From d945b59db8449ab8323995391c6a63525b3666f6 Mon Sep 17 00:00:00 2001 From: Jeff Layton Date: Thu, 6 Jul 2017 07:02:20 -0400 Subject: buffer: use mapping_set_error instead of setting the flag Signed-off-by: Jeff Layton Reviewed-by: Jan Kara Reviewed-by: Matthew Wilcox Reviewed-by: Christoph Hellwig --- fs/buffer.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'fs') diff --git a/fs/buffer.c b/fs/buffer.c index 161be58c5cb0..4be8b914a222 100644 --- a/fs/buffer.c +++ b/fs/buffer.c @@ -482,7 +482,7 @@ static void __remove_assoc_queue(struct buffer_head *bh) list_del_init(&bh->b_assoc_buffers); WARN_ON(!bh->b_assoc_map); if (buffer_write_io_error(bh)) - set_bit(AS_EIO, &bh->b_assoc_map->flags); + mapping_set_error(bh->b_assoc_map, -EIO); bh->b_assoc_map = NULL; } -- cgit v1.2.3-55-g7522 From dac257f7419c732be3e491bbbb568a82df60208a Mon Sep 17 00:00:00 2001 From: Jeff Layton Date: Thu, 6 Jul 2017 07:02:21 -0400 Subject: fs: check for writeback errors after syncing out buffers in generic_file_fsync ext2 currently does a test+clear of the AS_EIO flag, which is is problematic for some coming changes. What we really need to do instead is call filemap_check_errors in __generic_file_fsync after syncing out the buffers. That will be sufficient for this case, and help other callers detect these errors properly as well. With that, we don't need to twiddle it in ext2. Suggested-by: Jan Kara Signed-off-by: Jeff Layton Reviewed-by: Christoph Hellwig Reviewed-by: Jan Kara Reviewed-by: Matthew Wilcox --- fs/ext2/file.c | 5 +---- fs/libfs.c | 4 +++- 2 files changed, 4 insertions(+), 5 deletions(-) (limited to 'fs') diff --git a/fs/ext2/file.c b/fs/ext2/file.c index b21891a6bfca..d34d32bdc944 100644 --- a/fs/ext2/file.c +++ b/fs/ext2/file.c @@ -174,15 +174,12 @@ int ext2_fsync(struct file *file, loff_t start, loff_t end, int datasync) { int ret; struct super_block *sb = file->f_mapping->host->i_sb; - struct address_space *mapping = sb->s_bdev->bd_inode->i_mapping; ret = generic_file_fsync(file, start, end, datasync); - if (ret == -EIO || test_and_clear_bit(AS_EIO, &mapping->flags)) { + if (ret == -EIO) /* We don't really know where the IO error happened... */ ext2_error(sb, __func__, "detected IO error when writing metadata buffers"); - ret = -EIO; - } return ret; } diff --git a/fs/libfs.c b/fs/libfs.c index a04395334bb1..1b76f29799bf 100644 --- a/fs/libfs.c +++ b/fs/libfs.c @@ -991,7 +991,9 @@ int __generic_file_fsync(struct file *file, loff_t start, loff_t end, out: inode_unlock(inode); - return ret; + /* must call this unconditionally as it clears AS_* error flags */ + err = filemap_check_errors(inode->i_mapping); + return ret ? ret : err; } EXPORT_SYMBOL(__generic_file_fsync); -- cgit v1.2.3-55-g7522 From 87354e5de04fe727227ff619af164202adcfa4d4 Mon Sep 17 00:00:00 2001 From: Jeff Layton Date: Thu, 6 Jul 2017 07:02:21 -0400 Subject: buffer: set errors in mapping at the time that the error occurs I noticed on xfs that I could still sometimes get back an error on fsync on a fd that was opened after the error condition had been cleared. The problem is that the buffer code sets the write_io_error flag and then later checks that flag to set the error in the mapping. That flag perisists for quite a while however. If the file is later opened with O_TRUNC, the buffers will then be invalidated and the mapping's error set such that a subsequent fsync will return error. I think this is incorrect, as there was no writeback between the open and fsync. Add a new mark_buffer_write_io_error operation that sets the flag and the error in the mapping at the same time. Replace all calls to set_buffer_write_io_error with mark_buffer_write_io_error, and remove the places that check this flag in order to set the error in the mapping. This sets the error in the mapping earlier, at the time that it's first detected. Signed-off-by: Jeff Layton Reviewed-by: Jan Kara Reviewed-by: Carlos Maiolino --- fs/buffer.c | 20 +++++++++++++------- fs/gfs2/lops.c | 2 +- include/linux/buffer_head.h | 1 + 3 files changed, 15 insertions(+), 8 deletions(-) (limited to 'fs') diff --git a/fs/buffer.c b/fs/buffer.c index 4be8b914a222..b946149e8214 100644 --- a/fs/buffer.c +++ b/fs/buffer.c @@ -178,7 +178,7 @@ void end_buffer_write_sync(struct buffer_head *bh, int uptodate) set_buffer_uptodate(bh); } else { buffer_io_error(bh, ", lost sync page write"); - set_buffer_write_io_error(bh); + mark_buffer_write_io_error(bh); clear_buffer_uptodate(bh); } unlock_buffer(bh); @@ -352,8 +352,7 @@ void end_buffer_async_write(struct buffer_head *bh, int uptodate) set_buffer_uptodate(bh); } else { buffer_io_error(bh, ", lost async page write"); - mapping_set_error(page->mapping, -EIO); - set_buffer_write_io_error(bh); + mark_buffer_write_io_error(bh); clear_buffer_uptodate(bh); SetPageError(page); } @@ -481,8 +480,6 @@ static void __remove_assoc_queue(struct buffer_head *bh) { list_del_init(&bh->b_assoc_buffers); WARN_ON(!bh->b_assoc_map); - if (buffer_write_io_error(bh)) - mapping_set_error(bh->b_assoc_map, -EIO); bh->b_assoc_map = NULL; } @@ -1181,6 +1178,17 @@ void mark_buffer_dirty(struct buffer_head *bh) } EXPORT_SYMBOL(mark_buffer_dirty); +void mark_buffer_write_io_error(struct buffer_head *bh) +{ + set_buffer_write_io_error(bh); + /* FIXME: do we need to set this in both places? */ + if (bh->b_page && bh->b_page->mapping) + mapping_set_error(bh->b_page->mapping, -EIO); + if (bh->b_assoc_map) + mapping_set_error(bh->b_assoc_map, -EIO); +} +EXPORT_SYMBOL(mark_buffer_write_io_error); + /* * Decrement a buffer_head's reference count. If all buffers against a page * have zero reference count, are clean and unlocked, and if the page is clean @@ -3279,8 +3287,6 @@ drop_buffers(struct page *page, struct buffer_head **buffers_to_free) bh = head; do { - if (buffer_write_io_error(bh) && page->mapping) - mapping_set_error(page->mapping, -EIO); if (buffer_busy(bh)) goto failed; bh = bh->b_this_page; diff --git a/fs/gfs2/lops.c b/fs/gfs2/lops.c index b1f9144b42c7..cd7857ab1a6a 100644 --- a/fs/gfs2/lops.c +++ b/fs/gfs2/lops.c @@ -182,7 +182,7 @@ static void gfs2_end_log_write_bh(struct gfs2_sbd *sdp, struct bio_vec *bvec, bh = bh->b_this_page; do { if (error) - set_buffer_write_io_error(bh); + mark_buffer_write_io_error(bh); unlock_buffer(bh); next = bh->b_this_page; size -= bh->b_size; diff --git a/include/linux/buffer_head.h b/include/linux/buffer_head.h index bd029e52ef5e..e0abeba3ced7 100644 --- a/include/linux/buffer_head.h +++ b/include/linux/buffer_head.h @@ -149,6 +149,7 @@ void buffer_check_dirty_writeback(struct page *page, */ void mark_buffer_dirty(struct buffer_head *bh); +void mark_buffer_write_io_error(struct buffer_head *bh); void init_buffer(struct buffer_head *, bh_end_io_t *, void *); void touch_buffer(struct buffer_head *bh); void set_bh_page(struct buffer_head *bh, -- cgit v1.2.3-55-g7522 From 76341cabbdad65c10a4162e9dfa82a6342afc02f Mon Sep 17 00:00:00 2001 From: Jeff Layton Date: Thu, 6 Jul 2017 07:02:22 -0400 Subject: jbd2: don't clear and reset errors after waiting on writeback Resetting this flag is almost certainly racy, and will be problematic with some coming changes. Make filemap_fdatawait_keep_errors return int, but not clear the flag(s). Have jbd2 call it instead of filemap_fdatawait and don't attempt to re-set the error flag if it fails. Reviewed-by: Jan Kara Reviewed-by: Carlos Maiolino Signed-off-by: Jeff Layton --- fs/jbd2/commit.c | 16 ++++------------ include/linux/fs.h | 2 +- mm/filemap.c | 16 ++++++++++++++-- 3 files changed, 19 insertions(+), 15 deletions(-) (limited to 'fs') diff --git a/fs/jbd2/commit.c b/fs/jbd2/commit.c index b6b194ec1b4f..3c1c31321d9b 100644 --- a/fs/jbd2/commit.c +++ b/fs/jbd2/commit.c @@ -263,18 +263,10 @@ static int journal_finish_inode_data_buffers(journal_t *journal, continue; jinode->i_flags |= JI_COMMIT_RUNNING; spin_unlock(&journal->j_list_lock); - err = filemap_fdatawait(jinode->i_vfs_inode->i_mapping); - if (err) { - /* - * Because AS_EIO is cleared by - * filemap_fdatawait_range(), set it again so - * that user process can get -EIO from fsync(). - */ - mapping_set_error(jinode->i_vfs_inode->i_mapping, -EIO); - - if (!ret) - ret = err; - } + err = filemap_fdatawait_keep_errors( + jinode->i_vfs_inode->i_mapping); + if (!ret) + ret = err; spin_lock(&journal->j_list_lock); jinode->i_flags &= ~JI_COMMIT_RUNNING; smp_mb(); diff --git a/include/linux/fs.h b/include/linux/fs.h index 803e5a9b2654..8ac8df1b3550 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -2514,7 +2514,7 @@ extern int write_inode_now(struct inode *, int); extern int filemap_fdatawrite(struct address_space *); extern int filemap_flush(struct address_space *); extern int filemap_fdatawait(struct address_space *); -extern void filemap_fdatawait_keep_errors(struct address_space *); +extern int filemap_fdatawait_keep_errors(struct address_space *mapping); extern int filemap_fdatawait_range(struct address_space *, loff_t lstart, loff_t lend); extern int filemap_write_and_wait(struct address_space *mapping); diff --git a/mm/filemap.c b/mm/filemap.c index 6f1be573a5e6..e5711b2728f4 100644 --- a/mm/filemap.c +++ b/mm/filemap.c @@ -309,6 +309,16 @@ int filemap_check_errors(struct address_space *mapping) } EXPORT_SYMBOL(filemap_check_errors); +static int filemap_check_and_keep_errors(struct address_space *mapping) +{ + /* Check for outstanding write errors */ + if (test_bit(AS_EIO, &mapping->flags)) + return -EIO; + if (test_bit(AS_ENOSPC, &mapping->flags)) + return -ENOSPC; + return 0; +} + /** * __filemap_fdatawrite_range - start writeback on mapping dirty pages in range * @mapping: address space structure to write @@ -453,15 +463,17 @@ EXPORT_SYMBOL(filemap_fdatawait_range); * call sites are system-wide / filesystem-wide data flushers: e.g. sync(2), * fsfreeze(8) */ -void filemap_fdatawait_keep_errors(struct address_space *mapping) +int filemap_fdatawait_keep_errors(struct address_space *mapping) { loff_t i_size = i_size_read(mapping->host); if (i_size == 0) - return; + return 0; __filemap_fdatawait_range(mapping, 0, i_size - 1); + return filemap_check_and_keep_errors(mapping); } +EXPORT_SYMBOL(filemap_fdatawait_keep_errors); /** * filemap_fdatawait - wait for all under-writeback pages to complete -- cgit v1.2.3-55-g7522 From 5660e13d2fd6af1903d4b0b98020af95ca2d638a Mon Sep 17 00:00:00 2001 From: Jeff Layton Date: Thu, 6 Jul 2017 07:02:25 -0400 Subject: fs: new infrastructure for writeback error handling and reporting Most filesystems currently use mapping_set_error and filemap_check_errors for setting and reporting/clearing writeback errors at the mapping level. filemap_check_errors is indirectly called from most of the filemap_fdatawait_* functions and from filemap_write_and_wait*. These functions are called from all sorts of contexts to wait on writeback to finish -- e.g. mostly in fsync, but also in truncate calls, getattr, etc. The non-fsync callers are problematic. We should be reporting writeback errors during fsync, but many places spread over the tree clear out errors before they can be properly reported, or report errors at nonsensical times. If I get -EIO on a stat() call, there is no reason for me to assume that it is because some previous writeback failed. The fact that it also clears out the error such that a subsequent fsync returns 0 is a bug, and a nasty one since that's potentially silent data corruption. This patch adds a small bit of new infrastructure for setting and reporting errors during address_space writeback. While the above was my original impetus for adding this, I think it's also the case that current fsync semantics are just problematic for userland. Most applications that call fsync do so to ensure that the data they wrote has hit the backing store. In the case where there are multiple writers to the file at the same time, this is really hard to determine. The first one to call fsync will see any stored error, and the rest get back 0. The processes with open fds may not be associated with one another in any way. They could even be in different containers, so ensuring coordination between all fsync callers is not really an option. One way to remedy this would be to track what file descriptor was used to dirty the file, but that's rather cumbersome and would likely be slow. However, there is a simpler way to improve the semantics here without incurring too much overhead. This set adds an errseq_t to struct address_space, and a corresponding one is added to struct file. Writeback errors are recorded in the mapping's errseq_t, and the one in struct file is used as the "since" value. This changes the semantics of the Linux fsync implementation such that applications can now use it to determine whether there were any writeback errors since fsync(fd) was last called (or since the file was opened in the case of fsync having never been called). Note that those writeback errors may have occurred when writing data that was dirtied via an entirely different fd, but that's the case now with the current mapping_set_error/filemap_check_error infrastructure. This will at least prevent you from getting a false report of success. The new behavior is still consistent with the POSIX spec, and is more reliable for application developers. This patch just adds some basic infrastructure for doing this, and ensures that the f_wb_err "cursor" is properly set when a file is opened. Later patches will change the existing code to use this new infrastructure for reporting errors at fsync time. Signed-off-by: Jeff Layton Reviewed-by: Jan Kara --- drivers/dax/device.c | 1 + fs/block_dev.c | 1 + fs/file_table.c | 1 + fs/open.c | 3 ++ include/linux/fs.h | 60 +++++++++++++++++++++++++++++- include/trace/events/filemap.h | 57 ++++++++++++++++++++++++++++ mm/filemap.c | 84 ++++++++++++++++++++++++++++++++++++++++++ 7 files changed, 206 insertions(+), 1 deletion(-) (limited to 'fs') diff --git a/drivers/dax/device.c b/drivers/dax/device.c index 006e657dfcb9..12943d19bfc4 100644 --- a/drivers/dax/device.c +++ b/drivers/dax/device.c @@ -499,6 +499,7 @@ static int dax_open(struct inode *inode, struct file *filp) inode->i_mapping = __dax_inode->i_mapping; inode->i_mapping->host = __dax_inode; filp->f_mapping = inode->i_mapping; + filp->f_wb_err = filemap_sample_wb_err(filp->f_mapping); filp->private_data = dev_dax; inode->i_flags = S_DAX; diff --git a/fs/block_dev.c b/fs/block_dev.c index 519599dddd36..4d62fe771587 100644 --- a/fs/block_dev.c +++ b/fs/block_dev.c @@ -1743,6 +1743,7 @@ static int blkdev_open(struct inode * inode, struct file * filp) return -ENOMEM; filp->f_mapping = bdev->bd_inode->i_mapping; + filp->f_wb_err = filemap_sample_wb_err(filp->f_mapping); return blkdev_get(bdev, filp->f_mode, filp); } diff --git a/fs/file_table.c b/fs/file_table.c index 954d510b765a..72e861a35a7f 100644 --- a/fs/file_table.c +++ b/fs/file_table.c @@ -168,6 +168,7 @@ struct file *alloc_file(const struct path *path, fmode_t mode, file->f_path = *path; file->f_inode = path->dentry->d_inode; file->f_mapping = path->dentry->d_inode->i_mapping; + file->f_wb_err = filemap_sample_wb_err(file->f_mapping); if ((mode & FMODE_READ) && likely(fop->read || fop->read_iter)) mode |= FMODE_CAN_READ; diff --git a/fs/open.c b/fs/open.c index cd0c5be8d012..280d4a963791 100644 --- a/fs/open.c +++ b/fs/open.c @@ -707,6 +707,9 @@ static int do_dentry_open(struct file *f, f->f_inode = inode; f->f_mapping = inode->i_mapping; + /* Ensure that we skip any errors that predate opening of the file */ + f->f_wb_err = filemap_sample_wb_err(f->f_mapping); + if (unlikely(f->f_flags & O_PATH)) { f->f_mode = FMODE_PATH; f->f_op = &empty_fops; diff --git a/include/linux/fs.h b/include/linux/fs.h index 8ac8df1b3550..78b5c2901712 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -30,7 +30,7 @@ #include #include #include - +#include #include #include @@ -392,6 +392,7 @@ struct address_space { gfp_t gfp_mask; /* implicit gfp mask for allocations */ struct list_head private_list; /* ditto */ void *private_data; /* ditto */ + errseq_t wb_err; } __attribute__((aligned(sizeof(long)))); /* * On most architectures that alignment is already the case; but @@ -868,6 +869,7 @@ struct file { struct list_head f_tfile_llink; #endif /* #ifdef CONFIG_EPOLL */ struct address_space *f_mapping; + errseq_t f_wb_err; } __attribute__((aligned(4))); /* lest something weird decides that 2 is OK */ struct file_handle { @@ -2526,6 +2528,62 @@ extern int filemap_fdatawrite_range(struct address_space *mapping, loff_t start, loff_t end); extern int filemap_check_errors(struct address_space *mapping); +extern void __filemap_set_wb_err(struct address_space *mapping, int err); +extern int __must_check file_check_and_advance_wb_err(struct file *file); +extern int __must_check file_write_and_wait_range(struct file *file, + loff_t start, loff_t end); + +/** + * filemap_set_wb_err - set a writeback error on an address_space + * @mapping: mapping in which to set writeback error + * @err: error to be set in mapping + * + * When writeback fails in some way, we must record that error so that + * userspace can be informed when fsync and the like are called. We endeavor + * to report errors on any file that was open at the time of the error. Some + * internal callers also need to know when writeback errors have occurred. + * + * When a writeback error occurs, most filesystems will want to call + * filemap_set_wb_err to record the error in the mapping so that it will be + * automatically reported whenever fsync is called on the file. + * + * FIXME: mention FS_* flag here? + */ +static inline void filemap_set_wb_err(struct address_space *mapping, int err) +{ + /* Fastpath for common case of no error */ + if (unlikely(err)) + __filemap_set_wb_err(mapping, err); +} + +/** + * filemap_check_wb_error - has an error occurred since the mark was sampled? + * @mapping: mapping to check for writeback errors + * @since: previously-sampled errseq_t + * + * Grab the errseq_t value from the mapping, and see if it has changed "since" + * the given value was sampled. + * + * If it has then report the latest error set, otherwise return 0. + */ +static inline int filemap_check_wb_err(struct address_space *mapping, + errseq_t since) +{ + return errseq_check(&mapping->wb_err, since); +} + +/** + * filemap_sample_wb_err - sample the current errseq_t to test for later errors + * @mapping: mapping to be sampled + * + * Writeback errors are always reported relative to a particular sample point + * in the past. This function provides those sample points. + */ +static inline errseq_t filemap_sample_wb_err(struct address_space *mapping) +{ + return errseq_sample(&mapping->wb_err); +} + extern int vfs_fsync_range(struct file *file, loff_t start, loff_t end, int datasync); extern int vfs_fsync(struct file *file, int datasync); diff --git a/include/trace/events/filemap.h b/include/trace/events/filemap.h index 42febb6bc1d5..ff91325b8123 100644 --- a/include/trace/events/filemap.h +++ b/include/trace/events/filemap.h @@ -10,6 +10,7 @@ #include #include #include +#include DECLARE_EVENT_CLASS(mm_filemap_op_page_cache, @@ -52,6 +53,62 @@ DEFINE_EVENT(mm_filemap_op_page_cache, mm_filemap_add_to_page_cache, TP_ARGS(page) ); +TRACE_EVENT(filemap_set_wb_err, + TP_PROTO(struct address_space *mapping, errseq_t eseq), + + TP_ARGS(mapping, eseq), + + TP_STRUCT__entry( + __field(unsigned long, i_ino) + __field(dev_t, s_dev) + __field(errseq_t, errseq) + ), + + TP_fast_assign( + __entry->i_ino = mapping->host->i_ino; + __entry->errseq = eseq; + if (mapping->host->i_sb) + __entry->s_dev = mapping->host->i_sb->s_dev; + else + __entry->s_dev = mapping->host->i_rdev; + ), + + TP_printk("dev=%d:%d ino=0x%lx errseq=0x%x", + MAJOR(__entry->s_dev), MINOR(__entry->s_dev), + __entry->i_ino, __entry->errseq) +); + +TRACE_EVENT(file_check_and_advance_wb_err, + TP_PROTO(struct file *file, errseq_t old), + + TP_ARGS(file, old), + + TP_STRUCT__entry( + __field(struct file *, file); + __field(unsigned long, i_ino) + __field(dev_t, s_dev) + __field(errseq_t, old) + __field(errseq_t, new) + ), + + TP_fast_assign( + __entry->file = file; + __entry->i_ino = file->f_mapping->host->i_ino; + if (file->f_mapping->host->i_sb) + __entry->s_dev = + file->f_mapping->host->i_sb->s_dev; + else + __entry->s_dev = + file->f_mapping->host->i_rdev; + __entry->old = old; + __entry->new = file->f_wb_err; + ), + + TP_printk("file=%p dev=%d:%d ino=0x%lx old=0x%x new=0x%x", + __entry->file, MAJOR(__entry->s_dev), + MINOR(__entry->s_dev), __entry->i_ino, __entry->old, + __entry->new) +); #endif /* _TRACE_FILEMAP_H */ /* This part must be outside protection */ diff --git a/mm/filemap.c b/mm/filemap.c index eb99b5f23c61..d7a30aefee0d 100644 --- a/mm/filemap.c +++ b/mm/filemap.c @@ -553,6 +553,90 @@ int filemap_write_and_wait_range(struct address_space *mapping, } EXPORT_SYMBOL(filemap_write_and_wait_range); +void __filemap_set_wb_err(struct address_space *mapping, int err) +{ + errseq_t eseq = __errseq_set(&mapping->wb_err, err); + + trace_filemap_set_wb_err(mapping, eseq); +} +EXPORT_SYMBOL(__filemap_set_wb_err); + +/** + * file_check_and_advance_wb_err - report wb error (if any) that was previously + * and advance wb_err to current one + * @file: struct file on which the error is being reported + * + * When userland calls fsync (or something like nfsd does the equivalent), we + * want to report any writeback errors that occurred since the last fsync (or + * since the file was opened if there haven't been any). + * + * Grab the wb_err from the mapping. If it matches what we have in the file, + * then just quickly return 0. The file is all caught up. + * + * If it doesn't match, then take the mapping value, set the "seen" flag in + * it and try to swap it into place. If it works, or another task beat us + * to it with the new value, then update the f_wb_err and return the error + * portion. The error at this point must be reported via proper channels + * (a'la fsync, or NFS COMMIT operation, etc.). + * + * While we handle mapping->wb_err with atomic operations, the f_wb_err + * value is protected by the f_lock since we must ensure that it reflects + * the latest value swapped in for this file descriptor. + */ +int file_check_and_advance_wb_err(struct file *file) +{ + int err = 0; + errseq_t old = READ_ONCE(file->f_wb_err); + struct address_space *mapping = file->f_mapping; + + /* Locklessly handle the common case where nothing has changed */ + if (errseq_check(&mapping->wb_err, old)) { + /* Something changed, must use slow path */ + spin_lock(&file->f_lock); + old = file->f_wb_err; + err = errseq_check_and_advance(&mapping->wb_err, + &file->f_wb_err); + trace_file_check_and_advance_wb_err(file, old); + spin_unlock(&file->f_lock); + } + return err; +} +EXPORT_SYMBOL(file_check_and_advance_wb_err); + +/** + * file_write_and_wait_range - write out & wait on a file range + * @file: file pointing to address_space with pages + * @lstart: offset in bytes where the range starts + * @lend: offset in bytes where the range ends (inclusive) + * + * Write out and wait upon file offsets lstart->lend, inclusive. + * + * Note that @lend is inclusive (describes the last byte to be written) so + * that this function can be used to write to the very end-of-file (end = -1). + * + * After writing out and waiting on the data, we check and advance the + * f_wb_err cursor to the latest value, and return any errors detected there. + */ +int file_write_and_wait_range(struct file *file, loff_t lstart, loff_t lend) +{ + int err = 0, err2; + struct address_space *mapping = file->f_mapping; + + if ((!dax_mapping(mapping) && mapping->nrpages) || + (dax_mapping(mapping) && mapping->nrexceptional)) { + err = __filemap_fdatawrite_range(mapping, lstart, lend, + WB_SYNC_ALL); + /* See comment of filemap_write_and_wait() */ + if (err != -EIO) + __filemap_fdatawait_range(mapping, lstart, lend); + } + err2 = file_check_and_advance_wb_err(file); + if (!err) + err = err2; + return err; +} +EXPORT_SYMBOL(file_write_and_wait_range); + /** * replace_page_cache_page - replace a pagecache page with a new one * @old: page to be replaced -- cgit v1.2.3-55-g7522 From 819ec6b91d5ba1ca313066a306461774eff6b567 Mon Sep 17 00:00:00 2001 From: Jeff Layton Date: Thu, 6 Jul 2017 07:02:27 -0400 Subject: dax: set errors in mapping when writeback fails Jan Kara's description for this patch is much better than mine, so I'm quoting it verbatim here: DAX currently doesn't set errors in the mapping when cache flushing fails in dax_writeback_mapping_range(). Since this function can get called only from fsync(2) or sync(2), this is actually as good as it can currently get since we correctly propagate the error up from dax_writeback_mapping_range() to filemap_fdatawrite() However, in the future better writeback error handling will enable us to properly report these errors on fsync(2) even if there are multiple file descriptors open against the file or if sync(2) gets called before fsync(2). So convert DAX to using standard error reporting through the mapping. Signed-off-by: Jeff Layton Reviewed-by: Jan Kara Reviewed-by: Christoph Hellwig Reviewed-and-tested-by: Ross Zwisler --- fs/dax.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) (limited to 'fs') diff --git a/fs/dax.c b/fs/dax.c index c22eaf162f95..441280e15d5b 100644 --- a/fs/dax.c +++ b/fs/dax.c @@ -856,8 +856,10 @@ int dax_writeback_mapping_range(struct address_space *mapping, ret = dax_writeback_one(bdev, dax_dev, mapping, indices[i], pvec.pages[i]); - if (ret < 0) + if (ret < 0) { + mapping_set_error(mapping, ret); goto out; + } } } out: -- cgit v1.2.3-55-g7522 From 372cf243ea9a36d88ff67ae44f4512f64a6bca81 Mon Sep 17 00:00:00 2001 From: Jeff Layton Date: Thu, 6 Jul 2017 07:02:28 -0400 Subject: block: convert to errseq_t based writeback error tracking This is a very minimal conversion to errseq_t based error tracking for raw block device access. Just have it use the standard file_write_and_wait_range call. Note that there are internal callers that call sync_blockdev and the like that are not affected by this. They'll continue to use the AS_EIO/AS_ENOSPC flags for error reporting like they always have for now. Reviewed-by: Christoph Hellwig Signed-off-by: Jeff Layton --- fs/block_dev.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'fs') diff --git a/fs/block_dev.c b/fs/block_dev.c index 4d62fe771587..bcb0be6e423a 100644 --- a/fs/block_dev.c +++ b/fs/block_dev.c @@ -624,7 +624,7 @@ int blkdev_fsync(struct file *filp, loff_t start, loff_t end, int datasync) struct block_device *bdev = I_BDEV(bd_inode); int error; - error = filemap_write_and_wait_range(filp->f_mapping, start, end); + error = file_write_and_wait_range(filp, start, end); if (error) return error; -- cgit v1.2.3-55-g7522 From 383aa543c2f46f245d652c0e5c77390f07ece657 Mon Sep 17 00:00:00 2001 From: Jeff Layton Date: Thu, 6 Jul 2017 07:02:29 -0400 Subject: fs: convert __generic_file_fsync to use errseq_t based reporting Many simple, block-based filesystems use generic_file_fsync as their fsync operation. Some others (ext* and fat) also call this function to handle syncing out data. Switch this code over to use errseq_t based error reporting so that all of these filesystems get reliable error reporting via fsync, fdatasync and msync. Signed-off-by: Jeff Layton --- fs/libfs.c | 10 ++++++---- 1 file changed, 6 insertions(+), 4 deletions(-) (limited to 'fs') diff --git a/fs/libfs.c b/fs/libfs.c index 1b76f29799bf..3aabe553fc45 100644 --- a/fs/libfs.c +++ b/fs/libfs.c @@ -974,7 +974,7 @@ int __generic_file_fsync(struct file *file, loff_t start, loff_t end, int err; int ret; - err = filemap_write_and_wait_range(inode->i_mapping, start, end); + err = file_write_and_wait_range(file, start, end); if (err) return err; @@ -991,9 +991,11 @@ int __generic_file_fsync(struct file *file, loff_t start, loff_t end, out: inode_unlock(inode); - /* must call this unconditionally as it clears AS_* error flags */ - err = filemap_check_errors(inode->i_mapping); - return ret ? ret : err; + /* check and advance again to catch errors after syncing out buffers */ + err = file_check_and_advance_wb_err(file); + if (ret == 0) + ret = err; + return ret; } EXPORT_SYMBOL(__generic_file_fsync); -- cgit v1.2.3-55-g7522 From 6acec592c6bc9a4c3136e46430e14767b07f9f1a Mon Sep 17 00:00:00 2001 From: Jeff Layton Date: Thu, 6 Jul 2017 07:02:30 -0400 Subject: ext4: use errseq_t based error handling for reporting data writeback errors Add a call to filemap_report_wb_err at the end of ext4_sync_file. This will ensure that we check and advance the errseq_t in the file, which allows us to track and report errors on all open fds when they occur. Signed-off-by: Jeff Layton --- fs/ext4/fsync.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'fs') diff --git a/fs/ext4/fsync.c b/fs/ext4/fsync.c index 9d549608fd30..aae2c3971cef 100644 --- a/fs/ext4/fsync.c +++ b/fs/ext4/fsync.c @@ -124,7 +124,7 @@ int ext4_sync_file(struct file *file, loff_t start, loff_t end, int datasync) goto out; } - ret = filemap_write_and_wait_range(inode->i_mapping, start, end); + ret = file_write_and_wait_range(file, start, end); if (ret) return ret; /* -- cgit v1.2.3-55-g7522 From 1b180274f5bfa0b8b05f7e55d9962f77f387be9c Mon Sep 17 00:00:00 2001 From: Jeff Layton Date: Thu, 6 Jul 2017 07:02:30 -0400 Subject: xfs: minimal conversion to errseq_t writeback error reporting Just check and advance the data errseq_t in struct file before before returning from fsync on normal files. Internal filemap_* callers are left as-is. Reviewed-by: Darrick J. Wong Reviewed-by: Christoph Hellwig Signed-off-by: Jeff Layton --- fs/xfs/xfs_file.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'fs') diff --git a/fs/xfs/xfs_file.c b/fs/xfs/xfs_file.c index 5fb5a0958a14..6600b264b0b6 100644 --- a/fs/xfs/xfs_file.c +++ b/fs/xfs/xfs_file.c @@ -140,7 +140,7 @@ xfs_file_fsync( trace_xfs_file_fsync(ip); - error = filemap_write_and_wait_range(inode->i_mapping, start, end); + error = file_write_and_wait_range(file, start, end); if (error) return error; -- cgit v1.2.3-55-g7522 From 333427a505be1e10d8da13427dc0c33ec1976b99 Mon Sep 17 00:00:00 2001 From: Jeff Layton Date: Thu, 6 Jul 2017 07:02:31 -0400 Subject: btrfs: minimal conversion to errseq_t writeback error reporting on fsync Just check and advance the errseq_t in the file before returning, and use an errseq_t based check for writeback errors. Other internal callers of filemap_* functions are left as-is. Signed-off-by: Jeff Layton --- fs/btrfs/file.c | 13 ++++++++----- 1 file changed, 8 insertions(+), 5 deletions(-) (limited to 'fs') diff --git a/fs/btrfs/file.c b/fs/btrfs/file.c index da1096eb1a40..deeb4799da5c 100644 --- a/fs/btrfs/file.c +++ b/fs/btrfs/file.c @@ -2011,7 +2011,7 @@ int btrfs_sync_file(struct file *file, loff_t start, loff_t end, int datasync) struct btrfs_root *root = BTRFS_I(inode)->root; struct btrfs_trans_handle *trans; struct btrfs_log_ctx ctx; - int ret = 0; + int ret = 0, err; bool full_sync = 0; u64 len; @@ -2030,7 +2030,7 @@ int btrfs_sync_file(struct file *file, loff_t start, loff_t end, int datasync) */ ret = start_ordered_ops(inode, start, end); if (ret) - return ret; + goto out; inode_lock(inode); atomic_inc(&root->log_batch); @@ -2135,10 +2135,10 @@ int btrfs_sync_file(struct file *file, loff_t start, loff_t end, int datasync) * An ordered extent might have started before and completed * already with io errors, in which case the inode was not * updated and we end up here. So check the inode's mapping - * flags for any errors that might have happened while doing - * writeback of file data. + * for any errors that might have happened since we last + * checked called fsync. */ - ret = filemap_check_errors(inode->i_mapping); + ret = filemap_check_wb_err(inode->i_mapping, file->f_wb_err); inode_unlock(inode); goto out; } @@ -2227,6 +2227,9 @@ int btrfs_sync_file(struct file *file, loff_t start, loff_t end, int datasync) ret = btrfs_end_transaction(trans); } out: + err = file_check_and_advance_wb_err(file); + if (!ret) + ret = err; return ret > 0 ? -EIO : ret; } -- cgit v1.2.3-55-g7522