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-rw-r--r--drivers/dax/device.c1
-rw-r--r--fs/block_dev.c1
-rw-r--r--fs/file_table.c1
-rw-r--r--fs/open.c3
-rw-r--r--include/linux/fs.h60
-rw-r--r--include/trace/events/filemap.h57
-rw-r--r--mm/filemap.c84
7 files changed, 206 insertions, 1 deletions
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 <linux/percpu-rwsem.h>
#include <linux/workqueue.h>
#include <linux/delayed_call.h>
-
+#include <linux/errseq.h>
#include <asm/byteorder.h>
#include <uapi/linux/fs.h>
@@ -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 <linux/memcontrol.h>
#include <linux/device.h>
#include <linux/kdev_t.h>
+#include <linux/errseq.h>
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