||||
| -rw-r--r-- | fs/xfs/scrub/xfile.c | 312 | ||||
| -rw-r--r-- | fs/xfs/scrub/xfile.h | 57 |
8 files changed, 922 insertions, 1 deletions
diff --git a/fs/xfs/Kconfig b/fs/xfs/Kconfig index 52e1823241fb..152348b4dece 100644 --- a/fs/xfs/Kconfig +++ b/fs/xfs/Kconfig @@ -128,6 +128,7 @@ config XFS_ONLINE_SCRUB bool "XFS online metadata check support" default n depends on XFS_FS + depends on TMPFS && SHMEM select XFS_DRAIN_INTENTS help If you say Y here you will be able to check metadata on a diff --git a/fs/xfs/Makefile b/fs/xfs/Makefile index 0a5cebb9802b..f175f823fcd4 100644 --- a/fs/xfs/Makefile +++ b/fs/xfs/Makefile @@ -164,6 +164,8 @@ xfs-y += $(addprefix scrub/, \ rmap.o \ scrub.o \ symlink.o \ + xfarray.o \ + xfile.o \ ) xfs-$(CONFIG_XFS_RT) += scrub/rtbitmap.o diff --git a/fs/xfs/scrub/trace.c b/fs/xfs/scrub/trace.c index 0a975439d2b6..46249e7b17e0 100644 --- a/fs/xfs/scrub/trace.c +++ b/fs/xfs/scrub/trace.c @@ -12,8 +12,10 @@ #include "xfs_mount.h" #include "xfs_inode.h" #include "xfs_btree.h" -#include "scrub/scrub.h" #include "xfs_ag.h" +#include "scrub/scrub.h" +#include "scrub/xfile.h" +#include "scrub/xfarray.h" /* Figure out which block the btree cursor was pointing to. */ static inline xfs_fsblock_t diff --git a/fs/xfs/scrub/trace.h b/fs/xfs/scrub/trace.h index 73cf1002bd94..7165e2f7be9e 100644 --- a/fs/xfs/scrub/trace.h +++ b/fs/xfs/scrub/trace.h @@ -16,6 +16,9 @@ #include <linux/tracepoint.h> #include "xfs_bit.h" +struct xfile; +struct xfarray; + /* * ftrace's __print_symbolic requires that all enum values be wrapped in the * TRACE_DEFINE_ENUM macro so that the enum value can be encoded in the ftrace @@ -725,6 +728,124 @@ TRACE_EVENT(xchk_refcount_incorrect, __entry->seen) ) +TRACE_EVENT(xfile_create, + TP_PROTO(struct xfile *xf), + TP_ARGS(xf), + TP_STRUCT__entry( + __field(dev_t, dev) + __field(unsigned long, ino) + __array(char, pathname, 256) + ), + TP_fast_assign( + char pathname[257]; + char *path; + + __entry->ino = file_inode(xf->file)->i_ino; + memset(pathname, 0, sizeof(pathname)); + path = file_path(xf->file, pathname, sizeof(pathname) - 1); + if (IS_ERR(path)) + path = "(unknown)"; + strncpy(__entry->pathname, path, sizeof(__entry->pathname)); + ), + TP_printk("xfino 0x%lx path '%s'", + __entry->ino, + __entry->pathname) +); + +TRACE_EVENT(xfile_destroy, + TP_PROTO(struct xfile *xf), + TP_ARGS(xf), + TP_STRUCT__entry( + __field(unsigned long, ino) + __field(unsigned long long, bytes) + __field(loff_t, size) + ), + TP_fast_assign( + struct xfile_stat statbuf; + int ret; + + ret = xfile_stat(xf, &statbuf); + if (!ret) { + __entry->bytes = statbuf.bytes; + __entry->size = statbuf.size; + } else { + __entry->bytes = -1; + __entry->size = -1; + } + __entry->ino = file_inode(xf->file)->i_ino; + ), + TP_printk("xfino 0x%lx mem_bytes 0x%llx isize 0x%llx", + __entry->ino, + __entry->bytes, + __entry->size) +); + +DECLARE_EVENT_CLASS(xfile_class, + TP_PROTO(struct xfile *xf, loff_t pos, unsigned long long bytecount), + TP_ARGS(xf, pos, bytecount), + TP_STRUCT__entry( + __field(unsigned long, ino) + __field(unsigned long long, bytes_used) + __field(loff_t, pos) + __field(loff_t, size) + __field(unsigned long long, bytecount) + ), + TP_fast_assign( + struct xfile_stat statbuf; + int ret; + + ret = xfile_stat(xf, &statbuf); + if (!ret) { + __entry->bytes_used = statbuf.bytes; + __entry->size = statbuf.size; + } else { + __entry->bytes_used = -1; + __entry->size = -1; + } + __entry->ino = file_inode(xf->file)->i_ino; + __entry->pos = pos; + __entry->bytecount = bytecount; + ), + TP_printk("xfino 0x%lx mem_bytes 0x%llx pos 0x%llx bytecount 0x%llx isize 0x%llx", + __entry->ino, + __entry->bytes_used, + __entry->pos, + __entry->bytecount, + __entry->size) +); +#define DEFINE_XFILE_EVENT(name) \ +DEFINE_EVENT(xfile_class, name, \ + TP_PROTO(struct xfile *xf, loff_t pos, unsigned long long bytecount), \ + TP_ARGS(xf, pos, bytecount)) +DEFINE_XFILE_EVENT(xfile_pread); +DEFINE_XFILE_EVENT(xfile_pwrite); +DEFINE_XFILE_EVENT(xfile_seek_data); + +TRACE_EVENT(xfarray_create, + TP_PROTO(struct xfarray *xfa, unsigned long long required_capacity), + TP_ARGS(xfa, required_capacity), + TP_STRUCT__entry( + __field(unsigned long, ino) + __field(uint64_t, max_nr) + __field(size_t, obj_size) + __field(int, obj_size_log) + __field(unsigned long long, required_capacity) + ), + TP_fast_assign( + __entry->max_nr = xfa->max_nr; + __entry->obj_size = xfa->obj_size; + __entry->obj_size_log = xfa->obj_size_log; + __entry->ino = file_inode(xfa->xfile->file)->i_ino; + __entry->required_capacity = required_capacity; + ), + TP_printk("xfino 0x%lx max_nr %llu reqd_nr %llu objsz %zu objszlog %d", + __entry->ino, + __entry->max_nr, + __entry->required_capacity, + __entry->obj_size, + __entry->obj_size_log) +); + /* repair tracepoints */ #if IS_ENABLED(CONFIG_XFS_ONLINE_REPAIR) diff --git a/fs/xfs/scrub/xfarray.c b/fs/xfs/scrub/xfarray.c new file mode 100644 index 000000000000..ca4a4a307010 --- /dev/null +++ b/fs/xfs/scrub/xfarray.c @@ -0,0 +1,369 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * Copyright (C) 2021-2023 Oracle. All Rights Reserved. + * Author: Darrick J. Wong <djwong@kernel.org> + */ +#include "xfs.h" +#include "xfs_fs.h" +#include "xfs_shared.h" +#include "xfs_format.h" +#include "scrub/xfile.h" +#include "scrub/xfarray.h" +#include "scrub/scrub.h" +#include "scrub/trace.h" + +/* + * Large Arrays of Fixed-Size Records + * ================================== + * + * This memory array uses an xfile (which itself is a memfd "file") to store + * large numbers of fixed-size records in memory that can be paged out. This + * puts less stress on the memory reclaim algorithms during an online repair + * because we don't have to pin so much memory. However, array access is less + * direct than would be in a regular memory array. Access to the array is + * performed via indexed load and store methods, and an append method is + * provided for convenience. Array elements can be unset, which sets them to + * all zeroes. Unset entries are skipped during iteration, though direct loads + * will return a zeroed buffer. Callers are responsible for concurrency + * control. + */ + +/* + * Pointer to scratch space. Because we can't access the xfile data directly, + * we allocate a small amount of memory on the end of the xfarray structure to + * buffer array items when we need space to store values temporarily. + */ +static inline void *xfarray_scratch(struct xfarray *array) +{ + return (array + 1); +} + +/* Compute array index given an xfile offset. */ +static xfarray_idx_t +xfarray_idx( + struct xfarray *array, + loff_t pos) +{ + if (array->obj_size_log >= 0) + return (xfarray_idx_t)pos >> array->obj_size_log; + + return div_u64((xfarray_idx_t)pos, array->obj_size); +} + +/* Compute xfile offset of array element. */ +static inline loff_t xfarray_pos(struct xfarray *array, xfarray_idx_t idx) +{ + if (array->obj_size_log >= 0) + return idx << array->obj_size_log; + + return idx * array->obj_size; +} + +/* + * Initialize a big memory array. Array records cannot be larger than a + * page, and the array cannot span more bytes than the page cache supports. + * If @required_capacity is nonzero, the maximum array size will be set to this + * quantity and the array creation will fail if the underlying storage cannot + * support that many records. + */ +int +xfarray_create( + const char *description, + unsigned long long required_capacity, + size_t obj_size, + struct xfarray **arrayp) +{ + struct xfarray *array; + struct xfile *xfile; + int error; + + ASSERT(obj_size < PAGE_SIZE); + + error = xfile_create(description, 0, &xfile); + if (error) + return error; + + error = -ENOMEM; + array = kzalloc(sizeof(struct xfarray) + obj_size, XCHK_GFP_FLAGS); + if (!array) + goto out_xfile; + + array->xfile = xfile; + array->obj_size = obj_size; + + if (is_power_of_2(obj_size)) + array->obj_size_log = ilog2(obj_size); + else + array->obj_size_log = -1; + + array->max_nr = xfarray_idx(array, MAX_LFS_FILESIZE); + trace_xfarray_create(array, required_capacity); + + if (required_capacity > 0) { + if (array->max_nr < required_capacity) { + error = -ENOMEM; + goto out_xfarray; + } + array->max_nr = required_capacity; + } + + *arrayp = array; + return 0; + +out_xfarray: + kfree(array); +out_xfile: + xfile_destroy(xfile); + return error; +} + +/* Destroy the array. */ +void +xfarray_destroy( + struct xfarray *array) +{ + xfile_destroy(array->xfile); + kfree(array); +} + +/* Load an element from the array. */ +int +xfarray_load( + struct xfarray *array, + xfarray_idx_t idx, + void *ptr) +{ + if (idx >= array->nr) + return -ENODATA; + + return xfile_obj_load(array->xfile, ptr, array->obj_size, + xfarray_pos(array, idx)); +} + +/* Is this array element potentially unset? */ +static inline bool +xfarray_is_unset( + struct xfarray *array, + loff_t pos) +{ + void *temp = xfarray_scratch(array); + int error; + + if (array->unset_slots == 0) + return false; + + error = xfile_obj_load(array->xfile, temp, array->obj_size, pos); + if (!error && xfarray_element_is_null(array, temp)) + return true; + + return false; +} + +/* + * Unset an array element. If @idx is the last element in the array, the + * array will be truncated. Otherwise, the entry will be zeroed. + */ +int +xfarray_unset( + struct xfarray *array, + xfarray_idx_t idx) +{ + void *temp = xfarray_scratch(array); + loff_t pos = xfarray_pos(array, idx); + int error; + + if (idx >= array->nr) + return -ENODATA; + + if (idx == array->nr - 1) { + array->nr--; + return 0; + } + + if (xfarray_is_unset(array, pos)) + return 0; + + memset(temp, 0, array->obj_size); + error = xfile_obj_store(array->xfile, temp, array->obj_size, pos); + if (error) + return error; + + array->unset_slots++; + return 0; +} + +/* + * Store an element in the array. The element must not be completely zeroed, + * because those are considered unset sparse elements. + */ +int +xfarray_store( + struct xfarray *array, + xfarray_idx_t idx, + const void *ptr) +{ + int ret; + + if (idx >= array->max_nr) + return -EFBIG; + + ASSERT(!xfarray_element_is_null(array, ptr)); + + ret = xfile_obj_store(array->xfile, ptr, array->obj_size, + xfarray_pos(array, idx)); + if (ret) + return ret; + + array->nr = max(array->nr, idx + 1); + return 0; +} + +/* Is this array element NULL? */ +bool +xfarray_element_is_null( + struct xfarray *array, + const void *ptr) +{ + return !memchr_inv(ptr, 0, array->obj_size); +} + +/* + * Store an element anywhere in the array that is unset. If there are no + * unset slots, append the element to the array. + */ +int +xfarray_store_anywhere( + struct xfarray *array, + const void *ptr) +{ + void *temp = xfarray_scratch(array); + loff_t endpos = xfarray_pos(array, array->nr); + loff_t pos; + int error; + + /* Find an unset slot to put it in. */ + for (pos = 0; + pos < endpos && array->unset_slots > 0; + pos += array->obj_size) { + error = xfile_obj_load(array->xfile, temp, array->obj_size, + pos); + if (error || !xfarray_element_is_null(array, temp)) + continue; + + error = xfile_obj_store(array->xfile, ptr, array->obj_size, + pos); + if (error) + return error; + + array->unset_slots--; + return 0; + } + + /* No unset slots found; attach it on the end. */ + array->unset_slots = 0; + return xfarray_append(array, ptr); +} + +/* Return length of array. */ +uint64_t +xfarray_length( + struct xfarray *array) +{ + return array->nr; +} + +/* + * Decide which array item we're going to read as part of an _iter_get. + * @cur is the array index, and @pos is the file offset of that array index in + * the backing xfile. Returns ENODATA if we reach the end of the records. + * + * Reading from a hole in a sparse xfile causes page instantiation, so for + * iterating a (possibly sparse) array we need to figure out if the cursor is + * pointing at a totally uninitialized hole and move the cursor up if + * necessary. + */ +static inline int +xfarray_find_data( + struct xfarray *array, + xfarray_idx_t *cur, + loff_t *pos) +{ + unsigned int pgoff = offset_in_page(*pos); + loff_t end_pos = *pos + array->obj_size - 1; + loff_t new_pos; + + /* + * If the current array record is not adjacent to a page boundary, we + * are in the middle of the page. We do not need to move the cursor. + */ + if (pgoff != 0 && pgoff + array->obj_size - 1 < PAGE_SIZE) + return 0; + + /* + * Call SEEK_DATA on the last byte in the record we're about to read. + * If the record ends at (or crosses) the end of a page then we know + * that the first byte of the record is backed by pages and don't need + * to query it. If instead the record begins at the start of the page + * then we know that querying the last byte is just as good as querying + * the first byte, since records cannot be larger than a page. + * + * If the call returns the same file offset, we know this record is + * backed by real pages. We do not need to move the cursor. + */ + new_pos = xfile_seek_data(array->xfile, end_pos); + if (new_pos == -ENXIO) + return -ENODATA; + if (new_pos < 0) + return new_pos; + if (new_pos == end_pos) + return 0; + + /* + * Otherwise, SEEK_DATA told us how far up to move the file pointer to + * find more data. Move the array index to the first record past the + * byte offset we were given. + */ + new_pos = roundup_64(new_pos, array->obj_size); + *cur = xfarray_idx(array, new_pos); + *pos = xfarray_pos(array, *cur); + return 0; +} + +/* + * Starting at *idx, fetch the next non-null array entry and advance the index + * to set up the next _load_next call. Returns ENODATA if we reach the end of + * the array. Callers must set @*idx to XFARRAY_CURSOR_INIT before the first + * call to this function. + */ +int +xfarray_load_next( + struct xfarray *array, + xfarray_idx_t *idx, + void *rec) +{ + xfarray_idx_t cur = *idx; + loff_t pos = xfarray_pos(array, cur); + int error; + + do { + if (cur >= array->nr) + return -ENODATA; + + /* + * Ask the backing store for the location of next possible + * written record, then retrieve that record. + */ + error = xfarray_find_data(array, &cur, &pos); + if (error) + return error; + error = xfarray_load(array, cur, rec); + if (error) + return error; + + cur++; + pos += array->obj_size; + } while (xfarray_element_is_null(array, rec)); + + *idx = cur; + return 0; +} diff --git a/fs/xfs/scrub/xfarray.h b/fs/xfs/scrub/xfarray.h new file mode 100644 index 000000000000..3ef7911b104b --- /dev/null +++ b/fs/xfs/scrub/xfarray.h @@ -0,0 +1,57 @@ +/* SPDX-License-Identifier: GPL-2.0-or-later */ +/* + * Copyright (C) 2021-2023 Oracle. All Rights Reserved. + * Author: Darrick J. Wong <djwong@kernel.org> + */ +#ifndef __XFS_SCRUB_XFARRAY_H__ +#define __XFS_SCRUB_XFARRAY_H__ + +/* xfile array index type, along with cursor initialization */ +typedef uint64_t xfarray_idx_t; +#define XFARRAY_CURSOR_INIT ((__force xfarray_idx_t)0) + +/* Iterate each index of an xfile array. */ +#define foreach_xfarray_idx(array, idx) \ + for ((idx) = XFARRAY_CURSOR_INIT; \ + (idx) < xfarray_length(array); \ + (idx)++) + +struct xfarray { + /* Underlying file that backs the array. */ + struct xfile *xfile; + + /* Number of array elements. */ + xfarray_idx_t nr; + + /* Maximum possible array size. */ + xfarray_idx_t max_nr; + + /* Number of unset slots in the array below @nr. */ + uint64_t unset_slots; + + /* Size of an array element. */ + size_t obj_size; + + /* log2 of array element size, if possible. */ + int obj_size_log; +}; + +int xfarray_create(const char *descr, unsigned long long required_capacity, + size_t obj_size, struct xfarray **arrayp); +void xfarray_destroy(struct xfarray *array); +int xfarray_load(struct xfarray *array, xfarray_idx_t idx, void *ptr); +int xfarray_unset(struct xfarray *array, xfarray_idx_t idx); +int xfarray_store(struct xfarray *array, xfarray_idx_t idx, const void *ptr); +int xfarray_store_anywhere(struct xfarray *array, const void *ptr); +bool xfarray_element_is_null(struct xfarray *array, const void *ptr); + +/* Append an element to the array. */ +static inline int xfarray_append(struct xfarray *array, const void *ptr) +{ + return xfarray_store(array, array->nr, ptr); +} + +uint64_t xfarray_length(struct xfarray *array); +int xfarray_load_next(struct xfarray *array, xfarray_idx_t *idx, void *rec); + +#endif /* __XFS_SCRUB_XFARRAY_H__ */ diff --git a/fs/xfs/scrub/xfile.c b/fs/xfs/scrub/xfile.c new file mode 100644 index 000000000000..19d512887980 --- /dev/null +++ b/fs/xfs/scrub/xfile.c @@ -0,0 +1,312 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * Copyright (C) 2018-2023 Oracle. All Rights Reserved. + * Author: Darrick J. Wong <djwong@kernel.org> + */ +#include "xfs.h" +#include "xfs_fs.h" +#include "xfs_shared.h" +#include "xfs_format.h" +#include "xfs_log_format.h" +#include "xfs_trans_resv.h" +#include "xfs_mount.h" +#include "xfs_format.h" +#include "scrub/xfile.h" +#include "scrub/xfarray.h" +#include "scrub/scrub.h" +#include "scrub/trace.h" +#include <linux/shmem_fs.h> + +/* + * Swappable Temporary Memory + * ========================== + * + * Online checking sometimes needs to be able to stage a large amount of data + * in memory. This information might not fit in the available memory and it + * doesn't all need to be accessible at all times. In other words, we want an + * indexed data buffer to store data that can be paged out. + * + * When CONFIG_TMPFS=y, shmemfs is enough of a filesystem to meet those + * requirements. Therefore, the xfile mechanism uses an unlinked shmem file to + * store our staging data. This file is not installed in the file descriptor + * table so that user programs cannot access the data, which means that the + * xfile must be freed with xfile_destroy. + * + * xfiles assume that the caller will handle all required concurrency + * management; standard vfs locks (freezer and inode) are not taken. Reads + * and writes are satisfied directly from the page cache. + * + * NOTE: The current shmemfs implementation has a quirk that in-kernel reads + * of a hole cause a page to be mapped into the file. If you are going to + * create a sparse xfile, please be careful about reading from uninitialized + * parts of the file. These pages are !Uptodate and will eventually be + * reclaimed if not written, but in the short term this boosts memory + * consumption. + */ + +/* + * xfiles must not be exposed to userspace and require upper layers to + * coordinate access to the one handle returned by the constructor, so + * establish a separate lock class for xfiles to avoid confusing lockdep. + */ +static struct lock_class_key xfile_i_mutex_key; + +/* + * Create an xfile of the given size. The description will be used in the + * trace output. + */ +int +xfile_create( + const char *description, + loff_t isize, + struct xfile **xfilep) +{ + struct inode *inode; + struct xfile *xf; + int error = -ENOMEM; + + xf = kmalloc(sizeof(struct xfile), XCHK_GFP_FLAGS); + if (!xf) + return -ENOMEM; + + xf->file = shmem_file_setup(description, isize, 0); + if (!xf->file) + goto out_xfile; + if (IS_ERR(xf->file)) { + error = PTR_ERR(xf->file); + goto out_xfile; + } + + /* + * We want a large sparse file that we can pread, pwrite, and seek. + * xfile users are responsible for keeping the xfile hidden away from + * all other callers, so we skip timestamp updates and security checks. + * Make the inode only accessible by root, just in case the xfile ever + * escapes. + */ + xf->file->f_mode |= FMODE_PREAD | FMODE_PWRITE | FMODE_NOCMTIME | + FMODE_LSEEK; + xf->file->f_flags |= O_RDWR | O_LARGEFILE | O_NOATIME; + inode = file_inode(xf->file); + inode->i_flags |= S_PRIVATE | S_NOCMTIME | S_NOATIME; + inode->i_mode &= ~0177; + inode->i_uid = GLOBAL_ROOT_UID; + inode->i_gid = GLOBAL_ROOT_GID; + + lockdep_set_class(&inode->i_rwsem, &xfile_i_mutex_key); + + trace_xfile_create(xf); + + *xfilep = xf; + return 0; +out_xfile: + kfree(xf); + return error; +} + +/* Close the file and release all resources. */ +void +xfile_destroy( + struct xfile *xf) +{ + struct inode *inode = file_inode(xf->file); + + trace_xfile_destroy(xf); + + lockdep_set_class(&inode->i_rwsem, &inode->i_sb->s_type->i_mutex_key); + fput(xf->file); + kfree(xf); +} + +/* + * Read a memory object directly from the xfile's page cache. Unlike regular + * pread, we return -E2BIG and -EFBIG for reads that are too large or at too + * high an offset, instead of truncating the read. Otherwise, we return + * bytes read or an error code, like regular pread. + */ +ssize_t +xfile_pread( + struct xfile *xf, + void *buf, + size_t count, + loff_t pos) +{ + struct inode *inode = file_inode(xf->file); + struct address_space *mapping = inode->i_mapping; + struct page *page = NULL; + ssize_t read = 0; + unsigned int pflags; + int error = 0; + + if (count > MAX_RW_COUNT) + return -E2BIG; + if (inode->i_sb->s_maxbytes - pos < count) + return -EFBIG; + + trace_xfile_pread(xf, pos, count); + + pflags = memalloc_nofs_save(); + while (count > 0) { + void *p, *kaddr; + unsigned int len; + + len = min_t(ssize_t, count, PAGE_SIZE - offset_in_page(pos)); + + /* + * In-kernel reads of a shmem file cause it to allocate a page + * if the mapping shows a hole. Therefore, if we hit ENOMEM + * we can continue by zeroing the caller's buffer. + */ + page = shmem_read_mapping_page_gfp(mapping, pos >> PAGE_SHIFT, + __GFP_NOWARN); + if (IS_ERR(page)) { + error = PTR_ERR(page); + if (error != -ENOMEM) + break; + + memset(buf, 0, len); + goto advance; + } + + if (PageUptodate(page)) { + /* + * xfile pages must never be mapped into userspace, so + * we skip the dcache flush. + */ + kaddr = kmap_local_page(page); + p = kaddr + offset_in_page(pos); + memcpy(buf, p, len); + kunmap_local(kaddr); + } else { + memset(buf, 0, len); + } + put_page(page); + +advance: + count -= len; + pos += len; + buf += len; + read += len; + } + memalloc_nofs_restore(pflags); + + if (read > 0) + return read; + return error; +} + +/* + * Write a memory object directly to the xfile's page cache. Unlike regular + * pwrite, we return -E2BIG and -EFBIG for writes that are too large or at too + * high an offset, instead of truncating the write. Otherwise, we return + * bytes written or an error code, like regular pwrite. + */ +ssize_t +xfile_pwrite( + struct xfile *xf, + const void *buf, + size_t count, + loff_t pos) +{ + struct inode *inode = file_inode(xf->file); + struct address_space *mapping = inode->i_mapping; + const struct address_space_operations *aops = mapping->a_ops; + struct page *page = NULL; + ssize_t written = 0; + unsigned int pflags; + int error = 0; + + if (count > MAX_RW_COUNT) + return -E2BIG; + if (inode->i_sb->s_maxbytes - pos < count) + return -EFBIG; + + trace_xfile_pwrite(xf, pos, count); + + pflags = memalloc_nofs_save(); + while (count > 0) { + void *fsdata = NULL; + void *p, *kaddr; + unsigned int len; + int ret; + + len = min_t(ssize_t, count, PAGE_SIZE - offset_in_page(pos)); + + /* + * We call write_begin directly here to avoid all the freezer + * protection lock-taking that happens in the normal path. + * shmem doesn't support fs freeze, but lockdep doesn't know + * that and will trip over that. + */ + error = aops->write_begin(NULL, mapping, pos, len, &page, + &fsdata); + if (error) + break; + + /* + * xfile pages must never be mapped into userspace, so we skip + * the dcache flush. If the page is not uptodate, zero it + * before writing data. + */ + kaddr = kmap_local_page(page); + if (!PageUptodate(page)) { + memset(kaddr, 0, PAGE_SIZE); + SetPageUptodate(page); + } + p = kaddr + offset_in_page(pos); + memcpy(p, buf, len); + kunmap_local(kaddr); + + ret = aops->write_end(NULL, mapping, pos, len, len, page, + fsdata); + if (ret < 0) { + error = ret; + break; + } + + written += ret; + if (ret != len) + break; + + count -= ret; + pos += ret; + buf += ret; + } + memalloc_nofs_restore(pflags); + + if (written > 0) + return written; + return error; +} + +/* Find the next written area in the xfile data for a given offset. */ +loff_t +xfile_seek_data( + struct xfile *xf, + loff_t pos) +{ + loff_t ret; + + ret = vfs_llseek(xf->file, pos, SEEK_DATA); + trace_xfile_seek_data(xf, pos, ret); + return ret; +} + +/* Query stat information for an xfile. */ +int +xfile_stat( + struct xfile *xf, + struct xfile_stat *statbuf) +{ + struct kstat ks; + int error; + + error = vfs_getattr_nosec(&xf->file->f_path, &ks, + STATX_SIZE | STATX_BLOCKS, AT_STATX_DONT_SYNC); + if (error) + return error; + + statbuf->size = ks.size; + statbuf->bytes = ks.blocks << SECTOR_SHIFT; + return 0; +} diff --git a/fs/xfs/scrub/xfile.h b/fs/xfs/scrub/xfile.h new file mode 100644 index 000000000000..9328a37fedaa --- /dev/null +++ b/fs/xfs/scrub/xfile.h @@ -0,0 +1,57 @@ +/* SPDX-License-Identifier: GPL-2.0-or-later */ +/* + * Copyright (C) 2018-2023 Oracle. All Rights Reserved. + * Author: Darrick J. Wong <djwong@kernel.org> + */ +#ifndef __XFS_SCRUB_XFILE_H__ +#define __XFS_SCRUB_XFILE_H__ + +struct xfile { + struct file *file; +}; + +int xfile_create(const char *description, loff_t isize, struct xfile **xfilep); +void xfile_destroy(struct xfile *xf); + +ssize_t xfile_pread(struct xfile *xf, void *buf, size_t count, loff_t pos); +ssize_t xfile_pwrite(struct xfile *xf, const void *buf, size_t count, + loff_t pos); + +/* + * Load an object. Since we're treating this file as "memory", any error or + * short IO is treated as a failure to allocate memory. + */ +static inline int +xfile_obj_load(struct xfile *xf, void *buf, size_t count, loff_t pos) +{ + ssize_t ret = xfile_pread(xf, buf, count, pos); + + if (ret < 0 || ret != count) + return -ENOMEM; + return 0; +} + +/* + * Store an object. Since we're treating this file as "memory", any error or + * short IO is treated as a failure to allocate memory. + */ +static inline int +xfile_obj_store(struct xfile *xf, const void *buf, size_t count, loff_t pos) +{ + ssize_t ret = xfile_pwrite(xf, buf, count, pos); + + if (ret < 0 || ret != count) + return -ENOMEM; + return 0; +} + +loff_t xfile_seek_data(struct xfile *xf, loff_t pos); + +struct xfile_stat { + loff_t size; + unsigned long long bytes; +}; + +int xfile_stat(struct xfile *xf, struct xfile_stat *statbuf); + +#endif /* __XFS_SCRUB_XFILE_H__ */ |